TaiLG Electric Bicycle Scooter 48 Volt 12 Ah 250 Watt

[Alastor]

48V15Ah is kinda small for your scooter, but it is about the cheapest i have seen using the headway cells. the $434 was with the 30A BMS. but lifepo4 is the cheapest way to go for the long term and without the risks and short lifespan of the lipo. people like the lipo because it is so light and powerful but you can live with the weight of the headway cells since it is a scooter.

your controller will have a resistor divider bridge tied to the Vcc that is compared to a zener and when the Vcc drops below the Low Voltage Cutoff voltage then the controller is disabled.

to determine how to adjust it we will need to examine the input circuitry inside the controller. so if you go that way be prepared to open it up and examine how it works. it may be a controller we already know and maybe it can be reprogrammed like the other controllers that have been hacked here. but we may be able to figure it out from pictures you post up then.

I want to believe that its not the cheapest one and its reprogrammable because i don't want to open it up just yet in order to keep the 2 years warranty they gave me (or at least having a new controller next to me )
I think i got your point i saw a similar post with details about that bridge in a shunt mode article.To tell you the truth if the controller is rubbish i will probably upgrade it because its the weakest link getting hot easy with some extra load on the bike , that's why i try to think weight wise as well.

[dnmun]

18S of lipo is 80V and your controller will not take that.

you have a scooter, not a bike.

the only reason the SLA is in your scooter is because they are cheaper to make in china and to offer a finished scooter for the minimum price. lifepo4 will last for almost 10 times as many charge cycles as SLA and have a flat voltage during discharge instead of losing all their voltage to the peukert effect.

if you use lipo then you have to have the lipo protection from methods or other sources, so the cost needs to include that as well as the balancing chargers. then you still have the shorter lifespan of the lipo too.

that is why lifepo4 is cheaper for your situation over the lifetime of the scooter.

there is no evidence your controller is rubbish, it is normal for them to get hot. if you wanna keep it cool you have to upgrade the mosfets. not a fan.

[Alastor]

18S of lipo is 80V and your controller will not take that.

you have a scooter, not a bike.

the only reason the SLA is in your scooter is because they are cheaper to make in china and to offer a finished scooter for the minimum price. lifepo4 will last for almost 10 times as many charge cycles as SLA and have a flat voltage during discharge instead of losing all their voltage to the peukert effect.

if you use lipo then you have to have the lipo protection from methods or other sources, so the cost needs to include that as well as the balancing chargers. then you still have the shorter lifespan of the lipo too.

that is why lifepo4 is cheaper for your situation over the lifetime of the scooter.

there is no evidence your controller is rubbish, it is normal for them to get hot. if you wanna keep it cool you have to upgrade the mosfets. not a fan.

Yes i agree with you its all about the freaking money Lucky me i already have a nice balanced lipo charger that i can use if some small lipos get there way to me hands .
I think the best is to wait and buy a nice 15ah or even 20ah lipo4 pack with a 30A bsm the time my sla's die on me. 450 euros for the 48v 15 ah is kinda affordable after all.

[Alastor]

there is no evidence your controller is rubbish, it is normal for them to get hot. if you wanna keep it cool you have to upgrade the mosfets. not a fan.

One day i was ridding with a friend did some pedaling to climb some hills and on my way back home i felt the heat under the seat spot so hot that i stopped to chk it out the motor was not burning but it was ok to touch but the controller was like hellfire and that's concerning me because summer is closing in

[dogman]

Well, first lets get one thing straight. You say you have a 48v controller of 20 amps. Watts is amps x volts. So you have about a 1000w scooter, with a handy sticker to make it cheap at the licence place.

Second, you do need to improve the ventilation to your controller somehow. A small fan run on a 3s lipo pack would help, as well as some kind of way to scoop wind and direct it to your controller. Your controller is likely getting no ventilation at all now, and will run cool enough if it gets some breeze. So it's not so much a fan it needs, but just to have some wind reach it when you ride. You'd think engineers who design these things would have some commonsense, but they don't sometimes.

One thing you should know about controllers is that they make less heat when you ride wide open throttle. Half throttle makes the controller work harder, to shorten the pulse of the power, which makes some heat in the fets. So when possible, do more riding full throttle, then coast. It will help some with the hot controller.

As for the bike on hills. Well, just because they put a cool looking seat for a passenger on the thing to make it sell does not mean it was designed with climing a hill with two passengers on it. No real solution to that, 1000w is enough to get 180 pounds up a hill fine, But if you both combined weigh 300, better stick to the less steep hills as much as possible. A second scooter is the real solution. It's ok though on flat ground and mild hills to carry your girl. Just avoid really steep hills. It's very important not to overload the bike up steep hills. If it can't climb the hill at 20-25 kph, you are going to be heating up the motor real bad as well as the controller. A very short steep hill can be ok, just avoid long steep ones.

On to the batttery. Install a set of new connectors between the battery and the controller that you can get to easily. When you have discharged your lead battery as much as you want to, you can then disconnect the lead and connect some RC lipo. No need to use the inverter and charger.

Two 6s 5ah packs will do for a small range extender. 4 packs makes a nice battery with a bit more range. Connect the packs in series to have a 12s pack. If you have 4 packs, paralell connect two packs to make 6s 10 ah, then do the series connection.

12s RC lipo will charge to 50v, and finish at 44v. You will need a voltmeter added to the bike to be sure you don't go below 44v. Your scoot will run fine with 12s lipo. For a bit more pep, your controller can handle up to a maximum of 14s lipo. That's about 59v fully charged.

Another option would be a lifepo4 battery. A 48v lifepo4 battery of 48v 20 ah would be a perfect replacement for your lead. It would extend your range a lot further than you get from the lead now. One thing about short range though, you have to stop before things fry. With lots of range, you can ride till things melt.

How do you know when to stop? Lots of us use inexpensive thermometers to know. With a remote sensor, you put the sensor on the motor axle, or the controller, and the display on the thermometer will tell you when you are getting hotter and hotter, or if you are just warm, but stabilzed at that temperature.

[Alastor]

Well, first lets get one thing straight. You say you have a 48v controller of 20 amps. Watts is amps x volts. So you have about a 1000w scooter, with a handy sticker to make it cheap at the licence place.

Second, you do need to improve the ventilation to your controller somehow. A small fan run on a 3s lipo pack would help, as well as some kind of way to scoop wind and direct it to your controller. Your controller is likely getting no ventilation at all now, and will run cool enough if it gets some breeze. So it's not so much a fan it needs, but just to have some wind reach it when you ride. You'd think engineers who design these things would have some commonsense, but they don't sometimes.

One thing you should know about controllers is that they make less heat when you ride wide open throttle. Half throttle makes the controller work harder, to shorten the pulse of the power, which makes some heat in the fets. So when possible, do more riding full throttle, then coast. It will help some with the hot controller.

As for the bike on hills. Well, just because they put a cool looking seat for a passenger on the thing to make it sell does not mean it was designed with climing a hill with two passengers on it. No real solution to that, 1000w is enough to get 180 pounds up a hill fine, But if you both combined weigh 300, better stick to the less steep hills as much as possible. A second scooter is the real solution. It's ok though on flat ground and mild hills to carry your girl. Just avoid really steep hills. It's very important not to overload the bike up steep hills. If it can't climb the hill at 20-25 kph, you are going to be heating up the motor real bad as well as the controller. A very short steep hill can be ok, just avoid long steep ones.

On to the batttery. Install a set of new connectors between the battery and the controller that you can get to easily. When you have discharged your lead battery as much as you want to, you can then disconnect the lead and connect some RC lipo. No need to use the inverter and charger.

Two 6s 5ah packs will do for a small range extender. 4 packs makes a nice battery with a bit more range. Connect the packs in series to have a 12s pack. If you have 4 packs, paralell connect two packs to make 6s 10 ah, then do the series connection.

12s RC lipo will charge to 50v, and finish at 44v. You will need a voltmeter added to the bike to be sure you don't go below 44v. Your scoot will run fine with 12s lipo. For a bit more pep, your controller can handle up to a maximum of 14s lipo. That's about 59v fully charged.

Another option would be a lifepo4 battery. A 48v lifepo4 battery of 48v 20 ah would be a perfect replacement for your lead. It would extend your range a lot further than you get from the lead now. One thing about short range though, you have to stop before things fry. With lots of range, you can ride till things melt.

How do you know when to stop? Lots of us use inexpensive thermometers to know. With a remote sensor, you put the sensor on the motor axle, or the controller, and the display on the thermometer will tell you when you are getting hotter and hotter, or if you are just warm, but stabilzed at that temperature.

I called the dude that imports this model and he told me that he was referring to the circuit safe that is 20A Jesus ....The controller continues can handle 48 * 5 amps and burst some times 7 amps for a few seconds.so its not even close to 1000 watt but it is indeed 250 watt with a pick of 350 watts of a few seconds.I will make sure to make some sort of ventilation with a cheap rechargeable battery for now and probably install the cheap thermometer as well .

Thanks for your time

[ProDigit]

In all honesty, nothing beats the LiPo4 batteries at this moment!
If your bike is truly 250W like you say, it uses I=P/U=250/48=5.21A. If you want to use the battery pack independently, You must select batteries more powerful than 5.02A!!! 4.5A is not good enough!. If you want to use them in combination with the internal battery, any type of 12V battery could do.

The cheapest battery from BMSBattery will be more than enough!

The issue is the following:
Put in those 2 extra lead acid batteries from amazon, with convertor, and your bike will drive only marginally longer (20% max).

put in 4 acid batteries, 7A in series, and connect that in parallel with your current 48V20A battery and your range increase will be ~35% (minus the weight would be around 30% increase).
Your theoretical mileage per charge would be:
45km to almost 60km
60 km to almost 80 km.

You will have between 15-20km increased range max, but these batteries only last 250 cycles, remember that.
4 of these batteries weigh 25LBS, or 12kg.

@$25 per battery for a 7A battery,that's $100 total, they are large, and pretty heavy. They have a max charge cycle of 250 cycles, so in the long run, you're going to be spending the most money on these. In the short run these are your best option though (say,it's a good option for using the bike one year or less).


Second option is to put in the cheapest 10A Li ion batteries, @$233, and your mileage will increase by 20%, and puts you in the +10KM you wanted, but if you ask me is not the best option.
45 km to 55 km
60 km to 70 km
They are lightweight @ only 2.8kg!, powerful, and when using them in parallel with your current battery they will provide more amps and slightly higher voltage to your engine, resulting in more torq, tiny bit faster driving, and longer mileage.
Though if I where you, I'd replace the engine to a more powerful one. 250W engines are used to propel pedal (manual)bikes, not scooters.
When you do this li-ion mod, make sure the controller and engine stay cool!
Li or Li-ion batteries last you for 800 charges, that's over 3x longer than the lead Acid batteries, and usually have less issues too;
They are a better alternative, something you will benefit from financially if you ride your bike daily, for 2 to 3 years.

On BMS battery they don't sell LiMn batteries, but they are known to have 1000+ recharge cycles. Good for upto 4 years of daily use or 5,5 years of ordinary use.

Your last option, is most beneficial in the long run IF:
1- your bike does not get stolen,
2- Your bike does not get into an accident
3- You are not going to sell it, but keep driving it regularly:
4- Your bike does not overcharge (as this can cause fire, or damage the bike) or run dry empty for months (as this impairs the batteries).

In other words, if you will use it daily, and take care for it, the more expensive LiPo4 (or LiFePo4) batteries should pay you back your money over time!. They are rated 2000-4000 recharge cycles max. The cheapest one from the store will increase your mileage the same as the Li ion ones, by 20% (the 10A, $278.10 one). You will be paying only $45 more than Li-Ion batteries, but they last you more than twice as long, anywhere north of 5 years.
No one has experienced it yet, as these are quite new, (literally I've only heard of it for the first time this year, the newest production samples should be about a year out on the market, but according to the specs they should last almost 7 years.
In the long run these are the best solution!

Actually, not,
your best solution would be to buy the most expensive battery, as it will increase your current range by a 100%!
That means, if you buy the $530.10 battery, and connect it in parallel, (you will also need to buy a more expensive charger); your mileage would be:
from 45km to 90km
From 60km to 120km. (an increase between 45 and 60miles per charge)

The MBS Batteries should fit in your helmet compartment. Measure it, and verify with BMS (battery sizes are on their site) here: http://www.bmsbattery.com/56-48v?orderby=price&orderway=asc

I help you in all of this, because I have bought an Xtreme BX-700Li and am currently in the process of researching extending my range too. That's why I can help you in all of this, and share my finding! Whatever you choice you end up taking, please let the community know,so we can learn from your experiences!
Save this site in your bookmarks in case of something happening (like battery breakdown or so), so you can tell us about your experiences!

Don't be affraid to buy a battery with a too high amp rating. The higher the amps, the longer your mileage. They should almost be linear, meaning, a 10A battery has half the mileage as a similar battery with 20Ah rating.
And like mentioned, your 250W engine needs at least a 5.2A (that is a 7a) battery (because there are no 5.2A batteries on the market. There are 6A batteries on the market, but the problem with these is that when the voltage drops below a point still ok for the battery, your controller will shut down,and your mileage will be very low. So it's better to get at least 7a batteries, unless you plan on using them alongside the other battery, to re-inforce the amps.

[Alastor]

You guys are awesome trillions of thanks ; )

When i start making the modifications i will make sure to come back and post everything but it will take me some time since i just took the bicycle and i don't really have a money to invest at the moment.
I use BMS site for spare parts for my other bicycle and i am very pleased with there products-value they sell staff way cheaper than they do here in Greece...you see our market is tiny at the moment not many people use electric bicycles so a few shops monopolize all the market.I hope to get the first battery from two months from now to extend its range and meanwhile i will install a cheap thermometer and some kind of small heat sinks or remount the controller if possible from wiring to a better location to prevent if from overheating and i will come back with pictures and test results as soon as i manage to play with it.

In my opinion this small scooter-bicycle has its potentials and with little extra work from my part it can solve my small - mid range trips around the city even get me to the sea only 25 km from my house luckily the road is flat with almost no hills in between.

By placing the battery in to the helm compartment the controller will have a lot of air flow because the battery enclosure witch is a 20 kilo giant gets almost all space under the seat.
They say that it gets 60km range with the 12ah AGM battery's it has but i really don't want to go over 35 km per charge to double the cycles from 400 to 800 till i save the money for the new batteries , 250 cycles for the simple lead acid batteries AGM weight a little more 4.8 kilos per piece but they have reenforced cell plates for deeper discharge without damaging the battery cells that's why my battery enclosure is 20 freaking kilos With that care the batteries might make a lot of kilometers.I don't want to use the bicycle every day so the batteries will not be stressed hahaha.

Thanks again for all the help i will be in touch

[ProDigit]

Please do note, that you do not get the mileage increase by removing your old battery.
The calculations are made when you use your stock battery, together with these batteries.

In fact, if what you say is true, and the battery in your bike is only 12A, not 20A Like I had assumed, you will gain a lot more miles per charge adding a second battery!
What you basically need to do is wire the extra battery pack (4 x 12V batteries which are connected in series), in parallel with your stock battery.
If possible, use high power diodes on the anode (+ terminal).

Recalculated for a 12A battery, your mileage increase will be:

Internal battery + 4 Lead acid batteries @ 4.5A: + 130%
45 becomes 60 km per charge
60 becomes 80 km per charge
(15-20 km increase max)

Internal battery + 4 Lead acid batteries @ 7A: + 155-160%
45 becomes 70 km per charge
60 becomes 90 km per charge
(25-30 km increase max)

Internal battery + Li Ion or LiPo4 battery @ 10A: + 180%
45 becomes 80 km per charge
60 becomes 100-105 km per charge
35-45 km increase max.

Internal battery + LiPo4 battery @ 20A: + 260%!!!
45 becomes 115 km per charge
60 becomes 150 km per charge
70-90km max increase!

The above calculations are pure mathematical, under best conditions, meaning that all the energy from the secondary battery will be redirected towards the motor; and not towards the lights, horn, blinkers, breaklights, dashboard etc.
They also have a minimal mathematical compensation for the extra weight. Do know extra weight takes extra power, especially when the tires get flatter,and consumes more battery when accelerating.
In practice though you can take off perhaps 5 miles from the max km per charge increase you get; to get a more realistic outcome.

You can further increase mileage, by making sure your tires are inflated to a right pressure. you can also gain mileage by creating the bike's body more aerodynamic, taping off small holes and vents not used for cooling the interior.
By changing the lightbulbs to leds, or not using the lights at all; by lowering the bike (lower over the floor means less wind resistance), by bending forward while driving, by removing widshield, baskets, and mirrors if legally allowed, and by wearing tight clothes like jeans or leather jackets; and never wear loose scarfs or clothes on a bike, especially not if they could end up in the wheels.
Making sure that the battery compartment(s) are kept warm, meaning no freezing temps. If it is cold in the garage, plug in to charge your battery 30 minutes to an hour before departing, that way it can warm up. A warm (but not hot) battery performs at it's best between 20 and 40 degrees C.

If you ask me,
A bike like yours isn't meant for too heavy weight, and if you don't care about a +100 km driving distance (which, if you don't use it daily will just cost you more money to maintain these large batteries), I would recommend being satisfied with the cheaper Li-ion battery. Seeing that your bike will most likely run 2 years problem free,after which you will have to change the internal batteries, you might as well buy a regular Li battery, as your bike is made to last between 4 to 6 years. After that it probably will need some fixing, but you won't expect more than 8-10 years from it.
For that reason I'd recommend you to either go with a regular Li-Ion battery (without lead acid batteries). the 15 amps one, for $330 (and get anywhere between +10-15km extra range of what you currently have).
Use the cheapest ion battery (10A) together with your current batteries, you'd have about 180% of range added to your current range for $230.
The Li batteries (Li-ion or LiPo4/LiFePo4) are really lightweight, weigh less than a bookbag or a bottle of water. Lead acid batteries are different.
Or use the cheapest Lead acid batteries there are, the 7amps perform the best but if they don't fit in the helmet compartment, the 4,5 (or 5)A versions will most likely do (look around on amazon, where you can find these small cubes with 5A instead of 4,5)!

[Alastor]

Thanks for the information mate

I went out today to choose what type of battery to pick for the computer fun .I took some rechargeable Nimi AA's that i can drain without having alarms or other protection , cut off circuits to insure there well being because a lipo might be tricky if over drained without protection.As crazy as it sounds protection cut off circuits for lipos are quite RARE here in Greece hehehehe.

I also manage to locate the controller i added one small heat sink from an old cpu and i mange to fit a large computer fan with a nice dimmer to control its spin.Now i am at the state of charging the batteries up to see if i can run it on my small 4XAA's pack and solve the heating issues.

Already with the extra heat sink the controller is quite cooler in touch and after 10 kilometers of travel the motor was also cooler.I will come back tomorrow with some pictures of the installation after i double check everything

[ProDigit]

I would never use a fan on a bike like this. It's only adding weight and cooling very little, and consuming more battery.

If it was me, I'd look to see if the controller is mounted in a way that you can scoop air from underneath the scooter into the chamber where the controller is (probably under the seat or under the feet compartment).
That way as you drive you'll bring fresh air in without the need for fans. I'd make a small slit into the plastic and bend it in such a way that it scoops air from the front of the bike.
Then I'd create another slit on the back, bending it in such a way that whatever air gets pushed into the chamber by the first slit, will exit by the rear slit.

With a natural flow of air the controller will cool lots better than with a fan. Besides a fan is only good in spreading the heat of the controller into the chamber. If the chamber does not have a flow of cool air, or a lot of metal in it connected to the frame, it will heat up, and the fan will become useless in such a case as a fan's performance decreases the hotter the air in a chamber is.
(metal is a good heat conductor, plastic is not).

[ProDigit]

Well, first lets get one thing straight. You say you have a 48v controller of 20 amps. Watts is amps x volts. So you have about a 1000w scooter, with a handy sticker to make it cheap at the licence place.

Second, you do need to improve the ventilation to your controller somehow. A small fan run on a 3s lipo pack would help, as well as some kind of way to scoop wind and direct it to your controller. Your controller is likely getting no ventilation at all now, and will run cool enough if it gets some breeze. So it's not so much a fan it needs, but just to have some wind reach it when you ride. You'd think engineers who design these things would have some commonsense, but they don't sometimes.

One thing you should know about controllers is that they make less heat when you ride wide open throttle. Half throttle makes the controller work harder, to shorten the pulse of the power, which makes some heat in the fets. So when possible, do more riding full throttle, then coast. It will help some with the hot controller.

As for the bike on hills. Well, just because they put a cool looking seat for a passenger on the thing to make it sell does not mean it was designed with climing a hill with two passengers on it. No real solution to that, 1000w is enough to get 180 pounds up a hill fine, But if you both combined weigh 300, better stick to the less steep hills as much as possible. A second scooter is the real solution. It's ok though on flat ground and mild hills to carry your girl. Just avoid really steep hills. It's very important not to overload the bike up steep hills. If it can't climb the hill at 20-25 kph, you are going to be heating up the motor real bad as well as the controller. A very short steep hill can be ok, just avoid long steep ones.

On to the batttery. Install a set of new connectors between the battery and the controller that you can get to easily. When you have discharged your lead battery as much as you want to, you can then disconnect the lead and connect some RC lipo. No need to use the inverter and charger.

Two 6s 5ah packs will do for a small range extender. 4 packs makes a nice battery with a bit more range. Connect the packs in series to have a 12s pack. If you have 4 packs, paralell connect two packs to make 6s 10 ah, then do the series connection.

12s RC lipo will charge to 50v, and finish at 44v. You will need a voltmeter added to the bike to be sure you don't go below 44v. Your scoot will run fine with 12s lipo. For a bit more pep, your controller can handle up to a maximum of 14s lipo. That's about 59v fully charged.

Another option would be a lifepo4 battery. A 48v lifepo4 battery of 48v 20 ah would be a perfect replacement for your lead. It would extend your range a lot further than you get from the lead now. One thing about short range though, you have to stop before things fry. With lots of range, you can ride till things melt.

How do you know when to stop? Lots of us use inexpensive thermometers to know. With a remote sensor, you put the sensor on the motor axle, or the controller, and the display on the thermometer will tell you when you are getting hotter and hotter, or if you are just warm, but stabilzed at that temperature.

This made me think,
Dogman, do you know, I have an Xtreme XB-700Li bike coming soon;
It has a LiPo4 48V 10A battery pack in it (you know, the Chinese love to exaggerate, naming it 48V 40Ah, which it is not, it's 48V12 or 20A at best),

If instead of installing a second 48V battery pack, I could install 2x6V batteries in parallel, in series with the pack to increase voltage from 48V to 54V?
I believe the controller can handle upto 60ah, right? If Instead of using 12V batteries, I could use 6V batteries in series, I'd upgrade the voltage somewhat.

Would that help in improving speed? Or would the controller still limit the speed to 20MPH?

[Alastor]

I would never use a fan on a bike like this. It's only adding weight and cooling very little, and consuming more battery.

If it was me, I'd look to see if the controller is mounted in a way that you can scoop air from underneath the scooter into the chamber where the controller is (probably under the seat or under the feet compartment).
That way as you drive you'll bring fresh air in without the need for fans. I'd make a small slit into the plastic and bend it in such a way that it scoops air from the front of the bike.
Then I'd create another slit on the back, bending it in such a way that whatever air gets pushed into the chamber by the first slit, will exit by the rear slit.

With a natural flow of air the controller will cool lots better than with a fan. Besides a fan is only good in spreading the heat of the controller into the chamber. If the chamber does not have a flow of cool air, or a lot of metal in it connected to the frame, it will heat up, and the fan will become useless in such a case as a fan's performance decreases the hotter the air in a chamber is.
(metal is a good heat conductor, plastic is not).

I know exactly what you are trying to say but i took all the parameters you wrote in consideration while i was installing the second heat-sink and fan .The fan sucks fresh air from a large hole under the feet-chamber and directing it on the 2 heat-sinks and there is good space for air circulation as well.Also the fun is redirecting the hot air at the back of the scooter as natural air should flow and circle.It will be more clear when i manage to take some pictures.Even when the fun is off the scooter is not overheating i made a nice climbing with a second person and it didn't even got hot as before so i think its working ok.More testing will prove it or not

[Alastor]

Well, first lets get one thing straight. You say you have a 48v controller of 20 amps. Watts is amps x volts. So you have about a 1000w scooter, with a handy sticker to make it cheap at the licence place.

Second, you do need to improve the ventilation to your controller somehow. A small fan run on a 3s lipo pack would help, as well as some kind of way to scoop wind and direct it to your controller. Your controller is likely getting no ventilation at all now, and will run cool enough if it gets some breeze. So it's not so much a fan it needs, but just to have some wind reach it when you ride. You'd think engineers who design these things would have some commonsense, but they don't sometimes.

One thing you should know about controllers is that they make less heat when you ride wide open throttle. Half throttle makes the controller work harder, to shorten the pulse of the power, which makes some heat in the fets. So when possible, do more riding full throttle, then coast. It will help some with the hot controller.

As for the bike on hills. Well, just because they put a cool looking seat for a passenger on the thing to make it sell does not mean it was designed with climing a hill with two passengers on it. No real solution to that, 1000w is enough to get 180 pounds up a hill fine, But if you both combined weigh 300, better stick to the less steep hills as much as possible. A second scooter is the real solution. It's ok though on flat ground and mild hills to carry your girl. Just avoid really steep hills. It's very important not to overload the bike up steep hills. If it can't climb the hill at 20-25 kph, you are going to be heating up the motor real bad as well as the controller. A very short steep hill can be ok, just avoid long steep ones.

On to the batttery. Install a set of new connectors between the battery and the controller that you can get to easily. When you have discharged your lead battery as much as you want to, you can then disconnect the lead and connect some RC lipo. No need to use the inverter and charger.

Two 6s 5ah packs will do for a small range extender. 4 packs makes a nice battery with a bit more range. Connect the packs in series to have a 12s pack. If you have 4 packs, paralell connect two packs to make 6s 10 ah, then do the series connection.

12s RC lipo will charge to 50v, and finish at 44v. You will need a voltmeter added to the bike to be sure you don't go below 44v. Your scoot will run fine with 12s lipo. For a bit more pep, your controller can handle up to a maximum of 14s lipo. That's about 59v fully charged.

Another option would be a lifepo4 battery. A 48v lifepo4 battery of 48v 20 ah would be a perfect replacement for your lead. It would extend your range a lot further than you get from the lead now. One thing about short range though, you have to stop before things fry. With lots of range, you can ride till things melt.

How do you know when to stop? Lots of us use inexpensive thermometers to know. With a remote sensor, you put the sensor on the motor axle, or the controller, and the display on the thermometer will tell you when you are getting hotter and hotter, or if you are just warm, but stabilzed at that temperature.

This made me think,
Dogman, do you know, I have an Xtreme XB-700Li bike coming soon;
It has a LiPo4 48V 10A battery pack in it (you know, the Chinese love to exaggerate, naming it 48V 40Ah, which it is not, it's 48V12 or 20A at best),

If instead of installing a second 48V battery pack, I could install 2x6V batteries in parallel, in series with the pack to increase voltage from 48V to 54V?
I believe the controller can handle upto 60ah, right? If Instead of using 12V batteries, I could use 6V batteries in series, I'd upgrade the voltage somewhat.

Would that help in improving speed? Or would the controller still limit the speed to 20MPH?

In my experience its not safe to connect different types of batteries and if you do it after all make sure you check the main battery total AH and parallel a battery with the same total amps.If the batteries are not the same ah and if you don't install heavy duty blocking diodes the larger ah batteries might want to discharge on the smaller ones and this might be a hazard.Also i think that having different ah batteries will cause the blocking diodes to engage all the times consuming some power by heating up.Usually heavy duty blocking diodes consume 1v each as well.

Also controllers don't have a max Ah cap at my knowledge the only issue you might have and please correct me if i am wrong about this is that probably your bikes battery meters might not work properly because they are made for a specific amount of ah reading.

[ProDigit]

6V battery in series with the battery pack, to up the voltage from 48 to 54V
Instead of one 6V battery (with 7A), I wanted to use 2 in parallel with each other, to be able to handle the 10-20A from the battery pack.
it's a series-parallel connection, like this:


The batteries won't discharge when the bike is off.
When the bike is on, and driving, all you need to make sure you do, is make sure the 2 x 6V batteries are the same, and the sum of the current handling of the two batteries somewhat is the same as the battery pack.
IoW, if your bike has a 20A battery pack, and you'll use above schematic, and the 6V batteries are only 7A, you'll be limiting your motor to 14A sustained current.
If you only put 1 x 6V battery in series, no harm will be done to the battery, but you will be limiting your engine to 7A (or in other words to 364W, in my case about half my motor's power handling

[Alastor]

6V battery in series with the battery pack, to up the voltage from 48 to 54V
Instead of one 6V battery (with 7A), I wanted to use 2 in parallel with each other, to be able to handle the 10-20A from the battery pack.
it's a series-parallel connection, like this:


The batteries won't discharge when the bike is off.
When the bike is on, and driving, all you need to make sure you do, is make sure the 2 x 6V batteries are the same, and the sum of the current handling of the two batteries somewhat is the same as the battery pack.
IoW, if your bike has a 20A battery pack, and you'll use above schematic, and the 6V batteries are only 7A, you'll be limiting your motor to 14A sustained current.
If you only put 1 x 6V battery in series, no harm will be done to the battery, but you will be limiting your engine to 7A (or in other words to 364W, in my case about half my motor's power handling

Nice to know thanks.Really useful information.With the proper wiring this setup can also work as a speed booster (safer imo) because if you want to use it all the way as i suspect you will have to make sure that your controller can handle 59 + 14 ~ 74 volts in full charge.

[dnmun]

no, it is a bad idea because you will destroy all the batteries by over discharging them if placed in series like that. the LVC of a 48V controller is 40V.

you have to remember that when you ask for free advice, you get what you pay for.

why would someone buy two 6V SLA just to put them in parallel instead of just getting a large battery? why would someone use SLA anyway?

if you want to know what the controller can handle then open it up and look. no need to guess.

[ProDigit]

ok, The idea was more for me, since I've read the controller on my bike handles upto 60V. I would not know who would power a 40V controller (presumably meant for 24/36V operation I guess), with 48V

[Alastor]

I knew it was not safe to do this.Thanks for clearing this up.Something else is it safe to to connect SLA's and lipos together if they are the same voltage and Ah's ?
I am asking because in my knowledge it is not safe to connect different types of battery's but with all this conversation i am not sure .

p.s.
Jesus 2300 mah nims require 10 hours of charge the first time my inverter will melt .....

[dnmun]

it is not that it is unsafe, but that when you drain an SLA below about 10V it is damaged and doesn't fully charge up again.

i you have 4 1/2 of them in series and a 40V LVC on the controller then the voltage across each of the SLA is below 9V and that is hard on them.

combining batteries in parallel is fairly simple to understand.

if you have 2 lifepo4 packs which have the same voltage then you can combine them directly without diodes.

this includes a situation in which you combine different capacity packs as well, such as combining a 10Ah pack with a 20Ah pack in parallel.

after charging them up to the same voltage with the charger, you combine them by connecting the P- leads together first, then you put a resistor across the two positive (red) leads to equalize the voltage on each pack , then connect the two red leads together. from this point on you always keep the two batteries connected and charge them up together.

do not put switches between them, do not put diodes between them. when they are connected together this way, they share the load when discharging and they will split the charging current between themselves as well so that they both will climb in voltage together and reach full charge at the same time.

if you disconnect them and one pack is discharged separately, then you have to go through the same procedure, charging up and using the resistor to finally equalize them every time you recombine them in parallel.

you should never use a lifepo4 pack wihout a BMS, combining the two packs in parallel does not affect the BMS which functions normally and when one pack has reached LVC and the output mosfets shut off on that side then the current will continue to be delivered by the other pack until it cuts out at LVC.

this will be at two different pack voltages usually so you should recharge immediately when the first pack reaches LVC. at this point the battery remaining is having to produce more than twice the current it did at the start and so you want to restrict it's discharge rate at that time.

resetting the BMS that shut off and then continuing at dramatically reduced power may allow you enuff travel distance to get the packs back to the charger.

when charging two different capacity packs in parallel, the charging current will be split between the two packs proportionally to their capacity and they will both charge up to their full capacity at the final charger voltage. and then they balance at that voltage until the charger shuts off.

you should not combine two packs in parallel with different voltages, such as a 36V and a 48V pack even with a diode to protect the lower pack from the upper pack.

but if you have different chemistries, such as nicad or nimh or SLA combined with the lifepo4 in parallel you need to use a diode on the output of two packs to combine them, to prevent current from flowing from one pack to the other.

for this situation where you combine the two different types of packs, you would select a schottky diode capable of withstanding the maximum voltage difference between the two packs.

so a 48V nicad pack fully charged is about 54V and a 48V lifepo4 pack is about 58V so you would need a schottky diode of at least 4-5V but something around 20V is the smallest they sell for these power diodes and the higher the breakdown voltage the more expensive it costs. but more important is that the forward voltage across the diode when it is conducting is directly related to the the reverse breakdown voltage. you want this forward voltage to be small because that determines how much heat the diode produces. power =VxI.

the schottky diode has three legs in the To-220AB package. the current comes out of the center leg called the cathode, and you connect each battery's positive terminal to the outside leg of the schottky. that is called the anode.

all the current from the two packs flows out of the center leg and that is what you connect to the motor controller positive lead.

you can also use two axial schottky diodes, one for each pack, with the cathodes soldered together to the controller lead and the anodes to each of the packs.

after you know what voltage diode you need, then select the diode current carrying capacity that is able to handle all the current you expect your battery pack to produce at maximum discharge. this is why they are expensive because a large schottky capable of handling a lot of current gets expensive fast.

the problem with combining different battery chemistries in parallel is the restricted voltage range of the older SLA and nicad chemistries compared to lifepo4. a fully discharged 48V nicad pack is around 40V but the 48V lifepo4 pack will continue producing current down to about 32V.

to protect the nicad pack, the controller LVC of 40V will shut off the controller so the nicad pack is not over discharged. this leaves a lot of charge on the lifepo4 pack so you only are able to produce about 65% of the lifepo4 pack power.

so if you wish to combine the lifepo4 and the nicad, use a 36V controller and a 36V nicad pack. the 30V LVC of the controller will protect the nicad pack. then you would combine a 48V lifepo4 pack with the 36V nicad in parallel using a 20-30V diode since the nicad would be charged to about 40V and the fully charged lifepo4 would be around 57V.

in this case, the nicad would be restricted from releasing current through the diode because the output voltage is so much higher than the nicad fully charged voltage, and the lifepo4 would not be pushing current inot the nicad because the 20V diode blocks it.

when the lifepo4 pack has been discharged down to the 40V of the nicad then the nicad would add current through the diode to the current from the lifepo4 until the LVC of the controller shut off. this protects the nicad. the BMS on the lifepo4 protects that pack.

in this case with the 36V nicad and the 48V lifepo4, you would only need one axial schottky diode on the output of the nicad pack, and no diode would be needed on the lifepo4 at all.

looking in mouser catalog, ON semiconductor 1N5817G, 20V 25A axial diode is $.20. it has Vforward of .45V so when the max 25A current is flowing the diode is only producing about 10 watts of heat.

but that heat is only produced at the end of the discharge of the packs. if you also had a big diode in the lifepo4 pack output, it would be producing a lot more heat because it produces more current over a longer period, so it would need a heatsink.

but that axial diode on the nicad pack will get hot so mount it so it is not touching anything that will melt and is out in the open air for cooling.

that is the only situation in which i can see the need for diodes to combine two packs in parallel. a 36V nicad and a 48V lifepo4, in which you would be able to get the maximum capacity out of the two packs. and only a 20 cent diode needed.

this requires common sense to manage. charge the nicad up first and the lifpo4 next to insure that the voltage between the 2 packs does not exceed the 20V breakdown, or choose a 30V diode to be safer, 1N5818G 20V 25A .55V forward bias, 13 watts of heat at max current.

you can also find the same features in TO-220AC packages, so you could dissipate the heat with a heat sink too.

[ProDigit]

I never said of charging them together!
my post was also aimed at 2 packs in series, not in parallel.
2 different packs in series won't harm each other; in parallel they might,especially with high power li battery packs.

after you know what voltage diode you need, then select the diode current carrying capacity that is able to handle all the current you expect your battery pack to produce at maximum discharge. this is why they are expensive because a large schottky capable of handling a lot of current gets expensive fast.

My suggestion, buy 2 or 4 lower powered diodes, and solder them in parallel with each other to increase max current flow.

in this case with the 36V nicad and the 48V lifepo4, you would only need one axial schottky diode on the output of the nicad pack, and no diode would be needed on the lifepo4 at all.

I don't know anyone who would do such a thing,
It's much better to have 2 battery packs of the same voltage, so both of them are working together all the time.
By the time the voltage of the 48V dropped far enough for the 36V to kick in, the 48V battery will have a too low voltage per cell already.

If you know the discharge cycle of both batteries of SAME voltage you're going to buy, or know that one battery has a higher capacity than the other (eg: one has 10A, the other same voltage, but 15 or 20A, you can also make use of one single diode on the weaker battery. That way you also only have one diode.

You will have to charge them separately though.

after charging you can always measure the battery voltage to be sure.

and now I see what you mean by having 2 different battery packs connecting together; however with the use of one diode the issue is nearly non existent (unless you charge the extension battery, and forget to charge the internal battery, yes, that would be bad...

That, and if the 'unprotected' battery pack would have a bad cell. For that reason it's better to have both batteries protected by diodes.

I was thinking of buying 4x amazon item B005OFLMQW; D92-02 Integrated Circuit 20A 200V Fast Recovery Diode. That it's voltage is overrated can do no harm. These babies only cost $3,50 per item.
2 in parallel with each other to get a 40A power handling per battery.
I'm just unsure why this diode has a third leg, probably a ground or so,
They're very easy to mount on an aluminum bar, drill a hole in it, and the bar will act as a heat sink (just in case).

[dnmun]

mr pro, my comments about the SLA were to explain why the addition of another SLA in series was detrimental. i realize you do not understand my rational is based on the fixed LVC of this controller. you can make a pack built up anyway you wish. this guy has no electrical experience so i was trying to educate him and protect him from making a mistake and taking advice that would damage his battery pack.

i then proceeded to explain why some batteries can be combined, in parallel, not series since i consider combining different batteries in series backwards, not progressive.

i did explain the only situation in which i thought it made sense to combine two different chemistries in parallel which would allow one to recover all the power stored in each battery within the confines of the limits established by the LVC of the controller and using that LVC to protect the nicad pack. the BMS of the lifepo4 pack would protect it.

in that case, as i explained, you would only need a small axial diode of 20-30V breakdown, and about 25A max on the output of the nicad pack. no diode should be placed on the lifepo4 pack.

i explained the reason for selecting a diode with a small breakdown voltage (the heat produced when current flows through it), and why the reverse voltage a diode can withstand is related to the voltage across the diode when current flows through it in the forward direction. in this case the forward bias of that axial diode is specified to be .45V, not the one volt plus of the 200V diode. this is related to the doping of the semiconductor silicon during the diode manufacture.

you can also learn this stuff by taking courses in electrical engineering like i did. you don't have to learn anything from reading this but there may be someone out there who does learn something, that is who i explained it for, the person who reached this using a google search.

i hate for the endless sphere to be a source of misinformation that would denigrate its reputation with electrical hobbiest who get to the point where they are considering their options in combining different battery packs.

i had recommended that the original poster actually not combine his 48V SLA with anything else, but that he should actually buy another battery and sell the SLA. then if he did that we can open his controller and adjust the LVC of the controller down so he could use the 48V lifepo4 pack and get the maximum available capacity for use.

that is the simplest and most cost effective solution, and since all these little electric scooters are made in china, which is all of them, and all use the SLA for a battery, then this discussion should be relevant for these millions of people, not just the OP. so if the thread has no accurate information or explanation then many people who use google to find answers would be misinformed and the sphere would be responsible.

for the new or electronically naive person considering how to purchase an ebike kit to use, this is also important since the LVC of the ebike controller will determine their options when combining chemistries also which is why i explained that one should purchase a 36V ebike kit to use with a 48V lifepo4 battery since most people want to ditch their SLA and go to using the new lifepo4 packs. in that case, the only sensible combination of different battery chemistries is in parallel and it would be using a 36V nicad and a 48V lifepo4 with the small axial diode on the nicad. really very simple, and very cheap, and the heat produced by the diode would be the minimum available to this configuration of packs.

[Alastor]

Dnmun i really appreciate taking all this time to explain all this details in depth.I had no idea about LVC on controllers but now i can understand why it need modification if i use a lifepo4 battery on an SLA setup.Also i totally agree with you that the best way to go is buying a new lifepo4 battery as a replacement for the SLA's and modifying the controller should also be a nice project if not replacing ti.From my point of view the ebike is a way to move around and it has to be build to use easy.Sometimes we all might do a mistake and regret doing any modifications in the first place but knowing how it works it really helps to understand all the parameters and decide how to proceed.

I also use shock diodes in my solar setup and the only reason i was asking to clarify the connection which you did excellent for almost all theoretically battery connectivity is that in both theoretically DC circuits solar,e-scooters there is a controller in between with different limitations and functions.Knowing how the ebike controller works is the key to understand all the things you wrote.

You really helped me clarify a lot of things and save a lot of money.

[dnmun]

the little schottky diode i found was in the newark catalog, in the mouser catalog they have the ON diodes
for the axial diodes>
use mouser prefix 863-1N5817G 20V, 25A, .41Vforward vias, 28 cents each
-1N5818G 30V, 25A, .55Vforward bias, 26 cents


and for SMA package> 863-MBRA120ET3G 20V, 40A, .53V 27 cents
-MBRA130LT3G 30V,25A, .41V 24 cents

i cannot imagine a nicad pack pushing more than 25A but there are 40A series also. remember i am saying that the only diode needed for the 36V nicad, 48V combination is the diode on top of the 36V nicad pack. no diode would be needed in the lifepo4 current path since it is always superior in voltage.

i was thinking again of another combination, with the 48V SLA that you have on this scooter. or with a 48V nicad pack, and how to combine it with a lifepo4 pack so you could get all the storage of the lifepo4 and the SLA or nicad. this is using the 40V LVC of this scooter.

if you add a 60V lifepo4 pack in parallel, then that 20S pack would be discharged at around 42V, so it would be able to be drawn down totally along with the SLA or nicad to 40V.

the SLA will charge to about 56V and a nicad would charge to about 54V, and the 20S lifepo4 would charge to 73-74V. again in this case you could add a 20V or 30V axial diode, such as those listed above, and the 20S lifepo4 would provide all the power until the pack voltage dropped to the 54V of the nicad or SLA, and then both packs would be providing the current. sag would push them to 40V and shut down the controller while both packs were in safe regions, and the lifepo4 BMS would protect it if the voltage on any individual cell dropped below the 2.1V LVC. that would leave the SLA or nicad to push power to keep the bike running, and you could nurse it to a charger.

so consider the option of not selling the SLA, but add a 60V lifepo4 pack in parallel. that will give you good top speed when the pack is fresh and the old SLA will have the lifepo4 to share the load at the end so the peukert effect is minimized because the current draw is so much lower.

the problem with going to the 60V lifepo4 is the 74V charging voltage. that will be too much for the 63V caps on the input and the S/D busses. so they would need to be replaced with 100V input caps, along with changing the input power resistor to get the controller voltage regulation to work over the entire 40-74V range. that is pretty simple.

the other thing will be to look at the mosfets and see if they can handle the 74V and i bet they can. with any luck, you have the ubiquitous P75FN75 mosfets with the 75V 75A rating and they would work fine at that voltage.

i hope this makes more sense, now you can look at the capital investment in terms of one item, a new 60V lifepo4 pack.

say a 60V 15Ah pack from mr li ping since BMS battery does not carry that size, but that would give you the most bang for the buck. you could use that one lifepo4 pack until the SLA wore out and then add another 60V lifepo4 pack in parallel with it because you would still be using the 40V LVC controller. or you could use the existing BMS and add a second set of cells in parallel. especially easy if it is the headway since you would just buy another 20 cells and connect them in series with a sense wire jumper over to the other cells in the same row.

the problem with the lights and the need for an input power resistor swap could be managed by using a DC/DC converter from the 48V pack to produce the 12V rail for the controller and 12V lighting. less heating of the controller by the input power drop, and then add led lights to replace the incandescents to conserve juice.

the DC converter would have to be based on the 2596hv version of the 5 pin converter chip made to work up to 60V so it would run just off the lower pack at the 54V, of the SLA or nicad.

looking at worst case where the DC converter is left on to sink current through the controller, and then it reaches the 40V minimum for the SLA or nicad. if this happened while the 60V lifepo4 is fully charged then as the SLA or nicad drops below the breakdown voltage difference between the charged lifepo4 (67V resting) and the nicad/SLA. using the 20V diode, it would begin conducting reverse current around 47V and the nicad would take charge from the lifepo4 as the reverse current avalanched backwards through the schottky. but that current would be charging the nicad up as the lifepo4 dropped at the 20V breakdown level between the two packs, and stay there. so it would not break anything, but it would not stop the discharge of the pack if the controller stayed on because the DC converter was left on. that is another problem.

so i think this might be a reasonable option to pursue for your scooter. i never thought 60V lifepo4 pack would be relevant, but it seems the best fit, 72V lifepo4 is too high unless it has the irfb4110 mosfets, and the 60V lifepo4 will work with the p75fn75 mosfets. maybe $10-15 for the caps, 20 cents for input power resistor swap or $20 for the DC converter.

maybe you can special order the 60V pack with headway cells from BMS battery too. hope this makes more sense, kinda the least things to have to change, just add the 60V in parallel with the diode on top of the SLA, and swap the caps and the input power resistor.

there is no LVC change, no need to sell the SLA and the SLA would be preserved by reducing the current demand in operation if it is shared with the last portion of the lifepo4 pack.

call BMS battery and i see that EVassemble also can build you a 60V pack: http://www.evassemble.com/index.php?mai ... n7prv0k696

you should be able to get them to build you a headway pack for about $550. either one of them. that
would give you about 4 times the range you have now.

[Alastor]

Really nice to know .Thanks again man for explaining all this details

I found some times and took some more pictures from the computer fan installation and the heat sink also i installed a mono radio so i can hear some music while i travel The bicycle is slow as hell top speed 32kmph so i need to entertain myself till i get to my destination .

Everything is rechargeable and cost me nothing to recharge

My next move is to get a nice waterproof thermometer install it and make some uphill test rides to check how the system is performing.