36V SLA upgrade options

[DiverDuck]

Hi, I'm new to the forum a have a dead SLA setup (3 x 12V 12AH) for 800W scooter. The Motor is a MY1020, which has 29Amp current draw.

I'm looking for relatively cheap upgrade option to either Li/Lipo, that is simple to look after and manage. I'm willing to compensate a shorter travel range for a more reliable and longer life battery system.

I'd like to get some suggestion on upgrade choices. My research so far had lead me these 2 options

1) hobbyking options, where i will need

36v 10s 5000nAh
suitable 10S charger
charger PSU 350w to suit above
Custom Y cable (to support add-on's) and accessories to protect the battery.
Some sort charging rig.
Shipping

With this I can add capacity overtime with smaller outlay upfront. I'm new to lithium battery management so I expect there will be some learning curve in looking after the battery to ensure a long life and setting up the charging rig.

2) 36v 10AH - BMS battery + Charger.
I expect this will be a more 'set and forget' approach, but shipping from china is expensive. (the cost of charger and PSU locally). I'm not sure of the life or care required for this battery. But the setup and charge method seems simple to setup and manage for a similar cost as option 1

Are there other options I could consider? Any help would be great, thanks

 

[wesnewell]

5000mah of 12s 20C lipo would give you about the same range as you have now with 3 12ah 12v sla batteries if operated at the same speed. It will also give you a little faster top end and power if needed. Use a 12s balance charger like the Thunder 1220 with it. Should not be a problem for the controller, but controller LVC will be too low to cut you off no matter if you go with 10s or 12s lipo. You'll need to either adjust it, which you probably can't do, or monitor it manually with a volt meter. I use this to monitor my pack.
http://www.ebay.com/itm/Waterproof-Digital-Voltmeter-DC-15V-To-120V-Red-Led-Voltage-Digital-Panel-Meter-/170846310527
Wire it so it goes off when you turn your scooter off.
Charger and 2 6s 20C 5000mah lipos will cost ~$190. You'll also need a PSU to power the charger, but that Can cost anywhere from nothing for an old computer psu to maybe $50 for a new 15V 350W PSU.
http://www.hobbypartz.com/75p-1220-charger.html?gclid=CNa3z9_N57ICFayPPAod10MAPw

 

[DiverDuck]

Thanks for the reply,some great info.

I noticed the 5000mAh 6S 20C Lipo Pack is 22.2v, and not 36v like the original setup. Does that mean I need to wire these in series? Also, is ok its a 20c when the motor can pull 29amps.

Detail of the controller is:
YIYUN controller compatible 36V800W Brushed
Model Name: YK31C
Lots listed ebay, http://www.ebay.ie/itm/Scooter-Elec...13?pt=UK_Motorcycle_Parts&hash=item4d030da479

I think I need to read more about LVC, so I don't kill the battery.

On chargers, I was originally looking at the icharger because I was considering using a 10s battery. There seems to be a lot choice in chargers, in particular capable of doing 1-6 series. What to look for? Is my understanding correct that I can use 1-6 series charger to charge 2 x 5000mAh 6S 20C using a para-board as this gives me more options as well.The old PC PSU is a great idea, happy to give that a go if I need the grunt and end up choosing a more powerful charger

 

[dogman dan]

To use the 6s packs, yes, you'd be wiring them in series to 12s. That's 44v nominal, 50v fully charged. Some prefer 12s since many controllers can tolerate up to 63v maximum.

10s, often achieved with two 5s packs in series, is closer to 36v.

Many ways to charge, but the cheapest is often a 6s charger. Then you parallel connect all your packs in 5 or 6s to charge them. That can get tedious, so many love 12s or 14s chargers.

 

[DiverDuck]

Ok, so I need to make a decision on the type of battery, and then charger and PSU both with pro's and con's for each. Got it. (leaning towards 10s at the moment)

What about voltage protection, i see there are a variety of alarms and buzzers which can sit in-line with battery to warn when voltage is getting too low. Is there something that can also do auto cut-off. Happy to wire up a volt meter on the handle bars, but something else as a backup incase I lend the scooter to someone. (not much available for 10s, I see)

 

[dogman dan]

Once you gain some experience, a simple volts readout on the bars should be enough for you to stop in time. (unless you ignore it, or have a bad pack lurking in there)

But at first, it can be very good to have a couple of the buzzers. Another highly recommended tool is a cellog 8 or one of the buzzers that actually gives you a cell by cell voltage. This way you can look at the meter on your bars, and if you are about to ride into the last few watthours left in them, you can do a quick check of the packs to see if any one cell is low enough to make you stop right then.

But most of the time, if you are stopping before any cells drop below 3.7v all you need is the voltmeter on the bars. If you see that volts of the whole pack start to drop really fast, you just blew it and should have stopped sooner.

One charger of 6 or 8s capability can be all you need for a fairly small pack like 10s 10 ah. But get one at least 150 watts. Anything less is too slow, like the 50w ones. Don't get a 4 in one charger. Just get a decent one able to do your whole pack in a few hours.

Charge lico ( RC batteries) in a place where a big fire is OK.

 

[DiverDuck]

Wow, I've been doing some reading on RC Batteries. The stability (or lack of) has put me off a bit. The scooter will be kept in confined space in the garage and I don't really have a fire secure place to store the batteries without it being a real hassle of disconnecting and reconnecting them all the time. Pity as the price was good. Might have to start looking at LifePo4 and suitable BMS :?

 

[dogman dan]

I think that might be the wise thing for you to do.

I charge at my fireplace, and store what I'm using daily there in metal boxes. It would be possible for you to do a safe charging and storage setup, but not if you just leave the pack on the scooter in the garage.

A 36v 15 ah size lifepo4 or limn would be safe enough for you to charge in the garage. Just basic precautions, like don't set the charger on the pile of newspapers to be recycled, or other flammable stuff.

 

[wesnewell]

Wow, I've been doing some reading on RC Batteries. The stability (or lack of) has put me off a bit. The scooter will be kept in confined space in the garage and I don't really have a fire secure place to store the batteries without it being a real hassle of disconnecting and reconnecting them all the time. Pity as the price was good. Might have to start looking at LifePo4 and suitable BMS :?

Before you make your mind up, read through this thread and watch the videos.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=27241
Used, and charged properly, it's very safe. Going on 3 years using it.

 

[dogman dan]

I agree, I've had lipo ( lico, lithium cobalt) three years now and no fires. It's not like every user of lico has a fire.

I've had everything that could have started a fire happen along the way, learning the hard way as I tend to do. The one thing I did do right, is immediately retire any pack that got over discharged, over charged, or damaged. Knowing about it if any of those three happens is the trick. Good lico doesn't just burst into flames. But you will get bad ones from time to time, or wreck em yourself, and you must be able to sort out the bad ASAP.

I just meant that leaving a lico pack on the bike, then charging it leaning against the pile of recyclable newspapers or cardboard, while you sleep, is not a good way to do it.

You'd want to stand the bike clear of flammable shit even if you have lifepo4 or lead batteries too. It's not hard to be safe with your lipo. You don't have to have a bunker to charge in. But do know that just the smoke damage from a fire is pretty nasty.

But if you ignore safety long enough, you can have problems with lico. Particularly easy to have go wrong, is to get movement of the battery in it's container causing physical damage. Inspect the pack for damage regularly. Several of the fires I have heard about resulted after packs got holes rubbed in them, or were dropped.

This hazard of physical damage can still cause a fire if any chemistry of battery get's damage to the wiring, and it starts shorting out. Battery and or wiring caused fires are definitely still possible with any E vehicle. I once had a real big fire in a gas truck, caused by the 12 wiring shorted out.

 

[Wishes]

I also had a 36 volt SLA pack from an inlaws ebike that died and she came to me for a replacement. It had 3 x 12 volt 12AH SLA in a closed plastic case.

Lipo packs and a charger from hobbyking would have done the job well and at a very reasonable price. But she has no experience whats so ever with batteries, especially the Li- type batteries. So for many of the reasons already mentioned in this thread, that was not an option.

With the help of tremendous information available on this forum and some members guidance, I decided to make my own battery pack using individual cells and a BMS board. There are tons of information on this forum about making your own pack with a bms, it is not that complicated as long as your not afraid to use a soldering iron.

I decided to use lifepo4 cells. They don't pack the punch lipo's do, but for a 36 volt ebike application, they don't need to. And the lifepo4 cells are much less hazardous than lipos and generally less difficult to handle. I managed to find some 12ah 3.2 volt lifepo4 cells at a descent price. Putting 4 of them in series provides a nominal voltage of 12.8, which is almost exactly the same as a 12 volt SLA. And the dimension of these cells were perfect, I was able to fit 12 cells + BMS in her ebike battery case that was designed to fit 3 x 12 volt 12AH SLA standard batteries and connect everything up to the existing wiring of the case. Made a perfect drop in replacement.

Her 12 cells, a new 43volt charger and a BMS came out to a bit more than buying 4 new SLA's for her, but she will get 2000 recharge cycles from them versus the 150-300 cycles you get out of SLA. I did this battery pack in early March. It has been running flawlessly for her all season. I don't have any pictures of the pack finished, but here is a pick of the 4 x 12Ah life cells matched up against a 12AH SLA. They were the exact same width and length.

 

[DiverDuck]

I think that might be the wise thing for you to do.

I charge at my fireplace, and store what I'm using daily there in metal boxes. It would be possible for you to do a safe charging and storage setup, but not if you just leave the pack on the scooter in the garage.

A 36v 15 ah size lifepo4 or limn would be safe enough for you to charge in the garage. Just basic precautions, like don't set the charger on the pile of newspapers to be recycled, or other flammable stuff.

After bouncing around a number of sites in China, and looking at prices of LifePO4 packs and shipping costs, I've over looked that HobbyKing do have some lifepo4 packs, this one in particular http://www.hobbyking.com/hobbyking/store/__10311__Turnigy_4500mAh_6S2P_30C_LiFePo4_Pack.html might suit my needs albeit give a shorter range than my the original.

Although comments from other forum members are mixed http://endless-sphere.com/forums/viewtopic.php?f=14&t=38074 about the pack

 

[Wishes]

I think that might be the wise thing for you to do.

I charge at my fireplace, and store what I'm using daily there in metal boxes. It would be possible for you to do a safe charging and storage setup, but not if you just leave the pack on the scooter in the garage.

A 36v 15 ah size lifepo4 or limn would be safe enough for you to charge in the garage. Just basic precautions, like don't set the charger on the pile of newspapers to be recycled, or other flammable stuff.

After bouncing around a number of sites in China, and looking at prices of LifePO4 packs and shipping costs, I've over looked that HobbyKing do have some lifepo4 packs, this one in particular http://www.hobbyking.com/hobbyking/store/__10311__Turnigy_4500mAh_6S2P_30C_LiFePo4_Pack.html might suit my needs albeit give a shorter range than my the original.

Although comments from other forum members are mixed http://endless-sphere.com/forums/viewtopic.php?f=14&t=38074 about the pack

2 of those connected in series should do the job for your 36 volt application. Then just parallel a few of them to increase your AH and range.

Wishes

 

[wineboyrider]

I use 4s 5ah turnigy hardcase packs series with 5s 5ah turnigy for 9s 10ah on my ezip 650 scooter and I could still pack another 10ah of 9s lipo in there.
9s lipo gives you a safe lvc for lipo of around 3.4 as most 36v brushed controllers have an lvc of 31.5.....
9s

 

[DiverDuck]

Thanks all, I finally went for 2 of these, http://www.hobbyking.com/hobbyking/store/__10311__Turnigy_4500mAh_6S2P_30C_LiFePo4_Pack.html

Now with that over, How do I monitor the batteries so I dont run them into the ground, I thought I might get two of these
http://www.hobbyking.com/hobbyking/...er_6_Lipo_Life_Li_ion_Cell_Checker_Alarm.html But I've seen another poster moding a watt meter to place on the handle bars, looks impressive.

 

[Wishes]

Thanks all, I finally went for 2 of these, http://www.hobbyking.com/hobbyking/store/__10311__Turnigy_4500mAh_6S2P_30C_LiFePo4_Pack.html

Now with that over, How do I monitor the batteries so I dont run them into the ground, I thought I might get two of these
http://www.hobbyking.com/hobbyking/...er_6_Lipo_Life_Li_ion_Cell_Checker_Alarm.html But I've seen another poster moding a watt meter to place on the handle bars, looks impressive.

Just my 2 cents about that product. It does the job, but I have used those before, and personally I did not have much luck with them. I found that only after a short while using them, they became inaccurate in the voltage reading per cell. Not by a lot, but up to .08 volt difference when compared to my high end multimeter reading. This happened to me on 3 of them. So I eventually switched to these http://www.hobbyking.com/hobbyking/store/__8980__GT_Power_Voltage_Analyzer_3_in_1_2_6S.html . They are little more expensive, but I have had better luck with them and they have stayed accurate to .01 volt for 2 seasons so far.

Wishes

 

[DiverDuck]

Thanks for the suggestion, I've ordered a 3 Digit Volt meter, to mount to the handle bars as a start to help me keep track of things manually.

In terms of voltages, I've read 3.3v for lifepo4 is a full charge, for me thats 2 x 19.8v = 39.6v
to maintain battery health the lowest I should go is 2.5v-2.7v per cell, meaning = 32.4v

Are the safe estimates?

I powered up the scooter for the first time today, and wow! its bolts. . Not sure of the full runtime as yet, because I haven't give the batteries a full charge (only what they came with).

 

[Wishes]

Thanks for the suggestion, I've ordered a 3 Digit Volt meter, to mount to the handle bars as a start to help me keep track of things manually.

In terms of voltages, I've read 3.3v for lifepo4 is a full charge, for me thats 2 x 19.8v = 39.6v
to maintain battery health the lowest I should go is 2.5v-2.7v per cell, meaning = 32.4v

Are the safe estimates?

I powered up the scooter for the first time today, and wow! its bolts. . Not sure of the full runtime as yet, because I haven't give the batteries a full charge (only what they came with).

The charging voltage of a lifepo cell is 3.6 volt per cell. So in theory that should be its voltage a full charge. They might hit 3.6 during the charge, but don't tend to hold that voltage once you stop the charger.

They usually hold around 3.4 volts per cell fully charged after resting a few minutes. It will drop those extra voltage in the first few minutes of usage, then maintain its nominal voltage for 85% of the capacity. Lifepo do not have a constant voltage drop as you use up capacity like lipo's do.

Wishes

 

[wesnewell]

I don't use lifepo4, but I wouldn't go below 2.7V per cell no load. 3.0V per cell would be better. Lifepo4 doesn't have a large voltage curve like lipo does. Once it gets close to 0% soc, voltage will drop like a rock. If you're just using voltage to monitor it, you need to pay close attention to it when it starts dropping.

 

[Wishes]

I don't use lifepo4, but I wouldn't go below 2.7V per cell no load. 3.0V per cell would be better. Lifepo4 doesn't have a large voltage curve like lipo does. Once it gets close to 0% soc, voltage will drop like a rock. If you're just using voltage to monitor it, you need to pay close attention to it when it starts dropping.

Wesnewell has a point. That is one characteristic of the Lifepo4 that make them somewhat impractical for some people on ebikes. It is hard to tell how much charge you have left because the voltage will hold at 3.2 for 85% of its charge, then as wesnewell said, it will drop like a stone. So you do not get much advance warning with the voltage levels that your battery is about empty. The best battery gauge for a lifepo4 battery is a watt-meter that tracks the total AH used.

Wishes

 

[DiverDuck]

After a full charge, I took the scooter out for a run to see how it would travel. Unfortunately I got about 1km out of my 2.5km journey before I started losing power and the battery indicator was showing, amber/red. There were no hills and the surface was flat. I stopped riding to make sure I didn't run the battery down to unsafe levels.

Any thoughts as to why I'm getting such bad runtime?. I'm not sure if it matters but the battery harness I made it made of 10AWG and 14AWAG. Would that make a big difference?

I've connected up the battery to the ImaxB6 charger. One battery was detected as 6s and charged fine, the 2nd battery was detected as 4S, I continued to charge it. I later reset the charger and left it was for a while and once again detected the battery as 6s. I've give it another today.

 

[dogman dan]

Give them a few very short discharges and full recharges. Lifepo4 often needs a few cycles to develop the full capacity on all the cells.

Hope that helps them a lot.

There can be problems with the charger detecting all the cells every time, because of the cheap Jst plugs used on RC packs.

 

[DiverDuck]

After the 2nd charge, I tested is again at very constant low throttle (walking pace) and nearly made it the whole distance. Once again i recharged the batteries, I could tell one of them was a little bit swollen. The charger only detected the battery as a 5s (instead of 6s) I left it for a while to "cool down" after that it again saw it as 6s and seemed to charge without issue.

It appears high throttle or 'reving' really draws a lot a power, have I under estimate the power requirements for this scooter?

 

[dogman dan]

The puffing is a really bad sign.

Two things are going on here. One is that you are using more than you think, when you leave from a dead stop. The other is that the advertised performance of the HK lifepo4 packs is a joke. 30c? yeah right. So yeah, 4.5 ah of that stuff is really pretty small for running what you have. And then, in addition, it's just small to begin with so it won't go that far.

Last and worst, one bad cell completely stuffs you, leaving you with in effect, an extremely tiny battery. It will be better if you can get a pack without any defect cells together. But it will still have less range than you may have expected. 4.5 ah is not a huge capacity.

Have fun trying to get a replacement for that puffed pack, but give it a go.

Then, if possible, try again with 9 ah size by adding some more packs.