1000w upgrade ? or new kit ?

[rgvkid]

hi all,

converted my 12 yr old 26" mtb with a voilamart ebay 1000w kit and 13ah 48v battery back in september. all been going well, but am hankering now for more power.
2000w kits seem pretty dear, but am i right in thinking i can perhaps obtain new controller and battery (52v) which will push the motor harder?
don't want to break what i have, but not sure if this is perhaps more cost-effective route to get more power, than buying new 2000w kit ?
any help much appreciated,
cheers,
col

 

[Manbeer]

you can definitely push it harder, get a decent 52v battery, a controller upgrade can be had fairly cheap and even if you decide you still want a different motor later on at least the battery can be used on that. make sure it has a decent BMS as a lot of the hailong style packs and the like have 20-30a bms...so don't just get the first one you see that looks ok. first choice would be from a reputable vendor like grin, luna, or em3ev, but Unit pack power has some decent stuff and offers 40 and 50 amp bms on some models if cost is a concern

 

[amberwolf]

converted my 12 yr old 26" mtb with a voilamart ebay 1000w kit and 13ah 48v battery back in september. all been going well, but am hankering now for more power.
2000w kits seem pretty dear, but am i right in thinking i can perhaps obtain new controller and battery (52v) which will push the motor harder?

To get more power with less investment, get another 48v battery you can parallel with your existing one, so that there is less voltage sag on either one, so you get more actual power at any moment out of it, under heavier loads.

Then get a higher current controller--the one you have now is probably "20A", so if you get one that's "40A" it would double the power it can provide under heavier loads.

Those two things will slightly more than double the amount of power you could get out of it, theoretically, without halving your range (which is what would happen if you used twice as much power (all the time) without having twice as much battery).

It also depends on the batteries--if you post a link to the exact battery you bought (not just one "like it"), then we can look at it's specifications and see if it is even capable of giving you the 1000w your present kit asks of it.

Now...keep in mind that the extra power only directly helps you on hills and startups from a stop or other high-acceleration situations.

It isn't going to directly make you any faster, if that's what you are after. (though it does take more power to go faster, having more power wont' make you go faster if you don't also have the other necessary things).

To go faster, with the motor you already have, you'll need first to know what the kit you have is capable of to start with, and to find out, you'll need to do a test. If the motor wheel is the one that drives your speedometer, then this is simple. Flip the bike upside down or otherwise lift the motor wheel offground, and use full throttle to see what speed your wheel gets to. Then also note the fastest speed your bike reaches with you on it while riding on flat ground at full throttle. Post both of those here.


If nothing above sounds like what you're really after, then you should post exact details of exactly what you do what the bike to do for you that it does not do now, and under what specific conditions it has to do those things. Then we can help you figure out what you'll need to get to do that.

 

[E-HP]

...thinking i can perhaps obtain new controller and battery (52v) which will push the motor harder?
don't want to break what i have, but not sure if this is perhaps more cost-effective route to get more power, than buying new 2000w kit ?

You'll need a battery with good cells that can provide the necessary amps (52V, ~38A continuous), but on flat ground it shouldn't be a problem. If you have lots of hills, you should monitor your temps. For insurance, you could add ferrofluid to the hub to get better cooling.
To see how it might compare, use the Grin simulator to model your current setup, using a motor similar to yours. If yours is a 28 mph @ 48V version of a 9C clone, then use one of the 9C motors that goes 28 mph with a 48V battery, sort of like the example below. Then open a second system and change the battery and controller and run the comparison. You can add hills to see how long you can go before overheating, etc. You should read the whole page before making assumptions or understanding the output.

https://ebikes.ca/tools/simulator.html?motor=M2706&batt=B4816_GA&hp=0&axis=mph&motor_b=M2706&batt_b=B5216_GA&hp_b=0&bopen=true&cont_b=cust_38_96_0.03_V&cont=cust_22_56_0.03_V

If your battery can support it, the biggest gain would be in the torque curve, so better acceleration, and a gain in speed approximately proportional to the voltages.

BTW welcome to the forum :thumb:

 

[motomech]

"...more power." and "...push the motor harder."

What's that mean?

Do you want a higher top speed or to charge up the steepest hills, or both?

I believe your motor is a direct drive and they like Volts. Use the voltage that will get you to your desired top speed. Some increase in amps will probably will be needed to support the higher rpm range, but I would try and use the lowest value that will get the job done to keep the max Wattage reasonable. I'm not sure you would need 40 Amps max.

When total 'power" (Watts) goes up, you need to look @everything in the Power-stream, wires, connectors, anti-spark, controller sensitivity, Batt C rate, etc.

If you want to go stoplite to stoplite racing, maybe a geared motor (MAC), set the road speed w/ Motor speed and throw Amps at it.

 

[rgvkid]

hi all,

many thanks for all the replies. Just to clarify slightly, i'm basically trying to decide if i can adapt what i have eg upgrade battery/controller for a bit more oomph when going up hills. Top speed tbh is pretty much fine (i pedal 95% of the time whilst using it).
I've noticed unless the battery is pretty fully charged the battery, display "charge" drops to about half way when really under load going up a steep hill, which makes me think battery upgrade maybe certainly one idea. once not under load, battery charge goes back up.
not adverse to upgrading motor aswell, but really trying to work out if this is necessery ?

the battery i have is 48v 13ah : https://tinyurl.com/2gtlvtjj
spec below (13ah version in my case):
Type 2: 48V 10A

Specifications:
- Nominal voltage: 48V
- Maximum charging voltage: 54.6V
- Rated capacity: 10AH
- Charging mode: CC, CV
- Charging current: up to 2A
- Charge cut-off current: 0.03C
- Charging time: ≈ 5h (2A charger)
- Overcharge voltage protection (battery): 4.25±0.015V
- Overcharge voltage protection (packaging): 54.6V
- Maximum continuous discharge current: 25A
- Overdischarge voltage (battery): 2.8 ± 0.015V
- Over-discharge voltage protection (packaging): 36.4~41V
- Overcurrent discharge protection: 60±5A
- Cycle life: 600> 80%
- Weight: ≈ 5Kg
- range of working temperature
- Charging: 0~45°C
- Discharge: -10~60°C
- Storage temperature: -20 ° C ~ 45 ° C

and motor is here : https://tinyurl.com/1b31lxj4

thanks for any help, i'm not an expert by any means, just an enthusiastic amateur !! 8 )
cheers,
col

 

[amberwolf]

I've noticed unless the battery is pretty fully charged the battery, display "charge" drops to about half way when really under load going up a steep hill, which makes me think battery upgrade maybe certainly one idea. once not under load, battery charge goes back up.

This indicates the battery can't handle the current draw, if it's the meter on the battery itself that is dropping under load. Parallelling a second one would help with that, possibly fix it. The bigger/better the second one is, the more of the load it would handle. It would also extend your range.

If you don't have space for a second or bigger battery, then a better quality battery the same size/capacity you already have would help, but you would have to ensure you know that the new one has that much better cells in it, and/or that much better build quality, etc.

It's quite possible that just not sagging voltage that much would get you the extra power you want for the hills, without a controller upgrade.

How much does the bike slow down on those hills when it sags? Does it slow down before the sag starts?

If the meter on teh battery itself doesnt' drop but a meter on a controller/display does, it could be a connection problem between battery and controller causing it.

Other stuff we need to know to guesstimate the power you need:
How steep and how long is the hill?
What is the total guesstimated weight of you, the bike/electrics/battery, and anything else you carry going up the hill?

the battery i have is 48v 13ah : https://tinyurl.com/2gtlvtjj
spec below (13ah version in my case):
Type 2: 48V 10A
Specifications:
- Nominal voltage: 48V
- Maximum charging voltage: 54.6V
- Rated capacity: 10AH
- Charging mode: CC, CV
- Charging current: up to 2A
- Charge cut-off current: 0.03C
- Charging time: ≈ 5h (2A charger)
- Overcharge voltage protection (battery): 4.25±0.015V
- Overcharge voltage protection (packaging): 54.6V
- Maximum continuous discharge current: 25A
- Overdischarge voltage (battery): 2.8 ± 0.015V
- Over-discharge voltage protection (packaging): 36.4~41V
- Overcurrent discharge protection: 60±5A
- Cycle life: 600> 80%
- Weight: ≈ 5Kg
- range of working temperature
- Charging: 0~45°C
- Discharge: -10~60°C
- Storage temperature: -20 ° C ~ 45 ° C

Just to be sure, if yours is the 13Ah, does it have the same specs as the 48v 10Ah? If not, then wouldn't it be more like the "type 1" (36v) on that page, which is these specs, right? (except for the voltages):

Type 1: 36V 13A
Specifications:
- Nominal voltage: 36V
- Maximum charging voltage: 42V
- Rated capacity: 13AH
- Charging mode: CC, CV
- Charging current: up to 2A
- Charge cut-off current: 0.03C
- Charging time: ≈7h (2A charger)
- Overcharge voltage protection (battery): 4.25±0.015V
- Overcharge voltage protection (packaging): 42V
- Maximum continuous discharge current: 20A
- Overdischarge voltage (battery): 2.8 ± 0.015V
- Over discharge voltage protection (packaging): 28~33V
- Overcurrent discharge protection: 60±5A
- Cycle life: 600> 80%
- Weight: ≈ 5Kg
- range of working temperature
- Charging: 0~45°C
- Discharge: -10~60°C
- Storage temperature: -20 ° C ~ 45 ° C

Because that page only lists a 48v 10Ah, and a 36v 13Ah, and has no specs for a 48v 13Ah pack, though it does have one in the dropdown to buy. And the 13Ah (regardless of voltage) should have a higher current maximum output than the 10Ah, simply becuase it would have more paralleled cells in it, assuming they are all the same cells used. (and assuming they used the same BMS but just different voltage versions).

However...it is possible that to get the higher capacity they used cells that can hold more Ah, but can't output as many Amps, whcih is not that unusual. In that case, both 13Ah packs (36v and 48v) may be only able to output 20A current without a lot of voltage sag and heat, while the 10Ah packs (36v and 48v) may be able to output 25A in the same situation.

I'm just asking to clarify what your battery is *actually* capable of, to get a better idea of how you can improve the results you're getting to reach your goal.

If you aren't sure, you may have to ask the seller what the actual specs are for the specific battery you bought, and hope they understand the question, since their page doesn't actually have any specs for a battery that matches what you have.

and motor is here : https://tinyurl.com/1b31lxj4

The specs on that page indicate (irrelevant stuff removed)

* 48V 1000W and 250W super power Brushless Gearless Hub Motor
* Restricted to 250W and 16mph (25km/h) by default as a road-legal kit
* Adjustable 5 Level Intelligent Pedal Assist with twist throttle
* LCD Display shows battery level and pedal assistance settings
* Brake Levers cut off the power supply to the motor safely
* Crank speed sensor for 8 Point High Efficent Pedal Assist
* Allow you to swap two power modes between the full 1000W power or 250W power by a single blue switch wire is embedded in controller.(Only for Twist Throttle)
* Still remain the full 1000W power with no speed control.(Only for Pedal Assist System,"PAS")
So please connecting the Road-legal Switch Wire and disconnect the PAS on Road.

Motor: Brushless Gearless
Power: 1000W / 48V or 250W / 48V
Torque: 45 N.M
Max speed: 28 mph or 16 mph (45km/h or 25km/h)
Wheel Size: 26"
Max load capacity: 200kg
Net weight:11.16kg

So...first, do you have the 250w restriction jumper in place, or disconnected?
Are you using the PAS, or the throttle, or both?
Which assist level are you using it in?

Need to know these to know how much power you are probably pulling from the battery, to help you find a battery that will do what you want (and whether the controller/motor will do what you want).

 

[rgvkid]

hi,
thanks for the reply.
the battery charge indicator i'm talking about is the one on the lcd display, which i think has 5 bars and will drop to 3 bars under load when using maximum PAS going up steep hill with me pedalling. to be fair, it's still doing 18-23 mph ish, which is maybe as good as can be expected tbh from my setup.
re the battery on ebay, it's all a bit vague re spec, as you mention, as it doesn't actually give spec for my EXACT battery (i assumed the 10ah and 13ah ones would both be the same, other than the capacity).
don't really want to go down 2nd battery route tbh just due to weight, i don't need the bike to do vast distances, use it for 4 mile commute each way and when out for an hour's blast at night often cover 12-14 miles, so that's sufficient for me.
re guesstimates of bike specs/requirement, i'm 85kg, bike a mid spec 12 yr old mtb with the kit and battery, so suspect 22/23 kg for the bike. hills i do aren't overly long generally, maybe only few 100 yards of actually being relatively steep (would do them at about 8mph before electrified the mtb).
cheers,
col

 

[amberwolf]

the battery charge indicator i'm talking about is the one on the lcd display, which i think has 5 bars and will drop to 3 bars under load when using maximum PAS going up steep hill with me pedalling. to be fair, it's still doing 18-23 mph ish, which is maybe as good as can be expected tbh from my setup.

Is it maintaining the same speed it would have on a flat road, with you doing the same amount of pedalling (you pushing just as hard, in the same pedal gear)?

re the battery on ebay, it's all a bit vague re spec, as you mention, as it doesn't actually give spec for my EXACT battery (i assumed the 10ah and 13ah ones would both be the same, other than the capacity).

Usually not, though depending on which cell route they went they can be close in output capability (amps, rather than Ah).

don't really want to go down 2nd battery route tbh just due to weight,

Then a better quality / more capable battery to replace it is the "best" option there. LIkely to be a fair bit more expensive than the one you have. If it's only needed for that hill, and the hill is really short and not a problem to go slower up that hill, then it may not be worth doing.

The main problem you have ATM, from the information provided, is that your battery is not really capable of even the 20-25A the sales page claims, without being too heavy a load on it (causing significant voltage sag and cell heating). But your controller, when under a load like that hill, is probably taking that much it is pushing the battery to about the max it can really take (vs what it was advertised as).

It says the battery can do up to 60A or so for short bursts, but if that's even true , it's going to sag in voltage a *lot* more than it does now, and heat up inside more and faster.

It is also possible that it isn't fully charging some cells (unbalanced), and the sag on those cells is worse than the others. If tha'ts true, then leaving it on the charger as long as is practical between rides could eventually rebalance them and fix the problem. It's worth a shot.

The voltage sag you see directly affects the ability of the whole system, because power (watts) is V x A. So let's guess that 52v is the full marking of the meter, and 42v is the empty marking of the meter, and halfway across it is 47v. Let's guess that on that hill the ocntroller is pulling it's maximum 21A or so, for the 1000w it's made for--the seller page doesnt' specify the actual current limit of the controller, so we're only guessing. If the battery had no voltage sag, then at 52v x 21A it would get 1092 watts. It's not a lot, but almost 100w (about the same that most humans output on average, though you can do much more when cranking hard for short bursts), and can make a difference in a climb, etc. How much of a difference depends on the slope and the weight vs the speed, primarily.

i don't need the bike to do vast distances, use it for 4 mile commute each way and when out for an hour's blast at night often cover 12-14 miles, so that's sufficient for me.
re guesstimates of bike specs/requirement, i'm 85kg, bike a mid spec 12 yr old mtb with the kit and battery, so suspect 22/23 kg for the bike. hills i do aren't overly long generally, maybe only few 100 yards of actually being relatively steep (would do them at about 8mph before electrified the mtb).

If it is doing everythign else you need it to, and that hill is the only part you have trouble with, then you'll ahve to decide if it's worth potentially several hundred dollars or more to deal with it.

I can't estimate the power required for the hill at the speed you want to go without knowing the actual hill steepness and the actual distance. Rise over run, or how tall it is at the peak (no idea) vs how long it is (whatever "few 100 yards" actually is).

But if 1000w is enough for that, then you should already be able to do it, if the battery is able to handle it. If it takes more than that, you might need a bigger controller (the motor should be fine up to at least twice it's "rating" for such a short hill as long as it's not bogged down at really low speeds). The 1000w you have available is *input* power to the motor, and the output power (to the road) is variable from there based on conditions htat affect the efficiency of the motor (mostly motor speed), but you can guesstimate around 70-80% of the power going in ends up pushing you up that hill, so around 700-800w really available at the time. (cant' say for sure because each motor model is different)

That is assuming you have disabled the limiter and not being restricted to 250w (not likely if the battery sags that much...).


If you don't want to provide the info to us for whatever reason (which is fine, some people don't) then you can find calculators to determine approximate power needed to climb a hill of a certain distance and height at a certain speed, which will tell you how much power-to-the-road you must have to accomplish that. http://ebikes.ca/tools/simulator.html can be used this way, including motor and battery / etc information, but it's a bit more complicated than a regular calculator so you'd have to read its' full directions and .

 

[rgvkid]

hi,
going up steep hill with me pedalling it's not doing the same speed i would expect on the flat with the same amount of effort, though i would expect this, because i can see the 1000w is pretty good (maybe sports hatch equivalent to use car comparison) but it's not a ferrari.

so the gist of it seems to be the motor should be able to put out more oomph, but is being held back by mid-range battery and generic controller, from sounds of it.
it was built on a budget (£210 GBP each for the kit and same for the battery) and any upgrades would need to be relatively cheap, which i suspect they won't be..... as from a quick look uprated decent-ish battery probably about 350-450 GBP(cost of all my kit combined minus bike).

one of my key questions really would be am i better off selling what i have, and then reinvesting the money in a more substantial kit, with improved battery/controller and bigger motor ? sounds like 2000w motor is biggest you can normally fit in a standard mtb frame. if it's going to cost too much, i'll probably just keep what i have, as it's plenty of laughs, just got a hankering for more power !! and the wires to restrict the kit have never been connected ; )
cheers,

 

[amberwolf]

as from a quick look uprated decent-ish battery probably about 350-450 GBP(cost of all my kit combined minus bike).

Well, if you want to fix the problem of voltage sag under load, you don't want a decent-ish battery, you would have to spend real money on a really good battery that can handle *more* load than you will put it under (because as it ages it will be less and less capable, and presumably you would want it to stay able to handle what you need it to).

Batteries are the heart of the system, and if htey can't supply what the system needs, the system cant' do what you ask of it.

one of my key questions really would be am i better off selling what i have, and then reinvesting the money in a more substantial kit, with improved battery/controller and bigger motor ? sounds like 2000w motor is biggest you can normally fit in a standard mtb frame.

Without knowing the details you won't post, I can't tell you what you need.

But most likely the motor you have will do what you want if you had a really good battery. Even the controller could probably do it, but if not a 40A contorller probably would.

The key is the battery--if it cannot handle the load without sagging in voltage, the system cannot do what you want it to do regardless of what controller and motor you put on there. So you cannot cheap out on the battery if you have a specific goal you have to get a battery taht will do what is necessary to reach taht goal. You cannot find out (short of expensive experimentation) what battery or controller or motor you actually need unless you get specifics on your exact needs (terrain, wind, weight, speed, etc etc) and plug them into a simulator or calculator to find out what actual power levels you need to do it.

Or you can just spend money on stuff, test it, find out it doesn't do what you want, spend more money on more stuff, test it, find out it still doesn't, and keep spending more money on better things until you eventually get what you want, run out of money, or get tired of trying.

Up to you how you do it.

 

[rgvkid]

Thanks for the feedback, all, tried to digest while wfh, home schooling etc. Tbh from what I read sounds like I don't have the money required for an 'upgrade' at the mo, even a good battery upgrade just now is probably too much cash.
Will plan ahead and save.
Cheers

 

[E-HP]

Thanks for the feedback, all, tried to digest while wfh, home schooling etc. Tbh from what I read sounds like I don't have the money required for an 'upgrade' at the mo, even a good battery upgrade just now is probably too much cash.
Will plan ahead and save.
Cheers

Save up for a good battery. You’ll probably spend around 3x the cost of your kit as a good data point, since it is the main component for obtaining performance.


Sent from my iPad using Tapatalk

 

[rgvkid]

Yep, thanks for advice, sounds like that's the best starting point on a budget.