Battery power and controller help please

[thewelshguy]

Hi, few questions regarding my current project,

First question, is there a way to know my batterys power delivery capabilities?

It's a 48v 20.4ah Li-ion battery. No idea on cell types or brand but assume 18650

I have a Golden Motor pro kit 901 hub, rated to 1000w, its and external controller type.
They run between 36v up to 52v happily and I've seen them pushed even further (at risk) so I'm not stressed about the motor capability.

I've sourced a 1500w controller "DC Moto Controller" jobbie for the build.
Rating is 48v 35+1A (1500w) unrestricted or
15+1A (250w) restrictor button.

Am I likely to run into any problems with this combination in terms of safety?

Last question, the 3 phase wires on the controller are much thicker than the ones on the GM hub.. will that cause an issue?

Many thanks in advance for any advice or info.

Tom

 

[sjpt]

If there is nothing on the label to indicate the battery rating and you can't find its specs online it will be difficult to test. You'll find out when you connect it up on the bike and see how quickly power drops off on full assist mode. If it was a fairly cheap battery it almost certainly will struggle.

The most likely safety issues are if the bike's frame and brakes aren't suitable for the power.

I don't think there will be an issue with mismatched phase wire thickness (as long as the motor's wires are thick enough for the job).

Even when set to restricted the restrictor button doesn't make the bike legal to ride on the road, or off road in public places.

 

[thewelshguy]

Yes, as far as road legal.. it's a drift trike so it's purely a private land toy and I do not expect to be riding it in the street.

Again, the forks and frame are designed to take abuse, I'm having steel inserts machined to house the hub itself so it's almost like 'double torque arms'..
It was more 'electrical safety' I was concerned with, IE- 1500w controller overloading a 1000w motor,
Or motor phase wires based on them being thinner etc

I hear what your saying on the battery power, it was used on a 1000w bike originally, it's a hailong case (deeper size than my old 48v pack and just under twice the ah) .
There is a Model number : S039-5 but I cant directly find an exact spec or confirmed match online.

There will be no pedal assist, just thumb throttle.
I'll include a photo so you can see what it is I'm actually building.

Thanks

 

[thewelshguy]

Also I believe the battery was close to £400 originally, not sure whether that's deemed 'reasonably cheap' or not...

 

[matthewslack]

Just put a fuse in the battery positive lead, and start lowish, say 25 or 30 amps. And don't run the battery flat, leave 20 % minimum so you don't work it hard at its most vulnerable state, and just see what happens.

You'll blow some fuses but probably not cook the motor...

 

[thewelshguy]

Ok thanks, I'll bear that in mind.

I've just found out that the battery was running a 1700w hub with a 48v KT controller @ 35a so shortage of power shouldn't be an issue I'm guessing

 

[saneagle]

Ok thanks, I'll bear that in mind.

I've just found out that the battery was running a 1700w hub with a 48v KT controller @ 35a so shortage of power shouldn't be an issue I'm guessing

At 35A, it might work, but I'm pretty sure that it's not going to last long. that's lifetime, not single journey time. do you really need that sort of power. If you do it on the road, you're going to get noticed. what bike are you going to fit it to? What reinforcement are you going to do to the drop-outs. 35A is going to need some serious strength. Hopefully, you know about all this.

 

[thewelshguy]

It's a trike, not bike... based exactly off a design that's already been done a bunch of times and taken to production by a US company, even offering 52v taking up to 3000w front motors, the dropouts are machined steel designed and made for this exact fork and exactly this purpose so fingers crossed that side of it should hold up.

As far as 'do I need that amount of power', to be perfectly honest.. I have no idea and probably not, however my thinking was, if it's capable of more power than required, then I dont need to push it as hard and can controll it via throttle.

My electric mountain board is 7500watt and capable of 45 mph peak with 60a draw but I never ride at greater than 30mph and pull 30a. So I was applying the same principal to this to be honest.

I'd rather have it gutsy and reign it in, than gutless and always having to work it hard to achieve satisfactory performance.

Obviously I'm at the mercy of the boffins here in terms of safe parameters, or how much power one really needs for purpose.

Thanks

 

[saneagle]

It's a trike, not bike... based exactly off a design that's already been done a bunch of times and taken to production by a US company, even offering 52v taking up to 3000w front motors, the dropouts are machined steel designed and made for this exact fork and exactly this purpose so fingers crossed that side of it should hold up.

As far as 'do I need that amount of power', to be perfectly honest.. I have no idea and probably not, however my thinking was, if it's capable of more power than required, then I dont need to push it as hard and can controll it via throttle.

My electric mountain board is 7500watt and capable of 45 mph peak with 60a draw but I never ride at greater than 30mph and pull 30a. So I was applying the same principal to this to be honest.

I'd rather have it gutsy and reign it in, than gutless and always having to work it hard to achieve satisfactory performance.

Obviously I'm at the mercy of the boffins here in terms of safe parameters, or how much power one really needs for purpose.

Thanks

OK, you should have said what the project was in the first post.

 

[thewelshguy]

OK, you should have said what the project was in the first post.

In my defence my initial question wasn't regarding what I was building, it was regarding the phase wires, the other components I was using and the safe parameters between them. Wouldn't really make a difference if it was for abike, trike or shopping trolley

I have mentioned several other times in this thread that it's a trike including a photo.
Thanks for your input none the less

 

[Noodles]

There will be a limit to what current the battery can output. 35A is a big ask, so if it wasn't designed for it, you might just not achieve max power. It should function.

If it was designed for a 5A 250W ebike The real risk is the battery over heating. The internal wires and conductors may not be rated for that much current. Best case it would blow an internal wire/fuse. Worse case it would blow up a cell and catch fire.

 

[thewelshguy]

There will be a limit to what current the battery can output. 35A is a big ask, so if it wasn't designed for it, you might just not achieve max power. It should function.

If it was designed for a 5A 250W ebike The real risk is the battery over heating. The internal wires and conductors may not be rated for that much current. Best case it would blow an internal wire/fuse. Worse case it would blow up a cell and catch fire.

Thanks for the input, well the battery was running a 1700w motor via a 45a KT controller before so I can only assume that setup would have had the same issue if it was going to happen?? Yea, realistically 35a is probably peak bursts for what i'll be using it for anyway... more a case of 'having the power and not using it' vs 'having no power and wanging the nuts out of it to achieve smiles'