Battery suggestion for eGO Cycle 2 Classic?

[Chalo]

So I have this scooter here at my house. It belongs to a friend of mine, but she put it here with me when the batteries went bad. I replaced them and my wife used the scooter for a little while, but then the charger went fruity and cooked the new batteries dry.

Thus I am in the market for replacement batteries and a replacement charger for this thing. It has 24V/35Ah SLA batteries, but I don't think there's any good reason to go that way now that the charger is presumed bad. So I'm thinking one of the less pyrotechnic lithium batteries might be the ticket.

The eGO Cycle 2 Classic is expected to draw a peak current of 180-200A. Continuous current is much lower than that, but I don't know how much lower. This scooter will be operated by one of two different women who really, really don't want to have to understand or communicate with the electrical components of the machine. So the battery needs to have good high current capacity and effective BMS, I'm thinking.

And the battery solution must be reasonably cheap if this thing is to return to the road.

I have looked at a LiFePO4 pack from Electricrider in San Angelo, which promises adequate current capacity, 24V/20Ah, and integrated BMS plus charger for $440. My only misgiving about that is it uses an 8s-14p layout. That seems like a can o' worms to me. Is there anyone here who has tried the Electricrider LiFePO4 packs extensively, and how have they turned out?

What other options are there that offer 200A peak discharge and reliable service for a rider who can only be bothered to plug the thing in and nothing more?

 

[wesnewell]

If you are using 20ah, then any 10C battery would be rated for 200A. Personally, I wouldn't use anything less than 20C though. Are you sure about that 200A peak. That just sounds crazy to me. Just checked the specs. Calls for 180A max for the classic. Still sounds crazy to me. Should be able to do some big wheelies.

 

[Chalo]

If you are using 20ah, then any 10C battery would be rated for 200A. Personally, I wouldn't use anything less than 20C though. Are you sure about that 200A peak. That just sounds crazy to me. Just checked the specs. Calls for 180A max for the classic. Still sounds crazy to me. Should be able to do some big wheelies.

My data regarding peak power was gleaned from egocyclewiki. I assure you it does not wheelie, at least in its stock configuration. I assume most of that 200A peak power gets lost on its way to the show.

I'm not stuck on 20Ah; I just assume that a 20Ah lithium battery is similar in its usable capacity to a 35Ah SLA. And I also assume that loading it up with more battery capacity than that will cost more and weigh more.

I guess cell-man 20Ah pouch cell packs would work too, but I expect that as time continues to pass after the demise of A123 the existing stocks of cells get worse in quality. That's $435 without a charger, but the 8s-1p configuration sure makes more sense to me than 8s-14p.

 

[wesnewell]

I only use rc lipo and I think you're going to be hard pressed to find a 20ah 24V lifepo4 pack with a bms that will put out 200amps at a reasonable price if you can find one at all.

 

[Chalo]

RC Lipo would deliver the power, but would not be suitable for the intended users. Or their houses.

 

[dogman dan]

That scoot sounds as hard on batteries as my lawnmower. The mower has no controller, just an on switch, and thick grass can produce an insane amp spike.

I'd be inclined to look into a controller that won't produce more than a 40 amp spike. Then you can use batteries able to handle that, such as from Electric Rider, or use an allcell pack, which you can get from Ebikekit, or Chicago Electric bikes.

I've been wishing somebody would extensively test electric riders batteries. See what they really do, without excess sag. You know how it is, spec c rate, and what is practical out on the road are always two different c rates. Question is, how different for the ER packs?

For me, the cut all claims in half is still my rule of thumb, for sellers like hobby king for example. The pack has to stay relatively cool, for it to be a usable discharge rate over the long haul. I don't like to use a lithium pack that gets as hot as nicads.

 

[Chalo]

I'd be inclined to look into a controller that won't produce more than a 40 amp spike.

24V x 40A on a brushed motor scooter that has no pedals sounds like a recipe for having to push the thing up curb cuts, let alone real hills.

 

[dogman dan]

I started wondering about that amp spec, but according to this, 180 amps max controller.

http://www.varsitycycle.com/ego_scooter_specs.shtml

It's brushed, so replacing that with something less powerful might be a fairly cheap option. The catch 22 is that often the generic controller won't plug in with all the other stuff on the bike. But take a peek, if it has generic plug types, it might be easy to replace with a 1000w controller, which won't amp spike the battery so much.

If you think about it, 24 mph speed, it sure can't be doing anything much more than making heat out of any amps past 40 amps. Give it a 1000w controller, and they will have their top speed, but a slower take off will mean better battery lifespan.

Maybe just pop open that controller, and snip a few shunts? 180 w is just plain battery murder, unless you are running RC lipo.

 

[dogman dan]

How steep hills? What's the advantage of giving the thing more watts, once it's in a 60% or less efficiency rpm?

1000w will climb 6% fine.

Too bad you didn't put a wattmeter on it while you could, and find out what wattage real world use is needing.

 

[dogman dan]

It's true, at 24v it does take a lot more amps to get a practical wattage able to do much.

What about 60 amps? That's 1500w, and it it can't do it at that power level, you have need for a different vehicle entirely.

30 ah of 3c spec lithium battery should do that 60 amps well enough. Get a wattmeter on it, then start snipping shunts till the battery can handle it. If you only see 2c spikes in real world use with the stock controller, then you are ok.

I bet real world measurements show less than 2000w. But uphill starts from a stop sign might show more for a very brief time.