Can a 24 Volt Bike Take Any 24V Battery?

[Fixx42]

Hello all,

I'm new to bike commuting, and thinking of buying an electric bike so that I arrive at work a bit less worn out. One option I'm looking at is a used Synergy Cycles 7-Speed 24 Volt E-Bike for $200. The catch is that it needs a new battery. Unfortunately, however, I've been unable to find much information about the bike online, let alone spare parts.

Rather than finding a replacement Synergy Cycles battery, is there a possibility that I might be able to use a third-party 24 Volt battery? For example, could I perhaps jury-rig one of these Currie batteries to the bike? http://www.amazon.com/Currie-Technologies-24-Volt-Bicycle-Battery/dp/B002RR7RD2/ref=sr_1_2?ie=UTF8&qid=1338484409&sr=8-2

Thanks a lot for the information, I'm very much a novice here!

Fixx

[dnmun]

how can you be certain that the only problem is a dead SLA pack?

do you have pictures of the bike? what is the motor and controller?

the battery does not take charge at all or the guy just told you it was bad?

you should be able to put the dead battery on the bike and while it is charging then hold up the wheel and make the motor run under the charger power. if not, think about it some more.

[Fixx42]

Thanks for the reply dnmun. I only have this picture of the bike, I'm afraid: http://dl.dropbox.com/u/5166225/synergy.jpg

Those are good questions, which the seller doesn't answer in his posting (just says that the bike is in excellent condition but battery needs replacement). I went ahead and emailed him to ask if he would test the bike as you suggested. Thanks a lot!

If it does turn out to just be an issue of a battery at the end of its life and without an available replacement, do you think I'd be able to replace it with any sizable 24-Volt?

[dnmun]

looks nice, full suspension and pack in the middle, but 24V is slow.

see if he can tell you about the motor and controller. that currie pack is SLA i think. this bike looks like it may have a chinese lithium pack. in that case the current pack may be dead because of a dead charger.

so find out if the battery is SLA, and if the motor is a brushless DC motor, BLDC, and controller. with close up pictures we can count the wires running from the controller to the motor to know if it is brushed.

[dogman]

Not quite any 24v battery should run that bike. But any decent 24v battery for an ebike should run it fine.

Seller would have to prove it runs to get $200, then I'd want to still talk him down to $100, since that's not much of a bike unless you spend some money improving it.

Clearly you are on a budget, so get him to sell it for less. In some ways, you'd be better off paying $500 for a new ezip 24v bike. But at $100, it becomes more worth it for you to try to get this one.

If you are really on a budget, you could run this bike on sla's, but they need to be good ones, intended for EV use. Not lawnmower starter batteries.

[wesnewell]

Volts is volts, so any 24v battery would work. I sure wouldn't get SLA for it though. For short range a $50 6s 5ah lipo pack would work. Just make sure the battery you get can supply the amps it needs.

[d8veh]

Looks like 24v SLAs from the photor, for which there's loads of options.

Motors are normally fairly robust, so the seller's probably right that it's the battery causing the problem. I could also be the controller, but they're not too expensive. I'm with Dogman: I think it's a little expensive for a non-runner, which in the worst case could need $250 to sort it. If the seller can prove that it'll work with new batteries. then the price is more realistic. I would budget for a new controller and batteries - say $150, and then you'd be gambling on say a 10% chance that you need a motor, so that adds another $150 x .1. The bike would be about $300-$350 running, so $300 - $150 - $15 would be a par price. So $120 or less should be your target.

[dogman]

Yep. But I am of course, thinking in USA prices. I paid $40 for a non runner recently. It needed battery that I already had, and a $30 controller. Won that one. Another time I paid $100 for a non runner, knowing the current USA price for the motor only at that time was $150. Taking the chance, I won and the motor was good. But I wasn't going anywhere near $200 for a non runner.

[overbyte]

Here's a description of that bike when it was new: http://www.electricbikes500.com/electric-sierra.html.

It uses SLA (sealed lead acid) batteries, which are relatively cheap and easy to obtain, such as at a BatteriesPlus outlet store. You'd need to take in the exact batteries you pull from the bike's case. It will require two 12-volt batteries.

"Volts are volts" is a true statement, as far as it goes, but batteries and controllers differ in the maximum amount of current (amps) or power (watts) they can handle or produce. You need to match them up with each other's specs. BatteriesPlus probably has an exact replacement. I did exactly that when I replaced the two 12-volt batteries from my EVG eBike a few years ago, and the replacements worked fine.

One note of caution. My eBike had such dead batteries that they crystlized and cracked their cases inside the battery pack's outer case. I had a heck of a time getting them out because they had swollen and the heat they generated had fused the plastic cases. Also, the posting her which suggested that maybe more is wrong than just the dead batteries should be considered.

I heard that the manufacturer of the Synergy bikes closed his store in Santa Cruz and moved to Pacific Grove, California. Just an unconfirmed rumor. You may be able to find him for further advice.

Stan

[Drunkskunk]

Good advice from the first time poster. The bike he found is a diffrent motor than the one the original poster had the picture of. (hub motor VS external Currie motor.) But that could be a good thing. And its a good lead on the vendor.


I wouldn't give more than $100 for it.

Any battery you find will have to be able to deliver the amperage the motor needs. Some batteries were designed for other things and can't. Running a motor usualy needs a higher discharge rate than running a UPS, or a emergancy lighting, or a radio. You'll need to know what the controller's amp rating is, and then you'll be able to decide on a battery that is able to deliver those amps.