Advice please on precise spare battery specs

[LeonardYoung]

Hello,

It's along while since I posted. Several years ago I purchased a remarkably good chinese folder that is still in excellent condition and hasn't given me a moment's worry. However the 36V 200W 10AH battery has begun to expire after many many miles of good service. I think I could have extended its life beyond four years if I had charged it regularly when not in use.

I have found what looks to be the right replacement for around £199. All the measurements fit exactly my one. However there is what I hope is not a crucial difference. On my existing battery there is a row of four connection slots at the bottom but there appear to be only two brass coloured contacts, both at the outer slots which are marked plus and minus. The inner two slots appear to not have any contacts and look like they are just plastic (ie not in use).

However in the pictures of the replacement battery (ebay) it looks like all 4 contact slots at the bottom have what look like aluminium or steel contacts. This is a li ion battery. Do these batteries use all four contacts or do they just use the outer two?

Any expert advice would be gratefully received. Thank you.

 

[the_killjoy]

Could you post a link to the Ebay item.

 

[Deleted member 4366]

They just use two contacts. When you get your replacement,use a voltmeter to check that they're the same way round as your present one before slotting it in.

If they're the wrong way, it's a two minute job to swap them over. You have to take the four screws out of the bottom to gain access to them in the inside of the black plastic bottom piece. Most likely, you wob't have to change them over, but you must check.

 

[LeonardYoung]

Thanks for the answers. I have another quandry: I think I might have forgotten whether the original is 24 volts or 36 volts. If it is 36 and the motor or controller is set for 24v will it burn anything out? Is there a way I can use a meter to test what the voltage output is even with the battery fairly dead and flat?

 

[Deleted member 4366]

If you have a 24v system and stick a 36v battery in it, 99% of the time, it''ll work without burning anything; however it'll make your bike go faster and climb hills better, so bear that in mind.

 

[LeonardYoung]

If you have a 24v system and stick a 36v battery in it, 99% of the time, it''ll work without burning anything; however it'll make your bike go faster and climb hills better, so bear that in mind.

Thanks for that quick and knowledgable reply d8veh! Odd thing is that original seller describes battery as 36v but many websites with exactly similar batteries for sale including measurements, key position, charger etc describe them as 24v.

Presumably the corollary is also the case: that if I put a 24v battery on my bike and it has a 36 volt system, I would go slower up hill and along the flat?

Is there a quick way to examine the hub motor or controller to establish what voltage they are? Thanks for your very useful help.

 

[Geebee]

If the bike is 36v and you fit 24v it will not work as it will be below the cut off voltage of the controller.
The cut off voltage is to stop excessive discharge damaging the battery.
The easiest way to confirm the battery voltage is to see what voltage your charger has written on it, otherwise if you have a multimeter you could measure the old battery.

 

[LeonardYoung]

The charger says the output is 42 Volts. How do I know whether that means the bike is 36v or 24v?

 

[Deleted member 4366]

It's 36v, so another 36v battery will be exactly the same.

 

[LeonardYoung]

Thanks so much d8veh. Battery ordered £199 and arriving tomorrow. Excellent and quick advice which I really appreciate!

 

[Deleted member 4366]

I'll repeat my warning: When it comes, it's very important to check the polarity of the contacts. It's best to use a meter rather than the markings just in case they make a mistake.

If you have any problems fitting it, report back. there's always something you can do to make it fit including swapping the contents, but I don't expect that you'll have to do anything like that.