NImh battery charger connectors

[allotmenteer]

Hello all

I have been lucky enough to pick up a bargain on ebay - a currie electro-drive kit with 24V 9Ah Nimh battery (for £100 too! ). As I already have an 8Ah 24V powacycle battery and charger I am hoping to be able to keep one charger at work and one at home and use each to charge both batteries.

The only hitch is that the connectors are slightly different. They both have three pins but are different sizes. I would like to change them to be the same. They both have 3 pins (though the electro-drive one has male pins on the charger lead and the powacycle female) so one is +ve, one -ve and one for the NTC. They are both rated at 24V 1.8 Amp.

Will I be able to put a powacycle type connector on the electro-drive charger and will it charge the powacycle battery ok?

Thanks in advance.

Paul

 

[flecc]

Hello Paul

You can equip the Currie charger and battery with NTC connectors in place of the XLR ones it has at present, and you can get NTC connectors from Maplin.

But that's the easy bit, since the Currie charger may either not charge the Powacycle battery or overcharge and damage it. The reason is the thermistors in the two batteries are likely to have different characteristics, cut off points etc. I've found that the Powacycle battery thermistor is very different from the Giant Lafree one for example, despite very similar batteries, and the Powacycle charger cuts out within 30 minutes when attempting to charge a Giant battery.

If you do try it, keep an eye on the battery being charged by the Currie charger and watch it's temperature. If it starts getting very hot, switch off. Of course if it just cuts out early without completing the charge you'll know anyway.

A fairly cheap way to try this out is to buy an XLR socket and an NTC socket and connect them together with a short length of lead. Then this will be an adaptor you can have with the charger so you can use it either way. You'll see a similar flylead that I made for another application here:

Let me know how you get on.

 

[allotmenteer]

A fairly cheap way to try this out is to buy an XLR socket and an NTC socket and connect them together with a short length of lead. Then this will be an adaptor you can have with the charger so you can use it either way. You'll see a similar flylead that I made for another application here:

Let me know how you get on.

Thanks flecc, I shall try the flylead suggestion.

Are these ok? Maplin > Professional Quality 3-Pin XLR-Type Connectors: In-Line

Can't find the NTC ones though.

Paul

 

[flecc]

That XLR is a set of plug and socket Paul, but you can save money with this socket only from Maplin at £1.01 less;

XLR Line Socket

Although Maplin don't list NTC and don't illustrate them as NTC in their catalogues, it's one of life's mysteries that they do have them, albeit with a locking collar, but you can remove that. Here's the link, and the three pin one for you is FK23A:

NTC Line Socket

Scroll down, second item in the list at the foot, £1.79
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[Baboonking]

Hi Paul,

Just to add. You might find soldering to the xlr connectors or ntc connector pins a little tricky (i did ) In which case I'd recommend getting an xlr or ntc extesnsion cable and then soldering the wires from the pack to the extension cable.


Microphone cable XLR plug - XLR Socket 1.5m on eBay Microphone Accessories, Microphones, Pro Audio Equipment, Musical Instruments (item 180146649480 end time 16-Aug-07 20:07:37 BST)

If you have multimeter then that can measure the resistance of the termistors in both packs. Typically they are 7komhs cold (measure from the negative to the third pin of the connector). but can vary as Flecc says. If they both have the same value you should be ok, but proceed with caution, at least for the first few charges.

Thats great deal you've got yourself they're. lots of good upgrade options with the currie aswell.

 

[allotmenteer]

Many thanks to flecc and baboonking for the detailed information on the the connectors etc. I shall measure the resistance when I get home today. I've got a local maplin store so I should be able to pick up the connectors too.

It certainly was a fantastic deal on the kit, I can only imagine nobody else bid because it's the holiday season and all fellow electric bike enthusiasts must be sunning themselves in foreign climes. I've only had a 1 mile trip on it so far due to the constant rain and having to get down the allotment whenever the weather does break. It seems to pull well from a standstill but is quite noisy. Hopefully the weather will improve today and I'll take it for a longer run.

Paul

 

[flecc]

I think from memory the Powacycle thermistor is about 5 kOhms at room temperature Paul. I don't know it's B factor but suspect it's around 3500, it's definitely on the low side.
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