Has anyone tried to re-cell a pack with hybrid batteries ?

[jerrysimon]

Thanks for the correction Fecn , I've learnt something new

Me too both in learning something new and standing corrected

Obviously the one shown in the other thread is 24v. I was thinking of using 3*12v NiMh RC flight packs (4.2Ah- 4.6Ah) in series for a 36v power source. I have read elsewhere that it was better to charge the 3 packs seperately, rather than when they were all connected together in series. I guess Fecn has clarified that and provides a workable solution.

Again I am pulling off my expereince in the RC world where I have used 12v NiMH packs in my helis a lot, albeit using a dedicated intelligent charger to fast charge them. Obviously the discharge rates are also higher in this application as well.

I decided not to go down this route for my 36v source, mainly because of weight and the high cost of decent 12v RC flight packs. Also my mistaken belief that I would have to charge each of the 12V packs seperately. As you know, I am currently experimenting with 12 * A123 cells again split into two 6s packs.

At 8Ah-10Ah these Hybrid cells have excellent capacity. 3C also means that they are likely very suitable for ebikes. Again I am also assuming that they retain voltage during any moments of higher current draw ?

Regards

Jerry

 

[daniel.weck]

Again I am also assuming that they retain voltage during any moments of higher current draw ?

Yeah, I'd like to see the voltage sag graph...in practice, the relevant figure whilst climbing a hill is Watt power, not Amps.

(great to hear about alternative battery solutions by the way, I'm reading this with interest !)

 

[jerrysimon]

Dan check the other post the graphs look quite good at 1C (10amps).

Regards

Jerry

 

[keastan]

chazpope
I read your post with interest, checked your result's web page. The batt. looked the same as my folding £70 to recell yes will give it a go.
No the price of these batts in the Maplins Cat is now £20 for the pair, making it a bit expensive at £200. Will be interested to know how they performed.

 

[Grizzly Bear]

Guys, don't waste your money on NIMH, buy some A123 M1s off Ebay and a BMS from Ping. I've got two bikes on them now, absolutely the best batteries for an Ebike. The counterfeit ones are actually testing to be better than the "real" ones! It's a bit of a chore making the pack but worth it. You need to go to ebay.com for the best deals, about £6 each 2300mah 3.3 volts nominal. so 48 for a 9200mah 36 volt pack (actually more like 40 volts), peukerts constant almost 1, amazing! so you get 9200mah regardless of the discharge rate!

 

[Psycosis]

Like these i assume?

New A123 26650 Battery Cell 3.3v2300mah LiFePO4 8PCS - eBay (item 150447193375 end time Jun-22-10 11:41:29 PDT)

I haven't seen these before, but saves a bunch of messing about even if they are more expensive.
EP Buddy 4S1P 13.2V 2300mAh LiFe battery Type1 USA A123 - eBay (item 230442135649 end time Jun-24-10 17:55:30 PDT)

Pretty good price if they do indeed include free delivery

 

[tangent]

chazpope
I read your post with interest, checked your result's web page. The batt. looked the same as my folding £70 to recell yes will give it a go.
No the price of these batts in the Maplins Cat is now £20 for the pair, making it a bit expensive at £200. Will be interested to know how they performed.

If you want NiMH "hybrid" or "instant" batteries, I would recommend Home

Much cheaper than Maplin most of the time and they give good discounts for quantity. For example, they made up a pack of 20 NiMH 9Ah D cells for my Giant Lafree for £125 including delivery. Results so far are very good. They could not make the pack from the instant types though as they lacked the solder tags.

 

[Grizzly Bear]

Like these i assume?

New A123 26650 Battery Cell 3.3v2300mah LiFePO4 8PCS - eBay (item 150447193375 end time Jun-22-10 11:41:29 PDT)

I haven't seen these before, but saves a bunch of messing about even if they are more expensive.
EP Buddy 4S1P 13.2V 2300mAh LiFe battery Type1 USA A123 - eBay (item 230442135649 end time Jun-24-10 17:55:30 PDT)

Pretty good price if they do indeed include free delivery

Hi Psycosis
delivery $28 to UK on those, but to be honest the 4s1p not much help if your building a 12s4p pack, best use the individual cells. They are not easy to solder together as they have no tabs, but if you buy battery bars and tin both the battery and the bars it's not to difficult, I used hyperion bars, and a 125 watt iron for fast soldering which minimizes the risk of damaging the cells, but from what I've read they are pretty much indestructible! One thing I would advise though is that you check the space you have available for your pack, as they are an unusual size, and you need room for the BMS.

Peter