Dear Folk,

Could anyone tell me may I charge 2 pack of 8.4V 750ma at the same time with parallel wiring to lower the current? (since my Automatic-charger minimium output rate is 0.5A, start to get warm after 5 mins charging)

Thanks again!!

Hi Andy!

I think your'e saying the batteries are getting hot after 5 minutes. In that event, charging 2 packs in paralell would split the current to each pack in approximately half, with the same voltage to each. BUT, depending on the state of charge on each pack when you start the charge cycle, plus any mismatch between each of the cells in either pack, you would be unlikely to get them to charge equally and "peak" at the same time.

Just my thoughts.

Russ

Hi Russ,

Got it ! thanks !

0.5Ah is 500Mah, your batts are 750Mah. They should take about 1 hour to charge and they should definately show no heat at all after 5 mins. Sounds like a battery problem. Do they both exhibit the same behaviour?

Hey Andy,

If you want to do a parrallel charging, you better make sure you drain the batteries first.
A couple of (good) 12V car light bulb (i.e. in parrellel) would do the job in draining the batteries. I've using this method on my RC cars until I bought a charger/discharger unit.
If the probem persists, refer to Dodgey's reply.

i dont do parallel charging for that reason. the cells maybe warm from the deep discharge they have just received but batteries getting warm is normal. 1 pack should take an hour and a half to charge fully from a total disharge. and putting them in parallel would double that time, so the same as just putting one on the charge then the other.

Basically, slow charging is better than a fast charge. Once the battery warms up, the peak charge of the battery is somewhat shifted, resulting to a shorter flight time.
Well, in reality we don't want to wait. We want the charging to be fast and easy and that's where the blowfan comes in.
I am into surface R/C, both electric and nitro. For electric, usually 3300mA is forced charged to 30 minutest but "strong" blowfan is needed. I myself uses a ducted fan for this purpose as the previous fan I've used didn't help (burnt the pastic cover of the battery since the fan cannot suppress the heat) .

Thanks all

Hi Dodgey, I have the same thought as you that it should charge around 1 hour before getting warm. But the fact is it starts to get warm(after 5-8mins) to hot(estimate 50C)gradually until the charger switch to slow charge mode(after 45mins)

My charger is TLP-EXpro, LCD Display show it charges at 10.8V
, current at 0.5A, but output capacity stop at 600MA.

Thanks again.

BTW, I saw GP 300MAH NI-CAD in market, anyone had tried it before? Would it better than the Panasonic 250MA one?