nicads on fire !! (sort of )

muchalucha · Post by **muchalucha** » Wed Jul 15, 2009 10:15 am

In my FW , i have used the same nicads from day one , its a 1000mah , 9.6V sub c cell nicad . I made this pack up from a huge 24 V drill battery i bought from b and q in the sale , one porblem ive always had is hoe hot it gets , sometiems
after a complete dishcarge , its too hot to pick up and the tape its wrapped in gets all sticky and starts to melt !!! So my question is , how much damage is this doing to my battery and will taking all the tape of and glueing the cells togethor help at all , or is it an internal resistance problem ?

EpicentrE · Post by **EpicentrE** » Wed Jul 15, 2009 11:39 am

Just hazarding a guess, but I would imagine any batteries that were used in electric drills are designed for continuous current discharge, not bursts of very high ampage which is what you get from drive motors rapidly changing direction, stalling when trying to push things, etc.

I would advise buying some proper batteries

Simon Windisch · Post by **Simon Windisch** » Wed Jul 15, 2009 11:50 am

That sounds good to me, although my FW uses racing style NiMhs and they get pretty hot. You could use heatshrink to bind them together instead of tape? They wouldn't get sticky then. you could cool them with an old PC fan, they take 12v I believe.

As for the damage, we'll as with all things robot, you're abusing those batteries, I'm sure you're not expecting them to last as long as they would if you were using them in a drill.

Simon

muchalucha · Post by **muchalucha** » Wed Jul 15, 2009 1:01 pm

As for the damage, we'll as with all things robot, you're abusing those batteries, I'm sure you're not expecting them to last as long as they would if you were using them in a drill.

hehe , thats why i havent bought better batteries , as chances are they will get smashed to pieces at some point , im going to try taking all the tape of and using heatwhrink but they are pretty exposed liek that and god knwos where im going to get some heat shrink wide enough

Flippt · Post by **Flippt** » Wed Jul 15, 2009 3:59 pm

It might depend on how much you charge and discharge the batteries. Do you got a setting for a slower cycle time?

muchalucha · Post by **muchalucha** » Wed Jul 15, 2009 6:56 pm

the charger ive got is a fairly chepa one , it has a 0.5 , 1 and 2.5 amp charge setting , i always use 1 . I have a battery disharger (a half dead drill motor , with a tamiya conenctor soldered to it lol) i leave it going until the motor stops moving . so i think ina ll im taking good care of them , but they get extremely hot (in battle , they get slightly warm in charging) . im only running 2 drill motors from them , and until recently they only where getting warm , now there too hot to pick up sometimes.

widow_twanky · Post by **widow_twanky** » Sun Oct 11, 2009 9:17 pm

Bet they don't get as hot as hydras did at Guildford!! 90sub c's up in smoke at the same time

Just use them till they catch fire properly.

Over time I think heat will just reduce some of the capacity until it stops working.

Andy

muchalucha · Post by **muchalucha** » Sat Oct 17, 2009 9:43 am

A little update , i got some new 3400 mah nicads and they seem fine , but my pro peak charger is a little fierce , its charging at about 1.5 A when its supposed to be charging at 1 , 1000mah nicads don't like that !!