cookin' batterys

[Matt]

something is up - ive cooked two batterys in one weekend. i think my peak detection charger is sloppy on detecting the peak, and the batterys are over charing too much before the charger cuts off.

ive watched it with a voltimeter, and the batterys drop over 1v before they cut... it should be like no more than 0.2v

imagine the power loss im getting too!

what hurts is that each battery is $40 a pop, thats $80 gone in one weekend.

now, i can go and get another 3000mah battery for $40 or get a 1800mah battery for $20. races are only for 5 mins at a time and im sure that 1800mah will last for 5 mins... ? i dont have a modified motor but a stock 27 turn rebuildable Trinity motor.

[azzachaz]

I dont know much about battery times etc but
i swear by this...

[azzachaz]

picture didn't work in last post. It is a Supa Nova computer controlled charger. It is fully programmable and can charge up to 5A.

I run it off a computer PSU at home and a 12v SLA at the track.

It can charge NiMh NiCD PB up to 25 cells at once.

Mine is a newer version than that picture but much the same (silver not yellow) and I got it from toyworld for $100. They still sell them online for up to $250.

They have dropped in price because the new ones can charge LiPo

[Matt]

i didnt think you had any electric cars and that all of yours are nitro?

i just went out and bought a replacement pack. $39, BOOM. done with.

[BALISTC]

Best be talking to Ken about this, he is an electronics guru :P

[azzachaz]

I dont have any electric cars but dont forget each car needs 12 AA batteries (or equiv.) to run the radio/servos.

These need to be topped up all the time or you have run away cars

[Ken]

How old were the packs you fried and what were they? I know some packs just fry because they can't handle the amp draw through races. My friend fried 2 packs while cycling them at the track.

What kind of charger are you using BTW?

Lastly, what do you mean by, "batterys drop over 1v before they cut... it should be like no more than 0.2v"?

[Matt]

thats right, a good charger wont let the battery drop by much before seeing that drop and cutting it... however the one i have is letting the battery drop by 1v or more before cutting it. its overcharging them i suspect.

the batterys are no more than 2 months old and have probably been used 20 times each, one was a nicad and the other a nimh.

i have others in my collection but they were purchased after these 2 and coincidently these 2 were the first i purchased. BOOM, gone.

the charger is an Ansmann ACS 67p+ and the beautiful thing about this charger is that its dual 240v/12v and thats what attracted me to buying this one. its just a shame about the sloppy peak cut off. i have a voltmeter and i think i would be wise to monitor a battery charge closely and pull the pack off the moment i see it drop.

i just dont have the money for a "pro" $150+ charger at the moment :(

[Ken]

Ahh, I see. I thought you meant the pack is dropping 1 volt under discharge. That is a problem, I have a pack that is about 10 years old and that's still going strong and that was charged using a wall charger(the cheapy 8 hour one) for most of its life.

About the power input, just mod a computer PSU to run the charger. My 200Watt unit can power 2 chargers at once and the total cost of the conversion was about $25 including the power supply. Then, you can use any charger you want without having to use a 12V battery.

You can get good chargers for under $100. My old charger(now belongs to mc68) costs around $90 at RMS and can charge 1-10cells. My charger costs $100 at model flight, can do 1-10 NICD, NiMH, PB and Li-Ion. Look around and you cam find some good stuff that's cheap and there's always the option of buying secondhand.

[mc68]

lol too bad im scared of the PS, and i still need batteries to charge :P

[BALISTC]

Ken, do you still have that power supply for me? I gotta come and pick it up if you do!

[Ken]

Yeah, I went to the tip and bought 2, one for Andy and one for you.

Andy, I'll fix it for ya, just get a lot of electrical tape. :P