Battery Advice

farmboy · #1 12-10-2009

Hi - some advice wanted from a newbie. Can anyone recommend a good make/type/brand of battery pack for my Short Course Truck? Currently running with an Orion 4500 NiMH pack. Would love some advice...

Col · #2 13-10-2009

Stick or saddle layout?
Your current will be IIIIII for stick, or with a wire between eack 3 like this III_III.

Either way, second hand trakpower lipo's will be perect for the job, as they're not overly punchy and still have good runtime.
I've got 4900mah 25c stick in mine,
and 3200mah 30c (or 35c?) saddle are perfect for your needs.

Having said that, after you've bought the lipo, the charger and maybe a balance lead, are your 4500's really worth getting rid of?
I've a novak smart tray if you need to borrow one for them. (it's an equliser to get good life from nimh cells)

farmboy · #3 13-10-2009

My current pack is a stick. In the short term (and due to cost) I was going to get another NiMH pack, then switch to LiPos later when funds allow. Just after a recommendation for a NiMh pack to be getting on with.

mpg200 · #4 13-10-2009

I would stay with stick packs for now, The orion 4500 are good value and will keep you racing for a season, Do you just have 1 pack? you really need at least 2 (my lad can get 2 races on a 3300 saddle pack 540 class) although the car gets a bit slower towards the end of second race. so 4500 should last. NiMh dont really like being charged at high rates, I would suggest no more than 2C (9000mA in the case of 4500's), if you want to get the most life out of them. Try second hand ..put a post in wanted, I got 3 packs 'pre enjoyed' and they have been great only £5 each

keeps my lad going round.

Matt

farmboy · #5 13-10-2009

NEWBIE ALERT ***

Can I ask: what does 2C mean? I've seen it a lot when referring to batteries. Feel free to mock my dumbness!

jhammond · #6 13-10-2009

DELETED

jhammond · #7 13-10-2009

C stands for Coulomb. Which is equivalent to charge delivered in 1second at a rate of 1ampere.

Basically a higher C rating means the cells can deliver more charge over a determined period of time.

Julius.

neiloliver · #8 13-10-2009

Quote:

Originally Posted by mpg200

NiMh dont really like being charged at high rates, I would suggest no more than 2C (9000mA in the case of 4500's

Do not charge at rate >1C. (4.5A for 4500mAh NiMH cells). Read the advice issued by the BRCA regarding charging NiMH cells.

http://www.brca.org/BRCA/elecboard/n...20Practice.htm

The charge and discharge current of a battery is measured in C-rate. Most portable batteries are rated at 1C. This means that a 4500mAh battery would provide 4500mA for one hour if discharged at 1C rate. The same battery discharged at 0.5C would provide 2250mA for two hours. At 2C, the 4500mAh battery would deliver 9000mA for 30 minutes. 1C is often referred to as a one-hour discharge; a 0.5C would be a two-hour, and a 0.1C a 10-hour discharge. In practise temperature and rate play a big factor in the efficiency of the battery with lower temperatures and higher rates degrading the efficiency.

farmboy · #9 13-10-2009

Thanks for the info.

Col · #10 13-10-2009

Neil is spot on there - Never charge at more than 4.5 amps to be on the safe side.
Is your charger lipo compatible?

mpg200 · #11 14-10-2009

Quite Correct there 1C max.... what was i thinking?

Brain had switched off. Gone are the old days of charging 1700 scr's at 5 amps.

Big G · #12 14-10-2009

http://cgi.ebay.co.uk/7-4v-5000mAh-3...d=p3286.c0.m14

these are decent packs for the money. a friend has a couple of them and gets very good run times when he used them in his pro 4 TC. Ideal for a truck really. I'll be getting some soon.

farmboy · #13 14-10-2009

Current charger (MTroniks J4l is not lipo compatible, I'm pretty sure. I've used lipos on my mini helicopters but they are low capacity affairs and the chargers are pack specific. I am aiming to upgrade soon though. Just want another NimH to tide me over.