Lithium cell tests

Paul wrote: There is little point in harking on about what we all did years ago and got away with, it is what is expected today from a professional body that counts.

Granted, but these are the first batteries to undergo this kind of scrutiny. The question is, have they been proven safe enough and why does it take so much time to give this verdict?

What I think we can agree on is that NiCds can be quite dangerous when they start burning. How responsible is it of the FRA to allow them for future use if the pose a proven risk? How will the FRA insurers respond if an accident happens with a battery type of which we know there can be safety issues? I can expand this discussion to the whole ruleset, but lets not go there.

is it true that with these batterys you cant stay in after a fight for another one?

my dad said something like it but hes prob trying to get me not to buy any lol

when robot wars is back on tv ill def get some

but at shows i like to just stay in fights if i can fight in the next fight??

as with any batterries it depends on the capacity of your pack.

thats if its still working LJ

normaly now days its stops mind you the sidwinder has done 7 events now :) a record
just gotto sort flipper out and marios sorted that bit :)

Ok,

I have a question, and i wonder if someone can answer it if they know.

I run 2 x 24v Nicads in Ripper.
If i Swap to These new batteries what will i gain?

How much will they cost?
How much are the chargers / balancers going to cost?
I believe my voltage will go up to 30v, correct ?
What will be my weight saving?
will I need more space?

I am starting to think about the Uk champs and getting my hardox armour on ripper, but it means a drastic diet to get it in weight, thats why i am asking.

I know that we havent got any thing finalised, but if someone knows approx values so i know.


John

What drive does Ripper Use? Gear ratio, speedo and motors.
What Ah are you replacing?

2 bosch 750, 10.5:1 ratio, roboteQ

Replacing 2 x 24v 3amp nicads

JOhn

I normally calcualte the A123 as 3.3V 2Ah (even though they are a bit more). They weigh 70 grams each cell.

so 24V/3.3V = 7.2 cells, so 8 cells would do 26.4V nominal, 28.8V peak (3.6V per cell).

8*70 grams=560 grams, with shrinkwrap and balancing leads and 4mm2 wire say 650 grams.

3 of these packs will easily get you through a fight, so 650 * 3 = 1950 grams or 2 kg.

With 8 cells you have the advantage that you can use the cheap unitedhobby charger with integrated balancer.

For the same Ah and aboutish V rating you need 3 8 cell packs A123s parallel. Each cell is aboutish £7 and weights about 80 grams.

24*80=1.92kg (remember a 12V 7Ah SLA is 2.65 kg or more)
Total charged voltage is 26.4V and youll have 6.6 Ah at your disposal.

how much does a 24v nicad pack weigh?

Thanks for the info.

John