Lithium cell tests

[leorcc]

Lithium cell tests

I agree. I know of at least 2 heavyweight teams that are on the virge of buying new batteries and would like to go to A123 but this hold-up now means they might be forced to go with different ones. We already went for new SLAs instead.

For the record, no one of the organisation of DRG has any objections to the use of A123 in all weightclasses. Nicad fires are not an issue with these cells, and neither is thermal runaway. This has been told to me by a person who designs and builds chargers and balancers for all types of batteries including Lithium nanophosphate.

[leorcc]

Lithium cell tests

btw Gary: 2 cells A123 parralel is still lighter than 3 cells nicad in series (to get roughly the same voltage), and then the discharge figures are more in favour of A123.

[typhoon_driver]

Lithium cell tests

true but the bank balance figures are then in favour of the nicads. This is when including the price of a lipodapter and cells.

I think I am going to stick to nicads for the time being and see how the A123 cells perform when run in multiple machines.

I am however all for the acceleration of this issue which has been ongoing for a good 9 months or so if you look back to the start of this thread.

[geeza]

Lithium cell tests

The difference in Thz speaks for itself, but that is mainly due to the increased voltage. I think that when the rule is passed we will be looking to go with the A123s at the higher voltage aswell.

[m2xt]

Lithium cell tests

Gary, Having tested out A123s and obviously knowing how Bot-packs perform, all I can say is about the same at best.

I feel the FRA is right in researching these cells in order to provide appropriate guidelines and not taking the manufacturers claims as face value which was as it turns our rather wise in my opinion. 70A continuous discharge, no chance in the real world, the main issue is temperature rise. I look forward to seeing the FRA recommendations as soon as they are available.

[leorcc]

Lithium cell tests

Wether or not the performance is or is not the same is not a safety issue. There is no safety reason for these cells not to be allowed in all weight classes. Wether or not a roboteer will use them should be up to the roboteers.

[leorcc]

Lithium cell tests

When Nicads came into the picture no roboteers were forced to go to nicads, if they wanted to stay on SLA that was fine.

When NiMh became more interesting for feathers, no one forced roboteers to go to them, if you wanted to stay on Nicads or SLA thats fine.

No one is forcing anyone to go to A123 cells, if you want to stay on NiMh, Nicad, or SLA, that is fine. But do give the roboteers that do want to use them the chance to do so.

Decisions on the investment of batteries, packs, chargers, balancers should be up to the roboteers, in the end they are the one that will have to care for their investment. Those that want to invest in this should be allowed to do so.

[maddox]

Lithium cell tests

Even now a lot of roboteers stay on cheap SLAs like the Yuashas or over here, the PBQs. Even if the NiMH technology is matured a lot with a subsequent lowering of pricetag.

The A123s, in safety issues are even safer than the NiCDs of days past. I remember a certain machine shorting out the very expensive (for the day) NiCd botpacks. Without more issues than a lot of money gone up in smoke.

If roboteers want to smoke up a lot of money in abused batteries, without aggrivating arena safety issues, who cares.

[m2xt]

Lithium cell tests

Leo, Perhaps the FRA insurers will take your statement There is no safety reason for these cells not to be allowed in all weight classes. Wether or not a roboteer will use them should be up to the roboteers as gospel and not require any further evidence of due diligance but I doubt it. Not often I come out in support for the FRA but for once, I am encouraged to see proper research being undertaken on what is a new technology. 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.

[leorcc]

Lithium cell tests

Paul, all research on these issues have been done, and results of these tests have been shown here in this thread and all over the net. This is not a cell that just hit the streets 3 months ago, LiFePo4 has been in use for various automotive applications since 2005!

[bugs]

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.

[john]

Lithium cell tests

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??

[grant_ploughbot]

Lithium cell tests

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

[beast]

Lithium cell tests

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

[robotwars]

Lithium cell tests

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