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I have charged a new battery (Zippy 4S1P 4200mAh 30C) and it seems to have bulged down one side, its more like an air pocket and is not solid. I hadn`t used it and it was balance charged correctly along with the others.
Unfortunately its out of warranty as I got it at the beginning of the year, I got 8 and the other seven are fine.
Would this be considered safe to use?
No you will have to dispose of it at the correct place.
Not abnormal. Did you measure the cells in that pack?
If the cells after a working cycle differ in voltage by .5% then there is something afoot. More than 1% gets iffy.
But in the end, even with huge differences, the LiFePo4's won't burst into flames after real problems. Becoming a great smokegenerator is possible.
Also, if it is a HK Zippy LiFePo4, and you registered the pack by barcode, the warranty is 1 year.
Thanks.
I didn`t know about registering them but I will look into it. It hasn`t exploded yet :)
I bought a load of them around the same time, and after just two events they're all puffed to hell, same happened to Shockwave; there seemed to be a dodgy batch right around Season 1. They'll run your robot fine without exploding if they're LiFE, but don't expect them to last too long.
Thanks Rory - guess what, I asked Will what he was using in Shockwave and bought the same! will doubling them up help do you think? two pairs in parallel to give 8s.
We ran 4 5S packs (33V 8.4Ah) in Bullfrog. They puffed aftere a few charges, but the cell measuring told us that the cells themself were ok, and used them for another 3 years.
Untill one got drilled and went smokebomb.
Yeah, it seems to be high current spikes that kill them; I had a few puff up when Big Bully stalled a motor and blow an ESC, and the rest died when I was using them while load testing my new ESCs. In Nuts for Season 1 I designed for 3 packs in parallel, 2 in series to give 12.6AH at 8S. This was to get the current required to run the electric lifter mech as well as the drive. Once the lifter mech was removed I dropped it to 2 packs in parallel (8.4Ah).
So....
I now have 7 of these batteries left and I either buy another to have the two sets of four again or I treat them as a 1 set (and 3 spares) and buy something a bit better.
My winch motor will apparently take 120A and the drives are Bosch 750, all on 8s. Would these be a better bet does anyone think?
https://hobbyking.com/en_us/turnigy-...lipo-pack.html
or do I need to go higher? I hadn`t got the winch when I bought the first ones.
I wouldn't use the nanotechs. Those puff when you look at them.
I'd stop messing around with the crap hobbyking brands and get yourself some optipower or similar. Big discount on optipower with FRA membership as well.
We have good results with HK stuff tough.
Just keep in mind Chinese amperes ain't the ones we're used to. Call them hobby amperes.
Any recommendations before I part with the cash please?
After calculating all the tidbits, Optipower isn't that more expensive than the "better" HK packs.
So support a local supplier.
Found out there is an Optipower supplier where I live so will go and see them (Midland Helicopters)
Thanks all
You'll only get the discount going direct to optipower though.
ok thanks ill have a look on the site again
Is there an order page on the Optipower site? I can only find a reseller
Here's the instructions to get the discount. You have to fill in a form, send it to them then call up and pay over the phone.
http://www.fightingrobots.co.uk/cont...er-sponsorship
That's brilliant, thanks.
Ok I`m all ready to order I think but just wanted to check I`m buying enough power if someone could offer advice?
I`m running 2x Bosch 750s and a motor that will reach 120A if stalled. All on 8s. Should running two pairs in paralell of the Optipower Ultra 4s 50C 4000mah be ok or will I need more?
Thanks
Should be plenty for a fight. For reference I'm planning on running two T64s on a 6s 3000mAh pack. I expect around 1Ah to be taken out the pack at the end of a 3 min fight.
Brill, thanks for the help.