For a while now ThunderChild has been having issues with its 3 8cell 3000mah A123 battery packs' 1 of which blew at maidstone.
Its a been such an issue' that we're now considering replacing them completely' ether with 2 of these
http://www.robotmarketplace.com/prod...-4600N-24.html
or modifying 3 of these http://www.stuff-uk.net/p-396465.asp...FQjgGwodMzEIaw
I welcome your feedback
Optipower lipo all the way ceros runs 2x5000mah 30c they have been faultless not to expensive with discount. Just my thoughts
Agreed, go to Lipos, ideally Optipower. Dont waste your time/money on Nimh or drill packs, they just wont supply the current needed. Stick a pair of lipos in it, but not cheap ones.
You will also need a proper charger to go with the LiPo's. You can't just charge them with anything. Turnigy Accucell 6 will do the trick, just make sure you use the right settings.
I have recently gone over to LiPo batteries too. for Cherub and Gabriel, (the ones previously suggested) and I have to say they do work well I use a large two channel charger,
http://hobbyking.com/hobbyking/store...ger_800W_.html
It will charge the two packs at 15A each but dose require a power supply that can deliver 75A to power it!
I called it Brutus the battery charger.
I do have to say these batteries must be handled with extreme care, as the potential power stored, and chemicals used in them, means they can present a real hazard to yours and others health.
But they are good.
Some more things to know about swapping to Lipo packs:
They can supply WAY more current with less voltage sag than NiMH or even A123 packs, so you might find your ESCs or motors get hotter than before. Batteries used to be the weak link in the system but now they will happily fry your other components if they are under spec for the job.
Lipo packs do not like to be fully discharged and most people recommend leaving 20% charge in them. Fully discharging them can damage cells and in extreme cases, cause a fire.
Use the space and weight saving to add shock protection around the Lipo packs. The foam in exercise mats does a good job.
Using high discharge packs is a smart idea, even if you don't need the current rating. High current packs in the 50C to 65C range have lower internal resistance and don't get as hot. This means they can be recharged sooner (its dangerous to recharge Lipo when hot) and you can usually charge them at higher current. My 4.25AH packs are OK to recharge at 8C, which is 34 amps, very handy when you have back-to-back finals matches.
While everyone loves their Optipower packs, I have been very happy with my Turnigy nano-tech A-SPEC packs. They have performed flawlessly for the last two years and while they might not be quite as good as name brand packs, they are much cheaper.
What about these? http://www.hobbyking.co.uk/hobbyking...Lipo_Pack.html
5800mAh 25C = 145A.
On the low side for a heavy without active electric weapon.
But with a large gearratio to a decent motor for drive, fine.
Two in parallel might be more suitable, but would need careful balancing...
The balancing is mandatory. And the easier way is to recharge and balance in 1 go, as the most chargers are equiped with a balancing port.
Also, the 7S pack as example is annyoing in that respect , most affordable chargers have a 6S limit.
It's easier and probably cheaper to use 4 4000 mAh 4S 25C packs, 2 in series to create an 8S (+/-30V) block and 2 of those in parallel. Creating an 8S 8000mAh battery.
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