Batteries for heavyweights

[craig_colliass]

Batteries for heavyweights I saw these and wondered if they would do for A heavyweight robot


http://www.hobbyking.com/hobbyking/stor ... span_focus

8,400 mAh 30C 13.2v two of these should do what do you think?

[terry]

Some really good prices there Craig, am going to get a few hard case packs for my rc car after splitting one at the weekend the chemicals from inside were leaking out :shock: didn't cause any fire or damage though.
If we are allowed to use these some day then I will go for 6 seperate packs of 5ah 11.1v so would be 33v 10ah (6s2p) I am thinking of putting them on 1mm metal cases as if 1 exploded or caught fire ot would only affect 1 pack.

[maddox10]

Bullfrog uses 4 of the 5S 4200mAh packs to get 10S 8400mAh.

We're not unpleased with the performance.

[craig_colliass]

Terry

As far as I am aware, we are allowed to use them as they are LiFePo4 not LiPo. they are flat A123 batteries at least as far as the rules apply.

7.4 Approved Battery Chemistry for HW

NiCd (Nickel-cadmium)
NiMH (Nickel-metal Hydride)
Pb (Sealed Lead Acid)
LiFePo4 (Lithium Iron Phosphate)

This should cause a few posts

[Mouldy]

Looks good craig but i'd be a bit concerned by this review;

Dont be fooled by cheap price. 50pcnt of the packs they send out are DEAD ! This makes the third time i have tried the lifepo4 Zippy packs no more

Im also told hobyking's customer support can be a bit iffy when it comes to returns. Might be worth seeing if you can buy direct from the supplier and cut out the middleman.

[craig_colliass]

Good info Dave dose anyone know a reliable supplier?

[maddox10]

We bought 4 packs of the Zippy LiFePo4's, and all 4 are fine.

Yes, the comment about the failed batteries is not a good sign.
The 3 other reviews are a lot more positive, and the replies on those as well the likes are a lot better.

On the other hand, charge the LiFePo4's with the charger on LiPo settings, and you have a dead pack.

And unfortunatly, I don't know another supplier.

[grant_ploughbot]

That is the problem with hobby king - they use very cheap cells so a good number of the are DOA or die fairly soon after. Alot of people have good experience with them, but the lipo's I bought a couple of years back were aweful.
In my Lipo talk at the FRA awards/RC open day I am going over what to look out for and what makes a good quality lithium pack (not just Lipo) withthe help of Andrew from the manufacturers.
With the cost of hobbyking stuff sometimes it's worth a punt even if it doesnt work.

[leorcc]

This is not only with their LiFe packs, this is about all of their batteries including lipo.

It is not uncommon for Hobbyking to send out a faulty pack so always check your packs as soon as they arrive. Make sure you enter the warranty code immediately and don't be afraid to demand a replacement or money back if it is faulty. But once they've gone in a robot you have no hope of getting a refund. Check before use.

That said, with all the LiFe packs we've bought from them (3S and 5S packs) I so far have not had a single problem with them and all came in well balanced on storage charge.

edit: And I've never had a problem with their Turnigy Nanotech racingpacks either.

[craig_colliass]

So where to go to get quality LiFePo4 batteries at a good price with people who you can reason with?