LiPo Reccomendations?
 

Ive been reading on these forums for a while now, and there are still things I havent learned about LiPo batteries. I understand the whole series/ parallel and C rating thing, and its effect on voltage, capacity, and current handling, but I cant find a definitive answer on how much current handling I need for a 8L in a (relatively) lightweight Emaxx. I plan on keeping it at or near 14.4 volts, and Ill probably buy the cheapest packs that have the current handling I need. Can anyone reccomend any specific packs? Would 2 of the new Orion 4800 packs in series be able to handle this setup? I like the idea of a hard plastic case.

Heres my truck, to give you an idea what I meant by very lightweight:

http://memimage.cardomain.net/member...90_49_full.jpg

http://memimage.cardomain.net/member...90_46_full.jpg

And charging LiPos is a whole different issue for me. I understand you need a special lithium charger, but thats about where my knowledge ends. Can anyone shed some more light on this? I know a balancer is something that balances the voltage betweeen all the LiPo cells, but how does it do this? Does the charging current pass through the balancer then into the cells? Or is the balancer connected parallel with the charger somehow? Thanks alot for any help.

The Orion packs will work. In my mind, the problem with having a hard case on a Lipo is that if it were to puff up, you wouldn't know it. Then, the plastic case could explode from the internal pressure, spreading hot plastic shrapnel. But, they are more than enough in terms of amp handling capability.

For an E-Maxx like that, you would only need about 45amps continuously rated batteries. There are many choices out there, and usually (for me anyways) the budget is the limit.

Charging Lipos is much different than NiMh. They charge using CC/CV, which stands for constant current/constant voltage. This means that for most of the charge, the battery will be receiving the full number of amps (constantly) that you set the charger to charge at. Once 4.20v is hit, then the charger goes into constant voltage mode, where the battery is kept at 4.20v (per cell) and the charge rate tapers down.
Balancers keep a pack in good shape by equalizing the voltage of each cell at the end of a charge. There are many balancers out there, and some work differently from others. Hyperion makes one that goes between the charger and the battery, but usually the balancer is connected externally from the battery through things called "taps". Taps are external points for access to each individual cell. A standard balancer (unlike Hyperion's) will connect to these taps and basically discharge the cells until they have the same voltage (it will discharge the higher voltage cells).

Hope that just about covers it :).

Thanks A LOT. I learned as much from your single post as I have from the months Ive been reading on here.

FYI, you could make the truck lighter by switching to the single speed gorillamaxx transmission. It would elminate some weight and the need for a third channel while also improving durability. The new orion packs look nice and should work for your specific application.

Perfect information Metalman.

That is one light emaxx, it will fly with an 8L on 14.4 volts for sure!

I would use a singlespeed as well! it lightens it nicely and with this light setup and an 8L you don't really need a 1st speed.. All sorts of battery(lipoly) producers make a cell that could power up your beast, just get a good balancer, ThunderPower makes a nice and affordable balancer, i thought maxamps had one on sale.

do you happen to know the weight of your emaxx? It looks light. Just curious. ;)

im estimating around 8lbs rtr. mine was 8 1/2 but i didnt cut the chassis or anything.

No, Ive never weighed it accurately. The only scale I have that goes high enough is a bathroom scale, and you cant get a accurate reading at all.
Several people have told me I should get a single speed. The only thing stopping me is I like shifting. My real car is a manual, and I guess Im just used to it. It might get too fast with the 8L to have the leftover concentration for shifting, though. Its challenging enough with my hv maxx.
Also, my emaxx isnt quite that light anymore. Since these pics were taken Ive added fast lane combo bulks and shock towers, replaced the rear spool witha diff, and installed titanium hingepins. So the weight is up a little, but I think its still lighter than a stock E. And Ive had an hv maxx in there for a while now. Thanks for the replies.

I think Im going to go with a pair of 2s1p 4000mah packs from max amps. 85 dollars and 175 grams is as good a deal as I can find that can handle the amp load. Ill probably also go with the Hyperion balancer and charger from maxamps also. Or does anyone know if you can use the hyperion balancer with the thunder power charger (because its cheaper) ? Can anyone tell me any problems I might have with this set up, or that it should be good?

You can use any charger you want. The TP charger that (I think) you are looking at will only charge at up to 2.5amps, and it will take about 1hr. 45mins. for a complete charge. The Hyperion charger is a much better value (IMO). Also, make sure that you have Maxamps put on taps that will work with the Hyperion balancer.

P.S., Mike sells that charger for less, it's the Multiplex LN-5014. They are clones of each other. Tower Hobbies also sells the Multiplex version for less.

metalman, i was also checking out that charger (hyperion 5i or 7i). If i do end up getting one it will probably be the 7 so that I can charge at the higher rate. Do you know any place that has a review on them?

I don't know of any place in particular, but I have read that it is a good charger.

This is just Hyperion's version of it. It comes in different cases from other companies, with a different name for each one. I know Multiplex and Promax (and others) have their own version of this charger (in their own case), so if you look for a review on a similar-looking charger from either company then you can assume that it would be the same for every other charger (of this type).

Thanks alot to everyone who replied (especially Metalman). I just ordered a pair of 2s1p 4000mah LiPo packs from Max Amps. I also got the Hyperion balancer and charger, because Mike doesnt have the charger in stock, and tower wasnt enough of a price cut to be worth the extra hassle of placing 2 orders ( and probably not even enough to cover paying 2 shipping charges). I also have a 8L/ 9920 combo, heatsink, ubec, and Strobe slipper setup on their way from Mike. My truck is about to go from fast to insane. Thanks alot for all the help.

Congrats B15 on your order. Please keep us updated on the insane part.:D I'd sure like to know how fast that thing goes!