A lighter, more reliable Super RS4.

[gbone]

Been a while since I posted here. Not more than couple days after my 70 mph run I posted about here did I smoke the car into a side walk and over into a disgusting sludgy ditch.

Starting all over again with a new 18.97, super rs4 (motor was salvageable) I want to know what is a good li po to use.

I am pretty aware of the dangers of their use but I would like to go with something that is small and light. something between 3000-6000 mah as I just really want to reduce weight. also something that is well priced and can we wired in series. such as... two 2s4ps.

thanks,
g

[glassdoctor]

There's a bunch of good choices... and many lipo sellers will make a custom pack if they don't have what you want.

www.maxamps.com
www.starluckrc.com
www.pfmdistribution.com
www.tppacks.com
www.cheapbatterypacks.com


The Polyquest brand packs really look good to me. They have a nice charge guard device to use with them too. And they have several great options for sizes of cells for cars. Like the 4400 cells.. size of 6 cell nimh and good for @50A per cell. If you want more current draw... you could do a 2p pack of 3100s.... etc.

The options are endless.....

Having said that, I'm using some bare cells and making my own pack right now. But I'll probably get Polyquest next time.

[OptimaMan]

G - which motor was it that you ended up getting? I believe you got a pretty hot motor if I recall... in which case, I'd go with 11.1 volts. Being a Super RS4, you can get two 3s1p and series them. I've just ordered the 3s1p x 2 3100 polyquest packs for my emaxx. I'll tell you what they're able to handle. I plan on using them as 6s1p though. They're not cheap though - ended up paying like 230 for them.

The cheapest packs/continuous watt is probabaly the Kokam HD packs which are 15C and 2000 mah (each cell can give out like 100 watts continuous) so if you get like 3s2p, you'll easily give out 600 watts continuous and over 1000 watts *short* duration and the weight will be around 11 ounces. Get 3s3p and then you'll be up to 900 watts continuous, 11.1 volts, 6000 mah, and around 16 oz (about 6-7 cell GP3300). It'll peak out at close to two HP for short periods of time! Those packs could be found for 50 a piece so 150 will get you a 11.1 volt 6000 mah pack. while the polyquest is costing me 230 for 22.2 volt 3100 pack. On ebay, there's a dude selling older generation Chinese packs (I believe 4000 mah 11.1 volts for like 49.99) but they're not good for high current draws - I believe glassdoctor got them and is building them BTW, glassdoctor, tell me if those cells swell.

[glassdoctor]

cheap 4000 cells. Optima, with the size of these suckers... if they swell, I'm running away ASAP! ;) Can you say CAR BOMB?

I haven't been able to test mine yet, but they are probably only "good" for 4-6C before the volt drop becomes an issue. I just saw a discharge graph of the 4000cell at 4c (16A). The volts held up ok, and it got 80% of capacity at that rate. Not the greatest, but usable. I was hoping for better #'s, but for the price it's a great deal still.

So, these cells would make a nice BIG heavy lipo pack. I'll try a 2p pack and go to 3p if neccesary to get good performance.

A 4s3p of these would be 14.8V 12,000mah and 36oz. That's the same weight as 16 gp3300s for comparison. Oh.. and the cost would be $180 for that pack, plus diy construction and learning curve.

Don't mess with any lipos without extensive reading on the safety issues.

[glassdoctor]

Don't mean to hijack this thread, but thought this was appropriate... this is what happens when a lipo is abused... puffed cells shouldn't be messed with

http://www.helihobby.com/videos/LithiumBattery.wmv

[sugs]

I have a super rs4 as well that I'm going to install brushless and lipo into. I'm going with 4 - 7.4v 3100 mah lipos to make a 14.8v 6200 mah pack. I have the controller and motor on order now but probably won't get it till early january.