Revo Battery upgrade. A123 cells?

[Sammus]

Howdy, I'm sick of my cheap sh!tty chinese lipos, plus I had my revo over geared. I was running 6s 4000mah rated 20C constant 25C burst with a Feigao 11XL. The packs were good capacity, charging to around 4200mah every charge, but at the same time at 1C charge they hit the CV part of the charge pretty quickly and stayed there for a few hours and about 25% of the capacity before finishing - something I heard was a sign of poor quality cells.

Not too sure of the battery ratings, but my revo was geared 16/38 and had some incredible uncontrollable top speed that I really dont need. So basically, I was thinking I'm definitely gearing down (maybe 14/38 or lower) and also want new batteries.*

I didnt get a whole lot of runtime from the packs I had. Due to the massive amounts of heat generated I never ran it for longer than about 5 minutes, but I only got 2 or 3 of those runs in before it flattened.

Now, I was thinking of going 7s A123. due to the revo's small chassis I can only really fit a 7s1p pack on there. Will 2300mah give me pretty piss poor run time if I keep it geared properly (probably not more than 35mph)? I mean 10-15 minutes would be good, but I can't help but thinking I'll invest hundreds of $$ in these cells then wind up with 5 minute runs, 15 minute recharges.

It's either that or fork out big bucks for a couple enerland 6s 5 or 6Ah packs.

Anyone had experience running 1p A123 packs? Or perhaps any pics of layouts of 12 or 14 A123 cells on the truck?

Also, anyone elses gearing experiences would be good too (ie what gearing or geared for what speed, what motor/esc and batteries, runtimes, how hard you drive it etc) - and please, no penis size comps here guys, I want true honest opinions of how your trucks are running
Cheers

*The reason I havent tried this simple gearing change yet is because my batteries got all puffy and boiling hot from use in the revo and in my rustler with top speed gearing for out in the sand. Hence the need for new batteries as well!

[suicideneil]

I think for A123 cells to be viable in a 1p setup, you are really looking at a high voltage system, like about 9-12 cells with a suitably slow motor to match (and esc too). Mounting them is the biggest nightmare for sure, but there are some possibile solutions:

http://picasaweb.google.com/buikpijn...RevoConversion

Something like that, or double stacking them on either side of the chassis in sausage-type configurations. Certainly do-able, but it requires alot of imagination and work.

[Sammus]

Yeah I've already got a converted revo with a 11XL in it, so 6s lipo or 7s A123 is my limit without investing in a new motor. I could go 8s I think but its pushing it and I dont wanna push the mamba monster when i get one either :P

I might look into 7s2p config.. either that or just stick with lipo.

The interesting thing is that my current cells I imagine would perform OK had I geared it properly, and even if they are true rated, a single A123 cells is capable of higher power output.

[highflier]

I run a 6s1p pack in a e-maxx with a 9xl. I am happy with power. I have been breaking all the ussual weak linkes. Drive shafts, slipper, an now diff. I say this to indicate that you should have plenty of power on 6S or 7S packs. I get 10-15 min of run time (Bashing) and I charge in under 10 min. So with 2 packs I run none stop, or at least until my motor gets to hot.

Highflier

[Sammus]

Thats good to know.. What gearing do you use?

[highflier]

I don't recall, I am Mod 1 now that I went to RR clutch. I think my pinion is a 18 tooth and the spur is what ever RR has standard with the clutch.

Highflier

[Sammus]

Which emaxx/transmission do you have?

[highflier]

Hmmm,
It is the tranny that came with the Truck. I think it is the 3906. It is not the brushless ready, it's about 2 years old, I think it was called Widemax. Do I have that right?

The tranny is getting to be the only thing major component left that is stock :( But it's only because the upgraded motor/ESC has forced upgrades :)




Highflier