RC10Talk - The Net's Largest Vintage R/C Community

Well, my Turbo Optima Mid SE arrived today, thanks to transamman908 (smooth, painless, and entirely satisfactory transaction with excellent communication and he helped me out answering many dumb noob questions - can't recommend him enough). I've ordered a 960 Super Brain charger but as the buggie only came with a 7.2 v battery, I've started looking at upgrades for longer run-time.

I found an 8.4 v 5000 mah Ni-MH pack on the Bay, with adapters (I need a Tamiya connector), but for some reason it is listed as 184 mm long - much too long for the width of the Optima. Are the 5000 mah cells that much bigger than 1700?

I'd rather not go li-po as I don't have the charger for those, but I would consider it longer term. Can anybody recommend some 8.4 v Ni-MH hi-amp packs which would fit my buggie?

Thanks!

ps - I'll try and get some pics over Easter (I'm working in the field this weekend)

get a cheap imax b6 charger and some cheap turnigy or zippy or gens ace li po and be done. way better than nimh hands down!!

Jason

nimh is a dead technology by now... kinda like buying a steam-powered car If you still want to go nimh, forget about 7cells... this is a band-aid that was developped in the 80's to overcome the fact that the mills from BITD were wimpy. if you really really want nimh Get yourself a proper 6c pack and a proper mild BL (ezrun 60A 4300kv will be way faster than you can handle) and be done with it...

but you might want to go lipos' really $45 imax B6 and $35 hard-cased pack and you're all set forever

Paul

Thanks for the advice guys. My primary concern with going LiPo is the batttery running out. A mate with a modern brushless set-up told me that if the battery discharges fully then it is damaged, and loses capacity. Sort of the opposite to NiCd?

Whether I go NiMH or LiPo, I will keep the stock motor (Lemasn 240st) as I don't want to stress the car unnecessarily. It is old, and bought mainly for looks. It will get an occasional outing in my courtyard, or the office building, or anywhere else not too dirty, but that's about it!

if you get a modern ESC ( BL) almost all have voltage cutoff you can set (3.3V/Cell) then when that voltage is reached, the ESC will stop feeding power to the Motor thus you'll know that your Batt is already drain.

Rule ot Thumb,

-charge a lipo (7.4V) at 1C
- do not discharge the Batt lower than 3.3V/Cell or = 6.6V (2cell)
- when keeping long period of time and not using, store at least 70-80% charge capacity.
-a Good multi Chemstry Charger with balance plug.
- the lesser the battery in parallel the better ( e.g 2s1P).

Good thing with lipo is that you can use it repeatedly in one day, there are lots of good charger and lipo that can cater to your needs and BL Combo for your Car, like Hobby Wing EZrun/Xerun Series setup, i for one have the Xerun V2 120AMP with 8.5 T BL motor, its more than enough for me and my sun just for bashing.

and you may want to do a little googling about the Lipo fuzz so that you'll be famiiar with its characteristics.

gluck.

Ditto on the brushless setup. Modern speedos have voltage cutoffs, so it is a mute point. However, if you overdischarge a NiMh pack it will be damaged as well. And allot of brushed speedos don't have the voltage cutoff. -Jeff