Battery discharge?

[fsadvar]

I have been watching this sight for a while and this is my first post so bear with me. So far I have been reading and absorbing all the tech and how tos like a sponge. I used to run 2wd race trucks about 10 years ago and back then we made our own batteries by using certain brand matched cells and putting packs together. In those days we would after each race put them on a discharge device made of 1156 light bulbs and let them run down to nothing or close to it. So my question is on the new style Ni batteries. say 5000ma should you discharge them like we used to to maintain them and keep them from developing a memory or is that a thing of the past? I have heard you do not have to but I thought I would get some input.
I am new to crawling and scale and am in with both feet. Still a lot to learn.
Thanks in advance

Frank

[Trubble]

Discharging NiMh batts is not as important as it was with the old NiCads, not nearly as much of a memory effect. I find it's still important to cycle them periodically, but not down to dead short level. For cycling, down to 1.1/1.2 volts per cell is far enough. When recharging, slower and longer is better, so turn the amps down and let it soak. And be sure to let them cool before putting them on charge, also let them cool once they come off the charger (before using again).

[Charlie-III]

Originally Posted by Trubble

Discharging NiMH batts is not as important as it was with the old NiCads, not nearly as much of a memory effect. I find it's still important to cycle them periodically, but not down to dead short level. For cycling, down to 1.1/1.2 volts per cell is far enough. When recharging, slower and longer is better, so turn the amps down and let it soak. And be sure to let them cool before putting them on charge, also let them cool once they come off the charger (before using again).

For the most part, yes this is correct. NiCD's had to be really cared for, we used a Tekin battery discharger (I think it was a 10 amp rate) to bring the voltage down as well as see the remaining runtime we had left in them.
Then came NiMH, we still did the discharge, but more to check time remaining, not because of the memory effect.

Letting them cool, after use, before charging was a good thing, having them warm when you used them was good for early performance (same with NiCD), we used to actually charge them a few times just before a heat race to get them rather warm.

LiPO has so many advantages (small size & weight, no memory, very high power density) that it's worth the change. They can also be cheaper for similar voltage & capacity than NiCD or NiMH.

I used to build my own packs but found www.CheapBatteryPacks.com and I could get built packs shipped to me for about what I could build my own for.
I now use CBP for most of my LiPO's. They are also a vendor here.

PS, if you go LiPO, get a decent charger and see if your ESC has a LVC (Low Voltage Cutoff) for LiPO. You do NOT want to over discharge LiPO's, it's a good way to kill them fast.

[fsadvar]

Thanks guys, I am very interested in the Lipo for my newest project, and am trying to learn as much a bout them. I want to do the battery on the front axle and have been reading everything I can. As far as chargers for the lypos, my lhs has the onyx line. Any suggestions on a good charger or hows the onyx? I am really hooked on this crawler stuff and want to get in hole hog. I currenty have a Wraith and a highly modified Ridgequest. I am in the process of doing a Fastback2 with modded xr to ax axles and would like to know which small lipo would be the one for the front axle. I appriciate any and all help. This sight is great on getting info.
Thanks again for all help
Frank

[Trubble]

The 3S/1300 mAh LiPos I got pretty much fill up the front axle. I'd say that's about the biggest I can go. Even after using the longer beef tubes to do the XR mod, there's enough steering that the tires will still pick at the corner of the shrinkwrap. 1300 may not sound like much if you're coming from race trucks, but in both of mine, they're good for nearly 45 minutes.

As far as the Onyx line, I have a 230 for my LiPos, and a pair of 240's for my NiMhs (all purchased from the 'scratch & dent bin' of an online retailer). I like the Onyx line, but when I ante up for a bigger charger for my bigger LiPos, it'll probably be Hyperion's EOS 0720i, unless I can find something else with more wattage that still has AC capability.
For you, though, with crawler batteries, I'd suggest the Onyx 235 if you'd like to have a built in balancer. I use an external balancer, so that's not much of a selling point for me. The Onyx 245 is probably easier to use, but with only 4 charge rates to choose from, it doesn't offer the control I like having when learning the LiPo charging ropes. Does do two packs at the same time, though, if that matters.
I've had good luck with the Onyx line, and see no need to replace any of mine from a reliability standpoint.
There's also cheaper chargers available online, which I'm sure work just fine as well.