kx250ryder

One thing I found out for all those who use nimh, from the guys on the battery forum (thanks JNorton Red and others). Whenever you buy a new nimh pack, you need to form charge it. Do NOT peak charge it to start, or you will lose capacity. First take its charge rating, and add 25% to it. So for a 2000 pack for example (yes I know they are bigger, but this makes the math easier) 2000 + 25% of 2000 = 2500. So ram 2500 mah into it at C/10. This means take capacity (2000) and divide it by 10, which is 200. So force charge your battery at 200mA all the way to 2500. That is going to be something like 2500/200 = 12.5 hours. So make sure it stays charging the whole time. Afterwards, let it cool to ambient air temp, and then discharge the pack (again at c/10) to .9 volts per cell. So a six cell pack would be 5.4 volts when discharged. Then let it cool again. Cycle it three times to get maximum life.

I know this is technically a battery/charger forum topic, but I figured that since these batteries are so popular among 1/8th nitro, and not everyone gets over to the battery forum (I only did because I bought a new charger and glow starter battery) that this might be good to cross post.

If the first math example didn't do it for you, here is another:

My GP 3300 Nimh sub c cell (just bought for my glow starter). To form charge, I take 3300 and add 25% to it. That gives me 4125. Take that number and charge at capacity/10 (c/10) which is 3300/10 = 330mA. So 4125mAh/330mA = 12.5 hours to charge. Then discharge to .9 volts (c/10 for the rate of discharge). Repeat cycle 3 times. So you are looking at something on the order of 12.5 charge, and discharge 25 hours. Take that and do it two more times, so that is 75 hours worth of charging and discharging before you use it in your car.

Sounds like a pain I know, but for those of you who spend hours stripping your car down to the chassis, it isn't really that much more work to punch this into your peak charger (and discharger) and let it sit. This way you get the most run time out of your radio and receiver pack batteries.

J_Bone

My Feedback: (1)

Wow, that does sound like a lot of work for a rx pack.
I've always cycled my batteries and I've been getting above the rated mah that the cells advertise. My 1100’s get around 1250 or so and my 1400 usually get up to 1520mah. That's charging at .8 the first 3 cycles and 1 amp from there on out. They seem to be good. At the races I don’t discharge either.
I've done the same thing on my 3000's and 3300's and all still work good after a years of abuse from my son. Even my old cheap batteryspace.com batteries charge full mah's.

Not saying that doing that will not work! Just I've never had any problems doing it my old way.

xrichs

yea, me too

GRANT ED

I didn't do anything fancy to my new 2400mAh pack and I get over 2400mAh from a flat charge. Seams like a bit of a waste of time as J bone says, not saying it wont work just does not seam to be worth the effort. Especially after an hour of driving the most I have ever drained out of my pack is 1000mAh.

xrichs

baterries have limited cycle anyway.
it can't last forever.

Mine could stand over 50 cycle with peak chargger.

1 cycle means 1 week so it can last for 50 weeks

o yea, just a tip turn your TX and RX off while your car isn't in the track (resting). it'll save your batt energy a lot (in my experience at least)

Foxy

I can't believe how fast my tx (2PL) gets through alkalines...it's unbelievable. I replaced the batteries before I built my xray, when I finished the kit, I zeroed the servos and installed them. Then set up the linkages, trims, etc. etc. all in it took about 25 mins, and my tx has eaten 1.5v off the brand new alkaliness. I know the discharge curve is wildly different in rechargeables, but even so...Santa should bring me a 3pk and a spektrum module, so I'm not worried...

Engrose

I was hoping that Santa would bring me a Xray-buggy for christmas. But I guess that while he is in Greece to deliver the 3pk he can just as well take your Xray with him before he gets here....

Foxy

I'll put in a good word for you when I see him, but if he touches my Xray, mine will be the last house he visits. Ever...

kx250ryder

Try these, way way way longer runtime than alkalines:

http://www2.towerhobbies.com/cgi-bin...?&I=LXKYC8&P=7

SManMTB

Way overpriced IMO.

Try [link=http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=245]these 2300mAh[/link] batteries from Batteryspace.com instead. Can't beat $30 for 24 batteries.
I've used mine for more than a year now. [sm=thumbup.gif]

kx250ryder

Well, I listed the Venom cells because they were the cheapest I have found at hobby stores online. I wish I had seen those you listed before I bought my Orion 2300s, which were more expensive than the Venom cells and were only 2300s instead of 2400s.

J_Bone

My Feedback: (1)

Those are what I have been usingfor a year now too. I use them in my TX and I made a 5 cell pack with them for my Buggy.
They last forever!!

SManMTB

I made a few Rx packs from them too. [sm=thumbup.gif]
What do you use to wrap them up with? Haven't found the correct size crimp tubing so I've used duct tape. [sm=biggrin.gif]

J_Bone

My Feedback: (1)

I used clear shrink tubing. I have a bunch of different sizes and found one that worked.

SManMTB

What size and where to buy it?

J_Bone

My Feedback: (1)

It's 3-1/4" wide. I bought a bunch of different sizes from a few LHS. There are 16 differnt Hobby Stores through out the Phoenix Valley. Depending on where I'm working that day I usually try to stop in one or two.