Help Im not sure about charger

[Fiftygrit]

I bought a V6AC digital balance charger, Im using NiMh batteries one 1800 ma and one 3300 ma I set the charger at 3.0 amp. for the 3300 but there is no setting for the 7.2 volts and when I charge it, it goes to 9.5 volts and gets warm, on the 1800 ma I set it at 1.0 amp and it will shut off at 8.5 volts and it is a 7.2 volt, sorry for the stupid questions but this is the first RC I have owned, love my cheap crawler, just dont want to screw up the batteries, thanks for any help. Oh ya bought this charger as it will do Lipo, Life, NiMh, NiCd, and Pb.

[jdmguy760]

When you charge NiMH batts they get hot also there is no option for voltage when charging NiMH on that charger its normal I used to have it that charger

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[Fiftygrit]

Thank you, the 3300 gets warm the 1800 not near as much, so if there 8.5 and 9.5 volts it wont hurt, the good thing is it charges the batt`s a lot faster than that little over nighter. man its a learning curve, but for an old guy I am having a lot of fun with this cheap crawler. I can see how people get addicted. By the way do you know of any magazines for RC crawlers, I live up by Alaska and we dont have very much RC stuff here, cheer`s

[Charlie-III]

NiCD & NiMH are ~1.2VPC (Volts Per Cell) but charge to a higher voltage than that.
A decent "peak charger" will look at the pack voltage as it charges, when the rising voltage curve of the pack "flattens out", the charger stops.

Your "wall wart" charger does not detect voltage peak nor does it charge at a high rate, thus the long charge times.

Worst was the "timer chargers", you twisted a knob and the charge started. If you put a fully charged pack on it and didn't keep an eye on pack temps, you could melt the covering off the pack (my son did that very early on).

NiCD & NiMH really want to be a bit warm at the end of the charge.

Today, LiPO is the way to go.

[Trubble]

NiMhs and NiCads when fully charged should be around 1.45-1.5 volts per cell, so your 8.5-9.5 readings sound close enough.

Your 3300 getting warm sounds normal, they get warm when they're full, and hot when overcharged. I'm guessing the 1800 doesn't even get warm. At a one amp charge rate, you're only putting 1,000 milliamps back in per hour. If you drained 1800 out, and only put back 1000, stands to reason it probably won't be warm 'cause it ain't full. (I'm also wondering if you have a 'safety timer' that's shutting your charge down after 60 minutes.) I, personally would bump the amps up to two, or find out if you can push that safety timer out to 90-120 minutes.


As far as RC mags, if I remember correctly there's only 3 that I know of, and of those I think RC Car Action is most likely to have more consistent coverage of scalers, and maybe the occasional crawl. I think RCCA also has special editions out for certain genre's (such as strictly crawlers, or just short course trucks). Could see if back issues of those are still for sale.
To be honest, I let my subs go years ago. Just found more direct and more in-depth information out here in webby-land.




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Originally Posted by Charlie-III

Worst was the "timer chargers", you twisted a knob and the charge started. If you put a fully charged pack on it and didn't keep an eye on pack temps, you could melt the covering off the pack (my son did that very early on).

<----- Did FAR worse than that. Let's just leave it at "neither me nor the waterbed were harmed".

[Fiftygrit]

Wow this is a great site, you guys sure have the info, my timer is set at 120 min. I can change the amp`s, so I could put the 1800 up to 1.8 or 2,0 , one more thing is it better to set it at discharge & charge, or just put them at charge every time, I really appreciate the info.

[Trubble]

For NiCads, using discharge then charge would probably be a good idea.

For NiMhs, just charge 'em back up, as the memory effect isn't as pronounced.

[Fiftygrit]

Thanks every body, I tried the 1800 at 1.8 amp`s and it charged very quick and not much heat, appreciate all the help.

[monkeyracing]

I once cycled my cheap 1800 mah nimh race pack really hard 5 times in a row, allowing for cooling each time, then hit it with a 6a charge. It peaked at almost 10v. That was the only time I won an A main race. The battery was never the same after that.

[Charlie-III]

Originally Posted by Trubble

For NiCads, using discharge then charge would probably be a good idea.

For NiMH's, just charge 'em back up, as the memory effect isn't as pronounced.

+1.

Originally Posted by Fiftygrit

Wow this is a great site, you guys sure have the info, my timer is set at 120 min. I can change the amp`s, so I could put the 1800 up to 1.8 or 2.0. One more thing is it better to set it at discharge & charge, or just put them at charge every time, I really appreciate the info.

For any battery chemistry, I usually use a "1C" charge rate. While it's slower, it leads to longer pack life.
A "1C" rate is the pack capacity (mah) divided by 1000, thus a 1800mah pack charges at 1.8amps.
When I carpet raced, I charged the packs the night/day before then "topped" a few times just before the race to get them warm. Warm is good, hot is bad.
We used a "discharger" (made by Tekin IIRC) to bring the packs down and check remaining capacity.
For crawlers, I would likely not worry too much about getting the packs warm.

[Fiftygrit]

Thanks again guys, I think I have my head rapped around this now, Im doing like you said Charlie, the 1800 at 1.8 and the 3300 at 3.3 just a straight charge for now, works great, cheer`s