Battery trouble - again!

[petn7]

you fast charge some 720

you fast charge some 720 mah AAA nimhs at like 3 amps? after a few runs...bye bye batteries. nicads? you can get away with it for alot longer.

[petn7]

oh yeah, and if you

oh yeah, and if you overcharge your nimhs...again, less forgiving than overcharging nicads

[tmsmalley]

Jacob - You seem to

Jacob - You seem to know your stuff about batteries. How about an article for the SCR?
Tim

[jdbostrom]

Yeah, pleeaassse??? http://www.subcommittee.com/forum/icon_biggrin.gif

Yeah, pleeaassse???

[jsl]

Jacob - You seem to

Jacob - You seem to know your stuff about batteries. How about an article for the SCR?
Tim

Sure

But the article won't cover that much in Li-ion, as I have only little experience with those.

Jacob

[jdbostrom]

Great!!!

I've got one more question]

[color=#000000]Great!!!

I've got one more question]

[jsl]

Unless the damaged battery pack

Unless the damaged battery pack starts to leak, no harm will come to your transmitter.

The problem with the single damaged cell in the pack, is that it looses its charge well before the rest of the pack. Insted of actually supplying energy, the rest of the pack starts to pull current through the damaged cell, actually the equivalent of charging it in reverse. This is more or less fatal, and as a consequence people are adviced to avoid discharging a pack to less than 1 volt per cell. This prevents this reverse charging.

Theoretically, you could cut your damaged pack up and replace the damaged cell, once you have found it, but its really not worth the trouble IMHO. Besides, mixing new and used cells is just asking for trouble.

Removing or bypassing the damaged cell would probably make the pack functional, but the voltage would be a bit too small for normal use. If the transmitter is still able to transmit, the power of the transmitted signal will most likely be weaker. As the charged energy is used, the signal will become even weaker.

My advice to you, is to throw that old pack off for _recycling_ and buy a new one. (Believe me, you wouldn't like to know the effect of even minute amounts of cadmium in the human body)

Get whatever pack is cheapest. For low current tx purposes, brand and performance is secondary.

The charger you are looking at, looks to me like a good choice, after I ran through the specifications. But only for larger main battery charging. I'm a bit nervous about plugging a tx battery pack to that charger, unless the battery pack specifically is a fast charge pack. Even if you set the delta-peak voltage detection cutoff mode for 5mV, the battery pack is still recharged in a little over four hours. That is quite a bit faster than the recomended 12-14 hours.

It may work, but you must keep a sharp eye on the charger at every recharge to make sure it doesn't keep charging after the time, where the battery has recieved 1.4 times its capacity, has passed.

Did you have a standard wall-charger for your tx? Remember something about "55 mA" somewhere...

[jsl]

I'm a bit nervous about

I'm a bit nervous about plugging a tx battery pack to that charger, unless the battery pack specifically is a fast charge pack. Even if you set the delta-peak voltage detection cutoff mode for 5mV, the battery pack is still recharged in a little over four hours. That is quite a bit faster than the recomended 12-14 hours.

And that is at the lowest possible charge current of 500 mA.

[jdbostrom]

So as I understand it,

So as I understand it, you are saying that I should just stick to my wall charger that came with the system. I like this plan

[petn7]

do not use the MRC

do not use the MRC 959 just for your tx pack; it's not that critical. sometimes, if i'm in the mood, i'll charge my 600mah tx battery at 500mah on the MRC 959 to a peak charge.

[petn7]

take a look here for

take a look here for some more info

http://www.rcgroups.com/forums/forumdisplay.php?f=129

[jdbostrom]

Thank you.

So you guys would

Thank you.

So you guys would all agree then that I should go with the cheapest pack (probably NiCd) I can find, and just use the wall charger?

[skip asay]

I've been following this thread

[color=#000000]I've been following this thread with some amusement. It sorta smacks of throwing out the baby with the bath water. Or dumping that low mileage, year old car for a new double supercharged race car because of a flat tire.

Problem]

[jdbostrom]

Mr. Asay,
I'm just curious,

Mr. Asay,
I'm just curious, why do you prefer NiMhs? Unfortunately, the pack I have now is NiCd, and I am a little unsure which to go with, since as you can see, I am getting a lot of differing opinions and I myself am not knowledgeable enough to really decide what's best myself. So all I want is to hear everyone's own opinions on why NiCds are better than NiMh, or visa versa, and then I'll just have to decide what I like the sounds of most.

Jonathan

[tommydeen]

nmhi batterys imho are best

nmhi batterys imho are best suited for smaller boats that said
nickle metals have more power, longer run time, in a smaller
battery pack. the only downside is they cost more but so is
everthing in this hobby. i use nmhi batterys in all my smaller boats, with nmhi batterys and a geared motor i can run all weekend on one battery and that leaves more time for planning my next attack on the surface guys
Tom