Let's talk batteries here.

[ling427ttvette]

Since I am pretty new to the 1/10 scale scene and haven't dealt much with these batteries in these bigger R/C's.. I need to know about the dis-charge part.

I have three batteries, one 1500 mAh 8.4v Ni-Cad pack, and two 4500 mAh 8.4v Ni-Mh packs.

Do either of these need to be dis-charged before re-charging to keep the batteries functioning properly?

I don't have a dis-charger, but a common trick people use is to solder a plug-in onto a car headlight and plug the battery in until the headlight quits burning, then you know you are dis-charged. Not a problem for me as I have a spare headlight.

Is there any other tips or tricks that anyone feels I should know? I don't want to buy a ton of battery packs because of some n00b mistake.

[TripleXmodder(akaXXX)]

Uhhh, buy a charger w/ discharge .... isn't that the simple answer here?

[ling427ttvette]

Not the answer I was looking for. I want to actually know what to do with the batteries I have, if I do need to dis-charge them or not.. I know some batteries don't require it..

And I just spent $70 on my twin-peak charger, I'm not buying another for a while because this one is doing great.

[BART]

The Ni-cad should be discharged fully each time it is used and allowed to cool before being recharged again. The NIMH cells only need this done once every couple of months. Thats the short easy answer.

Edit: 2 1157 car tail light bulbs work great, hook them up in parallel and discharge until the light goes out and the pack cools. The best way is to monitor the packs voltage until it drops to a certain voltage per call but the above way is effective for what you are doing.

[ling427ttvette]

Definitely the information I was looking for. Thank you.

I just got done charging my two new batteries, and they got extremely freaking hot right before they were peaked out. The 1500mAh battery gets heated but it was not near as hot as these two got. I wish I had a temp gun.

My charger automatically charges at 4amps and automatically reduces to a trickle charge once the batteries have peaked. Right now the batteries are charged with 9.8v even though they are 8.4v batteries. Possible my charger is doing too much? It's supposed to have automatic detection and what not. Maybe next time I should just try one battery on the charger and see what happens.

[BART]

These are just very rough numbers but you should charge at a rate consistent with your mah. For example a 1500 pack should be charged at 1.5 amps and a 3000 at 3.0. Are you charging two batteries off of the same output on your charger? thats not a good idea as peak detection becomes very difficult. Fully charged they should get warm but never hot.

[ling427ttvette]

The charger has separate leads. It's designed to do two batteries at once.

The packs are 4500 mAh so going by the rough estimate a 4 amp charge shouldn't hurt it.

Sadly I can't adjust the amps it charges at, it's all automatic for the charger. I am going to try charging one battery and see what happens.

Do battery packs have a somewhat "break in" period? I've heard people say that usually after the first 5-10 charges you start seeing better run times and what not.

I just took it out in the rain with obviously water puddles and what not and pulled probably 15-20 minutes out of it. Not bad IMO. With the 1500mAh pack I doubt I would have gotten near that much time. I was going WOT most of that time too.

[BART]

Usually a NIMH pack will perform better the more it is used. The first charge is generally "flat". After they sit for a long period of time they usually need a few cycles to perform at their peak as well.

[ling427ttvette]

Ok, so I'm monitoring how much output the charger has while charging the battery and it's currently at 10.10v charging it, and it seems to be very slowly climbing. Is this normal?

I tested the volts in the dead back and it's around 8.4v. I thought the voltage dropped as the pack dropped charge?

I'm fairly sure it's not normal for the pack to test at a higher voltage than the pack is rated for is it?

[ling427ttvette]

Ok, at it's highest point the charger hit 10.4v while charging and that wasn't long before the battery was peaked. Again the battery got pretty hot.. charged it up to 9.8v again.

Anyone have any insight?

[reaper]

this is normal on that type of charger :)

if you are thinking of racing id would recomend a "real" charger and discharger , this way you can charge the cells to perform just how you want to
longer runs or more punch
if its just for messing i wouldnt worry

[ling427ttvette]

There's no real race competitions around here, if I could find one I would probably show up and try it out.. but this is just for messing around at the skate park, in my front yard and what not. Definitely not going to be competing seriously with it, but it would be nice to have someone to run with.

[Stampedekid]

Well I charge my 7 Cell 4500mAh at between 4.5 and 5.0A with no problems. I don't really need to discharge it unless I am storing it for a long period of time(which never happens since I'm always RC-ing.) But I use a Duratrax Onyx 230 for all of my packs, sometimes use a Hobbico 910 for my EZ-Starter battery but that's about it.