rsr427

I finally have my first hobby-grade kit on its way (including E-Firestorm, charger and 2 batts), and I want to make sure I do things the right way.

I ordered this charger:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXTSA4
which is fairly robust. I've read here and there that if its a 3000mah batt you'd charge at 3amps (etc.), if I read that right? But what would I do the first time I'm charging the batteries? (and thereafter).

I noticed that there are different trickle rates also? 100mah vs. 200mah?

For batts, I ordered:
4600mah Trinity Reference pack 6c nimh
3600 Trinity Critical Mass pack 6c nimh

I'd be interested to hear all the different techniques you've stumbled across.

Thanks, Ryan

guver

My Feedback: (325)

It is custumary to recomend a c/10 charge for 15 hrs to from/breakin/balance new cells in a pack. That is 460 and 360 ma for your packs. If yo had a wall-wart charger that was close then the important thing is to get a total of 150% of capacity by multiplying the rate by the time.

An example might be a charger that delivered 400 ma would work on both of your packs. 17.25 hrs and 13.5 hrs respectively.

If you don't have an old wall charger then the next best thijng is to allow the digital charger to trickle at 200 ma for a number of hrs AFTER the battery is full.

Smiff 24

Very happy for ya rsr... Thats a awsome truck too!
Be sure to form charge your batts. like guver said, they will thank you for it.
keep posting on the firestorm & let us know how its goin.

nikg

Guver (or Red) - Is there any danger in form charging more rapidly? For instance, what if you were to charge a 4600 pack at 3.6A for an hour and then finish it off by charging at 400mA for an additional 6-8 hours. Would the initial high current destroy or degrade the internals of the battery? Cause seperator failure? Not distribute the charge evenly? Or would everything still be fine?

I have found that new cells' voltage sometimes skyrockets when faced with high current initial charging, so I thought this might be a bad thing.

I may have asked this question in the past, but i can't remember.

guver

My Feedback: (325)

I'm not real sure, it is good question. My guess is that if it is really the first charge then it should be done the whole way slowly. If it is just a charge for a battery that sat a long time or is to balance cells then your idea would work just fine. Many chargers work in a sense the same way only they charge full , then charge at 100-300 ma for a pre-set time or until removed.

rsr427

guver, what does c/10 mean?

So basically, charge it at 460 and 360, respectively, until the charger says they're full and 200mah trickle charge for 4,6 or 8 hours? That's easy enough.

I'll have to look for what to do about taking care of the batteries after use too. I hope to make these two last...

Thanks, Ryan

guver

My Feedback: (325)

No, it means to charge at 460 ma and 360 ma for 15 hrs.

rsr427

I just found this FAQ:
http://www.hangtimes.com/rcbattery_faq.html

What do you think about the first 3-4 answers? If I wanted to get "set the peak level" by charging 3 times for a long period, how would I discharge it. Long periods of putting around at a slow steady speed? That would probably help in breaking in the engine too...

Thanks again for your help.

dafpnp

Now that you know what is C/10.
Discharge your batteries at no more than C/5 while you break in your new batteries..

guver

My Feedback: (325)

I'd agree with the answers given.

rsr427

So I started charging the 3600 nimh at 3.0 amps (highest AC level available). After about an hour, it peaked and went to 200 mah trickle. The battery was hot though. I could hold it in my hands, but I couldn't say it was "warm".

I've read a couple places where hot is bad, that's where charging should stop. The battery was somewhere around 8.4 volts (6 cell battery). Should I let it trickle still and make sure it doesn't get hotter?

guver

My Feedback: (325)

Allow it to trickle overnight and it will cool down in the proccess and be balanced, full and ready to use.

rsr427

Thanks, I started charging my 4600mah at a lower amp level and it charged "fully" in two hours and has been trickling since. It's probably been on Trickle for an hour now and the battery is only slightly warm. So I'll try that out overnight tonight.

Thanks again.

SilverFoxCPF

Hello Nikq,

The purpose of the "forming" charge is to evenly distribute the electrolyte and charge throughout the cell electrodes and separator. My opinion is that the best results come from starting with a discharged cell and using the 0.1C charge rate for the full 16 hours.

On the other hand, if you are trying to balance a pack, you can set the charge limit a little low, charge at 1C, then finish off the charge and balancing at 0.1C for a few hours. For example if you had a 4600 mAh pack and you are starting from a discharged condition, you could set your maximum charge limit to 3500 mAh, charge at 4.5 amps until you have put back the 3500 mAh into the pack, then drop to a 460 mA charge rate for a few hours to finish the charge and to bring the cells in the pack into balance.

This works great for balancing, but I don't think it is the best way to go for "forming."

Tom

Jazzy

I would advise against charging directly after a "HOT" peak charge. Obviously the packs limit in both charge rate and amount has been exceeded already and proceeding to add to this condition cannot be a 'good' thing. I would let it cool first before attempting to add charge to the pack.

I agree with the timed, long-slow-form-charge method and have personally witnessed the benefits. It is often the case that two or more long slow charges coupled with moderate discharge rates are necessary to reap the full potential of a pack.

I have used peak detecting chargers to form-charge various packs but the process is often more difficult.

Yes, one can 'speed charge' a pack from the get-go and it may work just fine. Would I want to trust a flying model worth $500 or more to this pack because of impatience?- No. A cheap (I use this term in a relative sense and intend no disrespect to anyone) park-flyer type - yeah, I admit I probably would.

Experience is a wonderful teacher. Experiment and good luck!!