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Old 05-16-2006, 05:53 PM   #1
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Default Help charging batteries

I know it sounds stupid, but I am kinda lost. I don't understand charging times for certain batteries. I have looked and yes I did check the battery university, but all it did was make me even more confused. Here's what I have. I have 2400 MAH battery packs and a Hobbico AC/DC auto-charger. Hobbico says that it is rated at a 1 amp trickle charge. It's cover says 35 to 75mA.

Please correct me if I am wrong. I want to trickle my packs. If I understand the university thread correct, for a 2400MAH pack, I trickle charge them for 24 hours?
Is this correct?

God I miss my old charger! Plug in and it told you when they were charged.

I also have several 3300 Nimh packs I got in a trade. Will the Hobbico charger charge them( asking cause I have seen nothing that says otherwise)? Would it charge for 33 hours?

I know these are very dumb questions. But I really truly thank whoever sets me straight on this.
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Old 05-16-2006, 06:16 PM   #2
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i was in your same situation a few weeks ago..... and ya, the battery university gave me more questions than answers.

but, from what i have read from many sources, nimh batteries dont like to be trickle charged; especially for days (nicad batteries can be trickle charged). so i ended up buying a digital peak charger and a 3300nimh battery. i followed the directions on the charger and it charges for about 80 minutes and gives me 3 hours of run time.

be sure that your charger can charge nimh batteries or else it will destroy them. i also recommend this charger from tower hobbies:
http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXCLD5
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Old 05-16-2006, 06:31 PM   #3
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Quote:
Originally Posted by Sync
i was in your same situation a few weeks ago..... and ya, the battery university gave me more questions than answers.

but, from what i have read from many sources, nimh batteries dont like to be trickle charged; especially for days (nicad batteries can be trickle charged). so i ended up buying a digital peak charger and a 3300nimh battery. i followed the directions on the charger and it charges for about 80 minutes and gives me 3 hours of run time.

be sure that your charger can charge nimh batteries or else it will destroy them. i also recommend this charger from tower hobbies:
http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXCLD5
I second that charger. It has so many features and it's only $50!
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Old 05-16-2006, 11:13 PM   #4
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The only problem with that charger is that if you use AC you have a max charge of 3.0 amps. If you go DC, then can go up to 5.0. Found that out after I bought it. I still use it, just hook it up to the 1:1 for the bigger packs (I charge 3300 at 4.5 and 3800 at 5.0).
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Old 05-17-2006, 09:23 AM   #5
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Charge time is as simple as filling a 5 gallon bucket at a rate of 1 gallon per minute or driving 55 miles at 55 mph, right?



a 2400 battery at a rate of 2400 ma will take an hr
At a rate of 1200 it will take 2 hrs.
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Old 05-17-2006, 09:39 AM   #6
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Quote:
Originally Posted by floogldood
Charge time is as simple as filling a 5 gallon bucket at a rate of 1 gallon per minute or driving 55 miles at 55 mph, right?



a 2400 battery at a rate of 2400 ma will take an hr
At a rate of 1200 it will take 2 hrs.
not quite. the charge rate to time graph is not linear. there is a limit to how fast you can/should charge batteries (for example: 4800 for 30min or 9600 for 15min). at least for nicad batteries (and i think for nimh), the charging is creating a chemical reaction in the battery. if you charge it too fast, the reaction wont be able to properly take place and you will just overheat the battery; causing damage to the cells.

Last edited by Sync; 05-17-2006 at 09:53 AM.
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Old 05-17-2006, 10:07 AM   #7
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Yes, I should have said "within limits" and for this purpose of explaining charge times I did not throw any over charge into the mix because it is pretty meaningless unless chargeing at slow rates.


Water leaking from a 5 gallon bucket at a rate of a drip per minute. right? during the fill up.

Hopefully hvydty1 sees how to figure the times now .

To trickle charge the packs use this 150 % or overcharge at a c/10 rate. 240 ma chargeing for 15 hrs for a 2400 delivery.
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Old 05-17-2006, 10:44 AM   #8
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Quote:
Originally Posted by floogldood
Yes, I should have said "within limits" and for this purpose of explaining charge times I did not throw any over charge into the mix because it is pretty meaningless unless chargeing at slow rates.
heh... i guess i read into it too far :-P
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