LDM

My Feedback: (15)

charging a lipo 1100 mah 7.4 v , the charger identifys the battery , start charging at 1amp , its seems to take over more then an hour and no beep indicating that its done .The battery is not hot , I keep checking it , not even warm .
Then I fly it in the GWS tigermonth and it last for a good 15 miniutes so it seems like its charged .
My question is the amp correct in the charge rate or I am doing something wrong , why does it take so long for such a little battery ?

ozrcboy

Initially the charger should start charging at 1C - so 1100mA. To fully recharge a 1100mAh it would need to charge at 1100mA for, you guessed it, 1 hour. However, as the LiPo starts to near capacity you can no longer force 1C into it, and the charger will start backing of the current. So the charger varies the current from 1100mA all the way to 0 the charge of a completely depleted LiPo takes somewhat over 1 hour.

Sounds like the charger is working okay to me.

mrasmm

yeah, sounds good to me too =)

My lipo's actually cool off as I charge them, but they defiantely should not heat up. If they were heating up, then there would be a big problem =)

If the pack is reading 8.4v when it comes off the charger, then it is charged.

LDM

My Feedback: (15)

Thanks I guess that is where I am the dummy of e-flight , been in glow for years and dabble in e-flight .
THe battery says 7.4 1100 amos yer it should read 8.4 when its done??? can you explane please

mred33

A LiPo is going to read around 4.2 Volts per cell when it is fully charger. It's like a car battery. It says it's a 12 volt battery, but if you check the battery after a full charge it will read around 13.8 to 14.2 volts. The battery is rated for a full load. In your case, it is 7.4 volts under load. When you check it with a volt meter, there is no load being put on the battery, so it will read around 8.4 volts. Any battery charged at the C-1 rate is a 1 hour charge rate. Mine normally take about 1 hour and 10 min to charged at C-1. If you are using a Triton charger, then it will taper at the end and put the last little bit in, but you can really take it off after 1 hour. The last 10 min is putting very little in the battery and while you can top it off, you don't gain much. Maybe an extra min of flying time if that. Leave the charger on long enough and it will finally beep, but 1 hour is plenty of charge. At C-1, the battery BETTER be cool, or there is something wrong with the battery. You can charge it faster, but you are going to kill the life of the battery and you take a chance of blowing up a good battery, and I do mean blow it up-as in fire and flames and all that if you are not REAL careful. The best way to charge is at C-1, so if you don't like waiting an hour for it to charge, get another battery or two and you can fly while you are charging the others.
Ed

LDM

My Feedback: (15)

Thanks , makes better sence , I guess if i get into bigger e-flight warbirds like the new H9 B 25 , I better get myself a heavy duty charger , or I will be charging for years [8D]

ozrcboy

Hi LDM,

Just to be sure - the maximum you should charge any LiPo at is 1C - so a 1100 mAh battery takes about 1hr 10 minutes, but so does a 4400mAh battery (cause you charge it at 4.4A - 1C). The only reason a LiPo should take longer than about an 1hr 10 - 1hr 20 is if the maximum current your charger can produce is less than the C of the battery. This is okay - it will just take longer (which may have been what you are alluding too, in which case sorry for telling you how to suck eggs).

Cheers,
Oz.

new-heli-pilot

Actually OZ, the triton charger(if he has triton 2 that is) does take slightly longer to charge. I have sat there and watched the charge rate towards the end of the hour it was supposed to take and it goes into a almost slow charge. I was charging an 11.1v 800mah battery and at the very end of its charge it slowly stops charging, so it went from.8A to .7A to .6A and so on until it finally quit.

LDM

My Feedback: (15)

yes I have the #2 , I am experienced at warbirds gas/nitro but this is all new so thanks for the help .
I am amazed that a small lipo takes as long as the monster ones