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Do your LiIon batteries use round cylinder style cells?
Moving to High Voltage
- Thread starter Torquerolljoe
- Start date
Do your LiIon batteries use round cylinder style cells?
camss69
70cc twin V2
Are they just discharged too much? I'm not familiar with that charger but you want to charge Fromeco LiIons on the LiPo setting of your charger. If they are discharged too much it's probably going to read them as incorrect battery type. If they are just too low a voltage for your charger to read them as LiPo then set your charger to nickel metal let them charge enough to get back to 7.0v and then switch your charger back to LiPo setting and let it finish up. If you really do have a bad cell you can just take off the shrink wrap and test with a meter to find out which is bad. Hope that helps.
Bunky.F.Knuckle
150cc
A little late to the party on this, but pull the pack out of the airplane and cut the shrink wrap off the pack. Take a multi meter, set it to DC volts and check each cell. If each cell reads correctly, then go to your output leads and check for proper voltage.
You may see the issue when you peel the wrapper off, a broken solder tab.....
stangflyer
I like 'em "BIG"!
Very accurate info. I have seen many Lipo's and LiIons that have done this. Basically, due to the chemistry of the battery, the charger will not see all cells if voltage is too low. It gets confused thinking it is something other than what it actually is. Charge it for a short time on NiMh. Once the voltage comes up just a little, switch it over to your Lipo setting and let the charger do the rest. Recently, (a week ago) my friend received his brand new LiIon's from Fromeco. Initially they were fine. He accidently left his switch turned on. KILLED the packs flat. We simply charged for about two minutes on NiMh and instantly they came back. He lucked out with no damage to the packs.
One other thing I will offer. I had seen a mah difference between the two new packs in my Big Yak upon recharging them today. After a good conversation with the battery gurus of Fromeco and Smart Fly, (Was concerned my SF board was having issues) It was suggested to do a "DEEP" cycle discharge and charge them back up to capacity. Huh, what do you know? Packs are fine and the difference I was seeing was really nothing at all. Both charged up perfectly within one mah of each other. If once your packs are fully charged, deep cycle discharge them and then charge them back up to capacity.
Twister
70cc twin V2
Great info, how do you deep cycle LiIons ? what would the low voltage setting be?
Thanks Jim
stangflyer
I like 'em "BIG"!
If you have an up to date charger, it should be capable of all battery chemistries. My X4 will do Lipo, LiIon, NiMh, Nicd, Pb...pretty much everything. It has a preset in the menu. When you select "Discharge", it automatically takes the battery down to the safe discharged voltage so as to not damage the cells. Thing to remember about LiIon especially is the harder you discharge and charge, the quicker it wears on your battery. It has to do with the ions across the cathode. They start breaking down. Usually you'll want to stay at or around 3.0 to 3.1 volts per cell. In other words, 7.4 volt LiIon can safely come down to 6.0 to 6.2 volts. My charger will monitor milli-amps discharged, however what is taken out is not near as crucial as what is put back in. Anything more than a 20% variance of rated battery value should not be used in an airframe. i.e., 5200 mah @ 20%=4160 mah. This is information I had found and been informed of. It must be kind of accurate. My 260 packs are going into their fourth season with a noticeable 3.5% variance from new.
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