lipo wont fully charge.

[nealj4]

Hi Guys, I have three, 4 cell 5000mah lipo batteries that I have been using for a year now. 2 charge no-problem, the other gets to 16.7 volts and wont go any higher. Even after being on the charger for an hour and a half it wont go that extra 1/10 of a volt or so( the others take about 20 minutes.) I have a SkyRC 400 watt , 20 amp charger. Any suggestions?? Is it possibly a calibration problem or is the battery done?
Thanks

 

[econfly]

A couple of things to check if you can: (1) check voltage on a second meter to get a little more resolution on that 1/10 of a volt -- is it a full 1/10 or just a few hundredths off?, and (2) check each of the 4 cells individually. You may have a bad cell or the battery may need to be re-balanced.

 

[nealj4]

Thanks econfly. It is a full 1/10 off which doesn't bother too much ,the cells are close enough together in voltage. I always balance charge my batteries, every time. What bothers me is the charger doesn't shut off because the battery isn't reaching full charge. All my other batteries, 3 & 4 cell, the Skyrc charger sends out an alarm that it is done charging , shows FULL and halts charging.

 

[cootertwo]

First thing I'd try, is to do a "storage charge" if your charger has that option. Then do a full charge, and see what happens. I'd monitor the whole process, as something might be wrong with the batteries, and you don't want no fire and smoke!

 

[econfly]

Thanks econfly. It is a full 1/10 off which doesn't bother too much ,the cells are close enough together in voltage. I always balance charge my batteries, every time. What bothers me is the charger doesn't shut off because the battery isn't reaching full charge. All my other batteries, 3 & 4 cell, the Skyrc charger sends out an alarm that it is done charging , shows FULL and halts charging.

If the total voltage is 16.7 and all 4 cells are at about 4.175 volts, then it is so close that I would wonder if the charger is just a bit out of calibration and is coming up a little short of the shutoff voltage. Or, it could just be that this is a bad battery. If you are seeing a difference between this battery and your others then bad battery is the most likely explanation.

 

[nealj4]

as a general rule , at what voltage difference per cell would you condemn a battery?
Thanks guys for your replies.

 

[Old Man]

If I had a battery where one cell was a full 10th lower than any of the others it would be out of the house and done. It would then get discharged outside and disposed of.


Sent from my iPhone using Tapatalk

 

[Phil550]

Hi Guys, I have three, 4 cell 5000mah lipo batteries that I have been using for a year now. 2 charge no-problem, the other gets to 16.7 volts and wont go any higher. Even after being on the charger for an hour and a half it wont go that extra 1/10 of a volt or so( the others take about 20 minutes.) I have a SkyRC 400 watt , 20 amp charger. Any suggestions?? Is it possibly a calibration problem or is the battery done?
Thanks

I have the SkyRC Quattro B6 and have a similar problem. After an hour of balance charging my Turnigy 5000 mah 4S lipos read 4.20, 4.19, 4.19, 4.20 (all 4 cells switching between 4.20 and 4.19) but the charger doesn't always shut off. Sometimes it can go to the 120min limit without ever switching off, other times it will turn off at these voltages so perhaps it could be a charger problem, or a bad connection with the balance adaptor board?

 

[nealj4]

Hey " Old man" you mean to tell me all your batteries are within 1/10th of a volt?? I have bought new batteries that aren't within a tenth.

 

[Old Man]

The cells in individual batteries are. Most within 2/100's. I have batteries with different total voltages just like anyone else. You can call me old man without parentheses if you like. I won't mind

 

[nealj4]

Do you have a more quality charger that brings the battery cells to this tighter tolerance or you just buying better batteries.??
Thanks again for your help.

 

[Old Man]

I don't think it's a better charger. Just a basic Hitec X2/400 multi charger and power supply. Perhaps it's the way I handle them. I always balance charge and try to charge at a 1C rate. The first charge is slow to keep heat to an absolute minimum. When the batteries are new I do not discharge to cell minimums. Instead is kind of pamper them for the first 5 cycles or so and only use about 60% of the charge. I try not to heat them up initially with a lot of hard flying. I let them cool before re-charging. I track flight time, charge time, voltage prior to charge and post charge and note mA in for every charge cycle.

I've noticed some brands just don't last as long as others and begin to get puffy without cause while still pretty young. I've got some high end batteries that are simply exceptional performers. I'll still use them if the voltage makes the grade and the cells are really, really close but all the charging for those gets done outside where they can't do any damage.

It may just be a matter of getting what we pay for, but how we treat them has a lot of impact across the entire quality range.

 

[nealj4]

I always balance charge as well and charge at 1c charge rate. I must admit I have taken mine down to 80% a few times. My break in procedures may not have been text book as well. Do you have a couple of preferred brands you like to use.??

 

[Old Man]

Pretty much the same as others, Tattu, Max Amps, Hyperion. In large batteries the Max Amps are great but the prices are very high. Some of that gets offset by the way they treat you, which is very good. The shortest life span batteries are always the ones obtained at low prices through Chinese vendors. I pull down to 80% too but not until they've been through a few "soft" cycles. In every case where I went busted 80% the batteries provided some evidence of damage and had sorter life cycles. Some would appear fine but not handle higher current loading and caused bus errors, triggering a failsafe. Some suddenly took longer to charge and provided less use time than before.