How long should an initial lipo charge take?

[French]

I received a new nano-tech 1800mah 3S 45C today. The initial resistance readings were 3, 5, & 8. I've been trying to balance charge it at 1C (1.8A) for nearly an hour and a half. I checked it around the 45min mark and cell 1 was at 4.2V after another 45min cells 2&3 are still below 4V (charging at 0.2A). I think I've put ~1,450mah into the whole battery already.

Is this a bad lipo? Should I just let it keep going until it's full?

Thanks.

 

[French]

Well, I didn't burn the house down. I think it ultimately took more than 4 hours to get all cells to 4.2V

I then ran a storage discharge at 1C and another balanced charge at 1C to cycle it. Each completed in about ~40min. Hopefully everything is good to go now.

 

[mikeporterinmd]

That's fairly unusual behavior. All may be well, but I've never seen that in the 20 Lipos I have and I always balance charge.

Mike

 

[pressalltheknobs]

"slow" cells are not unheard of and sometimes it can take a couple cycles to "wake them up". I have not experienced this personally but reading around it's not that uncommon. Balance charging when you have a slow cell and an out of balance battery can take a very long time because the way many balance chargers work is to charge all cells for a while then discharge the ones that go over and so on until the laggard catches up. If the cell is quite a bit lower then the others this can take a lot of cycles before that cell reaches the required charge.

 

[French]

From what I could see from watching my Hitec X2 AC Plus charger, when one cell is "full" it seems to switch to charge the remaining cells through the balancing port. Then the amperage dropped way down (0.1 to 0.2A). That's why it took so long.

Here's the official answer from HK:

Hello

From the information that you have given us your battery is not faulty. The amps of the charger will vary from what you set it at depending on how charged the battery is. It will not charge at 1 amp all the time. The initial charge time may take longer than normal as the storage chemical is still in the battery. Once you cycle the battery a few times and use the battery will not take as long to charge. As the battery did balance out and reach 4.2 volts it is not defective. Thank you for contacting HobbyKing support, Have a great day!

Devin

HobbyKing Product Specialist USCS, New York

 

[Snarls]

I still don't think a new battery should show up that unbalanced. The batteries I've received arrive at around 3.90 each cell and balance no problem. Although I do balance at a low rate (.5C or less) for the first few charges. The long time it took to charge is just because of how balance chargers work when one cell is significantly off from the others.

If you fly the battery and notice the cells are way off balance when its time for a charge, then I would contact HK again and say at lest one cell is failing/mismatched.

 

[French]

Thanks. Will do

 

[pressalltheknobs]

From what I could see from watching my Hitec X2 AC Plus charger, when one cell is "full" it seems to switch to charge the remaining cells through the balancing port. Then the amperage dropped way down (0.1 to 0.2A). That's why it took so long.

That make sense. I may have been mis-informed or there may be different strategies used. Either way, if it's out of balance it's going to take a long time to charge.

I would expect a new battery to be delivered balanced at storage charge. I read some where there may be new guidelines that say they should be shipped with less than normal storage to address aircraft safety concerns. Not sure if that is in effect yet.

Btw HK battery 30 day warranty seems to require you to register the battery with in 24 hours of receiving it. Or at lest it did last time I looked.