Measured voltage after charge cycle only 16.30 volts

Jun 17, 2016
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I posted this problem in another thread but I'm going to start a new one so I don't hijack it.

I have a new solo and 2 new batteries with less than 5 cycles on them.

I just finished a charge cycle on both and the batteries shut off as normal.

With the battery turned on, I measured the voltage in both with 2 separate multimeters.

Battery A is showing 16.22 volts which is 4.050v per cell.
Battery B is showing 16.30 volts which is 4.075v per cell.

When I put both batteries into my solo and power it up, they both report 16.6v in the 3dr solo app and 98% and 99% capacity respectively

I'm charging both batteries with the stock charger.

Shouldn't I be able to measure 16.8v directly from the battery after a complete charging cycle? That would be normal for a 4S lipo.
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You are correct. I've seen this before as well. I'd bet once you drain them down to empty and recharge, they'll fix themselves and show 16.8 at 100%
I've submitted a ticket to 3DR. I flew today with both batteries and took them down to 30%. After a charge I'm still measuring 16.30 on both. Perhaps I have a bad charger.
lol I was in a hurry. I wanted to discharge them so I could see if a charge cycle would fix the issue.

16.30 volts for both batteries seems like a pretty deliberate value though. I wonder if the smarts in the battery are keeping the cell voltage at 4.05 on purpose. Perhaps this is part of a battery break-in period and after x number of cycles it will increase.

The other concern I have is why the solo app is reporting 16.60. What I might do today is take the battery tray out and measure the voltage at the PDB connection when the solo is turned on.
Update. I received 2 new batteries from 3DR today (from the BOGOF sale).

I've charged them and they both show 16.30 volts.

Bad charger perhaps?
what voltage are you looking for, 16.3 seems about right. I did find this

9) It is not recommended to “top-off” a fully charged or near fully charged Li-Po battery. Attempting to do so may cause the charger to overcharge the battery, resulting in damage to the battery and possible fire. If the voltage of each cell within the battery is approximately 4.1V or higher, it is best to discharge the battery for at least a short time before attempting to charge it.
Do not charge a 2S (7.4V nominal) battery if it is at or above 8.2V Do not charge a 5S (18.5V nominal) battery if it is at or above 20.5V Do not charge a 3S (11.1V nominal) battery if it is at or above 12.3V Do not charge a 6S (22.2V nominal) battery if it is at or above 24.6V Do not charge a 4S (14.8V nominal) battery if it is at or above 16.4V
10) Li-Po cells should NEVER be charged to more than 4.2V. Any cell that is charged to a voltage higher than 4.2V may be damaged and could catch fire.
Do not charge a 2S (7.4V nominal) battery to more than 8.4V Do not charge a 5S (18.5V nominal) battery to more than 21.0V Do not charge a 3S (11.1V nominal) battery to more than 12.6V Do not charge a 6S (22.2V nominal) battery to more than 25.2V Do not charge a 4S (14.8V nominal) battery to more than 16.8V
I was expecting 16.80 (4.2v per cell) which is what most new'ish 4S lipos charge to.

Update: I took the battery tray out so i could measure the voltage with the battery installed and Solo powered up. Where the connection is made to the PDB I measured 16.60 volts which corresponds with what I see in the Solo app.

I don't know enough about smart batteries to explain this but there you go. It's not 16.8 but whatever. I'll update if 3DR responds to my ticket or I learn more.
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Stopping at 20-30% is a complete waste of time. There is no reason you can't fly it down to 5%.

16.8 volts is full. 16.3 is not full, and something is wrong if that's the best it will do. If both your new batteries are experiencing this as well, I would suspect the charger.
Yep, thats me. Even thought I'm not seeing a full 16.8 volts on the new batteries I'm calling this closed. It could just be these batteries are just getting old (shelf life) or that 4.15v is the cap that 3dr set for the cell voltage to extend their life.
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Update. I chatted with 3DR support and 16.60 is the expected voltage of a fully charged battery. .20v is electronics bleed (assuming smart battery electronics). Good to have the confirmation though.
I think I see where they're coming from. 16.8 is fully charged, not 16.6. However, after the battery has been sitting for a while, you power on the solo, connect to the controller, and notice the voltage in the app, I suppoe 16.6 is reasonable. But if you've just removed it from the charger and are checking it with a meter, it should be more than 16.6.

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