Solo battery output reduced when not connected to Solo

[Pedals2Paddles]

A few people have noticed when you put a meter on the battery, it reads low. This has caused many, myself included, to believe the battery wasn't fully charged. The lights show 100%, but the voltage is only reading 16.3 volts. At first I thought the battery must be out of whack, but then noticed all three of my batteries are doing this.

So, yesterday I discharged a battery completely using my LiPo charger's discharge mode (pictured below, super slow, but it was raining so I couldn't fly it). I then recharged it using a CC/CV power supply, and my meter in between so I could meter the voltage and current going back into the battery. It charged completely and correctly, with the voltage topping off at 16.8. It took on a full 5,148mah, so it was legitimately 100%, with little degradation. And that 16.8 volts was legitimate battery voltage. Upon completion, it was only charging at .1 amps, so that wasn't some inflated voltage reading coming from the charger only.

Immediately upon removing it from the charger, I connected my voltmeter and turned the battery on. It presented with only 16.3 volts (pictured below). WTF I said. I had two meters connected to this thing a minute ago while it was charging, it said 16.8. Thinking the smart battery may not be allowing full voltage without an actual load, I connected an external load to the battery. Even with a 6 amp load on the battery, it still only presented with 16.3 volts. I took a screenshot of the app showing full voltage. I did not take a picture of the meter connected to the battery terminals inside solo since I needed both hands to do it.

I put the battery on the solo and connected via the controller and app. It showed 100% and 16.7 volts. OK. So what is lying to me... the meter, the app, or the battery? I opened the battery tray up and checked the battery voltage while it was connected to the solo and powered on. 16.7 volts. Disconnected from solo, 16.3 volts. back connected to the solo, 16.7 volts.

So, the brain in this battery is limiting voltage when not connected to the solo. Strange. It's not limiting current or preventing the battery from doing anything. It's just dropping a 1/2 volt. Logic? IDK? Anyone?

Discharging

Full voltage connected to Solo.

Reduced voltage while not connected to Solo

 

[Nisouck]

Nice analyse; thanks.
Btw mine are also at 16,3V; now I know why!

 

[SPP]

Maybe without data pins of battery ( 3rd pin ?? ) connected to Solo brain, this whacky thing happens ?
0.4 volt sound like a diode voltage drop.

 

[Pedals2Paddles]

I was thinking perhaps that is the voltage drop across whatever high power mosfets it's using to switch. But that loss goes away once it's connected tot he Solo.

 

[Ed Beck]

Off-topic - there are projects that require continuous operation. I've read your thread on charging using your LiPo charger. Where can I get a setup like that? I have 6 batteries and would like the ability to charge them all at once. I figure I need 7 batteries to guarantee continuous operation (thinking that the ground based power station isn't an option for most gigs).

So what would you recommend I do?

 

[Toiletbowl]

Mine is fully charge and connected to solo but 15.7 dont know why also

 

[pyrate]

Smart batteries the mystery continues
I quit worrying about it, Phlilp said charge them up and dont worry about them
The only percaution I take is topping off if they have been in the bag for more than 2 days
And I have started getting close to home at 25 and landing no lower than 10

I have experienced a battery reading 0 but was able to fly a full 3 minutes more to get home
My belief is the reporting on these is set to keep nooby operators out of trouble

 

[Pedals2Paddles]

Mine is fully charge and connected to solo but 15.7 dont know why also

What are the lights on the back of the battery showing? And what is the % in the solo app showing?

Smart batteries the mystery continues
I quit worrying about it, Phlilp said charge them up and dont worry about them
The only percaution I take is topping off if they have been in the bag for more than 2 days
And I have started getting close to home at 25 and landing no lower than 10

I have experienced a battery reading 0 but was able to fly a full 3 minutes more to get home
My belief is the reporting on these is set to keep nooby operators out of trouble

I'm at that point now as well. I've always been very into anylizing the LiPo performance and capacity with my DIY birds. So I of course wanted to do the same with the Solo batteries. I've come to the conclusion that is futile. Charge, fly, enjoy... the whole reason I bought the solo in the first place. I still monitor the voltage in the app and rely on that more than the %. But I'm done worrying about nitty gritty battery details.

 

[pyrate]

I am just trying to figure out all of that on my DIY monster.
Think I am going to have to upgrade my radio or sharpen my MP skills to get voltage readings right.
That will make you appreciiate solo, it is all done for you there. On DIY it is all on you.

 

[Ed Beck]

The only percaution I take is topping off if they have been in the bag for more than 2 days

EyewingSuit recommends not storing batteries over 30% charge.

 

[PdxSteve]

Off-topic - there are projects that require continuous operation. I've read your thread on charging using your LiPo charger. Where can I get a setup like that? I have 6 batteries and would like the ability to charge them all at once. I figure I need 7 batteries to guarantee continuous operation (thinking that the ground based power station isn't an option for most gigs).

So what would you recommend I do?

The CCCV converters will also run straight off your 12v car battery. I built a 6 bay charger and yes, 7 is the magic number for batteries as far as continuous operation with a little wiggle room left over, assuming your charger is right there and you throw the battery on the charger as soon as you land. It will actually work on 6 but barely. Better to have an extra spare. By the time you're flying on your 7th battery, #1 is fully charged and ready to go again. They take about 1 hour each to go from 10% to full charging at 6A instead of the stock 3.3A. I also like to add 2 high power usb chargers for charging the tablet and other devices.

 

[SPP]

I was thinking perhaps that is the voltage drop across whatever high power mosfets it's using to switch. But that loss goes away once it's connected tot he Solo.

Yes probably

 

[looninho]

A few people have noticed when you put a meter on the battery, it reads low. This has caused many, myself included, to believe the battery wasn't fully charged. The lights show 100%, but the voltage is only reading 16.3 volts. At first I thought the battery must be out of whack, but then noticed all three of my batteries are doing this.

So, yesterday I discharged a battery completely using my LiPo charger's discharge mode (pictured below, super slow, but it was raining so I couldn't fly it). I then recharged it using a CC/CV power supply, and my meter in between so I could meter the voltage and current going back into the battery. It charged completely and correctly, with the voltage topping off at 16.8. It took on a full 5,148mah, so it was legitimately 100%, with little degradation. And that 16.8 volts was legitimate battery voltage. Upon completion, it was only charging at .1 amps, so that wasn't some inflated voltage reading coming from the charger only.

Immediately upon removing it from the charger, I connected my voltmeter and turned the battery on. It presented with only 16.3 volts (pictured below). WTF I said. I had two meters connected to this thing a minute ago while it was charging, it said 16.8. Thinking the smart battery may not be allowing full voltage without an actual load, I connected an external load to the battery. Even with a 6 amp load on the battery, it still only presented with 16.3 volts. I took a screenshot of the app showing full voltage. I did not take a picture of the meter connected to the battery terminals inside solo since I needed both hands to do it.

I put the battery on the solo and connected via the controller and app. It showed 100% and 16.7 volts. OK. So what is lying to me... the meter, the app, or the battery? I opened the battery tray up and checked the battery voltage while it was connected to the solo and powered on. 16.7 volts. Disconnected from solo, 16.3 volts. back connected to the solo, 16.7 volts.

So, the brain in this battery is limiting voltage when not connected to the solo. Strange. It's not limiting current or preventing the battery from doing anything. It's just dropping a 1/2 volt. Logic? IDK? Anyone?

Discharging

Full voltage connected to Solo.

Reduced voltage while not connected to Solo

Cited from smart battery doc for bq20z95 chip:

"Power Modes
The bq20z95 supports three power modes to reduce power consumption:
• In NORMAL mode, the bq20z95 performs measurements, calculations, protection decisions and data updates
in 1-s intervals. Between these intervals, the bq20z95 is in a reduced power stage.
• In SLEEP mode, the bq20z95 performs measurements, calculations, protection decisions, and data updates
in adjustable time intervals. Between these intervals, the bq20z95 is in a reduced power stage. The bq20z95
has a wake function that enables exit from SLEEP mode when current flow or failure is detected.
• In SHUTDOWN mode the bq20z95 is completely disabled."

so i think, the battery is in sleep mode and reduces the power (or voltage) when it doesn't detect a host (solo).