LiPo Battery on use while charging

[camilozk]

Dear Forum!

I have bought some battery light spots as seen in this link. The lights have inside a battery pack comprised by 16x 18650 LiPo batteries. These are the specs the manufacterer sent to me:

Capacity :14A
The maximum voltage :12.5V
The battery group : 16 batteries,each section 2800 mAh

The manufacterer says that it is not good for the battery life to use the light spots while connected to the electricity. The message was:

"Such as our phone ,if you use the phone at the same time to charge it. That is not good for the battery life time. The battery supplier explain us also like this, it is not good for battery life."

I tried to squeeze a real explanation, but got none, so I am here to ask. Could it be at any level true that using LiPo batteries while charging is not good for the battery life?

 

[BobK]

It is nonsense.

A battery cannot be charging and discharging at the same time, the current flows in only one direction.

So, if you have a power supply capable of providing the charging current and the operating current, the battery cannot tell if the power supply is powering the device or not, all it can see is its charging current coming in.

Now, if the power supply is not capable of supplying both currents at the same time, then the battery might be switching rapidly between charge and discharge, and that might lower its useful life, but that is the result of a poor design, not a rule you cannot get around.

Bob

 

[davenn]

The manufacterer says that it is not good for the battery life to use the light spots while connected to the electricity. The message was:

"Such as our phone ,if you use the phone at the same time to charge it. That is not good for the battery life time. The battery supplier explain us also like this, it is not good for battery life."

It is nonsense.

totally agree with Bob ... total rubbish

 

[camilozk]

if the power supply is not capable of supplying both currents at the same time, then the battery might be switching rapidly between charge and discharge, and that might lower its useful life, but that is the result of a poor design, not a rule you cannot get around.

Well, that could perfectly be the case. Now, how could I test what is in fact happening?

 

[BobK]

If there is a charge indicator, it could tell you. Otherwise, you would have to break the battery connection and monitor the current going in / out of the battery.

Bob

 

[camilozk]

so, this is a photo of the power supply:

Although below the sticker the information is different:

And this is a picture of the PCB where you can see the connection of the power supply (below) and the battery (left):

When the device is off and connected to the mains, the battery is being charged.

I measure 13V where the power supply is connected to the board and 12.5V where the battery is connected to the board.

Current between the power supply and the board:

Current between the board and the battery:

With the device connected to the mains, when I turn it on, I measure:

13.03V to 13.23V where the power supply is connected to the board
12.6V to 12.9V where the battery is connected to the board

Current between the power supply and the board:

Current between the board and the battery:

For the measurements I used an UT204A, on setting 40A, with the clamp around the red cables.

I hope you can help me make sense of all of this! Thanks in advance!

 

[camilozk]

It is nonsense

totally agree with Bob ... total rubbish

Guys? any insight you could provide by looking this information?
My limited knowledge restrain me to make sense of those numbers...

thanks in advance

 

[Martaine2005]

Having the meter set to 40A, looks like the current is around 2.7A.
Can you set your meter lower to 6 or 8A?. Then repeat your measurements?.

In any case, if it is 2.7A, the charger is max 4A so there will be no problem with using it while the adapter is plugged in.
But, if you use the lamp more with the adapter, why not put a switch on the battery +. Then you control when to charge or simply power from the adapter.

Martin

 

[camilozk]

Having the meter set to 40A, looks like the current is around 2.7A.
Can you set your meter lower to 6 or 8A?. Then repeat your measurements?.

In any case, if it is 2.7A, the charger is max 4A so there will be no problem with using it while the adapter is plugged in.
But, if you use the lamp more with the adapter, why not put a switch on the battery +. Then you control when to charge or simply power from the adapter.

Martin

thanks for your post martin!

I dont have a multimeter with a setting lower than 40A.

The switch is generally a good idea, but of course I would prefer to not have to do this in my 60 lights, if I can be sure that the battery is not suffering because of a poor design. Normally I use this equipment with the battery, but eventually, for some configuration is much better to have them connected to the electricity so I want to be sure that this is not killing my batteries...

 

[Martaine2005]

The only way to be sure is to have good measurement readings. Multimeters (some) are cheap and more reliable for lower readings.
Also another important factor is whether the board has circuitry to monitor charging and monitor battery temperature.

Martin