CHARGING FROM A BATTERY BANK.

[tarsus]

Hello all, I have battery bank which I use to charge phone camera etc. I uses a usb cable which has four wires two for power and two for data. I would like to be able to charge small lead acid batteries from it. Has anyone got a way to do this as without the data cables the bank will not supply. I think that I would need to feed the data wires to the bank from a sensing circuit so that the bank knows the state of the battery. Anything on the market?. I must add that I am well over 80 and not fully up to speed on the modern electronics. Thank you all in advance.

 

[Pommie]

I think you'll find your problem is not the data lines - powerbanks work with charging cables which don't have data lines. It is more likely that you're trying to charge a 12V (might be 6V - you don't say) battery from a 5V supply. If you can post links to both the battery and the power bank then someone may be able to offer a solution.

Mike.

 

[rjenkinsgb]

Many power banks only test for a load at intervals, and will only fully switch on when a load is present.

Try connecting something that will draw eg. 100mA and check the voltage across that?

 

[tarsus]

Thank you for the reply but the data wires in the usb cable must be in use. I have opened up a spare cable and find that with the data wires cut it will not charge my camera but on reconnecting them everything works ok. I did say that I was wanting to charge a small lead acid battery but in reality it is a set of four rechargeable batteries when connected together give 4.8 volts. AA type 1.2 volts each.

 

[JimB]

I did say that I was wanting to charge a small lead acid battery but in reality it is a set of four rechargeable batteries when connected together give 4.8 volts. AA type 1.2 volts each.

There is a BIG difference between a lead acid battery and AA cells.
What is the chemistry of the AA cells?
NiCd, NiMH, or ??

Incorrect information is worse than no information.

JimB

 

[Pommie]

I'll just keep quiet as it's obvious that the information supplied will be drip fed.

Mike.

 

[tarsus]

NiMH.

 

[Pommie]

Drip.

 

[alec_t]

Check out Battery University for info on the correct charging procedure for NiMh cells. There's more to it than just connecting a power bank to the cells.

 

[AWG]

Pommie is correct, a power-bank does not care about data lines, ever. What you need is a module were you can select a precise output voltage matching your battery characteristics and also limit the current. Powerbanks are usually marked at the USB plug what current they can supply. The link shows a module with both voltage (CV- constant voltage) and current (CC=constant current) adjustments. that one will work from a 4 - 38V in and can put 1.25 to 36V out. You can also browse for other devices with LCD showing both voltage and amps, but they add an additional load.

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[tarsus]

Hello again, Thank you all for all the advice and help and although I am being told that battery/power banks do not use data wires I did say in a earlier post the one that I have will not work if the data wires are cut. Mine is made by Imuto. I would be most grateful if someone can tell me why it will only work if these wires are connected Thank you.

 

[rjenkinsgb]

Mine is made by Imuto. I would be most grateful if someone can tell me why it will only work if these wires are connected Thank you.

That is definitely unusual.

This is a TI document listing the standard output control methods & none use the data lines...

https://www.ti.com/lit/an/slva770/slva770.pdf?ts=1634717934756&ref_url=https%253A%252F%252Fwww.google.com%252F

You could try connecting the two data lines together, or add a resistor (eg. 10K) from either or both data lines to the ground or positive connection, to see if that enables the output?