New guy here. No electronics experience (or knowledge) to draw on so thought I'd ask for help. Have a mobility charger 24v, 8amp output, 110ac input I believe. The old upright style. First I'd like to measure the voltage using an arduino with an SD card read/write. Secondly depending on the results of step #1 is it possible to manage/adjust the output of this old charger to a constant steady voltage of my choice?
Thxs

 

You need to post pictures of the charger, to see if it can be modified..

 

First I'd like to measure the voltage using an arduino with an SD card read/write.

Yes, you can.

.... is it possible to manage/adjust the output of this old charger to a constant steady voltage of my choice

Yes. Since this is an old charger, it is unlikely to have a regulator. You will need to design one / rewire the voltage feedback circuit of a available buck convertor.

 

You need to post pictures of the charger, to see if it can be modified..

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Assuming you want to see the inside of the charger.


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Yes. Since this is an old charger, it is unlikely to have a regulator. You will need to design one / rewire the voltage feedback circuit of a available buck convertor.

Not being able to read a schematic I doubt I'll be designing any circuits lol. I was hoping to be able to use some of the off the shelf break out boards like this. https://www.robotshop.com/en/voltag...MIncH4y7eR6AIVEb3sCh3h9g2xEAQYBiABEgIpafD_BwE

But as with any new hobby there is a bunch of vocabulary and what not that make it difficult to be precise when asking questions. The goal is to charge my 12v lead acid batteries ( 2 in series) more accurately and more completely. I'm struggling to define the problem...

Already have the sd card breakout board. I think I'd like to graph current and voltage if possible. Then talk about controlling the voltage...am guessing that is what the buck converter does. I use this charger daily for my wheelchair...so it's not a throw away project. I believe it also has a float voltage stage which I'll need to address at some point.

If yous can recommend user friendly boards that would be a huge step forward and help me focus. In addition to the board above I also see this one. https://czh-labs.com/panel-mount-50...MI8OXvq9WQ6AIVleNkCh0pRwXIEAQYAyABEgLtK_D_BwE

Thxs for the replies!

 

That's a switchmode type psu, mains input on the left side and DC output on the right side next to the relay, these type of psus chop the mains up with a Transformer in the middle, and use an optocoupler for voltage regulation, (U1) bottom of centre picture, this feeds the main chip on/off to keep the voltage stable. The main chip looks like it's on a plug in PCB on the mains left side..

 

This looks like a switch mode design. I don't think it is a good idea for you to try to modify that unit as most of the circuit is connected directly to the mains input. You would need to learn enough electronics to understand how switch mode power supplies work . There is no reason why you should not just measure the output voltage using an Arduino. Most Arduino's have ADC inputs so all you would need to do is scale the input voltage down to match the input rating of the ADC on the Arduino. Looking at your first link it looks like the board just contains two resistors to scale down the input voltage. The board in your second link looks like it should be suitable for measuring the output current. I thinkl your best option would be to use the output of the charger to drive an external buck or boost converter depending on what output voltage you require.

Les.

 

Thank you for the reply. Appreciate the help. Best not to start something I wouldn't finish. I'll read up on buck converters.