36v charger pcb

[Kein Kochendes]

Hello, I have a high quality Aspen ROQ-4 ni-cad charger that I don't use and would like to know if it could be modified to charge a 36v lithium ion battery pack.

The ac to dc board outputs 26vdc and 5vdc from 90AC-240AC.

Is there a dc to dc booster circuit I could purchase and install in the box, replacing the NiCad charging circuit, that would give me the output voltage necessary to charge a 36v battery pack?

If so, how do I control the amount of current going in to the battery. Is that controlled in the circuit or does the BMS of the battery control that?

Thanks

 

[amberwolf]

Hello, I have a high quality Aspen ROQ-4 ni-cad charger that I don't use and would like to know if it could be modified to charge a 36v lithium ion battery pack.

The ac to dc board outputs 26vdc and 5vdc from 90AC-240AC.

I know of no simple way to modify the stuff that's in the charger already to work for your purpose. It would likely require replacing a fair number of components, depending on it's design, possibly including the main transformer, which you might have to make yourself after calculating numbers of turns needed to change it's output from what it was to what you need, and associated voltage-limited components.

If it doesn't do current limiting then you'd also have to add a circuit for that (since you may not be able to use any part of the NiCd charging circuit, which likely has thermal shutoffs and voltage-change shutoffs that would preclude using them on anything else).

Is there a dc to dc booster circuit I could purchase and install in the box, replacing the NiCad charging circuit, that would give me the output voltage necessary to charge a 36v battery pack?

It's probably cheaper and safer (and certainly easier) to buy a new charger that's the correct output voltage, than a DC-DC that can do the current limiting and shutoff at end-of-charge that you would want in a charger. (or the multiple devices to do this, if you don't find just one that does it).

So if you got just a DC-DC converter with no current limiting and no shutoff, then you would need a separate current-limiting board to put in series with the DC-DC to the battery.

And if you wnat charge to shutoff automatically below a certain current (as most chargers for Li do), you'd have to add a separate circuit for that, too.