Feeding solar charge controller with computer power supply?

[DThames]

I am looking for cheap hardware to convert AC to DC and charge large batteries in a power out/cloudy day situation. This would be for emergency standby recharging if solar was not producing. The idea is run the generator during the day to get the battery up enough to carry critical demands through the night.

At low power levels I have powered PWM solar chargers with a laptop supply. It seems to work okay.

Any thoughts or experience out there.

reference videos:

Large power supply

Feeding solar charger

 

[Ped]

Ive always heard the pulse modulation will fry a power supply. No idea.

 

[electric]

I think it would be much more efficient to get a battery charger rated close to whatever your generator power output is, so you are not wasting gas on trickle charge thru the SCCs.
These are cheap, yet decent quality and high current output chargers for occasional use https://powermaxconverters.com/product-category/converters-ac-dc/
They are essentially power supplies which were updated with 3-stage charge profile for batteries. No need to run thru SCCs.

But, technically your idea of feeding DC supply thru SCC would work if voltages match and DC supply is rated for higher current than SCC, so it doesn't shutdown due to overcurrent protection.

 

[Maast]

Get a meanwell HRP power supply off of ebay or alibaba. It's what I'm using to charge individual cells @ 3.65V w/ large amperages and I've been elbows deep into charging/cycling profiles lately. You can adjust the voltage up/down about 10% from the nominal voltage.

The HRP line is current limited - which means if your draw goes over what the power supply can output it'll limit the current until the state of charge gets high enough it can stop limiting.
Basically they're perfect constant current/constant voltage chargers which is exactly the charge profile that lifepo4s need.
You can even stack them if you want more amperage. The HRP line goes from 75 watts all the way up to 1000 watts and 3.3 though 48V

What voltage and size is your batt bank at? I'll tell you the exact power supply that'll work. They're even power factor corrected so if your genset isnt the best they can accommodate it.

 

[DThames]

Get a meanwell HRP power supply off of ebay or alibaba. It's what I'm using to charge individual cells @ 3.65V w/ large amperages and I've been elbows deep into charging/cycling profiles lately. You can adjust the voltage up/down about 10% from the nominal voltage.

The HRP line is current limited - which means if your draw goes over what the power supply can output it'll limit the current until the state of charge gets high enough it can stop limiting.
Basically they're perfect constant current/constant voltage chargers which is exactly the charge profile that lifepo4s need.
You can even stack them if you want more amperage. The HRP line goes from 75 watts all the way up to 1000 watts and 3.3 though 48V

What voltage and size is your batt bank at? I'll tell you the exact power supply that'll work. They're even power factor corrected so if your genset isnt the best they can accommodate it.

That is great information and thanks. I had looked at them and wondered what the V+Adjust was.

I am expecting my battery bank to be 24v and in the 8kwh (300 amp hr) range. This thread is about worst case need some battery charge to carry thought the night event. To need this the power would need to be off for days (most unlikely) and the sky be cloudy at the same time. I will have solar charge ability by design. I have a gasoline powered generator that I can run as well to run my freezer and frig. But rather than run the generator all night, if I could dump some generator power into the battery during a cloudy day, then that is my goal. But spending more than a very small amount on a solution would not be warranted. I have an old AC welder, some LARGE diodes, and some large capacitors. So providing DC one way or another is not hard. Also, salvaged PC/Server switching supplies are next to free, or free. I just don't know how a solar charger would act hooked to a power supply that is much stiffer than what it would normally see. The MPPT type controllers will try to load the panels down to the best power point. I think that would be less than ideal unless its output current limit had priority above loading the panels. I am ordering a couple of cheap PWM chargers and will torture them to find out.

 

[Maast]

Well with a power supply like this one you can bypass the charge controller altogether. MPPT is all about matching the variable output of a panel to what the battery needs. I suppose you could just series connect 3 PC power supplies in series and have a charge controller step it down to charge a battery but I don't know. Would require an experiment to find out.
If you do one let us know how it works out! Sounds like it'd be fun to do.