Switching power supply as charger

[OM617YOTA]

Not seeing much discussion about this when searching, but it seems like an obvious charger solution - readily available and inexpensive. An example below, although these kinds of power supplies are ubiquitous and made by lots of folks. This one has adjustable voltage from 25.65-29.7v. Note that this is the 27v version, for a 24v nominal lifepo4 system, the 24v power supply won't be the right voltage.

https://www.mouser.com/ProductDetail/MEAN-WELL/LRS-600-27

I have two MPP LV2424s set up as split phase 240v, and per MPP, they need 240v input from a generator. I only have a 120v generator, so enter a separate charger. If this one works out, I'll buy a couple more power supplies and stack them up, to use as much of the generator's capacity as reasonable, and shorten the time the generator needs to run.

Maybe the reason this isn't more common is because it's not a set and forget solution. Although one could set the power supplies for the battery bank float voltage, which would work fine. My usage case will be for when charging from a generator, with monitoring of both the system as a whole, and the state of charge of the batteries.

Any thoughts? Anything I'm missing?

 

[fafrd]

Not seeing much discussion about this when searching, but it seems like an obvious charger solution - readily available and inexpensive. An example below, although these kinds of power supplies are ubiquitous and made by lots of folks. This one has adjustable voltage from 25.65-29.7v. Note that this is the 27v version, for a 24v nominal lifepo4 system, the 24v power supply won't be the right voltage.

https://www.mouser.com/ProductDetail/MEAN-WELL/LRS-600-27

I have two MPP LV2424s set up as split phase 240v, and per MPP, they need 240v input from a generator. I only have a 120v generator, so enter a separate charger. If this one works out, I'll buy a couple more power supplies and stack them up, to use as much of the generator's capacity as reasonable, and shorten the time the generator needs to run.

Maybe the reason this isn't more common is because it's not a set and forget solution. Although one could set the power supplies for the battery bank float voltage, which would work fine. My usage case will be for when charging from a generator, with monitoring of both the system as a whole, and the state of charge of the batteries.

Any thoughts? Anything I'm missing?

DIY 'Chargenectifier'

Based of the informative info recently posted by @ChrisFullPower in another thread I'm intrigued in DIY'ing a charger from used rectifiers. A quick search on eBay for '48v rectifier' has made me realize it's definitely doable at costs much lower than off the shelf options... I'll start with a...

diysolarforum.com

 

[OM617YOTA]

DIY 'Chargenectifier'

Based of the informative info recently posted by @ChrisFullPower in another thread I'm intrigued in DIY'ing a charger from used rectifiers. A quick search on eBay for '48v rectifier' has made me realize it's definitely doable at costs much lower than off the shelf options... I'll start with a...

diysolarforum.com

I saw that, but it quickly went to CAN programming and rather complicated steps for what I'm trying to do. I've now skimmed the whole thread, definitely not what I'm trying to do.

With the charger linked above, I should be able to set the voltage, put one kind of power in one end, get another kind of power out the other end, and that's it. Not looking for any auto controls, this will be for charging from a generator during a grid outage and prolonged dim spell, when I'll be manually starting + stopping the generator anyway.

 

[Consumerbot3418]

With the charger linked above, I should be able to set the voltage, put one kind of power in one end, get another kind of power out the other end, and that's it. Not looking for any auto controls, this will be for charging from a generator during a grid outage and prolonged dim spell, when I'll be manually starting + stopping the generator anyway.

Although one could set the power supplies for the battery bank float voltage, which would work fine.

I've been down this road.

An RV "converter/charger" works well, but is much more expensive per watt. The Mean Well SPS looks like a dead simple solution, but the issue is driving it with the correct voltage--set it too high, and it will enter overload protect and shut down. Set it too low, and you get minimal/zero output. As the battery charges, the "correct" voltage will change.

It would be nice if the CC circuit could be employed to limit to, say, 95% of rated output power (instead of 105-150% followed by shutdown after 3 seconds, per the datasheet).

 

[pollenface]

You can do it.

My favourite chargers are my 30v & 60v adjustable bench power supplies coupled with a timer switch.

I'm currently charging NCM batteries salvaged from disposable vapes @ 4.1v

 

[OM617YOTA]

Just tested this power supply, ran fine putting out nearly 800w for over half an hour, despite it's 600w rating. I only had 12awg wires on hand, they were getting a bit warm, will definitely use something more stout when I wire it in for good.

I'll be buying at least one more power supply to parallel, likely two. Very pleased.

 

[OM617YOTA]

Another update, this charger setup has continued to work fine. Used it to top up batteries when they were only half full, solar wasn't getting it done, and we had nasty weather coming so I wanted full batteries. Trucks along at full output without issue.

I do still need to wire it up properly, 12awg is laughably inadequate.