Best AC charging system for 100ah portable system

[HngrFatz]

I’ve been doing a ton of research on building a portable power pack for camping. That research has led me to order a 100ah SOK battery to set up with a 10-20a mppt solar charge controller and 200 watts of panels. The one thing I can’t figure out is the best way to charge the system via AC. I’ve seen people run an AC to DC power supply directly to the battery, some people mention connecting the power supply to the charge controller, and others just hook up an external charger as necessary.
Anyone care to share their opinion of what’s best and why?

 

[snoobler]

Welcome to the forum.

10A * 12V = 120W, so you'd want 20A MPPT.

Most 12V battery chargers will work fine provided they don't charge above 14.6V and don't float above 13.6V.

This charger would work:

High rate of charge on small Lead acid batteries - Meanwell Charger

Hello, I just received a Meanwell PB-300P-12 battery charger and I just wanted to tell others about the way it charges batteries. I looked at a number of different chargers and settled on this one, but I admit I did gloss over the recommended battery range it is designed for. Had I pad better...

diysolarforum.com

A power supply set to 13.6V would charge it to 95%+ SoC.

A ~18V laptop power supply connected to the MPPT input would work.

 

[HngrFatz]

Welcome to the forum.

10A * 12V = 120W, so you'd want 20A MPPT.

Most 12V battery chargers will work fine provided they don't charge above 14.6V and don't float above 13.6V.

This charger would work:

High rate of charge on small Lead acid batteries - Meanwell Charger

Hello, I just received a Meanwell PB-300P-12 battery charger and I just wanted to tell others about the way it charges batteries. I looked at a number of different chargers and settled on this one, but I admit I did gloss over the recommended battery range it is designed for. Had I pad better...

diysolarforum.com

A power supply set to 13.6V would charge it to 95%+ SoC.

A ~18V laptop power supply connected to the MPPT input would work.

Thanks for the info! Just to be completely clear, if I were to use an 18v laptop charger would I disconnect the solar input and connect the charger in its place?

 

[snoobler]

Yes. The laptop charger would simulate the PV panels. Simply putting a 3 way selector switch would work nicely...

A = PV panels
B = Laptop power supply
Off = both disconnected.

Probably wouldn't want A+B in that scenario unless you know the power supply is rectified to prevent back flow.

 

[HngrFatz]

Yes. The laptop charger would simulate the PV panels. Simply putting a 3 way selector switch would work nicely...

A = PV panels
B = Laptop power supply
Off = both disconnected.

Probably wouldn't want A+B in that scenario unless you know the power supply is rectified to prevent back flow.

I’m sure that was a no brainer for you but that was an epiphany for me lol! You have been very helpful and I really appreciate it.

 

[snoobler]

I’m sure that was a no brainer for you but that was an epiphany for me lol! You have been very helpful and I really appreciate it.

You're welcome. And thinking about it more, since the panels may have the potential to go notably higher in voltage than the power supply, even if it's rectified or diode protected, it might not be sufficient to protect against the panels, so A/B/off is the better option if you're looking for convenience in switching.

 

[Supervstech]

I mean... couldn’t you connect the power supply to the solar input cables? Don’t the panels connect with mc4 or similar?

 

[HngrFatz]

I mean... couldn’t you connect the power supply to the solar input cables? Don’t the panels connect with mc4 or similar?

Hmmm that’s a good thought too. It would simplify it a little and I wouldn’t have to place the power supply in the box. I could just keep it external and add the same connector that the panels use.

my entire goal with this is to power a 12v fridge in my work truck, power the fridge, my cpap, and a 12v fan when car camping, and have an emergency back up for my cpap at home if I lose power. Flexibility and portability is key for me but I wanted to DIY so I could expand when I eventually move from car camping to a small RV.

 

[Supervstech]

Will did a video on milk crate build, and he shows hooking up the power supply to the charge controller.
Set the supply to 30V or so, and Golden.