Quality "small" MPPT charge controller

[Browneye]

Where no circuit protection is needed, a dc breaker makes for an expensive switch.
>snip

You repeated all the same things.
DC min-breakers are not expensive. And technically, they're required by current NEC. A PV disconnect should cut both legs.

If you can easily get to your PV MC4 connectors then you can easily unplug them if necessary. If they're on your roof it's easier to have a cutoff switch for them so you don't have to climb up there.

This vid explains it nicely.

 

[BroomJM]

You repeated all the same things.
DC min-breakers are not expensive. And technically, they're required by current NEC. A PV disconnect should cut both legs.

If you can easily get to your PV MC4 connectors then you can easily unplug them if necessary. If they're on your roof it's easier to have a cutoff switch for them so you don't have to climb up there.

This vid explains it nicely.

I'm building a DIY portable power station. I have a 100a breaker between the battery and the positive bus bar but you're saying there should be another fuse/breaker between the SCC and the positive terminal of the battery? Since this is meant to be mobile, most of the solar charging will be with a couple of portable panels. I haven't done the math yet, but I suspect even a 20a SCC will be adequate. I have a spare 50a breaker, but that would be too large for this application, correct?

When you look at a commercially-made power station, it seems quite a bit simpler than when you start assembling one and try to get all of the various parts you really need into one package.

 

[Browneye]

I don't recall your battery size or type. For a lead acid battery an ANL or post fuse is fine, for lifepo4 a class-t is appropriate. It should be sized at 125% of your maximum current load to the battery. I didn't see an inverter size.

A quick look says you have AGM batteries but going to a 230A lifepo. I have a 120A bms on my lifepo, so I have a 150A class-t fuse right after the main positive battery post. And a main cutoff switch to completely disconnect the battery from the system. Pic below.

Wherever your solar controller attaches to your system, be it a bus or directly to the battery, that wire should also be fused - 125% of the rated charge current of the controller. A switching breaker or ANL fuse works well for this.

If you have an inverter, it too should have a fuse, but if it's attached directly to your battery it can use your battery main fuse.

You want to protect wiring based on maximum current carrying, plus 25% so it doesn't nuisance trip. Wiring to a 1000W inverter is going to be a lot larger than to a 30A solar charger since it can draw up to 120 amps. Each device or wire connection should be fused to protect that wiring.

Lifepo4 can put out so much current it can arch across a fuse and weld it's own bridge, and why a classT is spec'd for them.

My DIY 230A lifepo4 battery pack from prismatic cells. My solar chargers are breakered or fused where they attach to the system bus. My primary wires are 2awg to carry up to 120 amps. My inverter is a 600W, and total system current draw adds up to about 80-90A if I turned everything on.

 

[BroomJM]

That is incredibly helpful, Chris. Thank you!

 

[Dexx]

Are any of the small MPPT controllers from the likes of Alibaba or AliExpress well regarded? I'm after one to charge my 12V AGM lead acid battery from a 160W portable panel. I'm not after any 'smarts', and charge current need not exceed 10A. Just something cheap but not trash.

 

[Browneye]

I got a renogy voyager for that. Seems to work fine.
They have less water-resistant ones for less, indoor mount.
Windy nation, rich solar, bougerv, would also work. A PWM for this application works fine. It just “controls” current so as not to over charge your battery.

All can be sourced in US, with returns warranty. I would not source from either of those sites, but you could give it a shot and let us know how it goes.

 

[DenverGuy]

I'm building my own portable power station. I need a small MPPT charge controller (10-20 amp) that will charge 12 or 24 volt batteries. I'm considering the Rover Elite 20A unit. Is this a good choice? Is there something better, or at a better price point, that I should be considering? If I could get something with a smaller footprint that would be nice, since space is somewhat limited. I don't want to sacrifice on quality, though.

Sounds like you are looking for a small one.

 

[Zil]

Chris Brown is a good guy, with lots of good advice. Sometimes he forgets the scale of what we are building. This is small. think "milk crate".
I agree, search on Amazon and have easy return.

 

[Browneye]

Chris Brown is a good guy, with lots of good advice. Sometimes he forgets the scale of what we are building. This is small. think "milk crate".
I agree, search on Amazon and have easy return.

Sometimes I miss details. I'm kind of a 1000' level kind of guy. LOL
"Oh that looks good from 10' away...up close not so much." ?

 

[KMac55]

TriStar 45 MPW. Installed April 2017. 400W solar, 12V 690 ah GC2 battery bank. No problems. Going fine today.

Those Morningstar controllers last years. I've got both a 60amp mppt and the 45amp pwm. The larger one has Ethernet ip native as well as the usual Modbus type serial connections. The other has an adapter for the Ethernet. So I run a simple network. I used an old netbook to program both and now just keep it running and log into them remotely to watch graphs, data, and adjust occasionally. Huge heatsinks, so no fans or moving parts to wear out or fail, no noise, and very, very solid.

 

[aliciarich]

Victron! Definitely, I have experience with it and I'm so satisfied, take a look the prices are top!

 

[BroomJM]

I went with the Renogy Rover, 20A model. Before anyone asks, yes I connected the controller to my battery before hooking up any solar!

 

[A.Justice]

A warranty is fine if they honor it. There are so many things that can happen to it that aren't covered though. It does look like a pretty durable case

There's a guy on here who fried two of them, and Victron replaced them both even though it was pretty obviously a user error.

 

[Scph9002]

I don't recall anybody who owns a Victron looking back and regretting what they paid. (i'm certain its happened though)
I was sucked in with the 5 year warranty and my love for the product was solidified with the ease of use with the bluetooth app.

To me, the SCC is the heart and brains of a solar system. Getting a quality unit that will provide reliable service for many many years is a great investment. I have a Morningstar Tristar MPPT that i bought in 2010 that has worked without a hiccup 24/7/365.

Best $700 i spent, though i was convinced i was off my rocker when i bought it... one of my best investments ever.

meanwhile i spend 450usd for epevers largest 100a ssc. Im currently waiting for my third replacement in 1 year. Each replacement cost 140usd in shipping and tax

these controllers cant handle 150% of rated pv max power as the manual says...

Wont over panel above 100% of rated power on these large ssc anymore and i hope this last one will last.