Community Forums

Mike Bartelt · 06-07-2016, 04:29 PM

I'm a fairly bright guy, but for some reason some things just escape my grasp of understanding... I'm doing well with research but overthink things and can't find specific answers.

So this will be my ongoing thread of asking dumb questions as I'm stocking up on overhauling my Class A DP's electrical system.

Ok, so my total goal will be installing an inverter and solar to my RV. So far, I have purchased:

Magnum MS2812 Inverter / Charger with Battery Management Kit and Panel.
4 160w Grape Solar panels.

1) Any advice on best value quality / pricing / feature Solar Controller? (the Magnum is out of the question, I don't need support for 6000w of panels...) But it definitely seems like a good idea to buy a MPPT controller.

2) I can't do the main Inverter wiring work myself... and I'm having trouble finding someone to install in my area. Recommendations within 500 miles of the SF Bay Area would be greatly appreciated. I'd like a guy who has done this many times and can get it right without trial / experimentation.

3) Since I have the Magnum Inverter / Charger, I no longer need the stock Converter? Correct? I would keep my Automatic Transfer Switch, but I can lose the stock converter? Ok, this was a stupid question, I guess the answer is no because the charger on an inverter/charger is a converter charger.....

FWIW, I want it set up so I can combine all sources of power... like using the generator to boost battery power while drawing from solar. Is that as simple as wiring it correctly or am I missing components?

Thanks for any advice, suggestions or opinions you're willing to provide! It will be greatly appreciated!

Regards,
Mike

jrusselltx · 06-07-2016, 04:44 PM

1) There are a zillion choices for MPPT controllers so you need to first decide if you want any excess capacity. With the 4X160W panels, the most you could ever get at the battery would be about 640 W / 12 Volts = 53 Amps. You will get less because the battery will quickly charge above 12 volts and you will lose several watts in the wiring and controller efficiency. So you need at LEAST a 50 A controller. MPPT controllers let you put the panels in series which reduces the current going down from the roof so you can use smaller wire. If you put all 4 in series you would get a maximum voltage of 4 X 22.2 or 88.8 volts so the controller would need to allow that. Put two in series and two of those in parallel would be a good compromise. Then you need at least a 50 volt controller. That's a good compromise on wire size and sensitivity to shading and over all efficiency.

2) Can't help you there

3) Yes, you can ditch the converter.

Yes, you can run the generator in parallel with the solar. They both charge the battery and will take care of that automatically.

Good luck.

Mike Bartelt · 06-07-2016, 04:49 PM

Quote:

Originally Posted by jrusselltx

1) There are a zillion choices for MPPT controllers so you need to first decide if you want any excess capacity. With the 4X160W panels, the most you could ever get at the battery would be about 640 W / 12 Volts = 53 Amps. You will get less because the battery will quickly charge above 12 volts and you will lose several watts in the wiring and controller efficiency. So you need at LEAST a 50 A controller. MPPT controllers let you put the panels in series which reduces the current going down from the roof so you can use smaller wire. If you put all 4 in series you would get a maximum voltage of 4 X 22.2 or 88.8 volts so the controller would need to allow that. Put two in series and two of those in parallel would be a good compromise. Then you need at least a 50 volt controller. That's a good compromise on wire size and sensitivity to shading and over all efficiency.

Thanks! That's quite helpful. So the MPPT is definitely warranted. Good to know I was heading the right direction!

I guess the bulk of my difficulty will be finding an installer that will wire the inverter properly and prep me for self-install of the batteries and panels.

jackfish · 06-07-2016, 07:17 PM

For installers, scroll down on this page: Contact â€” AM Solar

vsheetz · 06-07-2016, 07:52 PM

I like the Morningstar 60a MPPT controller for your system with four Grape 160w panels. Quality unit and good tech support.

Mike Bartelt · 06-08-2016, 04:56 PM

Quote:

Originally Posted by jackfish

For installers, scroll down on this page: Contact â€” AM Solar

Thanks! I'll have a look!

Quote:

Originally Posted by vsheetz

I like the Morningstar 60a MPPT controller for your system with four Grape 160w panels. Quality unit and good tech support.

Hmm... I was looking at that unit a few days ago. For the price of the unit and controller I'm not far off from the price of the Magnum. Guess I'll keep researching, but thanks for the suggestion!

TomBr · 06-08-2016, 08:03 PM

Solar generally is costly to get good components, and you may want to rethink trying to do it on the cheap. There is a lot of Chinese junk out there that tends to leave unhappy customers.

Mike Bartelt · 06-08-2016, 08:42 PM

Quote:

Originally Posted by TomBr

Solar generally is costly to get good components, and you may want to rethink trying to do it on the cheap. There is a lot of Chinese junk out there that tends to leave unhappy customers.

Well, so far, I have the Magnum MS2812 Inverter / Charger, Battery Monitor Kit and Advanced Control Panel as the base for my conversion.

For panels, I haven't seen much out there for RV use. The 160w Grape Solar panels seem to be generally decently regarded. They're MIC, but most panels appear to be. For the life of me I can't see why the GoPower 160w panels of the same dimensions, both 12v monocrystalline costs nearly 3x the price except for the brand name. I don't think anyone can convince me that flexible 200w panels are worth 4x the cost.

And now I'm looking for the "right" MPPT controller. I don't want to spend $650 for the Magnum 100a because I'll never need support for up to 6000w of panels, but since it uses the same control panel, any other MPPT controller I would consider has to be priced low enough to be an option.

Batteries? I haven't decided. Either 3 155AH AGMs on the cheap for $1k or a 400ah Lithium bank that will run close to $4k. To start with. I may go higher or add more if necessary.

I think I'm being frugal and am building a rather high quality setup. But if you think I'm wrong, please be more specific.

TomBr · 06-08-2016, 09:20 PM

When you outline the whole system and plans, it sounds like you are on the right path. I just got the impression you might be looking at lower cost mppt controllers and there are several threads on here outlining some really bad experiences with some such units. Pick a good one, not necessarily the most costly but watch out for cheapies.

Mike Bartelt · 06-09-2016, 02:47 AM

I've been really cautious about picking good components.

Without much research, I had been planning on buying this GoPower Extreme 480w kit with 3000w inverter.
Amazon.com: Go Power! Solar Extreme Complete Solar and Inverter System with 480 Watts of Solar: Automotive
But after buying my coach, I started researching it further, found out that they don't offer out of warranty service, which makes everything in the kit disposable, which I didn't like.

I also realized I didn't need many of the included components including the transfer switch and the converter.

So, if I buy the expensive Magnum Solar Controller, I'll end up at about the same price as that GoPower kit but I'll end up having much nicer components and 4 panels instead of 3.

**CountryFit** · 06-09-2016, 07:45 AM

mike, you got the best magnum inverter, congratulations. what you'd need now is only the solar controller (other than batteries).
a real good one, if not the best, is midnite. they have different models, look at "light" versions, it's cheaper comparing the standard ones but might just work well for you. as you are self labelled as frugal, you might check craigslist, some times you may be able to mine some super deals.

as for gopower, i wouldn't recommend it as i don't think it's anywhere close to "good value". good luck with your adventure.

Mike Bartelt · 06-09-2016, 06:34 PM

Quote:

Originally Posted by CountryFit

mike, you got the best magnum inverter, congratulations. what you'd need now is only the solar controller (other than batteries).
a real good one, if not the best, is midnite. they have different models, look at "light" versions, it's cheaper comparing the standard ones but might just work well for you. as you are self labelled as frugal, you might check craigslist, some times you may be able to mine some super deals.

as for gopower, i wouldn't recommend it as i don't think it's anywhere close to "good value". good luck with your adventure.

Yeah, I've come to the realization gopower might not necessarily be crap, it's high price pays for search rankings.

I looked at the midnite products, a bit more than I'm willing to spend. If I pay that much I'll likely just get the Magnum solar charger. But thanks for the suggestion, they certainly look like a quality product.