solar vs inverter generator

[pianotuna]

Hi,

As some of you know my Yamaha 3000 iSEB was stolen.

I find myself back to considering a massive upgrade on the solar system (jumping to 2000 watts), or replacing the generator.

Going to 2k of solar would allow me to run the roof air from a large inverter.

I would need to have a rack fabricated to cover the entire roof of the RV. This would be more costly than replacing the generator--but it would give me a lot more independence, electrically speaking.

For the generator route, I need to decide between a Yamaha 3000 iSEB with Pinella remote added, or a much less expensive Champion 3500 watt inverter generator that comes with the remote right from the factory. I will need to have a secure rack fabricated to prevent another theft.

If I replace the Magnum, I have the possibility of moving to a 24 volt system, which would make upgrading the solar cheaper, and 24 volts DC to 120 AC is much easier on an inverter. It does add a layer of complexity as I'd have to have a DC to DC converter for all the 12 volt needs of the RV.

What choice would you make and why?

[pianotuna]

Hi Mex,

Rain seems to keep my existing panels clean. But a ladder would useful.

BFL13,

I'd be abandoning the existing system, so I'd be starting over with poly panels in series.

MEXICOWANDERER wrote:
Don if your entire roof gets paved with panels, how would you clean them?

[pnichols]

jharrell wrote:
That will be the only thing stopping me from adding more panels, have to leave enough walkway to get to everything on the roof. 6 160w panels might be pushing it on my 31ft.

That problem above is why "the whole RV world is waiting for" affordable and durable enough flexible solar panel material such that it can be used as the RV's awning while it's providing power! 😉

[CA_Traveler]

MEXICOWANDERER wrote:
Don if your entire roof gets paved with panels, how would you clean them?

Wait for rain?

Some possible ways:
1. Walk on them perhaps using some plywood panels.
2. Use a ladder on the side of the rig.
3. Washing poles (with water/soap flowing inside and curved/bent to access the roof. Curved brushes to clean boat hulls are common in marinas.
4. Above but adapted to a pressure washer.
5. Commercial truck washes often have cat walks to reach the trailer roof.

But regardless of solar panels roof access is required for normal maintenance and that access could also be used for cleaning.

[jharrell]

MEXICOWANDERER wrote:
Don if your entire roof gets paved with panels, how would you clean them?

That will be the only thing stopping me from adding more panels, have to leave enough walkway to get to everything on the roof. 6 160w panels might be pushing it on my 31ft.

[CA_Traveler]

BFL13 wrote:
When I tried 24 vs 12 it did not go 2 to 1 because the 24v panel was 60 cell, not 72. PT has funny panels, so can't say how that would work out.

Serial solves that problem. My ideal layout was for the panels to be mounted crosswise on the rig and the 65" length left plenty of access vs the 72 cell panels.

[MEXICOWANDERER]

Don if your entire roof gets paved with panels, how would you clean them?

[pianotuna]

Hi Phil,

It did not have a built in generator--and for four years I managed nicely without one.

The Magnum is not yet back from warranty repair, so I'm using a 1000 watt PSW unit.

When I had flooded Marine jars I got high charging rates, but now that I'm using telecom batteries, the only time I see power flowing to the house from the alternator is when I have a 300 watt load on the house.

I've not had this low a wattage available to me for a lot of years.

The starter battery is due for replacement. I'm hoping if I go AGM I'll start seeing more amps to the house jars again.

[pnichols]

Don,

You're still in a Class C ... right? If so, it's probably powered by a V10 ... right?

If so again, you might want to consider having the V10 retrofitted with two alternators so you can just idle the V10 for 2-3 hours here and there to top up your big battery bank. We do this quite often with only our V10's single 130 amp alternator. Our setup has so far provided up to 70 amps at idle into our 230 AH AGM battery bank. I believe that Ford V10's are harmlessly idled for hours in ambulance service. The idling V10 is ultra quiet and idles with very little odor.

Also I'm a bit confused about your rig. Doesn't it have a built-in generator like most Class C motorhomes? Why did you then also have a portable genny (that was stolen)? We carry a portable genny along too for extreme emergency backup, but rarely use it. We generally use the built-in Onan or idle the V10 for topping up our batteries when drycamping.

P.S. The "Gold Standard" for North American drycamping - Earthroamer - has no generator (or propane, either) on board. They're designed and delivered with solar for charging their large battery bank AND .... twin atlernators on their main engine for charging their large battery bank when solar isn't enough. (The Earthroamer uses a diesel cooktop and furnace. It's A/C is powered by it's large battery bank ... which is kept charged as I described.)

[BFL13]

When I tried 24 vs 12 it did not go 2 to 1 because the 24v panel was 60 cell, not 72. PT has funny panels, so can't say how that would work out.

[pianotuna]

Hi SMK,

I agree, but I'd be doing only 278 amp-hours @ 24 volts.

[time2roll]

pianotuna wrote:
No one has noted that 2000 watts of solar is overkill for a 556 amp-hour battery bank. The reason I want that is so even on a lousy day I'd get enough charging to keep the bank up (obviously no air needed at -30).

The OP said you would probably jump to 24 volts. That 556 at 24v would not be too bad although the additional weight is creeping up.

Need less with lithium as 100% capacity is available.
24v 300ah $6,500 just 318 pounds
Real benefit is virtually no absorption time.

[jharrell]

pianotuna wrote:
No one has noted that 2000 watts of solar is overkill for a 556 amp-hour battery bank. The reason I want that is so even on a lousy day I'd get enough charging to keep the bank up (obviously no air needed at -30).

My opinion is you can never have too much solar even with a small bank if you have something to do with it. Besides just being able to get decent power in bad conditions, which even overpaneling a controller is fine because of this.

I have a Magnum 3000 hybrid like you with just 2 Lifeline GPL-4CT's for 220ah and 320w of solar and I want more solar, much more. Will be going to 640w before long and maybe 960w after that.

With the Magnum hybrid it will "Load Support VDC" once the batteries are charged pulling them down to the Magnums float voltage and inverting the excess power from solar. I get usually an extra 1 amp at 120v lowering my shore/generator draw accordingly. Watching the shore/generator draw go down makes me want lots of panels. It actually pulls about 80 amps from alternator when driving and roof air on while generator provides the rest. Not sure If a like that or not on a 175 amp alternator, might do a disconnect.

I did a Micro-Air easy start on my Coleman Mach 15 to it starts no problem on the Magnum (70+ starting amps down in the 20's after). The Micro air would allow a small generator like a Honda 2000 to start it as well. Just easier on everything when the AC starts up now.

I can run my AC off the two batteries for 30-45 minutes no problem, not worth it, but with 2kw solar it might be feasible, either way I can lower gen fuel usage significantly.

[JiminDenver]

Hi Don

I was thinking you may need to worry about the charge rate but it's only around 144a.

[pianotuna]

Hi Mr Wizard,

I've been lucky with having friends and clients that allow me to plug in. Tonight is typical. I have two 15 amp circuits (both GFCI so I'd not be able to use the Magnum).

The battery bank is hungry from running the fridge for most of the day on 120 volt via the inverter. The PD is charging at 22 amps and voltage is only 13.4 (it went into boost mode).

I did my usual checks--and found that voltage dropped to 107. So I added the autoformer which boosted voltage back to an extremely acceptable 116.

The other line is running a 1500 watt (really not 1500) fan based heater. The front of the RV is up to 20 c now (68 f), and the bedroom is about 18 c (64 f).

Once I get the RV heated, I'll turn off the heaters on the autoformer and use the microwave to warm up some turkey!!! I may have to use the Wizard to lower the charge rate or even move it over to the other shore power cord.

I know I can manage -7 c (20 f) on two 15 amp circuits. After that I need three so it is off to the expensive local campground.

I'm missing the Magnum big time.