Another solar install: 310GK

[el Rojo]

Good job AL. Brian Boone did part of our electrical install and is a very good installer. He did the inverter, batteries and sub-panel. We added solar at a later date. You should have enough panels where you don't need to tilt them to get a full charge. Are you coming to the Quartzsite rally?

Red

[acadiaforever]

I’ve thought about converting our to tilting panels. I might crawl up there and see how much slack I have in the cabling.


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I think that the cabling is done with more slack for tilts. Sue (Brian's wife and business partner) did the roof. The very first thing she asked was, "is this a tilt installation?"

But you can always splice in more wire! [grin]

[Edited to add DMB's quote]

[acadiaforever]

Good job AL. Brian Boone did part of our electrical install and is a very good installer. He did the inverter, batteries and sub-panel. We added solar at a later date. You should have enough panels where you don't need to tilt them to get a full charge. Are you coming to the Quartzsite rally?

Red

Hi, Red.

Whether we need to tilt will be interesting. I really don't know how much sun we'll be getting there. Yes, we're registered for the Q rally and will actually be spending much of the winter boondocking in Q and Blythe. We'll probably be trying the other LTVAs as well.

-Al

[teamnash-rv]

Thanks for the write up. Very detailed.

Are the batteries installed in the front storage bay or mid storage bay? Hard to tell from the pictures. Since the roof wires came down through the small cabinet in the bathroom and the pantry closet in the kitchen I am thinking the batteries are in the mid storage bay?

Rich

[acadiaforever]

Thanks for the write up. Very detailed.

Are the batteries installed in the front storage bay or mid storage bay? Hard to tell from the pictures. Since the roof wires came down through the small cabinet in the bathroom and the pantry closet in the kitchen I am thinking the batteries are in the mid storage bay?

Rich

Thanks, Rich. Glad the post is useful. The batteries, solar controllers, and inverter are all in the front-most compartment. I've since added a shelf over the batteries, both to protect the terminals from having things fall on them, and to regain some of the storage space I lost.

The pass-through storage area was too precious to me; the wiring just shoots across the ceiling of that compartment into the front.

-Al

[The Max]

All in all, we're very happy with this install. Here's hoping 600AH and 1440W are enough for what we want to do! I'll let you know when we get to the desert.

We are hoping to get a 310GK or -R next year. Not sure what kind of RVing we are going to do, so I was going to get the Generator Prep just in case. Your setup is awesome. Is there anything that can be done on shore power or on a generator that you can't do? Can you run two air conditioners at once? In that case, I may skip the generator prep. Thanks.

[acadiaforever]

If air conditioners are important to you, you will need a generator. The definition of "reasonable" will vary between (reasonable) people, but from my point of view wanting to run air conditioners is incompatible with a "reasonably" sized solar system. Ours is probably on the larger end of the scale of solar installations, and we ruled out air from the very start.

That isn't saying don't get solar, but for air you would need to supplement it with a genny. They just draw too much current. I turned one of mine on today just to check (turned off the shore power), and it was drawing 167 amps out of the battery. That's just one.

We carry two (non-Honda) 2kW (peak) inverter gens in the truck, if we ever want to run the air while boondocking. They are VERY rarely used. I think we ran them three times all winter out on the desert, after consecutive very cloudy days. Matter of fact, I should run them up to exercise them. They've been sitting for a while. Another item for tomorrow's list.

But what we CAN do is what we need.

Here is our practice for the winter in the AZ desert, when the days are short and the sun is not strong. We run the refrig and water heater on propane, and we use the propane furnace instead of the heat pump that is in one of our AC units. We don't use the fireplace. We DO use the convection oven, microwave, electric hot water pot for coffee / tea / hot chocolate, and TV for several hours each night,as well as all the other "essentials" of life: hair dryer, electric blanket to take the chill off, two computers, printer, and a gazillion 5 volt "wall wart" chargers for assorted devices. We also sleep with a fan on all night. During the depth of winter, we were usually down to about 60% - 70% charge in the morning, and recharged by between 2 and 3 in the afternoon. I got so that I stopped monitoring stuff, knowing that it would just work.
-Al

[The Max]

If air conditioners are important to you, you will need a generator. The definition of "reasonable" will vary between (reasonable) people, but from my point of view wanting to run air conditioners is incompatible with a "reasonably" sized solar system. Ours is probably on the larger end of the scale of solar installations, and we ruled out air from the very start.

That isn't saying don't get solar, but for air you would need to supplement it with a genny. They just draw too much current. I turned one of mine on today just to check (turned off the shore power), and it was drawing 167 amps out of the battery. That's just one.

We carry two (non-Honda) 2kW (peak) inverter gens in the truck, if we ever want to run the air while boondocking. They are VERY rarely used. I think we ran them three times all winter out on the desert, after consecutive very cloudy days. Matter of fact, I should run them up to exercise them. They've been sitting for a while. Another item for tomorrow's list.

But what we CAN do is what we need.

Here is our practice for the winter in the AZ desert, when the days are short and the sun is not strong. We run the refrig and water heater on propane, and we use the propane furnace instead of the heat pump that is in one of our AC units. We don't use the fireplace. We DO use the convection oven, microwave, electric hot water pot for coffee / tea / hot chocolate, and TV for several hours each night,as well as all the other "essentials" of life: hair dryer, electric blanket to take the chill off, two computers, printer, and a gazillion 5 volt "wall wart" chargers for assorted devices. We also sleep with a fan on all night. During the depth of winter, we were usually down to about 60% - 70% charge in the morning, and recharged by between 2 and 3 in the afternoon. I got so that I stopped monitoring stuff, knowing that it would just work.
-Al

Thanks for the reply, great information. I was hoping to run a residential fridge on battery. Since you are not, I will do a lot of research before going with the -R option.

I wish I had use for a hair dryer (or even a comb), but DW does use one.

Max

[teamnash-rv]

Thanks for the reply, great information. I was hoping to run a residential fridge on battery. Since you are not, I will do a lot of research before going with the -R option.

I wish I had use for a hair dryer (or even a comb), but DW does use one.

Max

Here's how I look at it. I'd be curious what other folks think.

A residential fridge generally requires 15-18amps to run. Someone responded that the fridge in their 310GK unit uses 10a (amps). Let's use 15a for sake of discussion. So in 24 hours 15a * 24h= 360ah of AC current. You would also need to consider over a 24 hour period what other devices you want to power - lights, microware, hair dryer, heat, ... etc. For this discussion we'll just consider the fridge.

I am interested in installing solar so I would go with lithium batteries - the lithium I would use has 100ah of DC current. 6 batteries = 600ah of DC current.

To power the fridge you need to convert DC to AC current. Inverting DC to AC is not 100% efficient. I found below an efficiency curve on the web.



Note sure I have this correct (need to think about this more) but for discussion let's assume the inverter is 85% efficient. This means the 600ah of DC current from the batteries can supply 510ah of AC current. We calculated above fridge requires 360ah of AC current. Over a 24 hour period you would have 510ah - 360ah = 150ah leftover to supply your other needs.

With the lithium batteries you definitely need source to charge the batteries - solar, ... but the solar / lithium solution is not cheap :-(

I believe with the residential option on the 310GK an extra battery is supplied. I haven't done the math but I think the 2 batteries would only be sufficient to get you between campgrounds where you would need to be connected to an AC power source. The 2 lead acid batteries would definitely not be sufficient for you to be off the grid 24 hours or more.

My thoughts - If I get this wrong let me know how you think about it.

rich

[The Max]

Here's how I look at it. I'd be curious what other folks think.

A residential fridge generally requires 15-18amps to run. Someone responded that the fridge in their 310GK unit uses 10a (amps). Let's use 15a for sake of discussion. So in 24 hours 15a * 24h= 360ah of AC current. You would also need to consider over a 24 hour period what other devices you want to power - lights, microware, hair dryer, heat, ... etc. For this discussion we'll just consider the fridge.

I am interested in installing solar so I would go with lithium batteries - the lithium I would use has 100ah of DC current. 6 batteries = 600ah of DC current.

To power the fridge you need to convert DC to AC current. Inverting DC to AC is not 100% efficient. I found below an efficiency curve on the web.



Note sure I have this correct (need to think about this more) but for discussion let's assume the inverter is 85% efficient. This means the 600ah of DC current from the batteries can supply 510ah of AC current. We calculated above fridge requires 360ah of AC current. Over a 24 hour period you would have 510ah - 360ah = 150ah leftover to supply your other needs.

With the lithium batteries you definitely need source to charge the batteries - solar, ... but the solar / lithium solution is not cheap :-(

I believe with the residential option on the 310GK an extra battery is supplied. I haven't done the math but I think the 2 batteries would only be sufficient to get you between campgrounds where you would need to be connected to an AC power source. The 2 lead acid batteries would definitely not be sufficient for you to be off the grid 24 hours or more.

My thoughts - If I get this wrong let me know how you think about it.

rich

Rich, thanks for the reply.

I would go with a setup similar to @acadiaforever or DMB, and would be using lithium batteries.

Volts * Amps = Watts. If you go from battery voltage of 12.6 volts DC to 120 volts AC, there is about a factor of 10 difference (to keep the math simple.) So if the fridge uses 360 ah at 120VAC, wouldn't that be 3,600 ah of 12V DC? (Maybe I am looking at this wrong.) That would make things worse.

The fridge is not running all the time, so maybe it is using 1/2, 1/4, or 1/10 the power? Don't know. And I am sure the duty cycle varies with ambient temperature and how long door is open, etc.

And at least during the day, the solar cells are charging the batteries at the same time the fridge is draining the batteries, so the net power usage would be the difference between the two.

Someone correct me if I am looking at this wrong.

Max