Solar Van with micro inverters

[inetdog]

Then you do not have an MPPT controller. 240 watt panel should generate about 18 to 19 amps to a 12 volt battery. A 240 watt with a PWM controller will only give you 11 amps. Very simple math.

Or else the reduction from 19A to 11A corresponds to the reduced effective area and reflection losses from flat mounted panels (0 degrees elevation). The OP can check out the effect of panel orientation easily using PVWatts for his area.
No idea what latitude jony101 is at.

[Sunking]

A single 240 watt panel with mppt will get you about 11 amps lying flat on the roof.

Then you do not have an MPPT controller. 240 watt panel should generate about 18 to 19 amps to a 12 volt battery. A 240 watt with a PWM controller will only give you 11 amps. Very simple math.

[donald]

I have a 240 watt panel on my astrovan roof and it takes up almost the entire area, so from my view, I see 4 x 100 panels being a very tight fit. My advice would be to just get a single large panel, it will be easier to install (only 4 bolts.)

A single 240 watt panel with mppt will get you about 11 amps lying flat on the roof. A 12 volt fridge set at 40 degrees uses about 25 amps total in a 24 hour period. For cooking just get a 12 volt roadpro lunch bucket cooker (uses about 11 amps) will heat up most food in 30 minutes. You can probably find a 12 volt teapot or comparable.

A 120 ah agm battery should be good enough for the fridge and lights and laptops, as long as you stay away from the microwave and large inverters.

I use to run my 12 volt fridge edgestar fp430 24/7 on a 120 watt panel and 75ah agm battery, it was below the bare minimun needed, but It work for months at a time. No need to spend too much on the solar system, as long as you can get the right energy efficient 12 volt appliances. You might not even need a battery isolator if your energy needs are low, I never used one, not even when I had a 75 ah agm house battery.

That's good advice. Also install a voltmeter that you can easily read at a glance. This reading is the primary way you will know in the evening if you need to worry about power consumption.

You may not need an alternator connection. But the connection does allow your house battery to reliably get through absorption charging from solar on some days when you drive in the morning. How much this complete charging extends AGM battery life is unknown. Economically it is more important on a larger battery bank. With one battery, good arguments can be made both for and against the value of an alternator connection.

[jony101]

I have a 240 watt panel on my astrovan roof and it takes up almost the entire area, so from my view, I see 4 x 100 panels being a very tight fit. My advice would be to just get a single large panel, it will be easier to install (only 4 bolts.)

A single 240 watt panel with mppt will get you about 11 amps lying flat on the roof. A 12 volt fridge set at 40 degrees uses about 25 amps total in a 24 hour period. For cooking just get a 12 volt roadpro lunch bucket cooker (uses about 11 amps) will heat up most food in 30 minutes. You can probably find a 12 volt teapot or comparable.

A 120 ah agm battery should be good enough for the fridge and lights and laptops, as long as you stay away from the microwave and large inverters.

I use to run my 12 volt fridge edgestar fp430 24/7 on a 120 watt panel and 75ah agm battery, it was below the bare minimun needed, but It work for months at a time. No need to spend too much on the solar system, as long as you can get the right energy efficient 12 volt appliances. You might not even need a battery isolator if your energy needs are low, I never used one, not even when I had a 75 ah agm house battery.

[Sunking]

Brad you are getting in way over your head asking for the impossible. You cannot have it all. Solar is extensively limited. Refrigeration and cooking is done with LPG in a RV and camper. The large loads like refrigeration, cooking, heating, and air conditioning are just possible or feasible. Solar part is just for lighting, TV's and some lite cooking is possible with a large bank of batteries and generators to back things up and supply the bulk of the power. You do not have the money, space, or knowledge to pull it off. The amount of battery you are going to be able to fit and afford can only drive a 500 watt Inverter. You need to tap the breaks. If you continue on you run a very high risk of a fire trying to make equipment do what it cannot do.

[Sunking]

Seems like good advise to get started. As always I have a few questions:
I notice there are several different types of isolators, any advantage to the electronic types?

Huge advantages. To start no welded contacts first time you discharge your battery deeply. The big advantage if you use good ones like Sure Power you will note they are made for vehicle manufacture specific like Ford, GM, Dodge, Toyota etc. They are wired into the Vehicle Alternator taking voltage regulation to the Isolator so each battery port receives the proper voltage and current. Something a relay and most Isolators cannot do.

[inetdog]

But you have a problem with the 1000W load on a single battery. That would be a C/1.2 (1000W/12V=83.3A) discharge rate for a 100AH battery. Not even AGMs can handle that high of a discharge rate. You need a bigger battery. AGMs would be a maximum discharge rate of about C/4 and flooded batteries about C/8.

WWW

An AGM cranking battery could easily handle C/1, but the cycle life might not be very good.

[Wy_White_Wolf]

...This means I will need to look at 80% discharge. I understand that discharging to 80% will reduce battery life, but I may not have any other options. Of course we can always reduce our usage to match our available power. One option is to pony up for a Lithium battery, but this complicates design and as far as I can tell the technology is still evolving. ....

But you have a problem with the 1000W load on a single battery. That would be a C/1.2 (1000W/12V=83.3A) discharge rate for a 100AH battery. Not even AGMs can handle that high of a discharge rate. You need a bigger battery. AGMs would be a maximum discharge rate of about C/4 and flooded batteries about C/8.

WWW

[donald]

To work overnight on one house battery the cooler will need to be compressor based, like Engle. The cheaper 12v technology uses too much power, and is designed to be used with the engine running.
I have a large Engle. It is very nice, but somewhat pricey. I mostly use it as a freezer.

[Brad Taylor]

Donald - I get your point. I have 5KW of solar on my home roof and it works well, but translating that to an RV battery system, well I suppose I'm trying to do the impossible. I'm not quite ready to give up as I really want to spend significant time camping comfortably off grid. In that case I really want a small working solar fridge without running the RV for my veggies and cheese. As you suggest I can focus on reducing the power I use until it is practical. Going to look at some ultra insulated refrigeration now.

[donald]

You are trying to do far to much with electricity in a small vehicle with limit weight carrying capacity. You will need to do most cooking with fuel, unless you have a very large budget. Like a budget for electric in a racing yacht.
The way to get by without a generator in an RV is a large battery system than can be charged from a lot of panels, and a quality alternator connection. Even this only works if you drive most days to charge the battery. I don't see how you have anywhere near the space weight carrying capacity to do that kind of systems.
I do less electric in my camper and I have 450lbs of battery.
The place to start is to talk to others with your vehicle size. Don't focus on equipment first, but solving problems. You will struggle to be able to run an electric refrigerator overnight, much less cook. The "standard way" people travel and camp in your vehicle will be the right way. You simply don't have a big enough RV to reinvent the wheel with electricity.

Note the price, weight and performance of the device below compared to your solution:

http://www.webstaurantstore.com/portable-gas-stove-butane-burner-with-1-range/472E10SL.html

[Brad Taylor]

But before you buy one single panel, get a Electronic Battery Isolator so you can use your vehicle alternator to charge the batteries. .

Seems like good advise to get started. As always I have a few questions:
I notice there are several different types of isolators, any advantage to the electronic types? The relay based ones seem to offer lower drop. Will they automatically connect when the engine starts up and isolate when the RV battery is charging from PV or AC? Or should I just put these on a manual switch? Any particular models that work well? Thanks in advance

[Sunking]

Brad what you asking for is a Off-Grid System.

Use Grid Tied Panels because they are much less expensive than Low voltage battery panels, but you must use a MPPT Charge Controller to charge the batteries. As long as you are going 200 watts or more on panels, a MPPT system is less expensive. It takes a 300 watt PWM system to equal a 200 watt PWM system. A 200 Watt MPPT system ccost around $100 less than a 300 watt PWM system.

If you need AC power which you shouldn't in a mobile application, use one only large enough to meet you needs. Otherwise run every thing directly off 12 volts DC and eliminate the inverter.

But before you buy one single panel, get a Electronic Battery Isolator so you can use your vehicle alternator to charge the batteries. If you drive an hour daily you will not need panels as your alternator can generate more power in a hour than a van full of panels can generate in 2 or 3 days. A $50 Electronic Isolator does more work in an hour than a $1000 worth of panels can do in a day. Smart Money.

[inetdog]

Sunking - Agreed, this exactly why I'm asking this forum for guidance. I don't expect to be knowledge free forever though

Step one: For a mobile system like the one you propose, it does not make much sense to spend the money and carry the weight to provide a grid tied or hybrid system.
You will be best served by making use of your vehicle alternator whenever possible and going with a pure off grid inverter.
You can still use so called grid tie panels (high Voc) in combination with an MPPT CC though.
There is a small chance that a system using solar optimizers on each panel would work for you, but the Solar Edge works only with their own grid tie inverter.

Some pure off-grid inverters are listed on their (Chinese) sales site as "microinverters" just because they are small, so do not get confused. (Most of them are not safe and not worth the price compared to a reputable brand.)

[Brad Taylor]

Lithium is doable technically, but if you cannot afford to do it right with lead acid, there is no way you can afford lithium. To use Lithium requires a great deal of knowledge and cash to operate, and judging from your questions and statements you do not have the knowledge or cash.

Sunking - Agreed, this exactly why I'm asking this forum for guidance. I don't expect to be knowledge free forever though