Partial off-grid system design questions....

acidburn02zts

New guy here...  

Has anyone here (searched but couldn't come up with anything) done a partial off-grid system?  What I mean by that is my home is on the grid.  The home has a large addition which I would like to power via an off-grid solar setup.

I have most of the components already...       just looking for details on what I may need to do as far as system grounding, etc being as the single dwelling will have 2 power sources.

The components I already have:

6 - 100w Renogy panels (w/ home brew combiner box - each panel fused)
Xantrex C35 charge controller (will more then likely upgrade soon)
6 - 6v 215ah cart batteries (series/parallel @ 12v)
Xantrex ProWatt SW2000 inverter (1800 continuous, 2kw max, 3kw surge)

Up until a few days ago...   I was hard set on keeping a 12v system to make running simple 12v items directly from the battery bank possible..   however I've been told 12v isn't ideal at all due to amperage.  I've got plenty of properly sized cabe (2/0) and lugs (along with the proper tools for building the cables, etc).  I also wasn't aware that using a "mobile" inverter in a dwelling, permanently, is a no-no.  I won't be using nearly what the inverter can provide...   just wanted the head space for the 1kw surge of my small deep freezer (running wattage ~95).  Typical loads will be around 150-300w (lights, tv, etc...   couple hours a day.)

With that said, I will more then likely be stepping up to 24v or 48v sooner then later.  My main reason for going with the inverter I chose was cost as I don't have $1k+ to spend on a purpose built residential inverter.  Can anyone point me in the right direction to a quality, no frills inverter that won't break the bank that will provide similar power as the inverter I currently have?

I'll have plenty of questions...  just need to work out details before actually installing everything.

Photowhit

I use a mobile inverter and have for 10 years, a Prosine 1800 watt. I had a fan go out (I replaced it myself), but it's been fine. It's perhaps a better built unit and though one of my Prosine units does have a UL1741(?) residential endorsement. I know of no battery cable shroud for it. I know these were once used inside of stair elevator chair things, and perhaps it was entirely enclosed in a UL box? Many 'residential' inverters aren't done 'up to code' even in areas where code is enforced. Code typically requires a shroud and battery cabling to be in conduit to the battery box.

My inverter (and batteries) are outside. I've been told that it would be fine setup in this manner, by someone who works for electric company, but we have no residential code enforcement. Here the electric company doesn't (didn't?)care if your panels or wind genny is UL/ETL approved only that the inverter was approved, for grid tied systems.

I would want a larger system for just the loads you have described unless you are in a very sunny area. The panels to battery bank sizing looks to have a charging rate of about 5% and for regular use I'd suggest 10-15%.

12 volt even on 2/0 cable would require batteries to be very close to the inverter 4-5 feet, for a 2000 watt inverter. Moostly the losses have to do with high amperage use, so I would be fine with longer runs if your  constant loads were lower than 100-600 watts.

No real cheap 24/48 volt UL listed inverters for residential use (1741).  I think the Samlex Evo line is about as cheap as it gets, and for the money I might go with a Outback or Conext unit for $4-500 more.;

https://www.solar-electric.com/samlex-evo-2224-inverter-charger.html

acidburn02zts

Well...  the inverter will be within 4' of the battery bank to avoid voltage drop issues.  I really don't want a HUGE 12v bank though.  May just have to use this inverter for a short while until I can put back the coin for a "proper" inverter.

I was planning on going with 10-12 panels (only currently have 6 but will be ordering more before the install)...  so that should be covered for now.  Would like to be up around 2kw eventually as my install wont be perfect as far as angle to the sun and amount of time the panels are in sun..  etc.

Constant load on the inverter (or loads that will be on for any length of time) will be under 500w for sure.

We don't have much in form of "code enforcement" here either...   hell, as far as permits are concerned, I believe there are only 4 different permits you can get in this county.  Here, you can do everything electrical without permits except for installing the main drop and meter base.  Those require inspection.

Anyways, I just want the system to be safe and reliable.  I'm not overly worried about "code" as 90% of the homes in my area were built long before there was such a thing...    however safety is very important to me...  so proper grounding, etc. is something I'll need input on.

Thanks!

BB.

In general, running off grid power will cost you (very roughly) around $1.00 to $2.00+ per kWH. If you are in a "poor sun" region (weather, marine layer, mountain/tree/building/etc. shading), it can be much worse (price includes hardware, batteries, replacing batteries every ~5-7 years, new hardware every 10+ years, etc.).

I always like to start with the loads--Then design the system to support those loads. Since you already have a battery bank, we can design the system around the bank and estimate its performance.

For battery systems, we generally work with 12 volt, 24 volt, or 48 volt systems... For a 12 volt system, I would suggest your maximum AC inverter rating (power usage) would be in the ~1,200 to possibly 1,800 watt range. For the battery bank, generally if the battery bank is >~800 AH, I would suggest going to the next higher voltage.

6x 6 volt @ 215 AH battery bank = 645 AH @ 12 volts (8 batteries would give you 860 AH @ 12 volts or 430 AH @ 24 volts). This is not a bad size for learning about solar power.

For a 12 volt @ 645 AH battery bank, using our various rules of thumb:

• Max AC inverter = 645 AH / 400 AH per 1 kWatt @ 12 volts = 1.61 kWatt inverter max (also, roughly max recommended solar array)
• Average output = 645 AH * 12 volts * 0.85 AC inverter eff * 1/20 hour discharge = 329 Watt average load (such as 5 hours a night, two nights, 50% max discharge)
• Max continuous output = 645 AH * 12 volts * 0.85 AC inverter eff * 1/8 hour discharge = 822 Watt max continuous (less than 4 hours)
• Maximum output = 645 AH * 12 volts * 0.85 AC inverter eff * 1/5 hour discharge = 1,316 Watts (less than 1 hour, running well pump, etc.)
• Maximum surge output = 645 AH * 12 volts * 0.85 AC inverter eff * 1/2.5 hour discharge = 2,632 Watt surge (seconds to minute, starting well pump)
  

I recommend sizing the solar array based on two calculations. First is based on charging the battery bank (5% to 13% rate of charge typical). And second, based on your energy usage per day (seasonal loads, your location, etc.).

First charging:

• 645 AH * 14.5 volts charging * 1/0.77 panel+controller derating * 0.05 rate of charge = 607 Watt array minimum
  
• 645 AH * 14.5 volts charging * 1/0.77 panel+controller derating * 0.10 rate of charge = 1,215 Watt array nominal
  
• 645 AH * 14.5 volts charging * 1/0.77 panel+controller derating * 0.13 rate of charge = 1,579 Watt array "cost effective maximum"
  

5% rate of charge is good for weekend/seasonal use (during sunny weather, charge during day and discharge at night). 10%+ is good for full time off grid use (system usually "runs itself", less monitoring, better battery life).

Now, normally, we also check the the size of the array based on your loads... A typical off grid (reliable) system design is to size to 2 days of no sun and 50% maximum discharge (longer battery life). So, your battery bank would support (nicely) a daily load of:

• 645 AH * 12 volts * 0.85 inverter eff * 1/2 days * 0.50 max discharge = 1,645 Watt*Hour per day

Get a Kill-a-Watt meter to measure your loads--A very good start to understanding your system+loads.

https://www.solar-electric.com/kiacpomome.html

Getting your average sun for your region (say Seattle WA):
http://www.solarelectricityhandbook.com/solar-irradiance.html

Seattle
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 42° angle from vertical:
(For best year-round performance)

Jan	Feb	Mar	Apr	May	Jun
1.70	2.81	3.54	4.17	4.57	4.78
Jul	Aug	Sep	Oct	Nov	Dec
5.23	5.21	4.71	3.15	1.97	1.53

So, in the case for Seattle, there is very little sun in winter--February has something approaching decent sun. Take the "average daily load" from battery bank, and the "break even array" would be:

• 1,645 Watt*Hours per day * 1/0.52 off grid system eff * 1/2.81 hours (Feb) = 1,126 Watt array "break even" (February)

And you have 600 Watts of panels. That is a "minimum" array for your size battery bank. And would be good for a weekend/emergency backup situation.

The predicted power based on Seattle for February would be:

• 600 Watt array * 0.52 off grid system eff * 2.81 hours (Feb) = 877 WH per day (avg Feb)
  

I will stop here. Please feel free to ask questions and correct my guesses.

-Bill

acidburn02zts

Good information.

I do have a KAW meter but I haven't left anything plugged in for days...    just did some basic running wattage tests so far.

The main things in the addition are a small chest freezer (~950w surge on start, 95w running), entertainment area (~300w when computer is running...   around 100w when just the tv, modem, and raspberry pi), and a few LED lights.

I'm located in southern Indiana..   average sun hours are 4ish in the winter for where the panels will be (have a solar air heater in the same location and during cold months, it produces good heat for ~4hrs or so)  Based on the link you provided however, it says ~2hrs in the dead of winter...  5+ majority of the year.

I need to do some 24hr testing which I believe I'll start on tonight.

Based on the figures above...   If I go forward and step the array up to 10-12 panels...  and possibly 2 additional batteries, I should be in the sweet spot for the inverter (which I don't really want to go larger wattage wise...  possibly higher voltage down the road).  As it stands, it looks like I'll cover the minimum for my needs with what I've got.  At what point is it a bad idea to keep adding batteries in parallel? 

Would it be wise to get away from 12v and step up to 24 or 48 for an inverter this size?  I don't want to be replacing batteries every other year, etc.

Thanks again

Estragon

I didn't see an AC battery charger on the list of stuff you already have, and you don't want to have the bank sitting around self-discharging. You will need one anyway so you can charge when you get a run of cloudy days. They are often built in to bigger inverters but I don't think yours does.

More than two strings of batteries can be a problem. You have to keep differences in resistance to a minimum to prevent unequal charge/disharge. Using big, equal length cables to parallel, and good connections is important. They also need to be monitored closely so any issues can be corrected before they cause permanent damage.

acidburn02zts

big, equal length cables....    check!

I do have a nice little charger..   but that's the thing...  its little.  Its made by batteryminder and it's max output is 8a.

May look into something different for it.  I've tossed an idea around about turning my waste oil fired benz into a DC charging base...    Some 2/0 twistloc cable ends...   some 2/0 cable...     alternator puts out ~80a just off idle.  Hmmm...   

westbranch

using bills data you would be looking at approx.  60A charger or there abouts... I have an older 12V Truecharge40A charger .. great piece of kit as the Brits say... 
link to the new version http://www.xantrex.com/power-products/battery-chargers/truecharge-2-2.aspx 

Amazon.com has them24V/30A  at ~$520 US + shipping

BB.

Refrigerators (and freezers) are what move you from a "small system" to a medium size...

A typical efficient fridge/freezer runs 365 to >450 kWH per year--Or over 1.0 kWH per day. I would suggest a ~3.3 kWH per day system if you were running an off grid cabin/efficient home (lights, fridge, laptop computer, well pump, washer).

And that would probably be a 24 volt system minimum.

Typically, I suggest a single string of batteries as "ideal". With a suggested 2-3 parallel strings maximum. More than that parallel can be a pain to maintain. There are folks that do more than 3 parallel strings of batteries--But I would suggest avoiding that unless you have difficulty finding batteries in your area, or want to hit a price point (using golf cart or similar batteries).

For smaller systems, and especially first time off grid folks, 6 volt @ ~200 Amp*hour "golf cart" batteries are very nice for "training set". Pretty rugged and very cheap--And should last 3-5 years or so. Flooded cell are nice because you can check the specific gravity to monitor state of charge.

-Bill

Estragon

8A charger should work for keeping your bank charged for now, but only assuming they are already fully charged and have no loads.

If you have grid power to the site, why not use it to charge batteries if need be? Why not use it for the freezer for that matter?

acidburn02zts

Estragon said:

8A charger should work for keeping your bank charged for now, but only assuming they are already fully charged and have no loads.

If you have grid power to the site, why not use it to charge batteries if need be? Why not use it for the freezer for that matter?

As far as charging goes...     cost of the charger at this point.

This system is more just to make sure the addition of the house is always powered no matter what is going on.  No..  not very cost effective...   but worth it to me.

acidburn02zts

Crap...    a buddy and I did some brainstorming....

I have a mid 70's mercedes 240d with a ~60hp NA 4cyl. diesel. The engine runs good and currently runs strictly on waste oils [used motor oil, atf, hydraulic oil, etc] that is processed/thinned down. As of now.. costs around $.15 per gallon to make.

I parked the car last year due to clutch failure and I have been strongly debating on swapping the engine because the 60hp gives the car a top speed of ~74mph and it takes a good while to get there. With a plan to swap in a newer 5cyl turbo diesel, I had been wanting to build an oil fired generator out of this engine.

That got us to thinking.. well I can get 12 and 24v alternators that produce 60-100 amps for under $100 [a quality 60+ amp charger is over $500]. Mount the engine on a permanent concrete pad... some 2/0 to the battery bank... bam.. regulated battery charger that is nearly free to run. Then we started thinking about what else we could do.

I would remove the engine driven fan.... and with a heat exchanger, one could heat a well insulated thermal storage tank... heating domestic hot water and possibly some passive baseboard radiators.

Using a heat exchanger keeps the engine's cooling system separate [small electric fan on the radiator]... meaning it will still have a thermostat and still run at proper operating temp... but all the waste heat typically shed by the radiator and exhaust will be used to heat a thermal mass tank. This would work out really well as the main time the charger would be in use would be winter time. Not only will this keep the battery bank topped off during cloudy days... it would provide heat and decrease the use of the water heater. 

An alternator won't put much strain on the 60hp diesel...  so fuel consumption will be close to idle numbers which come in around 1/3 gallon per hour of run time...   on a fuel that costs $.15 per gallon for me to produce [ and I'm already sitting on 1500 gallons]...     hmmm...         may have to start a different thread for that project...

Estragon

The alternator will be almost a rounding error of a load on the 60hp diesel. You would want to set up sheaves so that alternator rpms are in the right zone at engine idle rpms. You would also want to be careful with cooling alternator and sustained load. Also, a good regulator with the ability to set proper charging regime for deep cycle batteries.

As far as using waste heat, a gallon of diesel has about 120,000 btu. You might get about 25% of that with a good heat exchanger from engine heat, and maybe another 15-20% from HX on exhaust. If you know what fuel use is around idle, you could make an educated WA guess at potential heat. My WAG is you'd use ~1 gal/hr., so potential is around 40-50000 btu/hr.

The main downside I see to the idea is that diesels often aren't happy idling with light loads. A 40 year old engine doesn't owe you much though, so if it gets a purpose in its decrepitude, why not?

solar_dave

Wouldn't you be better off running it at a 10 or 20 horse load, it would consume more fuel but you would get more out of it.

acidburn02zts

Well..  we are also thinking about doing some other things possibly to put it under a slight load.  Also, to get peak power output from the alternator, the engine would have to run around 1500-2k rpm which help.  We also preheat the fuel to help keep it thin.

Also..  waste oils have a lot more heat energy per gallon.  Depending on content, waste oil on average ~ 160-240k btu per gallon)  Lets say 200k...   45% heat energy based on your estimates...  almost 90k btu return.  That would be impressive!

The hard part is going to be keeping the injectors/bores clean with such a light load on the engine.  Gonna have to get creative.  Sounds like a fun project to tinker with over the summer.

I've also considered a belt driven generator head.... 

mike95490

Most diesels, you need to have loaded up some to get them hot enough to burn clean.
60Hp, being loaded to at least 30HP, is going to yield some serious power.
There is a lot of ideas at the microcogen.info forum, but mostly with 15hp or less engines.

Also, for keeping the carbon down (or cleaning it out) look into methanol & water injection 50/50
Seems to work pretty well, and takes a bit to dial in, but hey - it worked in WWII planes, and it works
now too
http://listerengine.com/smf/index.php?topic=7556.msg87529;topicseen#msg87529
and
try  https://www.google.com/search?q="water+injection"+site:http://listerengine.com&ie=utf-8&oe=utf-8 for more info

And with diesels, there is another trick to clean them out using propane gas, a light mix fed into the intake manifold (fumigation), Diesels won't run on pure propane, you need to keep about 30% diesel for pilot ignition.  ten minutes a week, and a spritz of water/methanol from a spray bottle would keep it clean

BB.

A 15 HP load (belted alternator running 60 HP diesel at 1/2 power):

• 15 HP * 0.50 overall alternator efficiency = 7.5 HP
• 7.5 HP * 745.7 Watts per HP = 5,593 Watts
• 5,593 Watts / 29.0 volts charging = 193 Amps charging current

Not a small amount of load...

Note that most (guessing) your car probably averages 10-20 HP to run 60 mph. You can probably work backwards if you know the mpg for the car (i.e., 30 mpg for 1 hour or ~2 gallons per hour of diesel...).

http://www.boatingmag.com/calculating-fuel-consumption

-Bill

acidburn02zts

mike95490 said:

Most diesels, you need to have loaded up some to get them hot enough to burn clean.
60Hp, being loaded to at least 30HP, is going to yield some serious power.
There is a lot of ideas at the microcogen.info forum, but mostly with 15hp or less engines.

Also, for keeping the carbon down (or cleaning it out) look into methanol & water injection 50/50
Seems to work pretty well, and takes a bit to dial in, but hey - it worked in WWII planes, and it works
now too
http://listerengine.com/smf/index.php?topic=7556.msg87529;topicseen#msg87529
and
try  https://www.google.com/search?q="water+injection"+site:http://listerengine.com&ie=utf-8&oe=utf-8 for more info

And with diesels, there is another trick to clean them out using propane gas, a light mix fed into the intake manifold (fumigation), Diesels won't run on pure propane, you need to keep about 30% diesel for pilot ignition.  ten minutes a week, and a spritz of water/methanol from a spray bottle would keep it clean

Do I know you from another forum.....?

Anyways...   we've been using water meth injection on our road engines that are waste oil fueled...   just not sure how well it will work in this application.  I've got an extra kit sitting in the garage so it'd be easy enough to try.  I've also heard of guys having good luck with propane fogging and waste oils.  Definitely worth a look.

I'll definitely be toying with this come spring/summer.

acidburn02zts

From the looks of it so far...   I should be within the 1645wh/d from your figures above.  I'll know for sure tomorrow night.  Will still more then likely step up to a 24v system ( easy enough...  just need to save up for an inverter)

While doing some testing...  I've been brainstorming on the need for a secondary charging system for the battery bank...    a friend and I came up with a somewhat wild idea.

I've got an old 70s 240d mercedes...   4cyl NA diesel...   engine is under powered for the car (been planning a 300d engine swap for a while).  The engine runs great on processed waste oils (motor oil, atf, etc...) and that is it's primary fuel source already.  I'm thinking about pulling the engine..    and turning it into an inverter based generator.  All I would need to do is install a second alternator strictly for charging the battery bank (easy enough to build the mounts...   plus they offer 12v and 24v 100a single wire alternators for under $100).

While on a 12v system, I could basically do it for free (and run it for free).  I'd have a little money in it come time to go 24v....   but it'd still be well under the cost of a quality charger.

Now onto the wild part...       I currently heat with wood (have electric furnaces - yes..  plural- but don't run them).  Considering the charger would mainly be needed in winter months...    how about turning it into a "cogeneration" system.  Basically, I'd use the heat produced by the cooling system to heat passive radiators in the house (simple heat exchanger, some pex, and a few baseboard radiators)...   and the best part....   running the whole thing for less then $.15 per gallon of fuel (what it costs me to process used oil into fuel).  It has the potential to be a very simple....  very effective system.  The engine is a fuel sipper as it is...   hmmm...

Better start drawing it up.  It's gonna be a long summer.  Lol

acidburn02zts

Estragon said:

8A charger should work for keeping your bank charged for now, but only assuming they are already fully charged and have no loads.

If you have grid power to the site, why not use it to charge batteries if need be? Why not use it for the freezer for that matter?

As far as charging goes...     cost of the charger at this point.

This system is more just to make sure the addition of the house is always powered no matter what is going on.  No..  not very cost effective...   but worth it to me.

acidburn02zts

BB. said:

A 15 HP load (belted alternator running 60 HP diesel at 1/2 power):

• 15 HP * 0.50 overall alternator efficiency = 7.5 HP
• 7.5 HP * 745.7 Watts per HP = 5,593 Watts
• 5,593 Watts / 29.0 volts charging = 193 Amps charging current

Not a small amount of load...

Note that most (guessing) your car probably averages 10-20 HP to run 60 mph. You can probably work backwards if you know the mpg for the car (i.e., 30 mpg for 1 hour or ~2 gallons per hour of diesel...).

http://www.boatingmag.com/calculating-fuel-consumption

-Bill

It'll be driving 2 alternators also...    1 for the starting battery...   1 for the 12v or 24v battery bank.  Then there is a potential to run a generator head with the engine as well...   or possibly a small water pump for the heating side of things...

Also...  our centrifuge is ran by an old powersteering pump (flows the oil at a high enough volume/pressure for a cheap price)...    could possibly process fuel while the engine is running instead of using an electric motor do drive the pump...      possibilities are pretty endless...

Hmm...

acidburn02zts

solar_dave said:

Wouldn't you be better off running it at a 10 or 20 horse load, it would consume more fuel but you would get more out of it.

Thats a lot of juice...     talking easily turning a 10kw gen head at that point...   which wouldn't necessarily be a bad thing.  Lol

acidburn02zts

Ok..  back to the solar side of things...

After some testing...    my battery bank wont quite cut it based on the numbers.  It doesn't leave enough on the table for multiple days without sun without pulling the bank under 50%.

Since adding more parallel batteries isn't a wise idea for longevity...   I probably need to step up to 24v now instead of later.  Sucks to have wasted money on the inverter...  but oh well.  Live and learn.

So...   I'm having trouble finding a pure sine inverter capable of 2-3kw @ 24v for a reasonable price.  I've found a few mobile inverters...  but have been told that a mobile inverter wouldn't be a good idea in a home as insurance may not cover anything if a problem came up.

I can't find much information on "residential specific" inverters...    and the few I have found have been north of $2k for an off-grid inverter.  Is that going to be the only route to take?  Any other options?

littleharbor2

Look at the Schnider Xantrex SW inverter line at the hosts website. They have very good prices.
https://www.solar-electric.com/schneider-electric-sw-conext-inverter-4024-120.html

acidburn02zts

I do like xantrex...  but a good bit out of my pricerange at the moment.  Going from my $300 xantrex pure sine mobile 2kw inverter to a $1600 3kw purpose built inverter hurts...   lol

May have to talk this one over with the wife a good bit.

Estragon

On the plus side, inverters in that range generally include good chargers, giving you the ability to use AC to charge if need be.

Photowhit

acidburn02zts said:
I can't find much information on "residential specific" inverters...    and the few I have found have been north of $2k for an off-grid inverter.  Is that going to be the only route to take?  Any other options?

I did send you a link to a @$1250 one in my first response. I don't know of any cheaper.

It might be worth asking your insurance company what they require. They may want an electrician signing off on everything, and they might be okay with the inverter being outside of the domical, and just having a breaker protecting the home. The Exeltech, XP1100 might be UL1741, it is UL to a telecommunication rating, arguably higher standard. I never got a response from them when I asked. I think it would start and run everything, but it will be minimal at 1100 watts with no power factor and it does include the shroud for the battery cables, an additional expense with most UL1741 inverters and the reason I say many are not installed up to code. It is hard wireable, even though it also has a front side outlet. They are NOT marked on the unit (I have one), They have a good reputation, in fact I'd probable look for one used as they also have a rebuild most repairs for $100 deal, It's not posted on NAWS web site now, but was last year. They go for @$300 used on eBay. I've also added a link to their manual, that says UL but not which UL...lol. I picked up the telecommunication info from their website somewhere in the past.

https://www.solar-electric.com/exxp24vol11w.html

http://exeltech.com/Manuals/xp600-1100-2000manual.pdf

I use the XP1100 as my outside inverter, and regularly run a "12amp" chainsaw on it and while there is no big startup rush, I have grounded the chain saw, stopped it binding in the wood and started it . and it should be well over the rating...

acidburn02zts

Well..  according to my insurance company (State Farm), they don't have any specifics on solar installations.  It is just covered under the dwelling policy (no premium additions, inspections, etc).  That came from my agent and he had contacted their underwriting department while I was on the phone.

I may give them a call back just to double check.

I had forgotten that you posted that link earlier.  Will definitely look into it.  Thanks

acidburn02zts

Just called again and talked to someone else.  Same answer.  They have no requirements, sign-offs, etc.  As long as I am satisfied with the coverage amount on the dwelling, they are fine.  I even told them I would be doing the installation and specifically asked if I needed an electrician to sign off on anything.  They said no.

littleharbor2

That's what the agents say.  I would hope the adjuster (god forbid you ever need one), feels the same way.

acidburn02zts

Is there anyway to find out for sure?  I know for sure he contacted underwriting as he called me back and said their only concern would be if the roof would support the added load of the panels + snow load.  No mention of anything else.

The only thing I can find (in my policy or otherwise) is that the only time they will not pay out is if it can be proven that the insured (me) caused intentional harm to the property.  I wonder who I could talk to to make sure that's the case...