Best 500 watt solar off grid system? Best inverter? What would you recommend?

[erod707]

I putting together 500 watt off grid system. I would like to know what would be a great inverter for this size. If you can provide with specific inverters please. thanks

[Sunking]

All depends on the battery type and size. A 500 watt panel system using a MPPT charge controller can only support up to a 12 volt 480 AH maximum battery. A 480 AH 12 volt battery FLA battery can only support an inverter of roughly up to 700 to 800 watts.

But I like to KISS and my rule is the inverter should be no larger than the panel wattage. That makes things DIY proof.

[inetdog]

These are the batteries am using, with the total 500 amps. They are UPG Sealed Lead-Acid Battery.

http://www.northerntool.com/shop/tools/product_200337581_200337581

Is this a good choice for batteries? You mentioned FLA batteries? What can you tell me about them?

thanks

Those are expensive batteries!
FLA stands for Flooded Lead Acid, or plain old batteries with filler caps and a visible electrolyte level. They are further subdivided into Cranking/Starting (not good for PV), Hybrid (like most Marine Deep Cycle or many Golf Cart batteries) or true Deep Cycle (more lead, stronger plate structure, lasting through more charge cycles).

Since AGM batteries can be both charged and discharged at a higher rate than FLA, you can justify using a larger inverter with yours, but the total power consumed per day is still the same limit. And you would potentially benefit from more panel wattage eventually to cover winter use, since you can and should charge the AGMs at a higher rate. The capacity, C, is 500AH for the two batteries in parallel. (Or are you using a 24 volt system with them in series, which would be better?), so the recommended charge limit for FLA would be about 80 amps, while the limit for AGM could be 160 amps or higher, depending on the battery specifications.

[Sunking]

These are the batteries am using, with the total 500 amps. They are UPG Sealed Lead-Acid Battery.

http://www.northerntool.com/shop/tools/product_200337581_200337581

Is this a good choice for batteries? You mentioned FLA batteries? What can you tell me about them?

thanks

What you are pointing to is a counterfeit Universal Battery UB8D. There are many clues that tip you off. First Red Flag is it state it is a 250 Amp battery which is meaningless. It should be stated as 250 Amp Hours. Second Red Flag is they claim it is an AGM battery, however it is not, it is a Gel Battery.

It is a piece of junk and you can buy a much better battery for about the same money. For example you can get top of the Line Concorde Sun Extender 12 volt 250 AH AGM model PVX-2580L for around $600. Concorde makes the absolute best AGM batteries. Shop around for industry 8D battery. The Concorde PVX-2580L can drive up to a 2000 watt inverter providing you could use 2/0 Flex Copper cable of no more than 2 feet 1-way. Bu tit can only do it for about 20 to 30 minutes.

[inetdog]

What you are pointing to is a counterfeit Universal Battery UB8D.

Counterfeit is such a strong term! How about knock-off, or just rip-off? I would expect a counterfeit to try to duplicate the appearance too.
Is this sort of thing common at Northern Tool? I know not to expect much (anything) from Harbor Fright, how does NT fit into the spectrum?
(If you can answer without getting the Forum in trouble.)

[Sunking]

Counterfeit is such a strong term! How about knock-off, or just rip-off?

Counterfeit too strong of a word? Me thinks not strong enough. The battery in question is what is called a Battery Counsel International (BCI) Group 8D. A BCI Group refers to the physical dimensions or size of the case, terminal post, and type/function. So armed with that knowledge now go GOOGLE BCI Group 8D and see what you get. Something like this. Now tell me which are the good and junk batteries. Please note some are Gel, and some are AGM.

[inetdog]

Counterfeit too strong of a word? Me thinks not strong enough. The battery in question is what is called a Battery Counsel International (BCI) Group 8D. A BCI Group refers to the physical dimensions or size of the case, terminal post, and type/function. So armed with that knowledge now go GOOGLE BCI Group 8D and see what you get. Something like this. Now tell me which are the good and junk batteries. Please note some are Gel, and some are AGM.

Without commenting on which are junk and which are good (which I agree speaks for itself), I will note that the UPG site (http://upgi.com/products/batterysearch.aspx) lists two different 8D sized batteries. One with black case which is AGM and one with white case which is GEL. No price listed on the manufacturer site, so I cannot compare the cost of their GEL versus AGM. The one the OP listed does actually appear to be AGM.
Agreed good AGM is good for PV, while good GEL is not, unless there is something very special about the GEL construction used. (Some mfgrs specifically list their GEL for high charging voltage.)

[inetdog]

Counterfeit too strong of a word? Me thinks not strong enough.

It all depends on what the meaning of "is" is.

I tend to reserve "counterfeit" for something like a "Rohex" watch or one that actually says "Rolex" but is not. Something that is confusingly similar in name but looks nothing like the real thing, or something that just fills the same functional niche although not as well, I would not apply that term to.

Now the company name Universal Battery Group (maker of OP's battery) versus Universal Battery Company, Universal Battery Corporation, and Universal Power Group does raise some flags. But they are not actually faking a trademark. (BTW, who is the actual manufacturer of the "Universal Battery" you provided a link to? )