Solar Question :::

Well....batteries can be added when of the same make, age and AH rating. Yes, if you double your stored AHs and if you draw the same amount of energy as when you had one, your two batteries will be less discharged and last longer...but they will require the same amount of energy to recharge as one did. The best answer is more panels. SoCal is one thing, Oregon is another regarding sunlight.

Another battery will extend your time to the same discharge level
Of both batteries
While then requires a longer generator runtime to recharge

Or
have the batteries at a higher level, for the same amount of use

If your not getting enough solar, to recharge one battery, you still need the generator to keep both batteries charged

Another battery will not change the amount of solar you get oto replace the amount you use

More battery capacity will make it better/easier on the batteries and they will have a longer life for the same amount of use

For more charging your need more solar and generator

Yes.... but...
I have 3 sets of 6v and 480w solar panels...

Right now, in Bend, OR yesterday and today I've had to run the Gen due to clouds/rain etc.

I'm sure others will chime in here, but adding another battery will basically just delay it a little bit...

I would recommend getting a Gen as a backup. Solar won't help much if in trees/snow/clouds etc.. and the extra battery might last another day or two, depending upon your use...

Hope that helps a little..

... and there are some who can probably use a flashlight battery and live off that for a week...
Depends on your usage...

good luck.