Newbie Kinda Question

[barfwinkle]

GA name is Bill and I have been utilizing solar power for over 20 years, starting with a 5w system (for maintaining sailboat batteries), then moving up to a 90w system (for nav equipment, radios, &/ lighting). More recently we purchased an off grid cabin in the nearby mountains where at first I used the same 20+ year old 5w panel to charge a 12v Battery.

Well as things progressed, we moved up to 100w x 2 panels and realized we still needed more panels, so now we're at 400w. The energy budget is modest; 4 LED 12v lights (.6w ea) and a 4.5 cu ft 12v fridge which the Energy Star Rating says it uses 269 KWhs a year. Now we have two group 31 AGM Interstate deep cycle batteries with 100Ah ea in parallel (12v), a good 40A controller & a 1500/3000w inverter. The cabin is located at 34.5W 94.3N and heavily forested but we have a pretty nice clearing for the panels (could stand to cut down more BUT we love the trees). So the system will not maintain the batteries to a level where we can run the fridge, which prompted me to start looking at a changing out the system or upgrading it. (BTW the batteries still have a year left on there free replacement warranty.) So I thought about just adding another battery but have always heard that generally speaking, you should not mix different age batteries.

Hench the question, should one mix 2 year old good batteries with new ones?

TIA

 

[Rocketman]

I would highly suggest getting a Victron Smartshunt (or another product like that).

That way you can know the status of the batteries are they getting a full charge every day? Are they at 50%, 90% or 18%.

Knowing exactly what is going on with your batteries can prevent you from murdering them.

Are your 2 year old batteries still good?

 

[barfwinkle]

existing batteries are great. I had a Vectron BMV 700 on my boat and I loved that thing. Now I am using a cheap china monitor with shunt.