Hey there. I've come here for some advice on diagnosing and upgrading my off grid setup at my Island house. I have made a very good living from 12v electrical since 1998 so I am completely familiar with batteries, ohms law, amps etc etc. My system is one my father installed perhaps 20 years ago before I took over the house and is very rudimentary. It consists of 3 panels for a total size of approximately 3'x4' but I do not have wattage specs on them. The charge controller is a tiny white box perhaps 3"x2" with a 4 posts (+- to array, +- to batt) and a red light. There are two 12v deep cycle batteries (from 2011) in parallel and we run about 5 lights and a few phone chargers. Pretty basic setup. This house is opened in late may and closed usually early September although I kept it open late this year. The batteries are left connected to the array but loads are disconnected through the winter.
On to my issue. In june of this year I checked the levels and both batteries were slightly low so I filled with distilled water. Fast forward to this weekend. I only had about 1 hour of lights before I had dead batteries. I ran for 3 days once when we discovered that the roofer never reconnected the array so this was odd. The next night we had the same result which means there was some recovery during the day even though it was cloudy and my angle is 20 degrees off for October. I disconnected the batteries and had roughly 11 volts coming from the panel on a very cloudy day at 10am 20 degrees off. Normal?
So I bring the batteries home when I close up this year. I figure they served their life but me being me I decided to put them on my charger. One read full charge, the other had 2 volts. Open the tops, both batteries had no visible electrolyte! I admit I'm not the best at battery maintenance. I only do it once a year and I forgot last year but there was still visible electrolyte in June when I topped them off.
So my questions are...Where did the water go? Should I expect more than 11 volts under those circumstances? How can I improve things?
I have a theory about the water. The dead battery caused the charge controller to see low voltage and continuously charge, boiling off the water in short order. Possible?
I appreciate the help. I've been reading on here for days all about the off grid systems. Seems like most are way cooler than mine but mine was one of the first on the island 20 years ago so it was cool then!
On to my issue. In june of this year I checked the levels and both batteries were slightly low so I filled with distilled water. Fast forward to this weekend. I only had about 1 hour of lights before I had dead batteries. I ran for 3 days once when we discovered that the roofer never reconnected the array so this was odd. The next night we had the same result which means there was some recovery during the day even though it was cloudy and my angle is 20 degrees off for October. I disconnected the batteries and had roughly 11 volts coming from the panel on a very cloudy day at 10am 20 degrees off. Normal?
So I bring the batteries home when I close up this year. I figure they served their life but me being me I decided to put them on my charger. One read full charge, the other had 2 volts. Open the tops, both batteries had no visible electrolyte! I admit I'm not the best at battery maintenance. I only do it once a year and I forgot last year but there was still visible electrolyte in June when I topped them off.
So my questions are...Where did the water go? Should I expect more than 11 volts under those circumstances? How can I improve things?
I have a theory about the water. The dead battery caused the charge controller to see low voltage and continuously charge, boiling off the water in short order. Possible?
I appreciate the help. I've been reading on here for days all about the off grid systems. Seems like most are way cooler than mine but mine was one of the first on the island 20 years ago so it was cool then!
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