Solar Battery Bank Replacement


Lead acid batteries typically only last 3-4 years in automobiles in Florida.  Very hot down here.  My previous set of golf cart batteries started failing at 5 years, a few batteries went as long as 6 years.  The Duracell batch from the local Sam's Club only made it 4 years this time.  I paid $85 each for them back then.  The price of lead has increased, driving up the prices of batteries.  However, I did some research and found I can get name brand Trojan T105 batteries for $112 at the local golf cart service center.  So that's exactly what I did.  I also ordered the Trojan Hydrolink battery watering system from eBay for around $200, half the cost being asked at the golf cart shop.

The old 8 sitting on the pallet in the background.  The new ones came from the pallet in the foreground.  I picked through them to get the same production date, and the newest.  All mine are stamped L6 on the lead battery post.  L indicates the month, December in this case.  And the number indicates the number of the year, or 2016 for mine.

The battery temperature monitoring system I built (Arduino based) was connected to each new battery.  If any go over about 115 degrees, a red LED flashes, and a buzzer sounds.

Once the new batteries were installed, I charged them most of the night with an Iota 75A grid powered charger.

After the Iota charger was disconnected, the batteries were allowed to rest for most of the night before being charged via my solar panels.  By the time I got home, the charge rate had dropped to 21.16 Amps.

Each charge controller has its own set of solar panels.  So each one supplies a different current.  The one on the left was supplying 12.9A, the one on the right 7.2A.  Added together, it adds up to the 21.1A measured with the meter in the previous picture.  All the outputs of the charge controllers go through a shunt, then to the battery bus bars.  That shunt gives a total charge reading constantly.  That meter was only $18 on Amazon, and included the shunt.

Battery voltage pretty much the same on all displays.

The Xantrex Link-PRO has been programmed with the total capacity of my battery bank.  Each 6V battery is rated at 225A.  Two batteries in series makes 12V at 225A.  Four pairs like this for a total of 12V at 900AH.  Now the meter can accurately measure the amount of current going in and out of the battery bank, giving a real-time status of how much is left, and how long it will last at the present rate of use.

The battery bank reached a 100% charge status.  Ready for full system usage.




It was an expensive weekend, but I'm running a portion of my house off-grid once again.  And we are ready for the next outage with little impact to our daily lives.  The Hydrolink battery watering system is really easy to use.  No more wrestling wires around to get the battery caps off.  What was a chore is now a momentary inconvenience!




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Last updated 02/08/17    All rights reserved.