OK, I'm back working on the solar power upgrade, and not a moment too soon. Another one of my Trojan L16H batteries developed a bad cell, so I had to disconnect one of the two battery banks. A dead cell raises all heck with the surviving cells causing them to overcharge while charging, and causing the good bank to discharge into the bad bank when not charging. The generator running in the middle of the night because the batteries were so low was the tip off that something was wrong.
This is the second of 8 batteries to develop a bad cell in the past 6 months, so they are clearly at the end of their life. I've been running them for 7, almost 8 years, so that's right about in the middle of the expected life for these batteries.
Anyway, back to the new system. I got 90% of the parts a few weeks ago, including the new 6KW 240V/120V inverter, 3.6KW of solar panels, dual charge controllers, and a whole host of breakers, wiring boxes, etc. I'm getting everything from the Alternative Energy Store, which is a great place.
The new batteries, which are 12 Surrette 4-KS-25PS 4 Volt, 1350AH are due to arrive tomorrow. These batteries will be tripple what I have now, and weigh 3700 lbs. I picked these particular batteries so I could have a single bank rather than two or more. It means fewer cells to maintain and water, and more reliable charging than parallel banks. However, their weight (315 lbs each) means they require end-to-end mechanical handling. We'll get to more on that later.
Today I spent building a battery box for these beasts. I had seriously considered buying a few of the metal job site tool chests that you may be familiar with to use as battery boxes, but in the end decided to build one out of wood. An insulated rather than conductive material is a nice safety precaution, and building a box I can keep it as compact as possible. Also, the basement where they will live has a low ceiling (only about 5 1/2'), and there needs to be clearance to lift a battery over the box edge and lower into the box without crashing into the floor joists. The batteries are 25" tall so there isn't a lot of wiggle room, and the job site boxes were a bit taller than I wanted.
The pictures are of the box at various stages of construction. It sure isn't fine cabinetry, but it serves the purpose. I'm polyurathaning the box inside and out to deter rot, and it will sit on 4 2x6 pressure treated skids on top of the crushed stone floor in the basement. This house is 200 yrs old, so the foundation is dry set granite blocks and a dirt floor. I've since mortered the joints in the walls and put down a vapor barrier and stone on the floor.
To get the batteries in and out of the box, I bought an engine hoist from TSC. This particular model has telescoping feet and boom so I can arrange it to reach far enough over the battery box to set the batteries in the second row even though the feet can't extend under the battery box as they would extend under a car. The only trick will be providing sufficient counter weight to lift the 300 lb battery without tipping over, but I think that's solvable. I'll have more on this tomorrow when I try it all out on a real battery in by garage. I want to be sure I can reach all the battery locations in the box before I haul everything down to the basement and try in while stooped over in cramped quarters.
