120W of power

Today was a mixture of very heavy rain, thunder, lightning and sunshine. As it was so changeable I didn't do an awful lot. I did put two SAE connectors onto my 20W solar panels. Those I then sat outside on the ground, in the sunshine. 

The battery was probably fairly low earlier in the day. When I first saw it, it was at thirty something percent. With the panels in place it climbed to 47% which looked really promising. The drain was something like the normal 0.02A and that is just the door lock controller staying alive. I used no other power whatsoever in the bus today.

Just before I put the exterior panels away for the night I noticed that the battery had fallen to 39%. That's a remarkable drop for about 4 hours with such a low drain. Tomorrow I shall turn the power from the charge controller off. Maybe I should put in a disconnect switch to make sure it really goes off? I have been unimpressed by the SLA batteries I've been using. The amperage output is not high and the longevity is questionable.

I'd say that since the batteries are now regularly giving me 11.9v instead of 12v to 13v they're probably toast. One is a Duracell that I bought in April of 2019 and the other is a Harbor Freight Thunderbird or whatever that I bought about a year earlier. So, both batteries are less than 3 years old and have never really performed spectacularly. Their capacity is absolutely fine. I have no problem with 70AH or even 35AH.

If every light in my bus was on then I'd be burning 10W. If every circulation fan was on I'd be burning less than 1W. I have no idea how much my USB chargers use. My shower pump and water pump are used so rarely they're not worth factoring in. Same for the door lock since 99.9% of the time that is run from AA batteries that I replace a few times a year. The door lock controller burns 24W maximum. If all those were on all the time I'd be using 35W or about 3A. In 24 hours that's 72AH. The fact is though that I don't use that amount of power. I have one or maybe two lights on, maximum and one circulation fan. Occasionally I'll have my extraction fans running but that'll be when I have a good amount of sunlight - enough for it to be hot inside the bus. In such occasions I have my solar panels outside, in the perfect place for the sunlight.

The battery I'm considering is about $200 or around the price of a pair of 35AH batteries. It's lithium and holds 20AH of power. That's enough for 120 hours of light from a single bulb or 60 from two. In short it seems to be about the perfect capacity for my low needs. Indeed I can always add a second if one is not enough. They're way smaller than my existing batteries which means I'd probably better make a housing that fits inside my normal battery hangers. Doing that, I can insulate it so it won't be affected by extremes of heat and cold. It'll also be enclosed so if it goes into a lithium thermal runaway then the bus will be protected from it. I see little worth in replacing my two lead-acid batteries since their performance from day 1 has been miserable.

In other news, I need to move my bus from where it's parked to another site on the property. This means I'll have to put down some crush and run (hardcore). Thus I've made an inquiry about the cost of crush and run. At the same time I inquired about getting my steel bent, having rechecked my measurements several times and agreeing each time that the angle is about 8 degrees.

Before I move the bus I need to do all the roof based operations as I'll be parked under a power line. I'll also have to replace the two backup cameras as I'll be reversing into position. I'll have to do a lot in a short time! That's the two cameras, the roof solar panel, washing the roof (and the bus), the roof vent and repaint some of the roof.

Thinking about the unused windows, I measured them the other day and any panel put in would have to have a slight gap at the bottom. That's no problem. It would probably annoy a purist though. I'm not a purist. I'm a cheapist. The windows are 28 inches wide including the separating section. I'd need to cover two separate windows on one side and 5 together on the other. The height of the baffle would have to be 24 7/8 inches. The width would have to be 28 for the single windows and 130 inches on the 5 together. The only issue is one of the smaller baffles and the big baffle would need a step folded into it. It all just makes it harder for somebody to break in. Since the bus will now be visible from the road, that's important, given the area it's parked in.