Thursday, December 6, 2012

Dark for the first time in over 3 years

Well the van went dark today with no electricity, for the first time since Friday, March 20th, 2009. That was apparently the date that I switched over from my old PWM controller to my new MPPT controller, and that's the date it had stored in memory as "the beginning of time". It was very strange to not have electricity! I'd forgotten what that felt like.

I did this because, after over 4 years, my Concord Lifeline GP4 batteries finally had enough abuse for one lifetime, and I replaced them. That's not a great duty cycle for these things, but I really did not treat them well-- deep cycling them a few times and not charging them back up promptly. It had gotten to the point where, last week, a couple days of rain and not enough hours of sunlight (only 9Ah of charge for the full day!!) had worn the batteries down to 12.1V by end of night. I've been studying the battery status for the last 3 months, since I've had the PC interface for the Sunsaver MPPT.

I use, on average, 20Ah-30Ah a day, depending on how much work I have. About 10Ah of that is my refrigerator, the rest of it is my computer. If I travel somewhere hot in the summer I might use much more, due to running the fan (4A at full speed, all day and night), but there's usually enough sun to recover.

So I swapped out the old batteries with two new, but smaller, Lifeline batteries, so now I have only 250Ah total capacity, instead of the 420Ah I used to have. A little math indicates that I can run behind on charge for only a few days now, then I have to charge them up, otherwise I'll be making the same mistake again. I have less margin now, but, better diagnostics too, and I own a converter, which I didn't have for years..

For wintertime, I'm thinking I should either get another solar panel to bump up my charging capacity, or maybe get a Honda generator. But both are costly. In the meantime, I've got a few places I can plug in to shore power to run my converter in the winter to charge up. Or, if I'm travelling, I can find an RV park with hookups and pay the $50 or whatever they want for that. Still cheaper than a generator or new panel.

I also could get one or two more batteries of the same make/model, and hook them up in parallel, to be able to go longer before recharges. Lots of options!

So the new batteries are in, and I had to change some of the wiring and hack up some different mounting in my battery box too. I took pictures too; maybe I'll post them in the Vandweller's list photo archives.

I also got rid of that insipid Cobra inverter, the one that made so much noise. I only really used it for my laser printer, and then it beeped and complained when the printer warmed up about the load being too high. I might just run that on shore power only, or with a generator if I pick one up. I have two smaller-- and silent!-- 150W inverters I could use for any small things I might need to run. But these batteries were expensive, and I'm going to make some of that back by selling off stuff I hardly ever use and could do without, like the inverter.


Anne Sigalet Henderson said...

I was wondering where you shop for batteries - I'm having a terrible time finding much selection.

Walden on Wheels said...

I called Concorde Batteries and asked where there was a local distributor. Turns out there's one in Hayward across the bay, but they're all over the country. And even if there isn't one close by, you can probably find one that will ship.

There are also two battery stores here, one off of Van Ness, and another in South City. One of the advantages of an urban area.

And any auto parts store, or Sears, or Wally World, will also carry AGM batteries.