Backup Power System, Part 3
I have been rambling about backup power and it is time to touch on the batteries and other topics. My advice on backup batteries is a little different than for solar systems. I advise that you get something that requires little or no maintenance. The reason for that is that you will probably lose interest in a system that just sits there doing nothing when the power company is doing there job, because the lights are usually on! Out of sight, out of mind. If you have flooded batteries (as I did) tucked away in an obscure place (as mine were) then it is quite likely that you will get lax about monthly waterings (as I did). If you don’t water flooded batteries, they lose power and start to emit acid fumes. Acid fumes eat up your terminals and battery racks and cause circumstances that are a lot more unpleasant than simply adding water.
SO, the best advice I can give is to use some sealed batteries, like AGM or some of those new-fangled lithiums. John has both kinds. You’ll find that AGM costs twice as much as golf car batteries and lithium…OMG. Well, that’s upfront costs. It may well wash in the long run. If the charging system is set up right, the AGMs can last twice as long. Lithiums last a lot longer and you can draw them down further without hurting them. That means a little lithium will keep the lights on as long as a bigger lead-acid model of same amp-hour rating.
There are all kinds of batteries out there, but these are the big players, the likely suspects. Just make sure you DON’T overcharge the AGMs and DO have a good battery management system (BMS) on the lithium. BMS is often built into the batteries and sometime come as a bolt-on.
Now, on another subject, did you get the Sun Electronics Christmas Eve email blast? You guys really need to read those things, even if John doesn’t make it easy. It was just a list of part number, quantity available and price. No real description. I got around to reading it Christmas day and decided to use the Miracle of Google to decipher some of these things. HOLY COW! I found that the listing “Outback PS1-3000” was a package that would allow you battery backup, grid-tie or the bones of a complete solar system. Charge controller, grid tie/hybrid inverter, breakers, surge protection, battery box, network control and more in one nice package you can bolt to the wall. They sold before I got to them because the price was $500 for a $5000 package!!! READ YOUR EMAILS!!! Somebody did and got all 3 of them.
Now, on the PS1-3000 package, this has been discontinued because there are some new rules about rapid shutdown. Outback came out with a new system that is similar, but has the rapid shutdown built in. Roberto, or one of the other salesmen, can give you the model number and price if you are interested in a package deal from a good maker.
That’s all for today. Next time is a time of soul searching and self-evaluation when I try to answer the question, “Can I install a solar power system myself?”
By: Neal Collier