I am reluctant to write too much about batteries. Mostly because I don’t know very much.

But I do know this: get a big system. And that means hours and ‘size’. Lots of amp/hours. We have 600. I’d prefer to have 1000. But, just so you know, you pretty much need a battery charger ‘sympatico’ with the amp hour or ‘reserve’ of juice those amp hours represent. The rule-of-thumb is that your battery charger should deliver at least 10% of what your reserve is. A 600 amp hour battery bank needs 60 amps of charger.

But not all amp hours are the same. That is why ‘size’ matters. Let me explain:

You can get a battery with 200 amp hours that will fit in the engine compartment of your car and weigh under 60 pounds. Or you can get one that has the same amp hour rating and you can’t lift it. “Why is that?” I dunno. Plate thickness mostly, I think. Makes no sense to me. But, essentially, it is like Bud Light and Regular Bud and, I suppose, Heavy Bud. All beers. All drinkable. But you want heavy Bud.

Heavy, deep cycle batteries last longer. That’s the simplest reason to have them. And the heaviest are the BIG Surette 2 volt batteries that retail for about $500.00 or more a pop. If you have a 48-volt system like I do, that means 24 batteries of 2 volts each weighing in at a total of almost 4000 pounds and costing a minimum of $12,000.00 not counting all the ‘bells and whistles’ (like cables). Batteries are the heart of your system.

So, in this case, go BIG if you want to stay home.

There are variables here, of course. You can choose to have a 12 volt system (which would mean less BIG batteries). You could go 24 volts. I went 48. The higher the voltage the less resistance in the lines and the less thickness you need to compensate. If I had to do it over again, I’d go 24 volt so that I could afford the BIG two (or four-volt) volt batteries.

Bear in mind that other mfgérs make BIG two-volt batteries and they don’t market them as much so they are not as expensive. But they are still NOT cheap. Big 2-volts well maintained can last 20 to 25 years. That’s important for a whole bunch of reasons not the least of which is transporting and carrying.

They are not, however, the best value. Not as a rule. The best value comes from getting the biggest battery you can that is still ‘mass produced’ and, in my searching, I concluded that D-8’s were the best bang for the buck. D-8s are 12 volt Caterpillar tractor/heavy-duty industrial batteries that are used in everything from forklifts to buses, from tractors to bull-dozers. Plus, at 150 pounds a battery, they are still somewhat manageable.

I have 12 D-8 batteries in the three ’48 volt banks’ and they add up to about 600 amp hours. The good part? They are about $200 each. They’ll last about 7 years – give or take. So, they are 1/3 as good as Surettes but at 1/3 the price and, because I have a 48 volt system, I can afford them as well as carry them.

You can also buy 4-volt batteries (almost as heavy-duty as the 2 volt), 6-volt batteries and, of course, the common 12-volt battery. And, when you do choose which ones to get, remember to get the ‘maintenance shockers”. These are little boxes that take a bit of juice from the battery and ‘shoot it back in at miliamps’ in an effort to stave off sulfation. They work. I have three of them – one for each bank. Cost: about $50 – 75.00 each.

If I was building a 1500 sft house and doing it again, I’d still go D-8’s even tho Surettes or other BIG 2volt batteries are better. And I’d get more of them. Plus, I’d ‘house’ them very well with thick insulation and even a bit of heat if I could. Get really heavy cables for connecting and keep the batteries topped up with ‘charge’ and water. Best tip: install them so that the battery tops are at waist level so that servicing and maintaining them is easy. Then do it. It goes without saying that even tho they are at waist level, they are covered with plywood (one battery exposed at a time) so that you don’t drop something on them or short them out.

Batteries is where it all starts and ends.

Having said that, this lead acid battery technology is just a step ahead of the horse and buggy. All sorts of universities and private companies are working on improving battery technology and I suspect that they are only about five years away from putting something better on the market. But, right now? BIG lead acid is the way to go.