I found some interesting info and am inching ever closer to devising a full plan, with an eye towards not having to expand it for a while, but being able to with ease if I ever do.
Expansion can be an easy thing to do, but it depends on what you have in mind when you say "expand." More on that in a bit.
My brother's wife's sister is the head of Human Resources at the Johnson Controls San Antonio Battery Plant, where they make several of the brands listed in that article, including Sears Die Hard, Autozone Duralast, Interstate and Everstart Maxx Marine batteries at Walmart (Exide also produces Everstart Maxx batteries). It was very interesting to take a complete tour of the facility to see how these batteries are made, and to see how identical batteries are manufactured on the same line using different brand cases and labels.
You mentioned using 12v AA chargers...but I can't do that with LaCrosse or Maha chargers. They'll have to be used via inverter, unless there's some other wizardy I am unaware of.
With Maha chargers, there is a
12-volt vehicle adapter for it, which also works with my JETBeam (Nitecore, Sysmax) i4 Intellicharger. It works great. I have a 12-volt power socket similar to
this one wired to the battery busbars (you can wire it directly to the battery terminals, as well, or use one with
alligator clips). I have the 12-volt adapter plugged into the socket, and when I need to use the i4 I just plug the power cord into the charger.
The
JETBeam IntelliCharger i4 PRO Charger V3 is handy because it automatically identifies and charges Li-ion, Ni-MH and Ni-Cd rechargeable batteries independently, and, amazingly, charges them properly. Rather than carry both a Li-ion and a Ni-MH charger out here with me, I just carry the i4 which does both. I leave the more complicated and time consuming cycling, refresh and battery forming operations for when I'm at home (although Eneloops don't gain anything from battery forming, just open the package and go).
With the La Crosse, the only one I'm aware of that is designed for 12-volt input is the BC-500. But I know people who have successfully used the
AccuPower adapter with it. Still, I'd still be hesitant to use my BC-900 with a 12-volt adapter, though.
They too, though, are usually used when I have shore power or am home, at which time I charge a mess of them.
I have with me in the van enough fully charged Eneloops to power all my devices, and enough spares for complete swap outs for everything. Plus a few extra. I use Li-ion 18650, 17650, 16340 (or CR123A primaries) and 14500 batteries to power my flashlights, and I have spares for all of those with me, too. They usually last me long enough so that I don't have to mess with recharging those in the van, although I do tend to throw the 18650s from the lights I use most often on the charger every couple of weeks just to keep them charged up. That way they will recharge in an hour or two instead of 8-12 hours when nearly drained.
So 200 amp hours is a high use scenario, most likely, though it is what I'm using as a guide. I think it wiser to do that than to be underpowered. My power needs will go up and down, to be sure, depending on season, if I have shore power or not (several of the Canadian places I park offer shore power) and if I am vancamping out in the desert or elsewhere.
Yes, it's better to overestimate your needs than to underestimate them. Plus, when you get reliable power from a house bank, the tendency is to discover new things you can use it for.
With all that in mind, I'm considering getting two
Trojan T6V AGM 200AH and will shop around for what else might fit the bill, as well as compare prices.
That's a good battery, and is probably about the Ah size you need. Do keep in mind that you don't want to discharge them down below 50% very often at all, as doing so greatly reduces the lifespan of the batteries (although not as dramatic as with wet cell batteries). For pricing on that and similar batteries, depending on where you live or where your travels take you, you might might to call
Staab Battery. They don't have that battery listed on their Web site, but they are a big distributor for Trojan. They're in St. Louis (Hazelwood on the north side off I-240 very near the Cabela's), and if you can go by and pick up the batteries yourself, they'll give you a substantial discount over anything advertised on their Web site. I live 4 hours away and the discount on four of the J-305E batteries is more than enough for me to justify the 235 miles to go get them. They also carry the
Lifeline Batteries, the cream of the crop of AGMs. The Lifeline GPL-4CT is a good one in that Ah and price range (especially if they give a big discount on Lifelines as well).
But, with these, because they are 6v, they have to be wired to make 12v and if I want more capacity in future, I will have to get another pair, correct? IF I end up going with 12v batteries instead and later decide to expand, can just one battery be added to the house bank for more power?
I have four 6-volt batteries. Each pair is connected positive-to-negative, and then the remaining positive and negative terminal becomes the terminal for that battery. Once you wire two 6-volt batteries together, they are no longer 6-volt batteries (3 cells each), they are a single 12-volt battery (6 cells). However, a single 12-volt battery will not last as long as a pair of 6-volt batteries wire in series, even if they have the same Ah capacity. It doesn't seem to make any sense, but it's true.
Now, as for adding more batteries later, that can be problematic. You're adding two brand new batteries to two older batteries. It's not all that different from using mismatched AA batteries, except it's worse with larger wet cell or AGM batteries. The older batteries are weaker and have less capacity, and they will constantly work on the newer, higher capacity batteries, thereby working both the older and the new batteries harder than otherwise. And the weaker batteries will take the entire bank down far sooner than if you'd gone with four batteries to begin with. In fact, if you're looking to add batteries to a battery bank, it's far, far preferable to replace the entire back with the necessary number of batteries than it is to add batteries piecemeal. It's best if all of the batteries in the bank have the same date of manufacture, Ah capacity, and brand. Two batteries with a couple hundred charging cycles suddenly mated with a couple of batteries with no discharge cycles on them is one of the ways that, "batteries don't die, their owners kill them."
If you add additional batteries to the bank, I wouldn't do it more than 6 months after the initial install.
Also, I like the idea of being able to use the house bank to help aid the starting batteries in a jump, if need be, and am unclear what has to be done to be safe for the system with that. Can that be done simply with the isolator (looks like yes with the one mentioned below), or does one need to also add a switch?
You generally won't need to add a separate switch, as most isolators have the option to simply connect a wire from the isolator to the ignition that will combine the batteries as needed. With others a switch is needed, but it's a very simple connectio
n. If you don't have a remote switch hooked up, you can just open the hood and connect a small, short jumper wire from the "remote switch" terminal to the "Auxiliary battery" terminal on the isolator. Another option is to use jumper cables from the house bank to the cranking battery (as both batteries are already grounded, only the positive connection need be made, and you can decrease resistance by connecting both the positive and negative jumper cables to the positive terminals).
I'm leaning towards the
Hellroaring Isolator, and like that they have an active tech department to help customers figure a good plan.
That's a really good isolator. it's so good that other than perhaps some questions you might have at installation time, you aren't likely to have a need for the tech support.
And yep, a decent monitor, at least for the house bank, is planned as well, probably the
Xantrex LinkLite. Little by little. . .
Couldn't hurt, but you really don't need a battery monitor for the cranking battery. As the battery is getting old, just throw it on a load tester once in a while to see if it's nearing it's end of life.
