Batteries for 120w panel?

[RVtrek]

My 2 cents: Get the biggest battery you can afford. You're never going to wish you had less amp-hours available to you.

 

[John61CT]

The size of your bank doesn't in itself make getting back to 100% Full harder.

Just keep consumption down to what you can put back in.

Bigger bank gives you some more leeway, without it you'd just run out completely sooner in cloudy weather.

 

[JadeOnWheels]

Thanks, everyone! You've been very helpful. I think I'm going to be fine with my 120w panels for now. I am hoping to be on the road next year sometime, so I'll be looking to meet you guys. Probably won't make the RTR, but maybe in 2019, or if there is a smaller summer meetup.

 

[frater secessus]

My 2 cents: Get the biggest battery you can afford.

Assuming one can get it fully charged every day.   In the unfortunate absence of SternWake I will warn against batterycide.

 

[John61CT]

The real challenge there is monitoring AH consumed accurately, or SoC itself.

With that ability in place, then you just stop using more than you can put back in per charging cycle.

If that amount per day is only 5% of AH capacity, the bank will last much longer, or you have the option of making each cycle last a week (shore power overnight).

A bank that doesn't mind PSOC conditions would be even better.

But all this costs more money than OP is talking about, just laying out what is possible technically.

 

[frater secessus]

I know they'll charge when I'm driving, or if I use shore power, but on a daily basis, not with my panel they won't.

Being in the city makes me thing you'll be moving the vehicle more than someone camped out in the desert.   Even a trip to the grocery store or laundromat can stuff a surprising number of amps into the house battery when the battery is low.

You may find it most efficient to do your driving early in the morning when the batteries need the big amps.*   Then solar has much greater chance of getting you to 100% charged by the end of the day.  Alternator + solar charging reminds me a bit of a two-stage rocket;  the first one stage gets the battery off the ground.   The second stage gets you the rest of the way.


* same reason generator folk run their gennies in the morning

 

[John61CT]

Nice analogy there!

 

[Weight]

what are golf cart batteries rated at 35 amp hr?

 

[lenny flank]

* same reason generator folk run their gennies in the morning

I thought they did that just to wake up everyone in the neighborhood.

 

[JadeOnWheels]

what are golf cart batteries rated at 35 amp hr?

I saw regular golf cart batteries at Walmart that said 35ah. They were the cheapest, but I would need four of them, which makes them more expensive. Deep cycle batteries went up to 200+ah, but I wanted to run them serially, so I want 100ah on each one.

 

[John61CT]

Walmart sell no true deep cycling batts of any quality.

Nor any other automotive or consumer big box.

Only exception AFAIK is Sam's Club and Costco's, 6V flooded GCs. Former much better than the latter.

 

[JadeOnWheels]

Being in the city makes me thing you'll be moving the vehicle more than someone camped out in the desert.   Even a trip to the grocery store or laundromat can stuff a surprising number of amps into the house battery when the battery is low.

You may find it most efficient to do your driving early in the morning when the batteries need the big amps.*   Then solar has much greater chance of getting you to 100% charged by the end of the day.  Alternator + solar charging reminds me a bit of a two-stage rocket;  the first one stage gets the battery off the ground.   The second stage gets you the rest of the way.


* same reason generator folk run their gennies in the morning

I'm a morning person, usually. I like to get my errands run before noon, but thanks for that info. I'll also be traveling from place to place, exploring different small towns (I love small towns), so I won't be sitting still much. That's why I figure I can get by on the 120 solar, because I'll be doing a lot of charging with the isolator. I doubt I'll be desert camping more than a month a year. I'm not really in love with the desert. I like trees and forests, which makes it even more important to have a shore power plug and isolator. If I can't get charged with solar, I want to be able to stay at a campground and charge them up overnight.

 

[John61CT]

For short driving spurts (under six hours) you'll get better charging results with a good AGM bank, they accept a much higher amp rate in the first couple hours. But the ones worth buying are expensive.

You're actually charging from the Alt, all the combiner (ACR, VSR, not isolator) does is close the connection between banks while charging and otherwise keep them isolated.

A shore power port to the outside makes it easy to plug in your shore charger. 30A if flooded, go to 80+A for AGM.

 

[frater secessus]

For beginners, note that John is talking about 30-80A chargers, not 30-80A shore power setups.  Chargers of that size will run easily off a normal 15A 110vac outlet.

 

[JadeOnWheels]

For beginners, note that John is talking about 30-80A chargers, not 30-80A shore power setups.  Chargers of that size will run easily off a normal 15A 110vac outlet.

I figured as much, since my friend runs his from his garage outlet via a special heavy-duty extension cord. I'll have to ask later about how to wire it into the system and what kind of switch to use. I have lots to digest right now. I'm having someone else wire the solar system, so hopefully, they'll know how. 

Y'all have been very, very helpful. I feel a lot better now about what I can and can't do.  Solar is my biggest budget item, because I want to do it right up front. I can live with a very basic build if I have that taken care of. Hey, you've gotta start somewhere! I figured I'd start with the most important thing.