More batteries vs more panels.

[rob58]

Hello all, new to the forum and while I understand the concepts and understanding how this all works, I have hopefully a quick question. First a quick background. Within the next year I will be selling everything I own, buying a truck and toyhauler, throwing the bike in the back and traveling for at least a few years. I want to be able to boondock a bunch. The trailer may have solar already installed. If not I will do it myself. My plan is to go with a medium to large system, so the guts of the system will be set up for that eventuality (3000w inverter, etc). My question is, if I had to choose between more batteries (ex. 600-900Ah) or more panels (1k-1.2k w), what would be the best option? I want to add on as I get a feel for what I will need on the road. These numbers are kinda just off the top of my head and are used as an example only. I realize that if there is an existing system in the rv, things will be different. Thanks for your time and opinions.

 

[sunshine_eggo]

Rather than on-the-fly feel, you should estimate your consumption with an energy audit and analysis of available solar. See link #1 in my signature.

Once you've established what you need from each, and decided that you want to buy a surplus of one or the other, the question becomes:

Do you want to be able to use more power daily, or do you want to go longer between charges?

More daily power = PV
Longer between charges = battery

Worth noting that no amount of battery can overcome over-consumption or insufficient PV production.

 

[JRH]

Interesting scenario as I am facing the same deciding how to grow…

In my neck of the hills , we don’t use math ,we use chickens ….

in this equation ,your not allowed to eat the chicken..( just go with me on this ,ok )

Chickens = batterys
Feed = PV power..
Eggs. = benefits received

So….

Too many chickens ,and not enough feed = Sickly weak chickens and few eggs = XXXX ?

To much feed and not enuf chickens = full chickens that won’t eat all the feed you are giving them
= wasted energy from the unused feed = few eggs as there’s few chickens = XXXX..?

Balance is the answer….= ? ..

Balance differs for everyone..= ??

Finding balance = ++++?

J.

 

[HRTKD]

Rob, the answer is, "It depends". If you have a fifth wheel toy hauler you're likely to have two or more air conditioners and most likely plenty of room the roof for PV and plenty of room in the pass-through compartment for batteries.

I have a bumper pull toy hauler. Space for PV and batteries is at a premium. I have 640 watts of PV on the roof and 560 Ah of LiFePO4 crammed into a void underneath a closet. To get more PV I created a 640 watt ground deployed system that plugs into the side of the RV. It works well for me and I camp nine to ten months out of the year. I think that will change to more months once I start traveling in the south instead of the north. The only time my battery bank has been below 50% state of charge was when I stress tested it by charging my EV.

I don't think you need as much battery as you're estimating. PV, yes. My hunting buddy has a Northwoods Arctic Fox fifth wheel (not a toy hauler) with 400 Ah of LiFePO4 and one 170 watt panel on top. The panel is of course too small for his trailer and he'll be upgrading soon. But the battery bank is just right. The last time we were out together I charged his trailer from mine during the day so he didn't have to run his generator.

Victron 12/3000
Victron MPPT 100/50 (x2)
Victron Cerbo GX
Victron BMV-712
4s 280Ah EVE LiFePO4 (x2)
Overkill Solar 4s 120 amp BMS (x2)

BTW, want to buy a toy hauler? I'm looking to upgrade.