Forum Discussion

scottkeen's avatar
scottkeen
Explorer
Jan 28, 2018

Onboard Generator or 2 Portable Generators + Solar + Battery

I have a 2011 Montana 347THT fifth wheel toy hauler and it has the gen-prep package with the shielded generator bay and wiring to a generator on/off switch inside the RV.

I just bought it used less than a month ago, and am looking for what power options I want to get for it. It came with a dealer-provided 12V 58Ah lead acid battery which will yieled 29Ah if I run it down to just 50%

I bought the RV with the intention of doing more dry-camping, boondocking and less campground-parks. My hopes are to go full-time and be largely energy independent.

I expect to follow-the-weather and run one 15K BTU AC only if I'm stuck somewhere in unbearable heat.

I'm considering my generator/battery/solar options with costs the same. Here's how I see it:

Option A: Onboard Generator - Gasoline
$3100 Cummins/Onan 4000 gasoline onboard generator (4000W rated)
$ 400 (est) gasoline tank under trailer between frame rails
-----
$3500
=====

Option B: Onboard Generator - LP
$3500 Cummins/Onan 3600 propane onboard generator (3600W rated)
=====

Option C: Portable Generator + Solar + Battery
$2050 (2) Honda EU2000i + EU2000ic with parallel kit (4000W peak, 3200W rated)
$ 640 Renogy 400W solar kit (PWM, upgrade to MPPT later)
$ 900 Renogy 12V 100Ah Lithium Iron Phosphate battery
-----
$3590
=====

I like the convenience and extra rated wattage of the gasoline onboard generator, and the convenience of the LP onboard generator and lower maintenance of LP vs gasoline.

But hard to argue with getting almost the same rated wattage from a couple of Honda portable generators and the option of only using one generator at 2000W (1600W rated) if that's all I need. Plus I would be getting a 400W solar kit and a much-desired 100Ah LiFEPO4 battery which I can run down empty, with more charge cycles and lighter weight than SLA.

I'm leaning highly to Option C, but the convenience and more power of Option A and B are really nice.

Your thoughts?
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Jan 29, 2018
    My first purchase was a $176 battery monitor. This provided me all of the input I needed. For example check the amp draw, turn on a light and the difference is the light amps. Input for a future LED in my case. Plus battery discharge amount, etc.

    My second purchase was paper and pencil along with learning and planning.
  • scottkeen's avatar
    scottkeen
    Explorer
    Jan 28, 2018
    kerrlakeRoo wrote:
    And to add to CATravellers comment, go solar first, when you install go big on the controller so you have plenty of ability to upgrade. You already know that they are not something you will later eliminate or
    replace. The golf cart batteries give the most bang for a low price. And you can use two or four to learn what you will need amps wise permanently. Also the lithium batteries in another year or two may be much cheaper as more come into use.
    Lastly, If you are relatively certain you won't use ac very much, just get a small Genny, 1000 to 2000 watts, an you then have a backup means to charge batteries. If you end up somewhere you have to have ac, go to a campground for a night or two while deciding where else to go.


    Everything said ^ makes reasonable sense. Thanks.
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Jan 28, 2018
    scottkeen wrote:
    CA Traveler wrote:
    Now install 2 6V flooded batteries and you'll jump up to 230AH at low cost.


    Would that be 115Ah at 50% discharge?

    Just wanting to get my numbers right!
    Correct.
  • kerrlakeRoo's avatar
    kerrlakeRoo
    Explorer
    Jan 28, 2018
    And to add to CATravellers comment, go solar first, when you install go big on the controller so you have plenty of ability to upgrade. You already know that they are not something you will later eliminate or
    replace. The golf cart batteries give the most bang for a low price. And you can use two or four to learn what you will need amps wise permanently. Also the lithium batteries in another year or two may be much cheaper as more come into use.
    Lastly, If you are relatively certain you won't use ac very much, just get a small Genny, 1000 to 2000 watts, an you then have a backup means to charge batteries. If you end up somewhere you have to have ac, go to a campground for a night or two while deciding where else to go.
  • scottkeen's avatar
    scottkeen
    Explorer
    Jan 28, 2018
    CA Traveler wrote:
    Now install 2 6V flooded batteries and you'll jump up to 230AH at low cost.


    Would that be 115Ah at 50% discharge?

    Just wanting to get my numbers right!
  • scottkeen's avatar
    scottkeen
    Explorer
    Jan 28, 2018
    CA Traveler wrote:
    ...plus from the OPs post he doesn't have the experience to get it right.


    Ain't that the truth!

    Like anyone else, I just hate the thought of buying once. And then buying again. And again. And again.
  • scottkeen's avatar
    scottkeen
    Explorer
    Jan 28, 2018
    KD4UPL wrote:
    Your current battery is way too small. Your proposed 100 AH battery is still too small. If you truly want to be "energy independent" as you say you should be looking for several hundred AH of capacity. Weight really isn't an issue here as I see it. Even 4 6v GC batteries will only weigh about 400 pounds. This is "nothing" compared to the total weight of your rig. Unless you are trying to get buy with a marginal tow vehicle which would also be a bad idea for full-timing.
    4 GC batteries will give you about 220 AH at 50% discharge for about $400. That's more than twice the 100% capacity of your lithium battery. What does it cost?


    One 100Ah Li would be just a start. Somewhere around 400Ah would be where I want to end up. At $900 each that comes to $3,600 when I get there. They weigh around 25 lbs each, so that's 100 lbs total.

    With 6V GC batteries, to get 400Ah at 50% discharge, I'm looking at around 8 batteries, about $800 and 800 lbs of weight.

    I should factor in charge-cycle lifetime with cost.
    The lithium is rated for 2,000 charge cycles
    Deep-cycle lead acid is around, what, 200-500 charge cycles. Say 500 cycles.

    That's a 1:4 lifetime ratio.

    (4 batteries @ $900) x 1 = $3600 lithium
    (8 batteries @ $100) x 4 = $3200 lead-acid

    So it's almost the same cost given those charge-cycles.

    I see the lifetime cost as equal, and the Pros vs Cons as this:

    Lithium = less weight, less space
    Lead-acid = less initial cost

    I like the less weight/space of lithium, but the idea to have 400Ah for about $800 with GC 6V might be the right way to go.

    Hmmm, some good arguments for either case...
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Jan 28, 2018
    Lantley wrote:

    In the OP's case do you want:convenience,best bang for the buck, maximum power and run time, maximum ability/time to stay off grid? Are you able to lift heavy things and maintain a portable set up?
    What is most important to you and you alone? This is really not an at large group decision.
    The answer is more about how you intend to use your rig vs. price.
    In the RV game it's always cheaper to get it right the first time, but in order to do so your expectations and intentions become critical
    I agree plus from the OPs post he doesn't have the experience to get it right.

    OP Consider going to a CG with power and leave the power off and learn what you need. Your battery will be discharged very quick, then turn on the power and try again the next day.

    Now install 2 6V flooded batteries and you'll jump up to 230AH at low cost. Then get serious about how much power you need, the costs, the starting point and future upgrades.

    Now you've spent less that $200 and have begun to build a foundation of knowledge and maybe just maybe you can get it right the first time.
  • KD4UPL's avatar
    KD4UPL
    Explorer
    Jan 28, 2018
    Your current battery is way too small. Your proposed 100 AH battery is still too small. If you truly want to be "energy independent" as you say you should be looking for several hundred AH of capacity. Weight really isn't an issue here as I see it. Even 4 6v GC batteries will only weigh about 400 pounds. This is "nothing" compared to the total weight of your rig. Unless you are trying to get buy with a marginal tow vehicle which would also be a bad idea for full-timing.
    4 GC batteries will give you about 220 AH at 50% discharge for about $400. That's more than twice the 100% capacity of your lithium battery. What does it cost?
  • scottkeen's avatar
    scottkeen
    Explorer
    Jan 28, 2018
    ford truck guy wrote:
    I can compare options A and C as I went from one to the other..

    I started using 2 of the EU 2000’s with a 5 gallon extended run fuel tank... It got old getting there, getting the generators out and set up, hooking them together and setting up the fuel...

    I then purchased a 6500 LP version, although the LP version gets thirsty when running at max, it sure is handy, and that what I was looking for...

    We dry camp usually 2-3 times a year, and stay in campgrounds probably 95% of the time, so for us, it made sense..


    Thank you. Coming from someone who has been-there-done-that on both options carries a lot of weight.

    I suspect my ideal solution is an onboard 5500 LP generator, solar and batteries out the wazoo, and maybe one 2000W portable generator for emergency backup, topping off the battery in low-sun, and just light-demand needs so I don't have to fire up the 5500.

About Fifth Wheel Group

19,009 PostsLatest Activity: Mar 20, 2025