Forum Discussion

radiojeffrv's avatar
radiojeffrv
Explorer
Aug 20, 2018

majestic 28a

Has anyone added a 2nd house battery to a Majestic 28A? Have some ideas about how to do it but would love some more ideas.
  • Yeah I did.

    I have a 23a tho.

    So on mine there is the battery outside under the coach. the rest of the rats nest of wiring plumbing, electrical boxes are under the corner bed.

    Under the corner bed is isolator blocks that bring in the power from the outside battery. then finish into the convertor/charger. there was enough room to put in another battery and bring in all the solar parts and now have 2 batteries with 300ah capacity.

    1 is not enough for anything off grid. adding the 2 gives me near unlimited power except for winter camping along with solar is my absolute top favorite mod for the rv.

    I would suggest locating the convertor/charger which can be under a dinette on some of these and find the isolator blocks you can then tap into it to add as many batteries as you have space for.

    even better then what i did would be bring them all inside. i have temp compensation on the one inside but not the outside one. Both are AGM's and have really improved the boondocking capabilities of this super basic rental machine.

    Also IMPORTANT only agms,lithium are allowed inside the rv. SLA's are not for inside unless you want an elaborate sealed vented battery box that you won't have room for and holes in the side of your rv.

    I like the other post on the extended tray system you could easily go this route as well. probably less hassle in the long run. This route tho might have voltage drop unless upgrading to welding cable coming into the rv. they use pretty silly wiring coming in. like 8 gauge or 10 i forgot. I put in 00 gauge for solar, less dc voltage drop.
  • Thanks Craz z!! I was thinking of putting the 2nd AGM battery under the Dinette where the converter is located...I just wasn't sure about AGM batteries inside. Did yo put it in a battery box?
  • Agm's require no battery box. Completely safe to run indoors with ZERO off gassing. Unlike SLA's or deep cycle walmart/costco type lead water batteries these can be installed in any position and require no maintenance except for proper charging inputs. I've got my solar controller set to high 14v and over 15v on equalize.

    Love em or hate em this guy is spot on with Solar. Best read ever to date on solar IMO. clicky

    Since following all of his advice in my install I've had EXCELLENT results with solar and my 12v side of the rv.

    I screwed in some hold down clamps and a strap to keep the battery secure. Example clicky

    Batteries i used where these so far 2-3 years in, VERY happy
    clicky

    Now if I could do it over again. I think I'd save up for these.
    clicky

    However the cold weather has me concerned for lithium but you would need about 1 of these to equal close to 2 of the VMAX's plus the benefits of quick charging and steady voltage drop free power is very very appealing with these.

    Coupled with a higher wattage invertor and maybe 2 of these lithiums your on par to taking out the generator for AC And microwave power. Currently the only 2 items that the onan 4000 gets turned on for. Another benefit is weight on lithiums are a fraction of AGM's and SLA's

    Also if you have room in your dinette for an invertor put one in and tap into one of the breakers and you will have power to the outlets and can watch tv and charge just about anything you want.

    I think on mine there was like 2-3 110v breakers feeding several outlets I picked the one that does most of the outlets including the tv but left out the fridge and microwave and now have power to all the 110v outlets in the Majestic. I used a 3000w Xantrex invertor and has been a very quiet free to live like normal RV experience.
  • For my 23A I used one of these.


    https://www.torklift.com/rv/hiddenpower



    For the 23A I had to modify the mount to go on the inside of the frame but hopefully the 28A has more room.

    Next to my battery there was already a distribution block so I just ran the battery to there.