Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×

Thread Tools Display Modes
Old 03-30-2017, 09:53 AM   #1
New Member
Join Date: Mar 2017
Posts: 3
Question on power system-no batteries.

Hey all!

I will be purchasing my bus in the next month or so, and have a few questions. I have already ran through the posts for a solution & found nothing.

First off, I am not wanting to run a battery bank, so that & solar are out.

I will be installing a shore unit in for most of the parked & a generator.

But my questions center around 12v power.

I am wanting to install a 12v mini fridge (hooked up to a converter for shore/gen when bus not running)

1 small window AC unit on an inverter & shore/gen when not running.

And 1 wall plug from the inverter as well (noting major plugged up. laptop, or cell chargers)

I guess my main question is: What do I need to hook up to,to run the inverter, and 12v fridge?

Can I just hook them to the starting battery, or do I need to rig some other system up?

The bus will just be for 2-3 day trips, with shore & gen at night. I really want to stay away from batteries banks & the such.

Mousez is offline   Reply With Quote
Old 03-30-2017, 11:43 AM   #2
Bus Geek
Join Date: May 2016
Location: Eastern WA
Posts: 6,400
Year: 2002
Coachwork: Bluebird
Chassis: All American RE (A3RE)
Engine: Cummins ISC (8.3)
Rated Cap: 72
If you don't have house batteries then your only option is to connect your 12v loads to the starting battery. Generally not the ideal situation.

I would strongly recommend some kind of house battery. Even if you went with a single modestly sized 12v battery and a battery isolator so that your coach charging system will run the loads and charge the house battery when the engine is running.

Running your house loads off of your starting batteries is a great way to find yourself stranded because you fell asleep with the TV on or similar.

Trust me... I have been stuck out in the woods 30 miles from town in a rig that ran 12v loads off of the starting battery. Somebody forgot to switch the inverter off and the draw was enough to drain the battery over a 16 hour period. Time to go home and our starting battery was dead. No cell service. We hiked out to the highway, in the rain, and flagged down a passing traveler who kindly drove us back to our campsite and jump started our (borrowed) rig.

If you elect to go ahead and run your 12v loads from your starting battery I would recommend that you carry: Jumper cables, warm clothes and an umbrella.....

Edit: Also, frequent deep discharge of your starting battery will significantly shorten its lifespan. Starting batteries and deep cycle (house) are built differently. True deep cycle will tolerate frequent deep discharge (50%) far better than a starting battery.
PNW_Steve is offline   Reply With Quote
Old 03-30-2017, 11:49 AM   #3
Bus Geek
ol trunt's Avatar
Join Date: Apr 2012
Location: So Cal
Posts: 3,195
Year: 1935
Coachwork: Superior
Chassis: Chevy
Engine: 317 ci/tid / Isuzu
M, don't even think about using your start battery to power an inverter for your AC (or anything else). First, the start battery isn't a deep cycle battery like you'd want for an inverter and second, you'd find yourself calling triple A for a jump start about 15 minutes after you turn on your AC. Furthermore, using a genny to power a converter to run 12 volt equipment will make you persona non grata in almost any camping situation. A small deep cycle battery bank is simple to install and will allow for much more flexibility when you are camping.

Try refining the questions you want answers to. The search function here is pretty picky. Many have better luck using Google to search
ol trunt is offline   Reply With Quote
Old 03-30-2017, 11:53 AM   #4
Bus Crazy
roach711's Avatar
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,966
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
Are you planning to run the fridge, AC unit and plugs off the starting battery through an inverter or will you be plugged into shore power/generator when they're in use?

As Steve said, running house loads off the starting battery is a bad idea.
The Roach Motel
roach711 is offline   Reply With Quote
Old 03-30-2017, 12:44 PM   #5
New Member
Join Date: Mar 2017
Posts: 3
Alright, for cost effectiveness, would this setup work?

3 of these batteries.
AutoCraft Marine / RV 12-Volt Deep Cycle Battery, Group Size 24M, 550 CCA

Plus a solar kit from harbor freight.
Solar Panel Kit - Save on this 45 Watt Solar Panel Kit
Mousez is offline   Reply With Quote
Old 03-30-2017, 12:52 PM   #6
Bus Crazy
turf's Avatar
Join Date: Apr 2013
Location: Colorado
Posts: 2,103
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
when i first got into this group, i resisted the "house battery" concept. my bus had 3 batteries, surely thats enough? nope.

those batteries are tasked to keep starting the motor. they can't handle double duty very long.
i was a bad camping neighbor in campgrounds since i had to run the gen 8ish hours a day to recharge the batteries.

i now carry 7 batteries, 3 start, 4 house. that runs my 12v fridge for a day and needs an hour of gen time to recharge.

you just have to do the math. figure your daily needs and multiply that by days in between charges. then double that, because you only use half a battery, then double it again for a safety factor.

i use about 100 AH/ day, my battery bank is 440 AH. once on the generator you can't recharge to %100, it just takes too long. 80% is real good on the road.

even in great systems, there is lots of inefficiency. keep your fridge on the 120v side and use it only plugged in. let the battery be for the bus.

you'll need batteries!
Turfmobile Build Thread
turf is offline   Reply With Quote
Old 03-30-2017, 03:08 PM   #7
Bus Crazy
roach711's Avatar
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,966
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
Marine batteries usually aren't true deep cycle batteries. Most are a hybrid starting/deep cycle. Any battery that lists CCA (cold cranking amps) is primarily a starting battery. You want true deep cycle batteries for what you want to do.

Running the fridge off batteries is doable short term but you'll need some way to recharge the house bank pretty regularly. Running the AC unit off batteries isn't very practical.

The problem with solar power is that you need to park in full sun. That's fine in cool weather but when it's hot you pay for those amps with a hotter bus.

A 45 watt panel isn't a lot of power. 45 watts @ 23.5v = 1.9 amps.
The Roach Motel
roach711 is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 01:39 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2023, vBulletin Solutions, Inc.