Upgrading the Battery - QS 8.1

Started by wdaltman, January 25, 2018, 05:55:50 PM

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So, we just made reservations for 8 nights in Glacier NP this summer.  Since moving from tent camping to the QS, we've gotten used to a few comforts that depend on electricity - mainly an ARB 12v fridge.  It is so nice not having to worry about ice to keep everything as cold as our home fridge (and colder if we want it).  Being a national park, there are no electric sites.  I know we could just go the way of ice for our food and batteries for our lights, etc.  But I'm wondering about options for upgrading the 75 amp hour battery that came with our trailer.  Here are some options:

1.  Purchase another 12 volt deep cycle battery and a solar charger kit and simply swap out the batteries as needed - use one while the other is charging.  The upside is that this would not be expensive and would require no modifications to the camper.  Plus the battery being charged could stay close to the solar panel as it is moved to sunny spots.  And, when we take the minivan out for daytrips, we could possibly connect the spare battery to the car battery and charge off the alternator.  On trips where we'll have electric sites, the extra battery and charger just stay home.

2. Upgrade to two batteries - either two 12 volts or two 6 volt golf cart batteries.  This would require some modifications and probably more equipment.  Could 2 batteries even fit up front, given that it's already a bit tight with one battery and a propane tank?  Would the additional tongue weight be a problem?  Would the current electric system even support this or would that need to be replaced?  The advantage is that 2 six volts would probably keep the fridge and minimal other things going for a week without a recharge.  But this would be way more expensive and more trouble than the first option.  When close to home, we're nearly always either in a state park with electricity or a private campground.  But we do a national park probably one week a year.

Does anybody have any advice or experience to point me in the right direction?  Thanks!

Bill Altman
Newburgh IN


I looked at the ARB website and couldn't find any amperage specs. But Engle, another high efficiency DC portable fridge, uses 30-40 amp hours a day. That is about a days worth for a 70 Ah battery because you don't want to draw it down below 50% for best life.

I like your first option best. It will let you move your spare battery to a sunny spot or hook it up to your TV when you go out for day trips to charge. Then swap it with the one on the trailer and keep doing that day after day.

With a 100 watt panel you will probably only get only 30 amp hours of charging each day- if it is sunny. So you will need your TV every few days to charge it up fully. There are a couple of ways to hook it up to your TV and you have to be careful about blowing the TV's fuses when you do that. Make another post if you want to follow up with this and I will address the options.

With option two you don't have a good way to recharge the batteries. Two batteries will mean you are out of power by the third day.



I did find the following from a website regarding the ARB fridge (ours is 50 liters).  And yes, I'd like to hear the options on how one can charge a battery from the tow vehicle.  Thanks!

Everything below is quoted from (http://www.offroadaussie.com/2015/07/arb-fridge-freezer-and-battery-life/).  The columns are the ARB fridge size, the current draw in Amps/hr, runtime with a 60ah deep-cycle, 80ah, 100ah

35L   0.85   49hrs   75hrs   82hrs
47L   0.87   48hrs   64hrs   80hrs
60L   0.89   47hrs   63hrs   79hrs
78L   1.07   39hrs   52hrs   65hrs

NOTE: These are theoretical maximums. Lots of factors will affect these times. For example, these times assume you discharge the deep-cycle battery 70% (30% of total charge remaining), and they assume that your battery has 100% of its' listed capacity. I'd suggest taking a few hours off each estimate just to cover yourself. I don't want your cursing my name when your beer goes warm! That's way too much responsibility for even my humungous, muscular, Adonis-like shoulders.


I was unable to locate any amperage specifications on the ARB website. In contrast, the Engle DC portable fridge uses 30–40 amp hours daily, while being another high efficiency model. Since you shouldn't drain a 70 Ah battery below 50% for optimal life, that's around one day's worth.

First choice is my favorite. If you have an extra battery, you may charge it in a sunny place or connect it to your TV for use on day trips. Then each day, switch it out for the trailer's and repeat the process.  geometry dash