Battery lesson

Reluctant to head back to home base quite yet, we have stopped in Quartzsite AZ for a few days of free camping in the desert.  We’ve been camped at the BLM’s “Roadrunner” area, which is about five miles south of the town.  This is classic boondocking, no services at all, no established campsites, and no fees.  The lack of amenities is balanced against the feeling of freedom that comes with staking out a little patch of gravelly desert and just enjoying the simpler pleasures of life.


However, sometimes reality intrudes on our attempts to “get away from it all.”  Last night I noticed that the Tri-Metric battery monitor was reporting strangely low voltage in our batteries, despite having used just 33 amp-hours of our total power reserve.  That’s about 15% of the theoretical power available.  Not long after, the voltage dropped to 10.8 volts, the lights began to dim, and I realized we had a serious problem with our batteries.

Around 9 p.m., the trailer was effectively dead. No power means no lights, water pump, or heat from the furnace.  Eleanor and I were outside in the dark examining our battery bank by flashlight.  We have a bank of four Optima “blue top” Absorbed Glass Matt (AGM) 12v batteries. We tried disconnecting each battery and checking voltage, hoping to isolate one battery with a problem, but they all reported the same voltage.  At that point we decided to reconnect all the batteries, and limp through the night without any heat.

By reducing the power load to the small amount required to maintain the refrigerator’s circuit board and a few other “parasitic” draws (radio memory, propane leak detector, etc.), the voltage popped back up to 12.2.  We all piled into one bed and stayed pretty warm, even though the trailer dropped to 46 degrees.

In the morning we hitched up and towed directly to Solar Bill’s, one of three solar installers in Quartzsite.  Solar Bill’s is a fixture in Q, having been in the same location for 22 years.  The guys did a load test on the batteries and found that two of them were dead as a doorknob.  The other two were fine, despite having been installed at the same time.

The problem seemed to stem from our wiring.  Our batteries should have been wired in parallel.  As it turned out, they were wired in two banks of two, in such a way that one bank took all the load while the second bank was basically just coasting.  That mistake contributed to the short life of the Optimas.  They lasted 3.5 years when they should have had twice that lifespan.

Although two of the batteries are still good, the recommendation with batteries is to replace them all at the same time.  This meant the two good batteries would also need replacement, an expensive procedure.  Solar Bill didn’t like the choice of four 12-volt Optimas, so he suggested 6v golf cart batteries, but they wouldn’t fit.

After weighing several options, the best choice overall was to remove all four Optimas and replace them with one huge Lifeline GPL-4D.  This eliminated the wiring issue and freed up our forward battery box for other uses (like tool storage).  The “supercell” sits in the forward storage compartment under our bed, in the space formerly occupied by two of the Optimas.

As a bonus, the Lifeline weighs about 40 pounds less than the batteries it replaced, with a theoretical power capacity about the same.  The two used-but-good Optimas will go to the Caravel, thus doubling the power available in that trailer, and we’ll have one Optima (from the Caravel) left over for future use.

But this has made for a very expensive week.  Four tires, and now a replacement battery.  I was happy with our relatively low maintenance expense in 2009, but so far in 2010 we’ve almost blown the budget for the year … and we are still awaiting the repair or replacement of our catalytic heater.  On the positive side, it seems like we’ve dealt with a lot of the big-ticket items, so perhaps the rest of the year will go well.


  1. Terry says

    Rich, the 4D batteries are the same used in big rigs, buses, and some big class A motor homes.

    If I’d known your catalytic heater wasn’t working, I could have loaned you our spare.

  2. says

    Bummer! But what a great battery you landed from Bill’s Solar. We bought the same battery and installed it inside and forward, under the bed, of our first Airstream, a CCD22. Man, it was great! And a bear to move into position under that bed. Fortunately my then 17 yr old son helped me muscle it into place.

    I really liked moving the battery weight further back from the hitch, like you’ve done. Hmm, maybe instead of adding a pair of golf cart batteries I could just add an AGM under the sofa — it wouldn’t tip the tongue weight as much as adding onto the A-frame would.

    So many possibilities so little money!


  3. says

    Just two days ago I was contemplating possible solutions to our lack of 12 volt capacity coupled with the lack of room needed for golf cart batteries. This seems a pretty hefty and expensive solution to the problem, but I can’t think of a neater solution.


  4. says

    Figures…we’re in Tucson, you’re in Q… We have had problems with our chassis battery(Optima-red)…it’s about 2 years old…what are the dimensions of your new battery, and an approximate weight? mike

  5. says

    Mike, the dimensions are 20.76″L x 8.70″W x 9.76″H and the weight is about 135 lbs. Lifeline also makes other sizes of AGM batteries, larger and smaller.

  6. Alice Wymer says

    We are feeling the battery budget pain as well. Tim had to replace both batteries in the diesel tow vehicle last week. The cold weather we are having in Florida pushed it over the edge. But at least we caught this two days before pulling out for The Can Opener in Santa Rosa Beach. We had a blast! Cold blast that is . . . camping with the nights in the low 20’s. Brrrrr. We were one of the 29 A/S diehards that went to the gathering.

  7. peter ferguson says

    safety issues regarding your new battery:

    weight – compartment built for concentrated 135 lb load?

    what supports this floor? what holds this load down?

    hydrogen venting? not possible with this installation. please read battery site regarding legal methods of venting. boom.. directly under your bed…ouch. this manufacturer goes into high detail for proper hydrogen venting and rightfully so.

    code requirement for battery disconnect. explosion proof? distance?

    Airstream installs batteries per code…saves booms.. and lawsuits…let alone life and property damages.

    besides traveling with this setup you will probably ‘plug’ it in when parked at home. even with not being totally garage enclosed, your a/s will have hydrogen building up in the compartment……..

    best of luck….oh, your LP bottles aren’t very far away from this compartment are they…?


  8. says

    Peter, the Lifeline is an Absorbed Glass Matt battery. We have used this type since 2006 because they do not vent hydrogen. It is perfectly safe to install in an interior compartment. Check out the specs sometime.

    As far as load, do you worry about falling through the floor of your Airstream when you stand on it? I’m pretty sure most Airstreamers weigh more than 135 lbs…

  9. says

    One battery that will almost replace your four? You’ve convinced me that this may be the solution to our battery situation. Though we’d be replacing two Life line batteries that came with our Airstream, we’ve done pretty well. And though we haven’t gotten seven years out of them we’ve come fairly close. For us, your informative write-up is most timely. Thanks!

  10. peter ferguson says

    great to hear back from you. yes, I know they are not ‘vent’ type batteries. however, I phoned Mike at the GPL company and he indicated venting of the comparment would be recommended. their specs on charging procedure for lifetime agm bat states: ” All batteries must be adequately vented during charging to avoid accumulations of explosive hydrogen gases. Never install or charge in a sealed container or sealed ”

    guess your compartments are pretty strong…mine are not.

    I give……….enjoy

  11. says

    Peter, perhaps this is a case where the Marketing Dept giveth and the Technical Dept taketh away. All of the marketing for Lifeline AGM batteries says no venting is needed, and that even under severe overcharging conditions hydrogen accumulation stays below dangerous levels.

    I think there may also be some difference in definition of “sealed container”. This front storage compartment is hardly sealed. It has 1/4″ air gaps along the bottom edge (interior) and many other leaky spots. Many RV’ers have used AGM batteries beneath gauchos, dinettes, and in storage compartments with complete safety, but none of those areas resemble anything “sealed.”

    Our front compartment is just another section of interior floor, as is the case in every Airstream I’ve ever seen. If yours feels soft or spongy, perhaps you have a little wood rot in the floor around the edges? Any Airstream compartment should be easily able to handle the weight of this battery.