Battered Batteries

Just loading up Towed Haul the other day and I noticed that the propane detector was flashing orange at me, rather than the regular green. Ooh... er... I thought.

As is usual in these cases, I ferreted out the manuals and had a look at what said orange light might mean and, in surprisingly plain language, the printed word informed me that I had low voltage. OK, I thought (I do a lot of thinking), we're plugged into the 120V 30amp supply, so that shouldn't be the issue but the little circuit diagram in the manual showed the detector to be wired directly to the battery. Aaah I thought. In a moment of rare lucidity, I hit the battery re-connect button in the trailer to see if the battery was sufficiently charged to power the lights and well, it did, but only just. 

Using my great knowledge of these things (ha!) I surmised that if I was plugged into the shore power then the batteries would be charging, and yet here were quickly flattening batteries crying out for help. Two possible causes of the problem came to mind, the first being that the batteries were fried and the second that the power converter that constantly charges the batteries when on shore power somehow wasn't working.

The batteries being only three years old shouldn't really have failed at this stage but, as is our habit, we do tend to leave the thing plugged in to shore power when it's on the drive, constantly charging the batteries, and I know from my chums on AirForums that the basic and unsophisticated power converter fitted by Airstream can cook those batteries when left on charge all the time. Rummaging for more manuals, I read through the converter's bumph and also downloaded a nice fault-finding flowchart from the manufacturer's web site. I dusted off my old Multimeter and set to measuring the voltage coming out of the converter. I was thinking at that point that a new converter might be in order and, as we could probably get it replaced under warranty, I thought that might be the most cost-effective option at this point, despite the inconvenience of dragging Towed Haul to the dealer's shop. That thought was short-lived, though, as the voltage was actually both present and OK. Must be the batteries I thought (see, there I go again with the thinking).

I went to our local battery specialist, Battery Boy, and they quoted $200 for a pair of new deep cycle batteries and would give me $10 a piece for the old ones. I wasn't happy to have to be forking out yet more money but hey, as the electric jack on the Airstream needs a good battery, it'd probably be be worth it.

So, there was I extracting the old units and dropping in two new ones, feeling a tad worried just in case I'd diagnosed wrongly but no, once connected, all systems really were go. Phew!

Battery Boy himself gave me a free hydrometer (C'mon science geeks, it's for measuring the specific gravity of the battery acid) and assured me that it was the only way to get a true reading of a battery's state of charge. Funnily enough I'd read just that snippet of information on a blog about RV battery care, so I snapped the fellow's hand off. Battery Boy also said that the secret of keeping a deep cycle battery good was to keep it charged up. Sounds like a plan (I thought), although that might not be so easy in the storage months. I think I'd better not leave the thing plugged in all the time in future but, even if I did, new batteries are not the most expensive things I will ever buy and at least I know I have reliable power for the foreseeable future.

The good news, of course, is that the propane detector is now winking green again. Result!