The world's slowest Airstream restoration

[uncle_bob]

Hi

If you are measuring at the battery posts with the DVM and the battery *is* going down to 5V .... the battery (or batteries) have a problem. That seems unlikely with a new battery, but stuff happens.

More likely, you are measuring a bit away from the battery and have a wiring issue. An open / poorly connected ground is one very likely issue. More or less:

14.48V on the converter = converter is up and running.
14.48V on the battery posts = battery is connected to converter
= battery is fully charged
5V under a tiny load at battery posts = battery is dead

Since the battery should be up in the 100AH range and your load is a couple amps, a fully charged battery aught to keep going for 10 or 20 hours. At that point the DVM should read around 12.1V or so.

So what to do:

1) Check on the battery posts with no load / no charging, you should get 12.6 to 13.2V. If it's below that, charge the battery.
2) Check on the posts with the fan running (about a 2A load) and see if the battery drops to 5V. If that happens, you have a defective battery. On the posts = directly on the lugs on the battery, not on a bolt or a cable attached to them.

Assuming the battery actually is ok:

3) Start from either battery post and work away from there. (with the fan running). Keep the DVM lead on one post and move the other lead along the connection chain away from the battery.
4) Repeat with the other post.

At some point along the wiring chain, you will go from 12V 12V 12V to 5V in your reading series. It's a good bet that whatever that point is ... it's a bit hot.

Since this *could* mean using 50' long DVM cables (and arms to match) there is an alternative as you get away from the battery:

Find a clean spot on the shell / frame and measure both posts to that point. Hopefully the negative will read near zero and the positive around 12V. If the negative reads 5 or 6V then that is a *very* good indication that you have an issue in the negative side. Then as you move away from the battery, take your readings to shell / frame rather than to the battery post.

Be sure to include the DC bus arrangement (however they did it in "your era") as well as the DC fuse (probably not breaker ) panel as you do the measuring.

Bob

[hampstead38]

And, yes, stuff happens fairly often when towing a 50+ year-old travel trailer.

The battery isn't brand spanking new... and we did spend the past three months putting on some serious miles occasionally over unpaved roads. The battery itself is an Optima D27M "dual purpose" marine battery. Normally, I understand them to be good batteries, but there's always the chance of getting a dud.

The battery is mounted in the rear of the Overlander under the port side bed. When I took the measurements, my leads were on the battery posts. As noted, with shore power on I measured 14.48v on the posts. With shore power off (and a small load), it dropped like a stone. Since I was getting 14.48v on the converter outputs it sounds like the battery is kaput.

Normally, the Optima blue top has a two-year warranty. Unfortunately, we didn't buy the battery ourselves so I don't have the paperwork I'd need to press for a replacement. But you mentioned a good notion. I'll pull the battery, charge it using another device, and see if it holds a charge. That should provide definitive proof. The battery isn't mission critical at the moment. We have a Honda 2200 generator we use when we don't have shore power. Still, I'm one of those old school guys who likes everything to work.

We had an issue with the circuit running the fan back in July. We tried mightily to find the short, but we ended up abandoning the wire in place and running new wire from points we knew were good. The next time I wire a vintage Airstream, there are a few things I'd do differently... not particularly useful information given that I'm unlikely to do this again. Thanks for your wealth of knowledge on DC electrical stuff, much appreciated.

[hampstead38]

Curtains over the galley counter and stove.

[hampstead38]

A big box hardware store had very thin stone adhesive tile. I thought it looked better than the usual Dometic frig door inserts.

[uncle_bob]

Originally Posted by hampstead38

And, yes, stuff happens fairly often when towing a 50+ year-old travel trailer.

The battery isn't brand spanking new... and we did spend the past three months putting on some serious miles occasionally over unpaved roads. The battery itself is an Optima D27M "dual purpose" marine battery. Normally, I understand them to be good batteries, but there's always the chance of getting a dud.

The battery is mounted in the rear of the Overlander under the port side bed. When I took the measurements, my leads were on the battery posts. As noted, with shore power on I measured 14.48v on the posts. With shore power off (and a small load), it dropped like a stone. Since I was getting 14.48v on the converter outputs it sounds like the battery is kaput.

Normally, the Optima blue top has a two-year warranty. Unfortunately, we didn't buy the battery ourselves so I don't have the paperwork I'd need to press for a replacement. But you mentioned a good notion. I'll pull the battery, charge it using another device, and see if it holds a charge. That should provide definitive proof. The battery isn't mission critical at the moment. We have a Honda 2200 generator we use when we don't have shore power. Still, I'm one of those old school guys who likes everything to work.

We had an issue with the circuit running the fan back in July. We tried mightily to find the short, but we ended up abandoning the wire in place and running new wire from points we knew were good. The next time I wire a vintage Airstream, there are a few things I'd do differently... not particularly useful information given that I'm unlikely to do this again. Thanks for your wealth of knowledge on DC electrical stuff, much appreciated.

Hi

As soon as you start rolling again, having a working battery *is* mission critical. Without a working battery, you have no break away capability. That is a required feature.

I have used Optima batteries for various things. They do not (for some reason) seem to do well at all in RV applications. Since you pay a premium for them, that's not a good combo. If yours is shot, it will not be the first one to die an early death in an Airstream.

There is a pretty convincing argument to be made for "whatever brand deep cycle RV battery Costco has on sale this week" in terms of a replacement battery. If you don't go on battery power much (and don't need extended off grid usage) it's generally the bang for the buck winner. The only caution is to be sure what you get *is* indeed a deep cycle battery.

Bob

[hampstead38]

We wrapped up the renovation last July and spent the final 6 months of our 18-month sabbatical mostly camping in the Overlander aka "Helen Wheels." We settled down a couple of months before COVID hit and haven't done much camping since.


The '67 Overlander made it through a few more states from Kansas up to Montana, over to Washington, back down to Wyoming and east to Maryland/Pennsylvania. It will be a 49-state Airstream sooner or later.


Still on the "to do" list is installing an awning. I need to find a different foam for both the mattress and front seating. The memory foam just isn't comfortable and the front seating needs a bit more "cush." The electrical demons are mostly banished (for the moment) but the overhead AC unit has a problem I hope is the switch. The propane systems all work like a champ and the Princess marine stove is something I'd buy again. After years of fiddling around, it was good just to log some camping months.

[Jeremy J]

What a great looking trailer and I'm happy you're finally getting o enjoy it after all this time. Congratulations on that! Thanks for sharing. I can't wait until I finally get to load up my family in ours and head out on an adventure.

[ALANSD]

former owner of 4 different Airtreams here- had a 66 Overlander, did not do well with Optima batteries, worked better with a cheaper car battery fromA dvance auto.Also be careful to check the ground for cleanliness.Great looking resto there. enjoy it, i did
for years.

[hampstead38]

We had planned on a camping a bit this year (despite a new job), but COVID put a crimp in our plans. I appreciate the tip on the Optima batteries. I'm going to try a Universal AGM and see if I have better luck. My winter/spring projects are buying foam and redoing cushions and the mattresses. Once we unlock the secret of the comfortable bed and seating, I think we're in good shape.