I think I messed up my batteries

[Airslide]

Wow Gene... and im complaining about 30* temps here in Calif..

16" inches of snow? Stay warm!! The airstream will be fine.. she's just chillin right now dreaming of the spring campout!

[Motoman]

Regarding multi-stage chargers in this thread. My understanding is that none of the Magnetek/Parallax converters have three stage charging. I talked with an engineer there two years ago and he told me they don't think it is necessary and has certain problems when you are trying to maintain voltage in the 13.2 to 14.2 range to properly supply 12 volt appliances.

Parallax does have a two stage option on some models with a T in the model number but that model is not used by Airstream. Regarding the 7400 model, one can review the brochure for that model at: http://www.parallaxpower.com/7400/74...ctbrochure.pdf
and other models can be looked up at: Electronic Switch-Mode Power Converters

Best Converter does have replacement charger sections to provide 3 stage charging but I believe they are from an aftermarket company rather than the original manufacturer.

[Gene]

Now that I've looked at the paperwork, it's true the Parallax does not have a 3 stage charger. The ones with the "T" option use a timer. The converter charges at 14 v. for 13 hours after it's plugged into shore power, then goes down to 13.5 v. to prevent overcharging. If you unplug it for 2 minutes, then it goes to 14 v. again for 13 hours and the cycle repeats. Kind of crude system. The paperwork is for a series 7300.

Later I'll go look at the converter to confirm model number and the absence of the "T" option.

The Airstream owner's manual says different things. First, it calls it a MagneTec converter. Both companies have Indiana addresses, but I don't know if they are one and the same. There really is no clear guidance about overcharging. It does say "The charging circuit automatically controls the current, reducing it as the batteries increases in charge." Ignoring the grammatical mistake, the Parallax paperwork says the same thing. Current = amps, not volts. It seems to me amps will reduce to nearly 0 when a battery is fully charged because there's no load (except for propane detector and some other items that draw small amounts of amps from time to time) and this has nothing to do with overcharging.

When storing the trailer, the owner's manual advises to take out the batteries, put them in a cool and dry place so they won't freeze, and charge them periodically. I'm not sure who has a cool, well ventilated place where we have real winter. It isn't good to store batteries inside because of the potential for nasty gas to build up, so I leave them in the trailer.

The solar panel appears to have a three stage charger and should keep the batteries ok. So I'll keep the shore power unplugged except when I need to run the heat or refrigerator and will monitor the batteries. If the charge gets low, I can plug in shore power for several hours.

Gene

[bevman]

When boondocking, I had the fridge running on 12v until I noticed that it wasn't. Battery out of juice. Is there a gadget that I can add to measure battery status and cut it off before deep discharge, saving the battery from damage?

[azflycaster]

Running the fridge on battery will not last long, propane is the preferred method without hookups. I would check with Randy at BestConverter - Converters, Inverters, Electrical Supplies, Electronics to see if they have the device you are looking for. They do have a monitor that alarms when a thresh hold voltage is reached: Voltminder

[bevman]

Thanks for that lead. I'll check with Randy. (The PO changed out the three way fridge in 1974 to a 120/12v Norcold -- I'd love to find a vintage unit to put back, one that had the propane option).

Cheers!

[Gene]

Bevman, I understand the desire to restore everything to original, but the new refrigerators are so much better—more efficient, don't need to be almost perfectly level and better in all other ways. Having remodeled a 1919 cabin in the 1990's, I had to struggle all the time to balance between modern conveniences (such as insulation that worked; we did find a 1930 stove that worked perfectly and we brought it with us when we moved, but used a new refrigerator) and restoring a much abused building to look like it was supposed to.

Gene