Learned something about inverters the hard way ....
I recently had to vacate my hangar where the bus was stored because the owner sold it. We had installed 50A power there, and it was a great place to stay.
Anyway, found an indoor RV storage solution out near Lake Perris at a pretty reasonable cost (for CA standards), and after spending a week in the bus out at Rancho CA, I put the bus in it's new home.
Because it only has a 15A circuit, I dialed down the inverters and left the bus. 4 days later, I decided to go back out to the bus (1 hour drive), to check on a video issue I had seen on my previous trip. I arrived to find the bus dead as a doornail, with the storage sites external circuit breaker tripped.
Evidently the night watchman at this site had been trying to plug in a personal air conditioner in a garage 2-3 down from me, which evidently shared the same 15A circuit. Evidently he popped the breaker a number of times (according to the manager), and they ultimately ran him a long power cord from another unit, but unfortunately, they left the breaker in the "broken" position, and my coach inverted itself to death over the 4 day period. (Refridgerator was on).
I was able to fire up the coach and the generator and start the batteries charging. I understand later, talking to Marathon, it would have been better to not start the bus and hit the batteries with 270A of charging, but anyway, that's another story.
Anyway, on to what I learned about the inverters. I hope this might be instructive to others. (This is on a Trace inverter)
1. There is a charge-only setting on the inverter panel. Rather than selecting "On", select "Chg", which is the far right menu entry. According to the manual what this does is pass A/C through, charges the batteries, but IF the external power goes down, it does not try to invert. It specifically says it's to handle the case where public power goes down.
If I had used this setting, I would have lost the food in the fridgerator, however I wouldn't have damaged my batteries.
2. When I tried to dial both inverters down, and set them into charge mode, the aux inverter kept resetting, on/off. What I finally surmised is that besides setting down the input cord size (amps), you may also need to turn down the amount of amps available to the charger (battery charging menu, #10)
Ultimately what I did was turn the aux inverter off, and set the input amps to 12A. Then I dialed down the battery charging amps to 10A, and this then was safe in bringing my batteries back up.
A couple of other things, based upon previous discussions regarding the charging time setting on batteries. We've had discussions that for many of us who do not boon-dock, we could turn down the bulk charge time from the default of 3 hours to something less.
As it turns out, I don't think this is really necessary. What I discovered after watching the charging voltages and amps very closely over a couple of weeks is that although the inverter will be in bulk charge mode, the actual current charging will be limited by the batteries need. I.e., if your batteries are fully charged (like you just drove 100 miles), then even though the inverters indicator lights will show bulk charge, although they may only be actually trickle charging at that point (on the order of 1-2A).
It is my guess that the bulk charge timer value as set in the battery charging menus is used as a fail-safe, that after the appropriate amount of time, the charge will go to float mode, whether or not the charger was charging at full bulk mode. I think this is a safety to prevent a bad battery from causing bulk level charging to happen over long periods of time.
Obviously our coaches can all be wired in many different ways, but I found that turning off the aux inverter/charger, I was better able to regulate the charging current (because of the darn 15A circuit), and all the batteries were still being charged.
Please note if you do turn off an inverter, when it is turned on, it comes back at default settings, so it's expecting a 50A shore cord, full-rate charging on batteries etc, so you may need to dial them down to fit your particular needs.
For those of us who don't have 30 or 50A power available at a storage site, using the "charge-only" setting may help you from destroying a set of batteries. As we know, it costs somewhere around $3500 to $4500 to replace a full set of coach batteries.
ray
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