Updated August 4
I completed the install yesterday. I did install a fuse at the coach batteries. I'll post a more complete blog in the future on the details of the install. The meter works well. I set the low voltage alarm at 12.1V (about 50% depth of discharge, or DoD). The meter is very accurate. I measured the voltage at the coach batteries and compared to the display. I also measured the mV at the shunt and compared to the ammeter display (has a 75mV shunt). After charging the coach batteries I killed the AC to the coach and with the meter powered, the fantastic fan at speed 1 and an overhead fluorescent on, this was the display. The battery voltage is high because it has some surface charge:
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| Voltmeter-ammeter-wattmeter with voltage alarm |
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| Meter in Case, with DC power "Off-On" switch |
Making progress. The cabling is in, the shunt is mounted, and I've wired the meter case. I should complete in another hour or so. However, today (August 1) it was overcast and so I worked on the travel trailer; I'm using Meguiar's® Fiberglass Oxidation Remover on the cap. Got about 70% complete before the rain came in. I'll be working on that for another couple of days, weather permitting. Can't do this in the sunlight, or the rain. After completing with the Remover I'll be using No. 45 Polish followed by No. 56 Pure Wax.
Today I wired the meter case, and assembled jumper cabling to extend from the coach batteries to the cable run to the meter.
Original Post, July 28, 2017:
Current project is to put a decent DC electrical meter into the 210P, to monitor the coach batteries.
The 4-LEDS (L-F-G-C) or "Low-Fair-Good-Charging" indicate G "good" at 11.95V, which is not good IMHO. I really don't know the point at which the G indicator goes out, and the F "fair" indicator is illuminated. I don't think I want to find out.
Why my concern? The 11.95V which the LED "G" indicates "good" charge level, is actually a 40% charge level (60% DoD, or "Depth of Discharge") for the AGM coach batteries. Why do I consider that to be a problem? To get best life out of the AGMs it is my understanding that one should not repeatedly discharge below 50%, although these batteries can be discharged 80% (11.66V). The bad news? Doing so repeatedly will shorten the life. How much? As much as 50%, or a 5-8 year battery will make only 2.5-4 years.
So I'm interested in knowing the DoD and a good voltmeter will tell me that. My 210P has the AGM coach batteries, and I replaced the first set a few months ago; they were about 4-1/2 years old.
Is there an alternative approach? I considered just adding meter jacks, but G would have had some difficulty with that, so I'm putting in a digital ammeter-wattmeter. Probably the most difficult was determining how and where to mount it, because routing the cabling is a real pain. After figuring it out I purchased the parts. Should be up and running in a few day, assuming I find some time to complete.
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