I recently installed a Trimetric 2020 meter to monitor battery voltage, amperage, amp-hours remaining, and several other useful parameters of our two group 27 batteries. The meter is made by Bogart Engineering, and I purchased it through Back Woods Solar at
www.backwoodssolar.com as a kit for $190. I will shortly fit the optional lightning protector. These were very helpful people, and the install went without a hitch. I used the 100 amp shunt for greater accuracy than with the 500 amp shunt. I consider it an excellent instrument. Prior to buying the meter, I noticed that the two batteries would only last about 4 days when not attached to 120 v shore power, even when the trailer was unoccupied, and only the refrigerator was running, but on propane. Using the Trimetric 2020 I found that the current drain in the 1988 Excella was 1.30 amps. At 31.2 amp-hours a day, and reckoning on about 50 usable ah from each battery, then they would clearly be run down after 3 days. I traced the consumption of 1300 milliamps by switching off one appliance at a time. The results were:
Charging cellphone 70 ma
Climate control on Dometic refrigerator (forgot to switch off!) 490 ma
Refrigerator without climate control 310 ma
(Refrigerator with climate control therefore 800 ma)
Propane detector 40 ma
Jensen radio on standby 230 ma
Display panel over front couch 130ma
Trimetric 2020 meter 30 ma (16 ma with display off, according to the manual)
These total 1300 ma, and I will be taking steps to reduce this total. Remembering to switch off the climate control would be the easiest fix. I will be looking at fitting switches to the radio and the display panel. This has the disadvantage that clocks and selected wavelengths will need to be reset. I will also use the tow vehicle battery when I need to charge the cellphone when boondocking. I will investigate the feasibility of running the refer in limp mode, with battery power disconnected. Other intermittent loads were:
1 incandescent 1141 bulb light 1370 ma (Compact fluorescents are on the to-do list!)
Water pump 4100 ma
Furnace 6470 ma
12v TV 2400 ma
Radio on 70 ma
Stove vent fan 1650 ma
Bathroom vent fan 2250 ma.
I recommend the Trimetric 2020 meter. Used in conjunction with an Intellipower 60 amp charger and Charge Wizard, its ability to monitor amp-hours remaining as well as current and voltage gives me the knowledge I need to maintain and use the batteries.Nick