Originally Posted by thomanddebbie
2014 FR Georgetown. When we are at home I plug into 110 shore power to keep battery charged. However have found out that when I start up refrigerator a day or two prior to departure, it causes my coach batteries to drain even though we are plugged in. My only thought is that the 110 shore power is not adequate due to voltage drop?....distance??....whatever...from house. Rest of time it is adequate. Voltage regulator/protector in basement reads out 110 - 120v, 60 hrts, as it cycles. When refrigerator is turned on....read outs drop to 109 -112v ranges. This drain happens when the coach installed battery disconnect switch is in the OFF position. Like everyone else who have commented.....no idea why?
Suggest you get a clamp AC/DC meter and actually measure what is going on by clamping your positive battery wire when plugged in ONCE you are fully charged...which means plugging into the house for a couple of days.
1. 1st question is HOW do you know you are fully charged? Unless you have disconnected the battery negative wires for 24 HOURS after charging and not used them at all....a voltage reading DOES NOT indicate state of charge.
IF you disconnect for 24 hours and THEN take a voltage reading...then you should see 12.6-12.7Volts.
2. ANY voltage reading you take with the fridge ON ...DOES NOT indicate the state of charge
of your batteries. Any reading you take after turning the fridge off does NOT tell you the state of charge of your batteries.
Again...you must disconnect the batt - wire and WAIT to see the true voltage.
This is one reason people buy true battery monitors...so they can know what is actually going on in real time. That's a $150 buck investment that can pay for itself. (Search TRimetric & Victron here for details)
First thing I would do once I knew I had a FULL battery in GOOD condition is to plug in and measure on the terminals & positive battery cable. You should be seeing 13.2-13.4V and measuring just a couple amps on the red wire which would be the charger on float stage. If you show LESS than 13.2V....you have a converter problem or wiring issue from the converter.
Assuming all is well...it is time to test the impact of the fridge. Again...turn the fridge on ....then measure the amps on the red wire. You should NOT see any major amp load on the battery wire since the ELECTRIC fridge heating element is powered by AC.
You can measure the AC load with a clamp meter too but you need to get one of these splitters so you don't have to cut up your house wire to clamp it.
Since you can only get 15 AC amps out of the wall...any big number here (don't forget to switch to AC amps from DC on the meter!).... will explain why there is little left for the converter to work with to keep the batteries charged from their OTHER loads.
Hope this gives you some things to eliminate as causes. My GUT feel is that you have compromised batteries...but you have to go through the steps outlined above to figure that out.
One of these 20 buck load testers from Harbor Freight might be helpful to test how your batts can stand up to a load.