wa8yxm wrote:
Ok the lights going DIM then brightening back up suggests something is drawing one HECK of a lot of 12 volts.
One possibility is bad batteries (They suck the converter down) as suggested up in fact I'd rate 'em high on the list and there are often self-resetting thermal breakers in the main battery line. along with other types that you need to manually reset depending on the RV.
It is also possible something else is sucking 'em down.
My bet is the reverse:
- When the charger is on, you have nice high voltage (somewhere on the order of 13.5-14V) ...the lights burn brightly as the charger compensates for a failing battery.
- When the charger shuts down, it's only the bad battery feeding power and since the battery is bad, the voltage quickly falls to maybe something like 8-10V...and the light burns dimly.
- On seeing the low voltage, the charger kicks back on and the cycle repeats.
Most any autoparts store will load test a battery for free. While it's not really the right test for an RV house battery, if it fails, it's good enough to show you have a bad battery.
If you have a multimeter (which is a good idea...and learn how to use it), disconnect the shore power and check the voltage after an hour or so. You can check sooner but voltage is really only a good measure if the charging source has been off for a while. You should see something north of 12.6-12.7 volts. Certainly if it' down around 12.0 or lower after sitting with no loads after being charged, that's an indication of a bad battery.
It's possible it's something else but I'm betting battery.
