Will bad house batteries cause 120v shoreline power issues?

[bkf]

Hi all! I've got a ~2013 Class A that we've full- or half-timed in for the past almost-6 years. It's got 4 Group 24 (EDIT: actually Group GC2 6-Volt) flooded batteries, with a Magnum charger/inverter. We're almost 40' so almost never boondock except for an occasional night here and there in a WalMart parking lot while we're getting from point A to point B 🙂 I've got the Flow-Rite system to keep the batteries topped up with distilled water.

The batteries definitely don't hold a charge like they used to, but it's never been a problem, as we don't really use them much. But…

During the past 2 weeks, things seem to have gone downhill, fast. The batteries are 6 years old, so my hunch is that they just need to be replaced, BUT… I want to make sure there's not another problem going on. We're on 30amp shore power, but our rig can handle 50amps.

Symptoms in the past 2 weeks include:

• 12v lighting goes pretty dim, then will occasionally kick on to full brightness.
  
• The little Magnum control panel inside the coach turns on the red light, but often the screen says something about missing AC power, which is odd to me.
  
• Some of my 120v outlets will go through periods where they lose power for about a half-second, every few minutes. This power cycling will happen for hours, then will just stop and everything'll be fine. Oddly, this isn't all outlets. The clock on the microwave doesn't reset, but my cable modem (we're in one park for the next ~year; atypical for us) will reset every few minutes, and my computer charger will blink off, on a separate outlet).
  

If it was just the 12v lights going dim, I'd be much more comfortable replacing the batteries. But with the 120v AC power acting up, I'm worried the dim 12v might be a symptom and not a cause. We'll be plugged in for the next year, so I don't want to drop a ton of money on new house batteries only to discover I didn't need them and should have spent the money elsewhere.

I'd love advice or experiences from anybody who knows more about batteries and inverters/converters/chargers! Thanks!

[BFL13]

dougrainer wrote:

BFL13 wrote:
Disconnect the house batteries entirely. The Magnum charger should make your 12v just fine. If still having problems, it will be possible to trouble shoot that.

A bad battery might create problems for the charger in the inverter/charger. Your symptoms suggest another problem though.

You only need house batteries if you need to survive periods with loss of shore power and go onto inverter for 120v and battery for 12v (including the inverter)

You could be having shore power problems or transfer switch problems. Disconnect house batteries to remove them as a "distraction" for going trouble shooting, since they don't even need to be there right now.

YOU NEVER OPERATE AN INVERTER/CHARGER WITH NO BATTERIES. BATTERIES ARE REQUIRED FOR THE INVERTER/CHARGER TO FUNCTION. BAD BATTERIES WILL CAUSE SOME INVERTER/CHARGERS TO MALFUNCTION. BUT IT IS RARE, IT USUALLY JUST ALLOWS MINIMUM 12 VOLT POWER TO THE RV. Doug

PS, Some Inverter/Chargers will not even power up without a battery(good or bad) connected.

My goodness! Are you saying that if you have an inverter/charger and no house batteries at all, that it won't pass-through shore power 120v to the RV's 120v things and also run its own charger from the 120v it is passing through (to run the 12v things)?

[dougrainer]

12 volt power problems will NOT cause Shoreline power issues. That said, there is a small caveat to that statement. Some RV's have a built in 120 EMS system that monitors and sheds certain 120 appliance loads. NOT ALL 120 loads just 4 to 5 appliances. It takes 12 volts to operate this EMS system. If NO 12 volts or below 11 volts, this EMS will not power up and close the relay's for those appliances. But the REST of the 120 system will power up. Your 120 Transfer relay for Shore and Genset is 120 volt powered. Doug

[dougrainer]

BFL13 wrote:
Disconnect the house batteries entirely. The Magnum charger should make your 12v just fine. If still having problems, it will be possible to trouble shoot that.

A bad battery might create problems for the charger in the inverter/charger. Your symptoms suggest another problem though.

You only need house batteries if you need to survive periods with loss of shore power and go onto inverter for 120v and battery for 12v (including the inverter)

You could be having shore power problems or transfer switch problems. Disconnect house batteries to remove them as a "distraction" for going trouble shooting, since they don't even need to be there right now.

YOU NEVER OPERATE AN INVERTER/CHARGER WITH NO BATTERIES. BATTERIES ARE REQUIRED FOR THE INVERTER/CHARGER TO FUNCTION. BAD BATTERIES WILL CAUSE SOME INVERTER/CHARGERS TO MALFUNCTION. BUT IT IS RARE, IT USUALLY JUST ALLOWS MINIMUM 12 VOLT POWER TO THE RV. Doug

PS, Some Inverter/Chargers will not even power up without a battery(good or bad) connected.

[2oldman]

6 years is about time, especially for acid tubs. Let 'em charge then take voltage readings about every 15 minutes for a couple hours. If they're bad they'll drop to the low 12s or lower...assuming they charge up to 12.8 or so.

[BFL13]

Disconnect the house batteries entirely. The Magnum charger should make your 12v just fine. If still having problems, it will be possible to trouble shoot that.

A bad battery might create problems for the charger in the inverter/charger. Your symptoms suggest another problem though.

You only need house batteries if you need to survive periods with loss of shore power and go onto inverter for 120v and battery for 12v (including the inverter)

You could be having shore power problems or transfer switch problems. Disconnect house batteries to remove them as a "distraction" for going trouble shooting, since they don't even need to be there right now.

[MrWizard]

from the description
it sunds like your magnum inverter/charger is failing
it has 120v power pass thru, so those intermittent circuits could be outlets connected to the magnum

i think there is a power off, battery disconnect , reset sequence
it should be listed in your manual
i would try that, then i would charge the batteries with a stand alone battery charger, be fore replacing them

[MDKMDK]

Get yourself an PI EMS, like a PT50X 50A model and see what kind of AC power you're getting from the post. It'll help eliminate park power as being involved. Or, just try another post or outlet?
It's still probably old/weak/failing batteries, but you never know, and there are many stories on here and elsewhere about bad park power causing all sorts of problems.