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!

[time2roll]

bkf wrote:
Thanks for continued discussion, all.

time2roll wrote:
Need to separate the batteries and test them individually. Then reconnect verified good batteries to the inverter and monitor the charging voltage is correct based on the settings. Post the results.

When you say monitor, are you meaning from the Magnum's remote screen, or with a multimeter, or something else? Just curious so I approach it in a recommended way. (I'm handy with a multimeter, but not a pro.)

Since you are in diagnostic mode I would verify with the multimeter direct on the battery terminals. All batteries should measure virtually the same voltage once all connected. Then compare the reading to the Magnum remote. The comparison should be within 0.1 volt. Possibly a little more if heavy charging or heavy load on the inverter. Once you establish the remote is reading same as the battery then you can trust the remote to be reasonably accurate.

Electrical issues are diagnosed by separately testing component functions and verifying operations of each component.

[BFL13]

Terryallan wrote:

time2roll wrote:

Terryallan wrote:
Hmmm. Every thing in my TT works just fine without a battery connected, as did my last TT. Never a problem

What inverter/charger do you have?

The one that came with it. Not something I look at. It works, as did the one in the last TT. That is all that matters.

No. What matters here, is that you most likely have a converter and not an inverter/charger at all.

[Terryallan]

time2roll wrote:

Terryallan wrote:
Hmmm. Every thing in my TT works just fine without a battery connected, as did my last TT. Never a problem

What inverter/charger do you have?

The one that came with it. Not something I look at. It works, as did the one in the last TT. That is all that matters.

[bkf]

Thanks for continued discussion, all.

newman fulltimer wrote:
You have a loose or burned wirenut on the inbound wire at the inverter.I have seen this to many times.

Any advice on what to look for? None of the wires or connections seem to be visibly damaged. But this sounds like a promising area of exploration.

newman fulltimer wrote:
IF YOU HAVE THE HEADROOM (they are taller) use of 4 GC-2 (About the same price) gives you 440 Amp Hours and TRUE Deep Cycle (whqt you have now is really a starting battery)

Are you saying that 12v batteries aren't true deep cycle? I'd always thought the difference was in the size of the internal plates. The batteries I have definitely aren't starter or dual-purpose. (I had a starter for a house battery in an old Class C when I bought it. Didn't work well 🙂

SidecarFlip wrote:
Keep in mind that HEAT kills batteries (especially flooded cell tubs) faster than cold ever will and it's hot this summer.

Definitely. We've been in a reasonable climate for the summer, only a few days in the high 80s or low 90s, so I don't think it's that. At least, not as a cause for the rapid change I've experienced.

time2roll wrote:
Need to separate the batteries and test them individually. Then reconnect verified good batteries to the inverter and monitor the charging voltage is correct based on the settings. Post the results.

When you say monitor, are you meaning from the Magnum's remote screen, or with a multimeter, or something else? Just curious so I approach it in a recommended way. (I'm handy with a multimeter, but not a pro.)

[wa8yxm]

Generally 12 volt will not cause 120 volt issues save for those devices that use 12 volt for CONTROL power.. Fridge, Water heater, A/C(s) all use 12 volt for CONTROL power.

IF you have an Intelletec EMS it may also use 12 volt (Do not know) this is load shedder measures the current in the neutral line and if you are on 30 amps will turn an A/C or selected other loads on or off to keep it below 30 amps.

Progressive Industries EMS is a totally different animal. it will cut off 120vac to your RV if it is not close enough to 120V and 60Hz.. This is a good thign.

But it sounds like your converter may be flakey as well.

Oh and you said 4 G-24's that's about 300 amp hours of battery

IF YOU HAVE THE HEADROOM (they are taller) use of 4 GC-2 (About the same price) gives you 440 Amp Hours and TRUE Deep Cycle (whqt you have now is really a starting battery) that's nearly 50 percent more power and over 100% more usable power and no additional cost. Just move a few wires about (Since the GC-2 is 6 Volt.) Think about it.

[time2roll]

Terryallan wrote:
Hmmm. Every thing in my TT works just fine without a battery connected, as did my last TT. Never a problem

What inverter/charger do you have?

[Terryallan]

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.

Hmmm. Every thing in my TT works just fine without a battery connected, as did my last TT. Never a problem

[BFL13]

dougrainer wrote:

BFL13 wrote:
I have been on this forum for a while, and have never heard of such a thing!

If it is true, it is an amazingly stupid set-up. I have a single use 2000w inverter that does need house batteries, but if I have shore power I don't that inverter at all.

I have a converter/charger that does not need any batteries to make 12v from 120v. So I would be fine on shore power with no batteries at all.

Hard to believe an expensive inverter/charger instead, would require a battery to even run its 120v. What about using the engine battery to get the inverter/charger operating using the boost interconnect that Class A MHs have?

Just ridiculous!

You are confusing PASS THRU 120 power with the CHARGER section of the Inverter/Charger. YES, I am saying, MOST Inverter/Chargers will not function the Charger section if NO batteries(good or bad) are connected. Remember, Inverter/Chargers are NOT like CONVERTERS. Inverter/Chargers supply power TO THE BATTERIES, then the batteries supply power to the RV 12 volt systems. Inverter/Chargers NEED a load(batteries) to determine what to do with the 12 volt charger section. Magnum Inverter/Chargers, if the batteries are totally dead and you connect 120 volts, the Inverter/charger usually will NOT charge the battery bank. You need to either start the chassis engine to supply excitation voltage to the dead batteries or connect a stand alone 12 volt charger for a few minutes to get the voltage to trip the Inverter/Charger to start its BULK charge. The Inverter/Charger monitors what the batteries are doing to determine how and what charge to send to the batteries. Doug

PS. the 120 will pass thru, but you do NOT want to do that with no batteries.

Yes, I always thought the charger portion of an inverter/charger was like a converter. I assumed having a separate inverter and a deck mount converter up by the batteries was equivalent to an inverter/charger set-up.

My Vector portable smart charger has that same feature that it won't run unless the battery has a minimum voltage.

Thank you for the explanation.

[SidecarFlip]

Keep in mind that HEAT kills batteries (especially flooded cell tubs) faster than cold ever will and it's hot this summer. My house batteries share a compartment with my FW tank which I keep full so the FW tank moderates the compartment heat and keeps the batteries stable longer.

[dougrainer]

BFL13 wrote:
I have been on this forum for a while, and have never heard of such a thing!

If it is true, it is an amazingly stupid set-up. I have a single use 2000w inverter that does need house batteries, but if I have shore power I don't that inverter at all.

I have a converter/charger that does not need any batteries to make 12v from 120v. So I would be fine on shore power with no batteries at all.

Hard to believe an expensive inverter/charger instead, would require a battery to even run its 120v. What about using the engine battery to get the inverter/charger operating using the boost interconnect that Class A MHs have?

Just ridiculous!

You are confusing PASS THRU 120 power with the CHARGER section of the Inverter/Charger. YES, I am saying, MOST Inverter/Chargers will not function the Charger section if NO batteries(good or bad) are connected. Remember, Inverter/Chargers are NOT like CONVERTERS. Inverter/Chargers supply power TO THE BATTERIES, then the batteries supply power to the RV 12 volt systems. Inverter/Chargers NEED a load(batteries) to determine what to do with the 12 volt charger section. Magnum Inverter/Chargers, if the batteries are totally dead and you connect 120 volts, the Inverter/charger usually will NOT charge the battery bank. You need to either start the chassis engine to supply excitation voltage to the dead batteries or connect a stand alone 12 volt charger for a few minutes to get the voltage to trip the Inverter/Charger to start its BULK charge. The Inverter/Charger monitors what the batteries are doing to determine how and what charge to send to the batteries. Doug

PS. the 120 will pass thru, but you do NOT want to do that with no batteries.

[newman_fulltime]

You have a loose or burned wirenut on the inbound wire at the inverter.I have seen this to many times.

[time2roll]

Need to separate the batteries and test them individually. Then reconnect verified good batteries to the inverter and monitor the charging voltage is correct based on the settings. Post the results.

[bkf]

Hi all. Wow, thanks for the responses.

2oldman wrote:
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.

The Magnum "remote control" module at the front of the coach showed the batteries at ~9v an hour ago. After resetting the Magnum, flipping the 30amp breaker at the source, etc., it went up to 11.5v, and now is at 8.8v. EDIT: Now it's at 11.2v. Not sure how much I trust that.

The remote screen is flashing a fault for just a fraction of a second, every ~5-30s or so. The fault (when I can read it) is either "Over-temperature" or "No AC In" (more rarely). I think I've also seen a "Low Battery", I think, but it flashes so quickly it's hard to tell. The unit itself is cool to the touch, and the ambient temperature is mid-60s F.

The green light on the main Magnum unit isn't doing anything that the manual outlines. The manual outlines off, slow flash (blink every 8 seconds), medium flash (blink every 1s), and solid on. What it's doing is off for ~10-15s, then on for 3-15s. Off means there's the inverter's off and there's no AC power to it. On means it's bulk charging and in standby mode.

I know the battery voltage is obviously outrageously low. But with the weirdness with the Magnum, I'd hate to buy brand new batteries then destroy them if the Magnum's the root cause here. Or if it's something else. The lights on the Magnum seem like it's not actually getting power. The interior 120v outlets blinking off might be the shoreline cutting out and the inverter not picking it up in time

Thanks for the advice to help me figure this out.

In the morning I'll review this thread again and try some things:

• Plugging into my neighbor's power to see if the issue persists.
  
• Read through the manual to see if disconnecting the batteries would cause problems. Seems to be some debate on that point in this thread 🙂
  
• ? Maybe just get new batteries, since I'm sure they wouldn't hurt. If putting 'em in doesn't fix the problem, I'd take 'em out to avoid damaging them.
  

Thanks, everybody. I'll update with more info when I have it.

[BFL13]

I have been on this forum for a while, and have never heard of such a thing!

If it is true, it is an amazingly stupid set-up. I have a single use 2000w inverter that does need house batteries, but if I have shore power I don't that inverter at all.

I have a converter/charger that does not need any batteries to make 12v from 120v. So I would be fine on shore power with no batteries at all.

Hard to believe an expensive inverter/charger instead, would require a battery to even run its 120v. What about using the engine battery to get the inverter/charger operating using the boost interconnect that Class A MHs have?

Just ridiculous!

[KD4UPL]

I think your shore power problems are really problems with your inverter. The outlets that are temporarily losing power are likely powered thru the Magnum. If your batteries are getting very low it could make the Magnum inverter do weird things.
I must say, I've never tried running an inverter charger with no batteries but it sounds like a terrible idea. I wouldn't have thought it would have even powered up with no batteries. That's what I suspect is happening, your batteries are in such bad shape that a 12v draw on them is dropping the voltage low enough to give the inverter problems.