RE: Inverter Not Working when connect to DC

[KEN9XL]

Residential Refrigerator operates on battery power (12VDV) with inverter or shore power (120VAC) only, no propane function.

Inverter operates fine when on shore power (green light) and shows 120VAC, but when towing inverter only registers 8.8 VDC (yellow light) which puts me at 2/3 rd power yet the battery display inside the camper shows 100% charge.

WHY???

I checked the connections at the battery and all connected properly, tight & solid. Also checked the reset button at inverter, operated it and made no difference on power. Questioned if I can still run while traveling.

What am I doing wrong? What do I check next?
At campground now but will be traveling soon. Any help would be appreciated.

Thank you in advance.

[Skip12]

I suggest getting a multimeter to prove everything is connected properly.

I had a similar issue when my camper was new. Turns out that the dealer didnt hook up the second battery properly. It wasnt getting charged. So, inverter worked great for PDI but not after that. This forum, a multimeter and an additional jumper cable fix my problem.

[formerFR]

your Fridge, which is a 120v residential model like many of us have, works ONLY on 120v power, not 12volt power.... though I suppose you meant that when you are not 'plugged in' to 120v Shore Power, it is drawing it's power via the 12v battery power source, inverted to 120v power by the Inverter.

The Inverter will invert(change) the 12v battery power into 120v power to your fridge outlet, and any outlets that the Inverter is connected to. Sometimes on smaller trailers and coaches, the inverter is only powering the Fridge, while on other larger coaches the inverter is powering some or all of the outlets throughout the coach, including the fridge, the microwave, TVs, and general receptacles.
When the battery power is providing 12.0volts or higher, the inverter has no issues changing that to 120v power.
When the battery power starts to fall to lower levels, the Inverter may have a built-in LBCO(low battery cutout) where it automatically cuts off the Inverter in order to save the batteries from being over-discharged, usually with a RED light indicator, or beep, or both.

It sounds like you are seeing two different read-outs/levels of your batteries, with the Inverter showing one thing, and the remote panel showing another.

How many HOUSE batteries do you have?
Are they 12v or 6v types?
How are they wired - parallel, series, or both?

Where is the remote panel/level indicator/sensor connected? to the batteries, or to the Inverter?

You may also have an issue with the batteries not getting charged, either from your Converter, or the integrated Inverter/CHARGER, if you have one.
What model Inverter is it?

The inverter simply passes thru 120v Shore Power when you are plugged in, so whether it has battery power or not won't matter - it only matters when you 'unplug'.

Run a simple test: unplug, turn on the Inverter, and plug something into one of the outlets and see if it works. If it does, your inverter is working fine, no matter what the difference in the indicators. If the fridge, though, doesn't look like it has power, if it's light does not come on, then the inverter is not providing power to it.

[Bama Rambler]

First off, don't trust the lights in the display. They're very inaccurate. Do as Skip said and get a cheap multimeter and learn how to use it.

Sounds like you could have a/some bad connections or weak battery or batteries. However, we need to know a few things before making that decision.
1) How many batteries you have?

2) Do the batteries start off showing 12+ volts at the inverter and slowly drain to 8.8 volts?

3) How old are the battery/batteries?

[CHICKDOE]

just a possibility. when the battery monitor light shows 100% it really means it is seeing a charging voltage, not that the battery is fully charged. you say you see this when you are hooked up and towing. the monitor light could be indicating that it is seeing a charging voltage from the tow vehicle.

the inverter is indicating a discharged battery. it could be that the battery is truly discharged but yet it is getting a minimal recharge from the tow vehicle. just for drill disconnect the electrical cable for the tow vehicle and go look at the monitor lights to see if they change. also, a cheap multimeter would be a great investment. when we tow with our residential refrigerator it is very important to make sure the batteries are fully charged each morning. how are you ensuring that yours are fully charged?

[KEN9XL]

Originally Posted by Bama Rambler

First off, don't trust the lights in the display. They're very inaccurate. Do as Skip said and get a cheap multimeter and learn how to use it.

Sounds like you could have a/some bad connections or weak battery or batteries. However, we need to know a few things before making that decision.
1) How many batteries you have?

2) Do the batteries start off showing 12+ volts at the inverter and slowly drain to 8.8 volts?

3) How old are the battery/batteries?

OK! To answer questions -
I have two 12 volt batteries, both 3 years old which I think are wired in series (all black leads on negative terminal & all red leads on positive terminals). Remove them each winter, bring into house, and leave connected to a trickle charge.

Here is what I've done -
Checked each battery with a VOM (jumpers removed), both read 12+VDC.

Reconnected jumpers, then unplugged AC from wall outlet at inverter.

Checked input at inverter before & after bus fuse. Both readings at 12VDC.

Checked and reset breaker at inverter to be safe.

Turned on inverter, AC still disconnected, see red light then switches to yellow light with reading displayed of 8.8VDC.

When I connect to AC (120 volts shore power) and activate inverter, then shows green light 120VAC, without any issue. Issue is only on battery or 12VDC side.

My guess is the inverter is bad. Just guessing & asking, unsure.
Is it possible for one battery to carry the other?

[CHICKDOE]

1. the two 12 volt batteries are wired in parallel.

2. what does your voltmeter show the dc voltage to be across the inverter 12 volt terminals when the inverter is showing 8.8 volts? (no ac connected). if it shows 8.8 the problem is probably not the inverter. if it shows 12 then the inverter becomes suspect.

3. make and model of inverter would be helpful.

4. when you inverter is showing 120 vac output when connected to shore power this may be a pass through voltage from the incoming ac feed.

[Bama Rambler]

See comments below in blue.

Originally Posted by KEN9XL

OK! To answer questions -
I have two 12 volt batteries, both 3 years old which I think are wired in series (all black leads on negative terminal & all red leads on positive terminals). Remove them each winter, bring into house, and leave connected to a trickle charge.

The batteries are actually connected in Parallel. No problem.

Here is what I've done -
Checked each battery with a VOM (jumpers removed), both read 12+VDC.

You could have a bad cell in one or both of the batteries, so it may be a good idea to take them and have them load tested.

Reconnected jumpers, then unplugged AC from wall outlet at inverter.

Checked input at inverter before & after bus fuse. Both readings at 12VDC.

Checked and reset breaker at inverter to be safe.

Turned on inverter, AC still disconnected, see red light then switches to yellow light with reading displayed of 8.8VDC.

Did you use the VOM to check the voltage at the inverter when it reads 8.8 volts? If not, then do that and report back.

When I connect to AC (120 volts shore power) and activate inverter, then shows green light 120VAC, without any issue. Issue is only on battery or 12VDC side.

Connecting to shore power actually deactivates the inverter and it most likely has a bypass transfer switch.

My guess is the inverter is bad. Just guessing & asking, unsure.
Is it possible for one battery to carry the other?

Can you tell us the make and model of the inverter?

[MR.M]

tighten the battery connections at the inverter .

[babock]

Measure the voltage at the 12V input to the inverter with no 120V AC load. While doing that, have some one fire up the microwave or other heavy 120V AC load and see how much the 12V DC dips. The inverter has a low voltage cut off, usually at 11.5V, and you may be hitting that. With 3 year old batteries, that would be my guess. Could also be low gauge wiring between your batteries and inverter. I also suggest not using a circuit breaker between the battery and the inverter. A fuse has less voltage drop across it that a circuit breaker does.



This where AGM batteries are better. They have lower internal resistance and get lower voltage drops when you have a heavy hitter like an inverter attached.

[KEN9XL]

Originally Posted by CHICKDOE

1. the two 12 volt batteries are wired in parallel.

2. what does your voltmeter show the dc voltage to be across the inverter 12 volt terminals when the inverter is showing 8.8 volts? (no ac connected). if it shows 8.8 the problem is probably not the inverter. if it shows 12 then the inverter becomes suspect.

3. make and model of inverter would be helpful.

4. when you inverter is showing 120 vac output when connected to shore power this may be a pass through voltage from the incoming ac feed.

At Inverter terminals reading is 13.5 VDC (12 volts +) with AC disconnected.
Yet the inverter display panel shows 8.8 VDC (yellow light).

Make is WFCO and model # WF-5110HP

[Bama Rambler]

Sounds like it's time to call WFCO. Those units have a 2 year warranty. Hopefully you're not past the warranty. Even if you are, it'd be worth calling them about it.

[KEN9XL]

Originally Posted by Bama Rambler

Sounds like it's time to call WFCO. Those units have a 2 year warranty. Hopefully you're not past the warranty. Even if you are, it'd be worth calling them about it.

Bought my unit in February 2017.
Me thinks I have past warranty, but as you stated it may be worth calling.

Thanks all

[KEN9XL]

Bama Rambler ...

FYI - called tech support to verify unit model # and any recalls none (877-294-8997)
Explained problem & what was done to prove it.
Tech was in agreement, inverter problem.

Now I must call warranty department per tech support but they go home at 3PM.
Missed by some 20 minutes according to Tech Support.

Must try again in morning and hope I can talk my way into a new one. :-)
Only time will tell.

Again all, thank you for your help in isolating problem.

[Bama Rambler]

Hopefully they'll warranty it for you. Good luck.

[KEN9XL]

FYI - Inverter was not covered under warranty .....

After receiving new inverter, removing old & replacing with new found all my same test results duplicated at inverter. Conclusion - it was not inverter.

Next called a mobile RV service tech who determined existing old inverter was good. He stated my batteries, one in particular, was the problem. Both functioning independent without a load. Upon further test he found some variable indications that one battery could not handle a load verses other (11VDC - 12VDC). The tech pointed out to me that I had 24 month batteries and asked how old batteries were. I stated they were bought with TT in February 2017 (27 months old).

Is it possible for one battery, not both to be failing & causing false readings?
Everything in my travel trailer works on 120VAC, but not 12VDC.
I guess I must replace batteries, as in both, not just one.

Can I replace with automotive batteries or must I use Marine/RV type? Other than Lithium type, due to expense, what would you recommend?
What about maximum monthly rating (24 month, 36 month, etc)?


FYI ... sent new inverter back to company at no charge to me other than postage

[formerFR]

let me tell you about a similar experience with mine, and maybe it also applies to you...

[formerFR]

After 4 years of great success with our Inverter, it suddenly started to just 'cut off', for no known reason.

I started to realize that when it happened, sometimes just while watching TV, while off-grid, the TV and RECEIVER would just suddenly lose power - and very aggravating, as the Receiver has to then go all thru it's 'acquisition' of the satellites all over again when power is restored - a sometimes lengthy process.

After several times of this happening, I started to really investigate the issue.

I could turn the Inverter 'back on', and everything seemed to work fine, for a while.
What could be causing it to 'suddenly' shut off?

I realized it was the fridge's compressor coming on.
or, when using the microwave... basically, any 'large' sudden draw on the batteries(the Inverter).

So, I first thought that it certainly wasn't my batteries, as they had performed flawlessly for over 4 years, hardly ever needed any water, and generally were 'maintenance free', though they are FLA Lead Acid stock 6v batteries from the factory x four.

I assumed that it 'must' be something else, maybe a bad 12v cutoff switch, or something related to the 12v system, such as a solenoid coil. Nope.

After a lot of research... I finally invested in a single, inexpensive, but important tool for my batteries - a specific gravity reader - $1.98...

What did I find with my four batteries? THREE were all perfectly fine, but the fourth, and the fartherest back in the bay and the hardest to get to, had TWO CELLS that were below 'fair' levels.
So, after more research, I developed the idea that these 'low' cells could be the culprit, and although most anything 12v related worked fine, such as lights, fans, and starting the generator, etc., but the Inverter has moments when it is drawing a LOT of start-up amps for the Fridge, Microwave, etc., which is when the problems occurred.

This led me to believe that this sudden 'draw' of the batteries was creating a scenario where the fourth battery's 'volts' could not handle the sudden DRAW, and were dropping 'out' to the point that the INVERTER would think that 12v power was not available, if even for a instant, causing it to cut off - Just as if you hit the 12v disconnect switch.


so, the solution was to remove the suspect BATTERY

- drain it completely into a bucket

- refill it with distilled water

- run it through several full charges, overnight, with a 120v battery charger

- drain again

- refill it with new battery acid found at most auto parts stores

- take it thru several full charges again


you may find that now this battery is back to more of it's old self, and after reinstalling it, you may also find that your Inverter, like mine, no longer has any issues.

Now, maybe that's not your issue, but I might try this more simple exercise BEFORE totally replacing my battery bank, just to make sure the BATTERY is the solution.

-

[babock]

Replace with true deep discharge batteries. Better yet, replace with true deep discharge AGM and you will get less internal voltage drop within the batteries themselves. Dont us the RV/ Marine batteries.

[KEN9XL]

Originally Posted by babock

Replace with true deep discharge batteries. Better yet, replace with true deep discharge AGM and you will get less internal voltage drop within the batteries themselves. Dont us the RV/ Marine batteries.

I appreciate the info on the alternative to RV/Marine or lithium batteries.
I educated myself by Googling the True Deep Discharge Battery.
The deep cycle or deep discharge battery (sealed) vs flooded or wet (removable cap to add liquid).
Found the L-16 & AGM have a life span of 4 - 8 years (gelled & sealed) verses the marine at 1 - 6 years, yet the gelled deep cycle is at 2 - 5 years, plus the Golf Cart battery at 2 - 7 years.

Good Website: - https://www.solar-electric.com/learn...ttery-faq.html


formerFR I apreciate the information. Sounds like a lot of work but if it saves cost of new batteries for some, alright. I wonder, since my batteries are considered beyond their life expectancy as stamped on them at 24 months.

Thank-you to both for your advice.
I appreciate it.

Safe Travels