Shore power running but alternating to inverter

[kkdesigns]

Hey all,

Replaced the batteries today on my 2018 Tommy Bahama. I killed the originals with a lack of battery knowledge. Oops.

Anyway, replaced with 6V golf cart batteries. Got everything hooked up and plugged into the house at a 20amp outlet to fully charge the batteries.

The issue I'm having now is even though shore power is on, the inverter keeps cycling to batteries about every 30 seconds or so. 30 seconds on shore power showing 13.6, then the inverter kicks on to battery power. I've unhooked and re-hooked up the shore power. cycled on the battery disconnect, and looked high and low on the forum, but can't find any help on where to look.

Does anyone have a place to start looking?

[TG Twinkie]

Not sure what your issue is. I believe you have a converter not an inverter.
How are you determining the unit is turning on and off?
Is it just the fan coming on?
Which would likely be normal.

[kkdesigns]

It's not just the fan. While plugged into shore power, my battery display and the entire system cycles between the battery and shore. Its on shore power, than will switch to battery power, than back again. To get it to just shore power I unhooked the negative battery terminal. Pesto. It started on shore power.

[TG Twinkie]

Are you sure you have the batteries connected correctly?
It sounds like the converter is "crowbaring" ie shutting down due to an overload.
Another possibility is a bad connection.
What happens when on shore power and you shut off the converter?
Do you have the batteries connected in series? With the correct polarity?
The 13.6 volts is the converter output voltage. Not the battery voltage. The battery voltage when at full charge and the converter off should be 12.8 volts or close.

[Protagonist]

Nomenclature is important. If it's a converter, it makes 12vDC from 120vAC, and it should run when connected to shore power, and will charge the batteries. If it's an inverter, it makes 120vAC from 12vDC, and it should not run when on shore power, and if running will drain the batteries. If it's an inverter/charger, then it does both, but not at the same time.

The display cycling doesn't necessarily mean the system is switching from shore power to batteries and back. The display alone might be alternating between the two power sources just to monitor both. Especially if it's switching displays at regular 30-second intervals. If your power source itself was switching back and forth between shore power and battery power, it would happen at irregular intervals based on other factors than just time.

I think that your trailer is probably doing exactly as it should, and you're just misinterpreting the display. However, there is an easy way to find out. Try running an appliance that will run on shore power but not on battery power. Such as an air conditioner. If it runs and keeps running, you're not really switching to battery power after all, and only the display is switching to show battery charging voltage.

[uncle_bob]

Hi

Hopefully you got warranty money for your original batteries ..... regardless of how they died, that should be the case.

Back up a bit, get the inverter / converter straight in your head. Converter charges the batteries. Inverter turns battery power into 120V. Both can be wired wrong and cause issues. Hooking up 6V batteries can be done wrong and cause issues.

First question would be - are the 6V batteries wired correctly? One jumper in-between. All negatives to a single post. All positives to a single post.

Next question would be - is the inverter off and everything else turned off? Don't troubleshoot multiple things at once.

Next up - do you *really* have shore power? Plug in a hair dryer and see.

Now, grab a multimeter (buy one if you don't have one) and look at the battery positive. It should run around 12.4 to 12.7V with nothing going on (no shore power, no solar). 6.2V is a bad sign in this case.

Plug in shore power. The converter should come on and the battery will go up to about 13.7V. If it does not, the converter is not putting voltage on the battery. Something is not wired right.

Now punch the use / store button. Repeat the steps above in both the use and store settings. Some trailers put the converter on in store, others do not. This is about the only way to know which you have.

Assuming we made it this far, you probably do not have a massive wiring issue. Next step is to check various 12V loads to be sure they work (lights are a good first step). Inverter would be last on my list.

Now back to the converter. If it is cutting in and out, it may be broken. Do the fans come on? Watch the voltage on the battery with the multimeter to see what's going on. It should hang in there at 13.4 to 13.7V for quite a while.

Assuming this all checks out we are back to the display panel. To dig into it, we probably should get a picture.

Bob

[kkdesigns]

Yes, extreme newby. Learning everyday.

You were correct, 6v batteries do not go back together like their 12v battery cousins. Had it not running in parallel. That issue fixed. Now the sine wave 1000watt inverter won't power up. Pulled it out of the hole under the bed to get a better look at.

The breaker under the stove is good and fuse is good. There is a resettable ac outlet breaker on the bottom of the unit I cant figure out if its tripped, and just found out there is a inline fuse on the positive cable going to the battery I will check on the next stop.

Any other advise to look at or up you fine people can suggsst?

[Al and Missy]

Originally Posted by kkdesigns

Yes, extreme newby. Learning everyday.

You were correct, 6v batteries do not go back together like their 12v battery cousins. Had it not running in parallel. That issue fixed. Now the sine wave 1000watt inverter won't power up. Pulled it out of the hole under the bed to get a better look at.

The breaker under the stove is good and fuse is good. There is a resettable ac outlet breaker on the bottom of the unit I cant figure out if its tripped, and just found out there is a inline fuse on the positive cable going to the battery I will check on the next stop.

Any other advise to look at or up you fine people can suggsst?

Confused by "Had it not running in parallel". 6V batteries should be connected in series, not parallel. You should have all negative cables connected to the negative post of one battery, a jumper from the positive post of that battery to the negative post of the other battery and all positive cables connected to the positive post of the second battery. Maybe you have it wired that way, but your quote inferred that you now have them wired in parallel which is wrong. If you have them wired correctly now but originally had them wired in parallel (like the old batteries) you may have blown fuses in, or damaged, the inverter, converter, or solar charger.

Al

[kkdesigns]

Originally Posted by Al and Missy

Confused by "Had it not running in parallel". 6V batteries should be connected in series, not parallel. You should have all negative cables connected to the negative post of one battery, a jumper from the positive post of that battery to the negative post of the other battery and all positive cables connected to the positive post of the second battery. Maybe you have it wired that way, but your quote inferred that you now have them wired in parallel which is wrong. If you have them wired correctly now but originally had them wired in parallel (like the old batteries) you may have blown fuses in, or damaged, the inverter, converter, or solar charger.

Al

You are correct what you described. In series now. Positive to positive, neg to neg with one wire jumped too neg from pots. Now. Had wired in parallel on first install.

That is my fear that I torched the inverter.

Sorry. Terminology is bad. Just learning all this stuff. learning Curve is about a 60 degree incline for this stuff.

Thanks for your help. Hopefully I'll learn this stuff before I burn up half the rig.

If you have any furniture building questions, I'll be happy to answer those. That I'm knowledgeable about..��

[Protagonist]

Originally Posted by kkdesigns

You are correct what you described. In series now. Positive to positive, neg to neg with one wire jumped too neg from pots. Now. Had wired in parallel on first install.

Not right!

Positive-to-negative is in series. Current from one battery flows through the other battery. Disconnecting one battery breaks the circuit for both. This is what you want for 6v batteries.

Positive-to-positive is parallel. Current from one battery bypasses the other battery. Disconnecting one battery leaves the other battery powering a completed circuit, and you have to disconnect each battery to completely break the circuit. This is what you want for 12v batteries.

[TG Twinkie]

I think he means coach positive to battery positive; coach negative to battery negative.
With a positive to negative jumper between the batteries. Series connection.

[uncle_bob]

Hi

If you fired the system up with the 6V batteries set up the same way as the 12V batteries ( = in parallel) , you may well have damaged the converter / charger. If you tried the inverter in this configuration it *should* have faulted out (self protected). If for some reason it did not, you may have toasted it.

The inverter usually has a dedicated wiring setup both for positive and negative. Check them both out with an multimeter. A problem on either side will stop the inverter dead.

Keep in mind, you are going through all this for *maybe* a 10% boost in capacity ....

Bob

[TG Twinkie]

Check the output fuses (the two large fuses, 40 amp or greater depending on the converter) you may have just blown them.
The inverter may have a reset button. The inverter would (should) have low voltage protection. Normally they will shut down when the input voltage drops to around 10 volts.
You may be lucky.

[kkdesigns]

Ok. So went to Billy Max rv in Amarillo this morning to get this straightened out. By the way, this guy is awesome. Called his cell Sunday night to ask if he could fit me in. Yes he said he was swamped, butt come on by. Showed up Monday am first thing and he pulled me right up and got to work. Awesome!

He got me straightened out with battery wiring. I was so close, but still had some wires out of place.

Hee did some testing, and figured out I blew the big 100 amp breaker that hooks the inverter to the battery. He jumped it and everything fired right up. Whew.. So, last problem is finding that breaker. We hit 3 rv dealers, Grainger, and 2 electric supply places on the way out of town. No luck anywhere. So we are testing Amazon. Ordered one and having it delivered to the local USPS in Albuquerque. Should be able to pick out up tomorrow.

Cross your fingers.