12v inverter issue

[samTummo]

Yes I wrote inverter. 😎 I have a 400 watt inverter I used to use in my TV. When boondocking, I have in the past powered the tv inside the 5er with one marine 100a battery. Only used it for an hour or two. With my 2017 Cherokee I installed two 120ah 6v golf cart batteries and can’t power the tv with the inverter. I tried it and it kept shutting down. DW got cold, short on propane, I started the generator. When I got back inside, the tv was on, still plugged in the inverter, plugged in the 12v cig lighter.

Why couldn’t my batteries (at 93% cap) do it but the converter could???

Samtummo

[kcmusa]

Measure voltage going to inverter with then without gen running.
See if low voltage.

[fonzie]

Are your 6 volts batteries hook up in series? Also is the inverter hook up directly to batteries and one lead on + of one battery and - of other battery?

[SeaDog]

Check the battery wiring like was mentioned sounds like you have the batteries in parallel instead of series

[ardakota]

Sounds like your not hooked up right you should have one battery negative hooked to the positive of the other battery and then hook your supply leads to the remaining positive on one battery and the negative on the other battery.

[samTummo]

The batteries are hooked up correctly in series. I have a all inclusive cutoff switch on the battery box and a monitor wired into the battery bank. They offer 13.+ volts to the lights, tongue jack and slide and have never been discharged below 60%.
The inverter is plugged into the 12v “cigarette lighter” outlet by the tv antenna in the TT.

Samtummo

[tomkatb]

Did you change rv’s?

Does the battery monitor have historical graphs of voltage to look at?

What is the battery voltage three hours after charging 24 hours?

Wire size to the 12 volt plug for the inverter?

[samTummo]

Yes, went from 2001 Nomad Scout 5er to 2017 FW Cherokee 274RK.
No history on monitor.
Charged batteries in series with a 12v 10a not smart car charger for about 10 hours, then 2a until meter on charger zeroed out. Set monitor to 100% after about 6 hours resting.
Don’t know what gauge wires are, outlet Pre existing in TT.

Samtummo

[tomkatb]

Other possibilities.

I would suspect a diy installation of your 12 volt plug perhaps. Wire size matters a ton with 12 volt. Or it is connected into a small wire. Inverters are funny about that.

Two six volt gc2 batteries are more amps than most marine batteries.

[NavyLCDR]

The first troubleshooting step that you need to do is measure the input voltage to the inverter with both the generator running and the inverter on. Then continue to monitor the voltage when you shut off the generator and switch to battery power, with the inverter continuing to run. See what the voltage drops to and at what input voltage the inverter shuts off at.

[samTummo]

I’ll try that when I get back this evening. What doesn’t make sense to me is I’m sure the 12v outlet only has one source to feed it. So no mater what it is coming from the battery bank.

Samtummo

[NavyLCDR]

Originally Posted by samTummo

I’ll try that when I get back this evening. What doesn’t make sense to me is I’m sure the 12v outlet only has one source to feed it. So no mater what it is coming from the battery bank.

Samtummo

However, with the generator running, the converter is supplying a higher voltage to the batteries in order to charge them, possibly as high as 14.4 volts. This voltage is also maintained by the converter even with system load applied. When you turn off the generator, the converter will stop supplying that higher voltage, and your battery voltage will drop to about 12.9 volts with no load on it. Apply load to the battery and it will drop with the amount of load on the system. So you may be looking at a source voltage down in the 12 volt range.

Now you have to take into account voltage loss through the wire to the inverter. With the converter supplying as high as 14.4 volts to the battery connection of that wire, you may be seeing 12 volts at the end of the wire run to the inlet of the inverter. Turn off the converter (stop the generator), and you get closer to 12 volts at the battery connection of that wire, now the voltage loss in the wire might drop you down to below the specified input voltage of the inverter.

[tomkatb]

Makes sense.

The converter/charger is typically 13-14 volts or more.

A battery at full charge is closer to 12.6.

Add some #16 or #18 wire to the plug and you will have issues with an inverter.

Might be hard to see with a meter.

[rommroma557]

Measure voltage going to inverter with then without gen running.