Inverter Operation

[msteen]

After having my 2022 Oliver (Hull # 1256) on AC power and batteries indicating 13.7 volts, when I disconnect from shore power and go strictly on Inverter, the battery voltage drops to 12.4 volts. Is this normal? It seems low to me. I have checked and rechecked it several times and have gotten the same results. 

[Tom and Doreen]

Seems low but what equipment do you have and are you running any high power loads? What type batteries, what brand inverter, and what battery monitor are you using? If you have a Xantrex inverter and a Victron battery monitor do they both indicate the same voltage? 

[Wandering Sagebrush]

IMO, that is normal for a lead acid or AGM battery (batteries).  I don’t have experience with lithium batteries, so can’t opine.

[topgun2]

Perhaps the charts below will help - for lithium (see 1st chart) and lead acid and AGM batteries (see 2nd chart).

 

 

Edited June 30, 2023 by topgun2
added detail

[Rolind]

Any load on the battery will decrease the voltage while the load is present. The inverter draws a significant dc  load even when it is just turned on and not running any ac loads. The dc load will be significantly higher if the inverter is running some appliance like the microwave or air conditioning. This is the reason that determining state of charge from battery voltage is notoriously difficult and the main reason battery monitors such as the BMV 712 or a smart shunt are so popular. I also am new to lithium batteries and others might have additional or more appropriate input, but is sounds pretty normal to me.I won’t be back at the trailer for a couple of days but I will check out my readings the next time I am there.

[mossemi]

Welcome to the forum!

What type of batteries do you have and how many?  How are you reading the battery voltage?  What is the unloaded battery voltage at rest or about 15 minutes after you have remove it from shore power and without any DC loads drawing the battery down?  If you only run the inverter for a short time, like reheating your coffee, what is the voltage after you turn the inverter off?

More information included with a question = better answers.

Mossey

[msteen]

13 hours ago, Tom and Doreen said:

Seems low but what equipment do you have and are you running any high power loads? What type batteries, what brand inverter, and what battery monitor are you using? If you have a Xantrex inverter and a Victron battery monitor do they both indicate the same voltage? 

The batteries are AGM and there is no load on them when I turn the inverter on. I have only had the unit 9 months , camped in it for 33 nights, less than 4500 miles. It is the Xantrex Inverter that came with the unit. The issue came to my attention on our first boondocking trip when we ran out of electrical power during the middle of the night when I was running my CPAP machine. Thanks for your help.

[SeaDawg]

I would encourage you to open a service ticket.

If you disconnect from power, and don't turn on the inverter (which is at least a minor power draw), and dont have any orher powr draws on, and let the agms "settle" for 20 to 30 minutes,,what is your reading? (Oh, and do you have solar? If so, try this when the sun is down. If you have solar, even with ac power disconnected,  youll get some charge from the panels, unless covered or it's dark out.) Agm batteries are still a type of lead acid, and should need some time to "settle" after charging to get an accurate reading.

We run on two x 105 ah agms. I rate 12.4 as 70 to 75 per cent, on mine. 

To me, it looks like an immediate drop to 12.4 could possibly indicate a bad battery. But, I'm not at your trailer, so I can't know what else could be causing a load on your batteries. 

Make sure your inverter is off, and turn off electric to the water heater. A lot of people forget that very large load. 

 

[Rivernerd]

On 6/29/2023 at 7:12 PM, msteen said:

After having my 2022 Oliver (Hull # 1256) on AC power and batteries indicating 13.7 volts, when I disconnect from shore power and go strictly on Inverter, the battery voltage drops to 12.4 volts. Is this normal?

You may have the new bus bar Oliver started installing in 2022s.  We have one in our Hull #1291.  Have you checked the voltage at the battery bank with a reliable multimeter, then compared it to the voltage reading on the Seelevel monitor when using an appliance (like the microwave) on inverted power?  A significant difference between the two readings could be explained by the new bus bar, which causes a significant DC voltage drop.

We kept getting inverter shutdown under large (1400-watt+) DC loads until Oliver Service figured out that the new bus bar was draining lots of DC power.  We would have 13+V at the battery but the inverter was reading below 12V when under load.  The "solution" for us was to drop the Low Battery Cutoff setting on the inverter down to 11.5V, from the factory default of 12.0V.

I recommend you open a service ticket. 

[Steph and Dud B]

32 minutes ago, Rivernerd said:

getting inverter shutdown under large (1400-watt+) DC loads until Oliver Service figured out that the new bus bar was draining lots of DC power. 

Interesting. How was the bus bar a power drain? Our was it high resistance? 

[Rivernerd]

2 minutes ago, Steph and Dud B said:

Interesting. How was the bus bar a power drain? Our was it high resistance? 

My poor word choice.  Yes, the new bus bar has high resistance, so less DC power is getting to the appliance.

[John E Davies]

A properly designed bus bar should have close to ZERO ohms resistance. I suspect that poor wiring construction practices are contributing and that there is more to this story.

John Davies

Spokane WA