Inverter/Battery Charge

[scdock]

I was camping recently with no shore power and my batteries, on the 2nd day, were displaying low power on the inverter. My system is comprised of 2 160 watt solar panels connected to a Victron MPPT 100/50 controller, Victron Multiplus inverter/charger, BMV-712 monitor, and 2 BB 100ah batteries. The 120v used in my trailer was only 3 strings of mini lights, a satellite radio, and charging for phones. The 12v used for lights and water pump. Based on usage I should have had plenty of battery power to run the coffee maker in the morning but not so. The BMV was showing a 12.63 SOC which I thought was low based on power consumption but also thought it should have been sufficient to run a small electrical appliance. I'm running the refrigerator on propane so minimal draw from that so I'm not sure what might be causing the battery drain. At the end of the day the batteries were showing full charge, ran the same electrical appliances, along with the DWs hair dryer, and the next morning the same issue with low power. Is there something I should look for that might be putting a drain on the batteries? I have my inverter and BMV programmed for lithium batteries based on spec provided by BB but the SOC never shows above 13.93v rather than the 14.2 I've programmed. I hope all this makes sense? Any guidance would be greatly appreciated.

[TucsonJim]

I was camping recently with no shore power and my batteries, on the 2nd day, were displaying low power on the inverter. My system is comprised of 2 160 watt solar panels connected to a Victron MPPT 100/50 controller, Victron Multiplus inverter/charger, BMV-712 monitor, and 2 BB 100ah batteries. The 120v used in my trailer was only 3 strings of mini lights, a satellite radio, and charging for phones. The 12v used for lights and water pump. Based on usage I should have had plenty of battery power to run the coffee maker in the morning but not so. The BMV was showing a 12.63 SOC which I thought was low based on power consumption but also thought it should have been sufficient to run a small electrical appliance. I'm running the refrigerator on propane so minimal draw from that so I'm not sure what might be causing the battery drain. At the end of the day the batteries were showing full charge, ran the same electrical appliances, along with the DWs hair dryer, and the next morning the same issue with low power. Is there something I should look for that might be putting a drain on the batteries? I have my inverter and BMV programmed for lithium batteries based on spec provided by BB but the SOC never shows above 13.93v rather than the 14.2 I've programmed. I hope all this makes sense? Any guidance would be greatly appreciated.

Your write up is terrific and gives a lot of information.

When I run my 2000 watt inverter in the morning to make coffee or run the microwave, it sometimes starts beeping to tell me there is low battery voltage. But it won't shut down until the voltage gets down to a significantly lower level. I'm running three BB's and still get this warning. But, when I finish and turn off the inverter, the battery voltage comes right back up.

Try this tomorrow morning.

1. Record the battery voltage from your BMV712 before you turn on any devices. Make sure everything is turned off, including your inverter.
2. Turn on your loads such as the coffee pot and record your voltage while under load.
3. When finished brewing your coffee, turn everything off including 12V draws such as the refrigerator, wait five minutes, and then record your voltage.

What I suspect is happening is that the loads through your inverter are simply high, and they are pulling the battery voltage down because of it. This shouldn't hurt anything. As long as the batteries recover while at rest, you shouldn't be too concerned.

Jim

[scdock]

TucsonJim

Thanks for the advise, I'll record my the loads and post once I'm back to civilization. From your comments you were still able to run your coffee pot even though the you got a low voltage warning. I was not able to. The inverter would kick on and the coffee pot would run, then shut off. This happened a handful of times so I fired up the generator to finish. Is this normal?

[TucsonJim]

TucsonJim

Thanks for the advise, I'll record my the loads and post once I'm back to civilization. From your comments you were still able to run your coffee pot even though the you got a low voltage warning. I was not able to. The inverter would kick on and the coffee pot would run, then shut off. This happened a handful of times so I fired up the generator to finish. Is this normal?

It may be normal depending on how many amps you're drawing through the inverter. A question for you: What wire size is supplying your inverter? And how far do those wires run? Sometimes, if you have under-sized wiring, the condition is even more prevalent.

Jim

[scdock]

The wiring is 1/O from batteries to inverter (confirmed that yesterday as I was wondering if the wire size was too small). The run isn't that long as the batteries are mounted on the A frame and the inverter is in the pass thru. I'd guess 5 maybe 6 feet tops of wire run.

[TucsonJim]

What is the model number of your Victron Multiplus? If you have the 3000 watt model, it requires two parallel runs of 1/0 AWG wire. In other words two +12v wires and two ground wires. If this is the case, it could explain the issues you're encountering.

Jim

[ncitro]

Yeah for my Multiplus 3000 I ran 4/0 just to be sure I was covered. I think in the Multiplus settings you can set what voltages it will shutdown and warn at. You might want to take a look at those. When you are getting the low voltage shutdown what % does the BMV say if left in the batteries? Keep in mind to access those Multiplus settings you'll need to hardwire a laptop or Android phone to it, those cannot be accessed via Bluetooth.

[scdock]

My inverter model is the Compact 12/24v 2000VA 120v. I don't recall the setting on the BMV for low voltage shutdown. I modified the factory settings to those provided by BattleBorn. I have the USB to Ethernet box that allows my computer to interface with the Multiplus. I had to recently reset everything as the firmware updated the MPPT, inverter, and BMV which defaulted all to factory settings.

[ncitro]

My inverter model is the Compact 12/24v 2000VA 120v. I don't recall the setting on the BMV for low voltage shutdown. I modified the factory settings to those provided by BattleBorn. I have the USB to Ethernet box that allows my computer to interface with the Multiplus. I had to recently reset everything as the firmware updated the MPPT, inverter, and BMV which defaulted all to factory settings.

The low voltage cutoff is on the MultiPlus not the BMV, you need to connect the computer via the MK3USB cable, and then in the MultiPlus settings I think its in there. I will see if I can connect mine and grab a screenshot.

[TucsonJim]

I took a look at the Victron site and pulled the manual for the Multiplus Compact 12/24V 2000VA 120V set up. According to the installation guide, they recommend the following:



You have 200 Ah of capacity which is probably fine as long as you're not running the large loads for very long.

The issue that I see is your wire size which can have a significant loss of power. The manual says for runs of 0 to 5 meters, you should be running 70 mm2 wire. That converts to 2/0 AWG. By running 1/0, you will experience a noticeable voltage drop at higher current draw.

When I first purchased my 2000 watt inverter a few years ago, I had some 1/0 wire laying around and I elected to use it instead of the 2/0 that the manual suggested. When I tried to brew coffee, the inverter frequently faulted and shut down. After installing the proper 2/0 wire, it no longer shut off. But it still beeps once in a while with a heavy load...

Jim

[ncitro]

scdock

Here is a screenshot of my Inverter tab in the Multiplus settings in Victron Connect. There are settings for the DC input shutdown and reset voltages. I have mine set pretty low, but I watch it pretty closely and I trust my BMS to shut my batteries down before its an issue.

[ncitro]

I took a look at the Victron site and pulled the manual for the Multiplus Compact 12/24V 2000VA 120V set up. According to the installation guide, they recommend the following:



You have 200 Ah of capacity which is probably fine as long as you're not running the large loads for very long.

The issue that I see is your wire size which can have a significant loss of power. The manual says for runs of 0 to 5 meters, you should be running 70 mm2 wire. That converts to 2/0 AWG. By running 1/0, you will experience a noticeable voltage drop at higher current draw.

When I first purchased my 2000 watt inverter a few years ago, I had some 1/0 wire laying around and I elected to use it instead of the 2/0 that the manual suggested. When I tried to brew coffee, the inverter frequently faulted and shut down. After installing the proper 2/0 wire, it no longer shut off. But it still beeps once in a while with a heavy load...

Jim

Yeah I agree the wire size is probably the most likely culprit. You pretty much cannot run too big of wire. Keep in mind your wires that connect the batteries in parallel should be this big as well. While you are doing it check your terminations at your fuses and any switches and make sure they are good and tight. Loose connections lead to heat which leads to voltage drop, the enemy of an inverter running large loads.

With my system I can run either of my two A/C units with no soft start and the only sign its even working is the fan running on the MultiPlus.

[howson]

scdock -- Neil nailed it-- issue is the Multiplus configuration. Can't share from cmptr at my current location...hopefully Neil can share screenshots.

[Yoda]

I was camping recently with no shore power and my batteries, on the 2nd day, were displaying low power on the inverter. My system is comprised of 2 160 watt solar panels connected to a Victron MPPT 100/50 controller, Victron Multiplus inverter/charger, BMV-712 monitor, and 2 BB 100ah batteries. The 120v used in my trailer was only 3 strings of mini lights, a satellite radio, and charging for phones. The 12v used for lights and water pump. Based on usage I should have had plenty of battery power to run the coffee maker in the morning but not so. The BMV was showing a 12.63 SOC which I thought was low based on power consumption but also thought it should have been sufficient to run a small electrical appliance. I'm running the refrigerator on propane so minimal draw from that so I'm not sure what might be causing the battery drain. At the end of the day the batteries were showing full charge, ran the same electrical appliances, along with the DWs hair dryer, and the next morning the same issue with low power. Is there something I should look for that might be putting a drain on the batteries? I have my inverter and BMV programmed for lithium batteries based on spec provided by BB but the SOC never shows above 13.93v rather than the 14.2 I've programmed. I hope all this makes sense? Any guidance would be greatly appreciated.

You have gotten a lot of excellent advice. I have on question related to your battery drain . Are you leaving the inverter ON all the time? If so that is the draw. It consumes power even with no loads applied. It should be off until needed - at least that is what I have been told.

Keith

[ncitro]

You have gotten a lot of excellent advice. I have on question related to your battery drain . Are you leaving the inverter ON all the time? If so that is the draw. It consumes power even with no loads applied. It should be off until needed - at least that is what I have been told.

Keith

I’d say that depends on your needs and battery capacity. I leave mine on 24/7 (granted I’m pushing 600ah now), but the Multiplus uses comparatively low power when in standby compared to most inverters. Given our power usage (residential fridge running all the time) the inverter standby draw is rounding.