question

@newworldorder, the only thing connected to the NEG side of your battery bank should be the "Battery" side of the shunt; all other chargers and load NEGs (including your inverter) need to be hooked up to the "Chargers and Loads" side of the shunt (sometimes only labeled "Loads"). The POS, obviously, still runs directly to the battery or to your POS busbar. Once you have your inverter NEG connected to the "Loads" side of the shunt, your BMV will be able to "see" the current out that it's drawing.

Also note that all charge source NEGs also need to go to the "Chargers and Loads" side of the shunt so that the BMV can also "see" the incoming current and update your SOC accordingly.

Make sure you correctly set your Ah capacity in the BMV. Your BMV will always start at 100% SOC when you first hook it up (you can turn this off, but it's a bit late for that) but will adjust itself after you have everything set correctly and connected correctly and it's had time to figure out what's going on in your battery bank. Basically, give it about a day once you have everything set.

What would you consider a charge source? The only thing that is charging my battery bank is 400 watts of solar at the moment.

I am going to post a pic of what I think it should be hooked up as.

@newworldorder, well if your 6v batteries are FLA or AGM, first you have to account for the fact that of your 190Ah capacity, only about half of that is usable... and that's brand-new. So, fully charged, your 190Ah capacity is actually around 90Ah usable. That is then substantially decreased by any age/usage on your batteries, plus any deep cycles of the batteries... every time they're discharged, you lose a little capacity off the top, meaning that you can't ever recharge them to the same level they were before... this is just the caveat of FLA and AGM batteries. They're cheap, but they're heavy and you can only really use half their capacity at most, and that capacity steadily decreases over time and usage.

The other thing to consider is that a heater is a resistive load, which actually consumes far more amperage than a capacitive load, so you're more likely than not seeing close to an 82-95A draw (at 12v) on your inverter running that heater... plus the draw of the inverter itself, which depending on the brand inverter you have can be surprisingly high. So, all that in mind, consider that you're drawing close to -if not in excess of- your total usable capacity (maybe even more if the batteries are old) just by turning that system on, so I'm actually not at all surprised that you're getting a low-voltage alarm right from the start.

As an example of this, I have a 1500w heater here on my test bench that I use for testing battery throughput; running it at full-bore, it consumes in excess of 184A when all is said and done, including the draw of the inverter itself - and that's with a Victron inverter, which has pretty much the highest efficiency rating of any on the market.

So, several ways you can get around this: First, possibly upgrade your inverter. If you're using an AIMS or a Xantrex or any of the knockoff brands, get rid of it and get a Victron or a Magnum.

Second, increase your battery capacity... the more Ah you have available, the less voltage drop you'll see when running your load, because the draw gets spread over your available Ah.

Third, change your battery chemistry if you can... LiFePO4's are expensive, but you can use 80% of your capacity without negative repercussion... and they'll last longer and deliver a lot more power upon demand (for instance, a Battle Born 100Ah battery will deliver a continuous 100A if you need it).

And, finally, the other thing that will help is to upsize your wiring from your battery to your inverter... the thicker (and more strands) the wire, the less resistance and the less voltage drop you'll see when running a load.