Battery monitoring mystery

[amazinghank]

I have a Casita trailer with a new 105ah AGM House battery plus 4-105ah Lithium Batteries in a bank tied to a 4000 watt AIMS Pure Sinewave Inverter & Charger.
A year ago I installed a Renogy Battery monitor on just the Lithium bank (with a shunt) and everything was fine & worked as expected.
The original converter is still used to charge the house battery and run all the A/C breakers & DC equipment.
The two systems are separated by a switch that only switches the positive wires for either the shore power or the inventor power. The grounds are all joined (not switched) and have not had an issue until I recently added a 2nd Renogy Battery monitor for the AGM house battery and that seems to work fine, except that now the 1st monitor (lithium bank) showed consumption (-5.6 amps) and the % drops steady so that the 100% is down to 20% or less in 2-3 days ( with the lithium bank switched off) when I switch back on it goes back to 100% very quickly, as though the batteries aren’t really depleted.
Are the 2 shunts confusing the meters because the negative wire are common? I’m confused
Do I need to run negative wires through a switch to separate?

 

[MisterSandals]

4-105ah Lithium Batteries

4 batteries or 4 cells?
If batteries, are the connected in parallel in a balanced manner?

 

[MisterSandals]

Are the 2 shunts confusing the meters because the negative wire are common?

I am struggling to understand how you have this wired. Happen to have a pic or a diagram?

Its "possible" for a number of things to be happening, depending on how its wired.

 

[amazinghank]

4 batteries or 4 cells?
If batteries, are the connected in parallel in a balanced manner?

4ea 105ah 12v lithium batteries wired in parallel, same mfg & same type bought at the same time. All brought to depleted charge when set up

 

[MisterSandals]

4ea 105ah 12v lithium batteries wired in parallel,

There are many ways to "wire in parallel". Some good, some terrible.
Maybe not related to your monitoring issue but a VERY common issue.

Your 2 shunt wiring diagram or pic would be mighty helpful. There are a lot of eyes here that are willing to help.

 

[amazinghank]

Will work on that later today. Just went to trailer and checked, monitor said lithium (4-batter bank) was 70% turned on power to that circuit and inverter kicked on and it went to 100% in 15 seconds, telling me that they probably not at 70%. This only started the day I added a shunt to the house battery (1ea AGM) and that monitor always seems correct. If I am running on that battery for lights, pump or furnace it drops % wise according to the consumption.

 

[amazinghank]

Sorry for what looks like a bowl of spaghetti. Appreciate the help and advice. Everything was fine for 2-3 years, than last thing done was add AGM house battery and a 2nd battery meter. Anytime I’ve had an issue, when I went back to last thing done?!?

 

[MisterSandals]

First thing i see is that your 4 batteries are wired in the worst possible way. Its horrifically unbalanced. The battery that the charge and loads are connected to will get most of the charging and supply most of the loads. The lower ones will be neglected.

I don't see any DC loads coming off of your lithium bank. Is it charged solely by the inverter and only creates AC?

I am wondering whether your Aims inverter is depleting the topmost battery with high idle tare (any idea what idle watts are?). When disconnected, perhaps the 3 lower batteries help the topmost battery recover.

I don't know. One thing is certain, you have to fix the battery wiring imbalance. Maybe this is the root of what you are seeing.

My other guess is that maybe the neutral to ground bonding is wrong for your 2 inverters. Not my specialty. Maybe @John Frum can tell?

 

[John Frum]

My eyes are shot for the day.
I'm not even sure I understand the problem description.
Lateral pass to @Bud Martin

 

[John Frum]

Actual high res high contrast pictures might help.

 

[MisterSandals]

For best battery wiring for 4 batteries in parallel, see post #64 here:

Calculation of parallel string battery currents

My interpretation of all this: The goal is to have the exact same line resistance from each terminal to the common point where the load current is drawn. Is that correct? Andy For the "Posts" configuration, yes, the goal is to have the same cable resistance from each battery to the load points...

diysolarforum.com

 

[Bud Martin]

So looking at the pictures.
1) you have two separate inverter systems: correct? plus another power from Shore, correct?
First system is made of first Shunt monitor, four 12V Li in parallel to feed the AIMS 4000W 12V inverter. What is the exact model number of this AIMS?
Second system is made of Second Shunt monitor, and 12V AGM House battery to feed the stock inverter.

2) OP: The two systems are separated by a switch that only switches the positive wires for either the shore power or the inventor power.
Per picture, you show switching three 'L', one is from AIMS, second is from Stock converter, third is from Shore, so the load can be select between the power from AIMS inverter, or from Stock inverter, or from Shore, is that correct? using the word 'Positive' for AC system is not the term.
The wiring is confusing for the AC side. How does the load get selected to be connected to AIMS or the Stock inverter output?

Does the switch have OFF position? Info about that AC selector switch?


3) OP: except that now the 1st monitor (lithium bank) showed consumption (-5.6 amps) and the % drops steady so that the 100% is down to 20% or less in 2-3 days ( with the lithium bank switched off) when I switch back on it goes back to 100% very quickly, as though the batteries aren’t really depleted.

5.6A draw x 12V = 67.2W of power draw. What is the power consumption spec of the AIMS 4000W inverter with no load? Do you see this -5.6A when the AIMS power on/off switch is in the OFF position?

 

[amazinghank]

 

[Bud Martin]

That is big LF inverter. So idle consumption is about 3.5A. If inverter is on but no AC loads connected, the Battery drain is 84Ah per day (about 1kWh/day), 3 days = 252Ah (about 3kWh)

4000 Watt Pure Sine Inverter Charger 12Vdc to 120Vac Output ETA TBD

Get dependable backup electricity for power outages with the 4000-Watt 12VDC to 120VAC Output Pure Sine Inverter Charger from AIMS Power.

www.aimscorp.net

Input Specifications

• Nominal Input Voltage: 12.0Vdc
• Minimum Start Voltage: 10.0Vdc
• Low Battery Alarm: 10.5Vdc-11.0Vdc
• Low Battery Trip: 10.0Vdc-10.5Vdc
• High Voltage Shutdown: 16.0Vdc
• Low Battery Voltage Restart: 13.3Vdc
• Idle Consumption: <3.47 amps DC
• Power Saver Mode Idle Consumption: <0.53 amps DC

 

[amazinghank]

Answer to #1

View attachment 127096

1-AIMs Inverter & 1-Stock converter for distribution and charging of the AGM house battery. The inverter is used to invert the lithium batteries and provide 120 when off grid.

Answer to #2

0 = OFF no A/C power from either shore power or AIMs inverter from Lithium battery’s

Answer to #3

The battery monitor #1 (for lithium batteries) it has that power drain all the time, whether switch is 1, 0 or 2.

I’ve attached a photo of how I wired the lithium batteries since Mister Sandals believes this may cause issues, I’m still not sure which diagram of the 4 I should use. I put this system together, obvious to all by this post, not really sure of what I’m doing although has worked ok till I added 2nd monitor and new AGM house batteries. Prior to that, no drain or drop of % on lithium bank unless I was using. It would stay at 100% for months, until it was turned I on and used.

 

[Bud Martin]

So looking at the picture below showing AIMS inverter/charger and your battery wiring, when AIMS inverter Power switch is in OFF position, the Shunt in the picture is showing -5.6A, correct? if that is the case I would use clamp-on DC Amp meter to check the current flowing on either red or black wire attached to the AIMS, I cannot see you can have that much current draw when AIMS is off.
Also what is that Red wire with yellow terminal and blue sleeve is for? Is that wire also drawing current?
Notes: I still do not quite understand your AC wiring and function per explanation, I have to think about it more or some one can chime in if they understand on the AC wiring.

 

[amazinghank]

So looking at the picture below showing AIMS inverter/charger and your battery wiring, when AIMS inverter Power switch is in OFF position, the Shunt in the picture is showing -5.6A, correct? if that is the case I would use clamp-on DC Amp meter to check the current flowing on either red or black wire attached to the AIMS, I cannot see you can have that much current draw when AIMS is off.
Also what is that Red wire with yellow terminal and blue sleeve is for? Is that wire also drawing current?
Notes: I still do not quite understand your AC wiring and function per explanation, I have to think about it more or some one can chime in if they understand on the AC wiring.
View attachment 127104

So the Red & Black wire connect to a Renogy DC MPPT Charge controller that allows for the lithium bank to be charged by both the Alternator on the Tow Vehicle and Solar Panels at the same time.
I like the idea of using a clamp meter to see if there is a draw.

 

[Bud Martin]

So the Red & Black wire connect to a Renogy DC MPPT Charge controller that allows for the lithium bank to be charged by both the Alternator on the Tow Vehicle and Solar Panels at the same time.
I like the idea of using a clamp meter to see if there is a draw.

They look to be small gauge wires, I would put fuse on each one of the small Red wires so the wires will not catch on fire if the Renogy or the Smart shut have short circuit.

 

[amazinghank]

For best battery wiring for 4 batteries in parallel, see post #64 here:

Calculation of parallel string battery currents

My interpretation of all this: The goal is to have the exact same line resistance from each terminal to the common point where the load current is drawn. Is that correct? Andy For the "Posts" configuration, yes, the goal is to have the same cable resistance from each battery to the load points...

diysolarforum.com

Yes they are identical batteries, all purchased at the same time from Lion Energy and are the Safari UT 1300’s
So if I use this as the correct wiring for 4 battery parallel setup, where do I put the shunt? hw

 

[MisterSandals]

So if I use this as the correct wiring for 4 battery parallel setup, where do I put the shunt?

Anywhere on after the connection point of the 4 batteries (on the thickest black wire in the pic).

It turned out your wiring is “diagonal”, as shown in your picture, isn’t awful (as shown in your original sketch as “one ended”). But this should help balance better.