4 hours ago, KLEVA said:

Chris - Come back! There is a wrong way round?

Battery Negative -> Shunt -> Invertor Negative

If I look at the shunt/wiring the Battery Negative is connected to the brass bar at the top, the B1 & B2 connections plug in from the right hand side and the Invertor Negative is connected to the Brass bar at the bottom...

Addition: That warning of connect negative pole of the battery last is not being pedantic you do not want a spark near your shunt. You should be wiring this up with your battery isolator disconnected.

3 hours ago, KLEVA said:

While charging, Victron shows -9 A -480W (both negative)

I am almost sure you have it connected the wrong way round - my 702 has negative values whilst discharging.

Bingo! Thanks Mark & Chris, will fix in the morning - I definitely have this backwards then - Chalk up a new lesson learned

Mine has writing on it. The "to load" should go to the inverter. 

Haha... you lucky I had to leave when I did otherwise you would of had more problems. Have you come right now? How did the  DC  isolated work? 

On 2016/04/16 at 10:28 PM, KLEVA said:

Bingo! Thanks Mark & Chris, will fix in the morning - I definitely have this backwards then - Chalk up a new lesson learned

Is it solved...?

Sorry, haven't had proper PC access for a bit, combination of Telkom and Visual Studio locking machine until it completed an installation that took 36 hours.

Yes, the shunt was in backwards, no writing on mine and the manual & picture with mine didn't exactly make it clear that it should only go in one way. My history is a bit cockeyed for the moment, but will rest everything when I install the new fuses.

I'll be a bit quiet this week on forum, I am still fighting with Visual Studio in the evenings and am way behind getting software out.

2 hours ago, KLEVA said:

Yes, the shunt was in backwards, no writing on mine and the manual & picture with mine didn't exactly make it clear that it should only go in one way.

Minus more points for Victron 

Hi All, I am back, busy work week, so everything fell behind.

Task for this weekend: get the Victron data into my software properly. Seriously, that lovely VE.Direct protocol is annoying when you want to communicate like a normal program... keep getting that "lovely" text thrown back at me (JDP and others will know what I am talking about). Will discuss in another topic about checksums on the Axpert and Victron (I hate it when they don't follow their own rules/protocols).

More importantly, and still relevant to this thread:

• I have the Victron giving me decent data (or so I think), but am concerned that the load voltage drops way below the Axpert limit before I get to 80% on the Victron. For clarification: the Axpert minimum Voltage (when Utility supplied) is 44V, and there is no way to change that lower, without removing Utility power. I am also a bit wary about bypassing that Voltage limit in case something else is set wrong.
• Happily, the Victron software, and the Victron itself, tell me that my Ah max is under 40Ah (on a 200Ah bank), and I think I can trust that value, but that is way less than 50% DoD/SoC.
• The voltage from Axpert and Victron are similar at the time the Axpert kicks out, so I know that at least those readings are reasonably correct...
• When it kicks out, the Axpert will tell me as low as 35% (SoC) and the Victron will tell me +-81% (SoC). Whilst the Victron readings might be great for my batteries, this is not quite optimal, and also is the absolute lowest I can set. PS: My batteries are currently Ca/Ca, not optimal for the Axpert.
• Under heavy loads (when everyone forgets we running on batteries), and drawing about 50A+ from batteries, the Mid-Point alarm screams like a <redacted due to profanity>, but normally sits happily at 0.1v. I am hoping this is just a cable issue, but it gets to about 7% difference (about 2v) under these large loads. Do I need to be worried about my batteries yet?

Thoughts/ideas?

On 4/22/2016 at 7:44 PM, KLEVA said:

Hi All, I am back, busy work week, so everything fell behind.

Task for this weekend: get the Victron data into my software properly. Seriously, that lovely VE.Direct protocol is annoying when you want to communicate like a normal program... keep getting that "lovely" text thrown back at me (JDP and others will know what I am talking about). Will discuss in another topic about checksums on the Axpert and Victron (I hate it when they don't follow their own rules/protocols).

More importantly, and still relevant to this thread:

• I have the Victron giving me decent data (or so I think), but am concerned that the load voltage drops way below the Axpert limit before I get to 80% on the Victron. For clarification: the Axpert minimum Voltage (when Utility supplied) is 44V, and there is no way to change that lower, without removing Utility power. I am also a bit wary about bypassing that Voltage limit in case something else is set wrong.
• Happily, the Victron software, and the Victron itself, tell me that my Ah max is under 40Ah (on a 200Ah bank), and I think I can trust that value, but that is way less than 50% DoD/SoC.
• The voltage from Axpert and Victron are similar at the time the Axpert kicks out, so I know that at least those readings are reasonably correct...
• When it kicks out, the Axpert will tell me as low as 35% (SoC) and the Victron will tell me +-81% (SoC). Whilst the Victron readings might be great for my batteries, this is not quite optimal, and also is the absolute lowest I can set. PS: My batteries are currently Ca/Ca, not optimal for the Axpert.
• Under heavy loads (when everyone forgets we running on batteries), and drawing about 50A+ from batteries, the Mid-Point alarm screams like a <redacted due to profanity>, but normally sits happily at 0.1v. I am hoping this is just a cable issue, but it gets to about 7% difference (about 2v) under these large loads. Do I need to be worried about my batteries yet?

Thoughts/ideas?

My 2c.

• Under load you cannot look at battery voltage to determine SOC - the higher the load the more the voltage will drop because of the internal resistance of the batteries. When you remove the load, the voltage should also recover to a certain degree, depending on mow much it was discharged. If you get to 44V and the BMV still have not reached SOC of 80%, then it can be one of many things, e.g. 1.) BMV not calibrated with correct battery bank AH value. 2.) One or more batteries in the bank is faulty. 3.) Battery cables are too thin and/or too long and therefor the voltage drop over the cables is too high. 4.) Bad connection(s) in battery cabling causing voltage drops.
• I assume you are referring to the remaining capacity in the bank at that point in time - 40Ah - that is a SOC of 20% of DOD of 80% (80% discharged)
• Under severe loading the voltage readings might differ substantially depending on the position of the BMV - if it is closer to the inverter the readings might be closer, but if it is closer to the battery bank and you have long/thin cables between the bank and the inverter, the readings might be further apart. On no-load the readings should be close together, but might still differ a bit depending on the calibration of the inverter and BMV.
• The Axpert's SOC indication is pointless, as discussed many times before. It is based on a voltage reading only.
• The fact that the mid-point voltage indicates a 7% difference worries me a bit - that means that some of the batteries are charged / discharged more than others which indicates that one or more of the batteries might be old or starting to fail.

Hi all, although this was in another thread, just wanted to clarify here so that there is a continuation.
A week later it has turned out that there was at least 2 faulty batteries in my setup at installation of the BMV (the unfortunate thing was that it was one on each side of the midpoint to took longer to diagnose, hence the much large than expected voltage drops. With 1/2 my capacity and only 4 good batteries running, the situation was a lot different - the Axpert is lasting longer than even before, voltage drops at a much slower rate for the same load and the Victron now goes down to 65%/70% before the Axpert cuts out. Still not ideal, but that is promising. Victron already paid for itself by saving my banks, and even better supplier has already replaced the two faulty batteries under warranty. Will install the 2nd bank and restore my capacity as soon as all the batteries are balanced and the last battery (which may still be faulty) is ready/replaced.