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It really looks like this but with some kind of blue wrap around it. Perhaps it was one of these "drop in" FLA replacement Lithium batts I see around. Some do it right like Mastervolt, Some do it very wrong

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really gone wrong big-time, they look like Winston cells, CALB are blue or grey iirc. No matter what went wrong, aside from an internal short, the BMS hasn't done its job... looks expensive :wtf:

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What do you think would have caused this battery meltdown on the weekend

 

Multiple Lithium Iron Phosphate cells with no Battery management system?    Looks like the result of an ill informed DIYer.

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That makes sense. I had an argument with a guy on Trademe who is selling Lithium battery cells advertising that you can make your own "Power Wall" with them. The are AA cells and the idea is to just amass as many as you want to make a mega bank of Lithium battery cell. There is no charger and I told him he was being a little irresponsible. You can imagine the response i got from him. I expected such, so it was no shock to me. I just hopped someone else would read my comment and think twice about trying to make a Powerwall.

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If those are Lithium batts I see no obvious packing around the plastic battery box to keep them securely contained.  My research into Lithiums always stressed the need to lock the batts tightly into place.

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Looks like some sense wires for a bms going the terminals 

 

I saw that too,  but it didn't make sense to which terminals the single wires were going to.  You would have a single wire going to each positive and that setup is in series, so the conclusion I came to was it wasn't a balancing arrangement. 

 

You are also correct,  without the full story, we are only guessing. 

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Back to the idea of replacing the xantrex and balmar monitor with the Victron BMV712. I had a look at what I think is the charging controller ( https://photos.app.goo.gl/3TS1xD1L9eg8jWD8A ). I haven't had the time to trace the wires from the Balmar monitor, but I am guessing data Tx and data Rx go to the display?

 

Im guessing that whatever data is on that bus is propriety and integrate with the BMV712? That being the case will I loose some information ?

 

Cheers,

 

AG

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Finally traced wires from the Xantrex monitor. They go directly to the shunts.

 

Will trace the Balmar wires next then think about whether I can replace both monitors with BMV712.

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I did check the battery with a DMM - and it also read 13v. Engine turned over happily (its the starter battery).

 

Engine was not on during these tests, but the solar charger was probably putting something in.

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As IT says. Wait 10hrs at minimum, preferably 24hrs preferable before measuring Voltage.

A possible problem you have is called "Surface Charge". More common with Deep cycle, but still possible with a start Batt. This is when the surface of the plate has a charge, but the depths of the plate does not. It can give you a false reading and the reading can even be higher than normal, suggesting the battery is really good, when in fact it is not. There are several reasons why surface charge occurs. One is normal charging coupled with Time. A Chemical reaction is what produces current and current fed back at charging creates the opposite chemical reaction. Plates have a thickness. Very thick for Deep cycle, not so thick for starting and the chemical reaction is thus much slower to take place in the depth of the plate. This is why a good battery monitor that does the calculations for charge replacement is essential. A simple monitor that tallied the current out and summed it against current back in is next to useless. A Voltmeter is eve more useless.
By allowing some time, as IT has said, allows the charge to settle deeper into the plate. The resting Voltage will decrease as this happens. 10hrs will give you OK accuracy. If you are wanting high accuracy, you need to allow 24hrs.

Another way to wipe Surface charge is to turn on a load or wind over the starter for 15seconds or so.
For a failing battery, you may very well get  good voltage reading just after charging has finished. But the battery is flat the next day or does not last long when turning over the starter or what have you.
There are some chargers on the market that have an automatic feature when on shore power, that if the Bank has been in float mode for some weeks, the charger stops charging and applies a load to start a discharge cycle for a short time. Then the charger will go back into a bulk charge cycle again and ck to float. This is because another form of Surface charge can take place. The internal depth of the plate loses charge while the surface of the plate remains at a full float Voltage. By discharging, the surface charge is removed and then the battery can undergo a proper full charge again. If this is not done, then you could go to the boat at the end of winter and find the battery has little to no capacity, even though a Solar panel or shore charger may have kept the Battery all tickity boo all winter.

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Measuring SG (specific gravity) is a very accurate way to measure the state of charge and as Lateral has said, can be done without having to wait.  However, do be aware that there are many cheap Hydrometers on the market and it is hard to find a "real" one. If you do, they can be expensive. They can also be a tad tricky to use giving a bad result if you do not know what you are doing. There are also temperature compensation sums to do if you are wanting highly accurate readings.

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So to check Health, disconnect battery from all loads/charging. Read voltage and then wait 12-24 hours and read voltage again? THe closer the two readings the better??

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