Beccara 25 Posted May 1, 2019 Share Posted May 1, 2019 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 Quote Link to post Share on other sites
Ladyhawk 37 Posted May 1, 2019 Share Posted May 1, 2019 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 Quote Link to post Share on other sites
mcp 32 Posted May 1, 2019 Share Posted May 1, 2019 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. Quote Link to post Share on other sites
wheels 543 Posted May 1, 2019 Share Posted May 1, 2019 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. Quote Link to post Share on other sites
Ladyhawk 37 Posted May 1, 2019 Share Posted May 1, 2019 Looks like some sense wires for a bms going the terminals , but no signs of external large amp fusing... but hey without the full story its nothing but a guess... Quote Link to post Share on other sites
Dtwo 157 Posted May 1, 2019 Share Posted May 1, 2019 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. Quote Link to post Share on other sites
mcp 32 Posted May 2, 2019 Share Posted May 2, 2019 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. Quote Link to post Share on other sites
bigal.nz 59 Posted May 4, 2019 Author Share Posted May 4, 2019 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 Quote Link to post Share on other sites
bigal.nz 59 Posted May 11, 2019 Author Share Posted May 11, 2019 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. Quote Link to post Share on other sites
wheels 543 Posted May 11, 2019 Share Posted May 11, 2019 Should be same with the Balmar., The "sense" wires to these devices should come from the Neg cable Shunt so as charge and discharge is measured. Quote Link to post Share on other sites
bigal.nz 59 Posted May 26, 2019 Author Share Posted May 26, 2019 Can anyone explain why this is reading a healthy 13v but I only am showing 2 bars? https://photos.app.goo.gl/RDbw8a7DNtaPMBiX7 Quote Link to post Share on other sites
Beccara 25 Posted May 26, 2019 Share Posted May 26, 2019 Some kind of setup mode? Quote Link to post Share on other sites
bigal.nz 59 Posted May 26, 2019 Author Share Posted May 26, 2019 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. Quote Link to post Share on other sites
Island Time 1,235 Posted May 27, 2019 Share Posted May 27, 2019 Voltage is NOT an indicator of charge state unless the batts have been rested for 10+ hours. Rested means no charge, no draw. Quote Link to post Share on other sites
wheels 543 Posted May 27, 2019 Share Posted May 27, 2019 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. Quote Link to post Share on other sites
wheels 543 Posted May 27, 2019 Share Posted May 27, 2019 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. Quote Link to post Share on other sites
Island Time 1,235 Posted May 27, 2019 Share Posted May 27, 2019 And you cant use them on anything but flooded batts... Quote Link to post Share on other sites
wheels 543 Posted May 27, 2019 Share Posted May 27, 2019 Good point IT Quote Link to post Share on other sites
bigal.nz 59 Posted May 27, 2019 Author Share Posted May 27, 2019 Ok - good to know. I did start the motor but it starts fast, so that probably doesnt mean much. Another reason to get BM712. Quote Link to post Share on other sites
bigal.nz 59 Posted May 27, 2019 Author Share Posted May 27, 2019 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?? Quote Link to post Share on other sites
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