OK - I thought he was trying to do a top balance, which will be better a bit higher than 3.45, but not over 3.65V
Upgrading 15s Battery to 16s
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OK - I thought he was trying to do a top balance, which will be better a bit higher than 3.45, but not over 3.65V
boarder2k7
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@SeaGal I am nominally doing a top balance.
I have about 0.25 V drop across the wires since finding some appropriate washers to clamp down on some wires.
Multimeter on the cell is reading 3.4 V with the PSU currently supplying 3.65 V at 5 A. If I drop the PSU to 3.45 V current drops off to 1.5 A.
Sounds like I'm done then?
I have about 0.25 V drop across the wires since finding some appropriate washers to clamp down on some wires.
Multimeter on the cell is reading 3.4 V with the PSU currently supplying 3.65 V at 5 A. If I drop the PSU to 3.45 V current drops off to 1.5 A.
Sounds like I'm done then?
sunshine_eggo
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No. You're at 3.40V @ 5A.
boarder2k7
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My BMSs finally arrived!
Still no word from Eve if I can put those cells sideways.
Can anyone recommend a good crimping tool for these wires? Looks like JK used 7 awg which is odd. I think I'm looking for one of those v notch type crimpers so it can do varying sized rather than a die based crimper. The v ones seem more flexible.
Still no word from Eve if I can put those cells sideways.
Can anyone recommend a good crimping tool for these wires? Looks like JK used 7 awg which is odd. I think I'm looking for one of those v notch type crimpers so it can do varying sized rather than a die based crimper. The v ones seem more flexible.
I am not a fan of putting these cells sideways.
Creates a situation where the valve CAN leak.
Battery cells should point straight up...
I just redid my 4 big 200ahs.
Details in this thread with pictures:
https://diysolarforum.com/threads/d...nd-re-cabling-since-first-installation.77721/
Creates a situation where the valve CAN leak.
Battery cells should point straight up...
I just redid my 4 big 200ahs.
Details in this thread with pictures:
https://diysolarforum.com/threads/d...nd-re-cabling-since-first-installation.77721/
boarder2k7
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Understood, but with the cells I have I don't have a choice, they're too tall for the rack case.
I can search for other cells but if I can get away with laying the EVE cells down that's best as I already have them.
Can the rack case stand so the cells are upright?
boarder2k7
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That would mean that all the factory cells were on their side.
As it sits right now, either the 1 Eve cell will be on its side, or the 15 original cells would be.
boarder2k7
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Battery hookup just told me it's okay to lay the cells on their sides so I'm going to try that assembly method.
boarder2k7
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Bumping for visibility
Any recommendations for a good v style crimper? I'd like to avoid having to collect a lot of different dies
Any recommendations for a good v style crimper? I'd like to avoid having to collect a lot of different dies
boarder2k7
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Oh my goodness I just went to move the working original BMS from the fully charged battery on to the damaged battery, and discovered that the cells in the two batteries are installed opposite of each other!! Same cell arrangement in the case, but one was built in each direction so one has the positive in the front right, the other the negative. Super weird and something to look out for with these no-name batteries apparently.
Working on charging this one up and will then add the 16th cell and the JKBMS to both and get them fully charged and balanced.
Looking towards crimping tools again, do we think there is really any difference between the dozens of clones of this on amazon? I just picked one with a higher number of reviews than the rest. https://www.amazon.com/gp/product/B097YDWDLN/
Working on charging this one up and will then add the 16th cell and the JKBMS to both and get them fully charged and balanced.
Looking towards crimping tools again, do we think there is really any difference between the dozens of clones of this on amazon? I just picked one with a higher number of reviews than the rest. https://www.amazon.com/gp/product/B097YDWDLN/
boarder2k7
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Okay, finally got all the parts in and got the first battery set up with the JKBMS. I'm getting an error that the cell count is not equal to settings. I changed the settings to 16 cells, however the BMS is only showing 15 cells. I have double checked my connections and the black wire goes to the far negative, then one wire per cell positive through the rest of the pack, with the ultimate positive on the BMS also connected along with the last balance lead to the most positive part of the pack. I checked continuity from the connector to the positive of the 16th cell and I have a good connection both from the balance line and the final positive line. None of the voltages are showing anything strange like when one of the balance leads came off with the old BMS and caused one cell to be "missing" and the next cell to read double voltage.
Any thoughts would be appreciated.
Any thoughts would be appreciated.
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boarder2k7
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No that anyone here seems too interested anymore, but I figured out my issue.
I had dutifully gone through and connected one balance lead to each battery post, and missing the fact that since I have one battery that wasn't part of the welded together pack, I have two posts for "one" cell in the pack. I had connected 17 balance leads to 16 cells. Coming back with some more sleep and a fresh head is good!
The pack is now showing up properly and is in the process of it's first charge. The new cell is at a higher voltage than the rest of the pack so the balance function will have some work to do. Hopefully by tomorrow it will have leveled itself off. The balance wire resistance is higher than I would have expected, but it is equal for all the cells so I guess I'm not going to worry about it.
Next step will be ordering the Victron SmartShunt and finding a suitable load so I can capacity test this thing, then on to the second battery.
Am I going to get significantly different results if I load test at a rather low rate compared to running 20A or more? Not sure how much I can manage before buying an inverter.
Also noting that Eve did eventually get back to me (they were closed for new-years) and they said it was fine to mount the cells in any orientation as well.
I had dutifully gone through and connected one balance lead to each battery post, and missing the fact that since I have one battery that wasn't part of the welded together pack, I have two posts for "one" cell in the pack. I had connected 17 balance leads to 16 cells. Coming back with some more sleep and a fresh head is good!
The pack is now showing up properly and is in the process of it's first charge. The new cell is at a higher voltage than the rest of the pack so the balance function will have some work to do. Hopefully by tomorrow it will have leveled itself off. The balance wire resistance is higher than I would have expected, but it is equal for all the cells so I guess I'm not going to worry about it.
Next step will be ordering the Victron SmartShunt and finding a suitable load so I can capacity test this thing, then on to the second battery.
Am I going to get significantly different results if I load test at a rather low rate compared to running 20A or more? Not sure how much I can manage before buying an inverter.
Also noting that Eve did eventually get back to me (they were closed for new-years) and they said it was fine to mount the cells in any orientation as well.
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boarder2k7
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Alright, capacity test on the first pack is in! 102 Ah, 5.3 kWh. Looks like I really scored with this purchase!
One thing that is curious to me however is the discharge curve I'm seeing. All the cells were in lockstep voltage wise up through about 80 Ah of discharge, at which point the brand new 100 Ah Eve cell started falling behind the unknown 100 Ah cells in the pack, finally ending with that cell triggering the low voltage cutoff at 2.6V while the other cells were still around 3V.
I'd be interested to hear any thoughts anyone has, could it be that the unknown cells in this battery are just punching above their weight?
The BMS is off by a bit because it was reading a 3A discharge while the load tester was pulling 3.3A, I'll have to calibrate that in the future. The last picture is just starting to recharge.
One thing that is curious to me however is the discharge curve I'm seeing. All the cells were in lockstep voltage wise up through about 80 Ah of discharge, at which point the brand new 100 Ah Eve cell started falling behind the unknown 100 Ah cells in the pack, finally ending with that cell triggering the low voltage cutoff at 2.6V while the other cells were still around 3V.
I'd be interested to hear any thoughts anyone has, could it be that the unknown cells in this battery are just punching above their weight?
The BMS is off by a bit because it was reading a 3A discharge while the load tester was pulling 3.3A, I'll have to calibrate that in the future. The last picture is just starting to recharge.
sunshine_eggo
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Which is more accurate, the BMS or the load tester?
boarder2k7
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I couldn't actually tell you. I assumed that the BMSs needed cal as I've seen a few posts about it. I don't trust my clamp meter down to readings that low so didn't verify past it being in the same ballpark.
I should probably just buy the SmartShunt.
Currently recharging and the Eve cell is still the lowest in the pack, balance hasn't kicked in yet.
Very surprised that the nameless cells outperformed the Eve which is supposed to be 105 Ah but if I believe the BMS only provided 93 Ah as tested.
boarder2k7
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I just fed my benchtop power supply through an RC wattmeter into the load tester. All aligned within a few milliamps, so the BMS calibration is off as I suspected.
Looking around some more on calibrating the current I found one reference that alleged to have talked to a JK engineer who said the current measurement isn't very accurate under 10 amps, so that could be my issue right there.
I guess that means I likely have a functional 102 Ah pack, with some extra leftover in the original cells that are based on voltage readings punching well above their weight as supposedly 100 Ah cells.
sunshine_eggo
Happy Breffast!
Many BMS become downright worthless at < 2A.
What voltage did you finally top balance the cells to? Should be 0.1a at 3.55V then rest, and ALL cells need to reach this.
You can charge to 3.45, but you need to hold the amps down to 0.01a to achieve full charge.
3.65 also works, if the amps drop below 1A
boarder2k7
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On initial charge before installing the BMS I took everything up to 3.6V each (the original 15s pack and the 1 new Eve cell) and then let it settle. Recharged with the BMS installed up to 56.5V, so 3.53/cell and let the BMS finish balancing down to 0 mA.
Should I have done something differently?
The cells stayed balanced within 4 mV up until the end when the new Eve cell tanked and the original 15 still looked like they had plenty of room left in them to discharge.
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