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  1. M

    BMS cut off , one unbalanced cell

    Thanks, so when your battery gets to 14.2V during charging, what are the voltages and delta on your individual cells then?
  2. M

    BMS cut off , one unbalanced cell

    Well, you're right. I might seem fixed on this but to me it's quite simple . I set it up as per instructions (14.4v) and it doesn't not work as advertised. The battery cuts out even as low as 13.8V, an last time I spoke with Sterling they told me not to lower it anymore than 14.2V - the new...
  3. M

    BMS cut off , one unbalanced cell

    What is your absorption voltage, and what's your highest cell when you hit the absorption voltage ?
  4. M

    BMS cut off , one unbalanced cell

    No, if it's not reporting any incoming current, which it isn't below 5A on this battery (2A on the previous) then it's not balancing
  5. M

    BMS cut off , one unbalanced cell

    The battery is in the campervan so it's charged with solar, victron motto, 30A, but give the weather it's usually below 10A. So when the cell started running away(above 3.4V) i lowered current to 2A to give time to the BMS to balance. I couldn't lowered the balance start voltage much more...
  6. M

    BMS cut off , one unbalanced cell

    Ok so the Daily BMS has a icon which comes green when balancing takes place. The way the BMS is set on this battery is that it does not report any incoming or outgoing current if it's below 5A ( on the first battery it was 2 A). Simply put if you're charging or discharging battery with less than...
  7. M

    BMS cut off , one unbalanced cell

    The BMS I have balances with 35mA, how long would that take to balance 120ah cell? A LONG time! Apart from the fact that when the runner cell hits the balance start voltage (3.5V now but i tried with as low as 3.35V), then it only takes maybe couple of minutes before it gets to 3.75V. So 2...
  8. M

    BMS cut off , one unbalanced cell

    You can get the cells cheaper from china but you have yo wait like 2 months. There are UK based companies who buy them test them and sell with a next day delivery, that's why you pay extra. How much would you expect for a EVE 280ah cell?
  9. M

    BMS cut off , one unbalanced cell

    Yep, the battery is going back to where it came from - no doubt about it. I'm getting 280ah cells and a BMS and building it myself - something i had hoped I can save some time on by buying ready made unit. Where I live i can get 4 x 280ah cells for about 800 pounds plus about 150 for a BMS. If...
  10. M

    BMS cut off , one unbalanced cell

    Yeah and as few people on this forum suggested if on every single charging cycle the BMS cuts in(this is a safety feature not a "normal" way of operation) , it might eventually fail, and that is not good.
  11. M

    BMS cut off , one unbalanced cell

    The other thing which i wonder is how many people who buy a commercial battery actually check if it works as advertised? Wouldn't most people just connect it and if the light comes on then they're happy?
  12. M

    BMS cut off , one unbalanced cell

    Yeah, you would think that they will test the replacement thoroughly before sending out. The first battery i had was bought from a supplier, not Sterling directly, was actually better than the second one which was swapped directly by Sterling. Two batteries with one cell off - makes you think...
  13. M

    BMS cut off , one unbalanced cell

    I agree almost 0.4V delta is huge! You could balance cells this way or in many other ways but for that you need an access to the cells. Since this is a sealed unit there is not much I can do -that 35mA of balancing from Daly BMS won't do much in this century. This should have been done at the...
  14. M

    BMS cut off , one unbalanced cell

    Well, i got the battery replaced, the second has exactly the same issue plus it came in with misconfigured BMS ( completely wrong max discharge and charge limits), not detecting anything going in or out of the battery if it's less than 5A . As it is right now i have one runner cell which hits...
  15. M

    Daly Smart BMS “Discharging” while charging???

    I got the battery replaced and now it's not reading anything below 5A... Basically there is a setting in the BMS (don't remember the exact name) where you can set it(don't know what th minimum value is though), but you can't do it over the Bluetooth, you need to connect the PC, so if you have a...
  16. M

    Daly Smart BMS “Discharging” while charging???

    ok, so I got the battery replaced today, as it came it at 45% charge it's still charging so we'll see how well balanced the cells are this time. In a mean time I've noticed that the BMS(Daly) is not reporting "Current" (charging / discharging) unless is above about 10 A. I was getting about 16A...
  17. M

    Daly Smart BMS “Discharging” while charging???

    If my math is correct your equasion gives roughly 128 days of constant balancing, of course it will be much much more in practice since it only balances when charging and with at least 2A current.
  18. M

    Daly Smart BMS “Discharging” while charging???

    So what's the point of having it to begin with, especially on a high capacity cells if it can do pretty much nothing at all?
  19. M

    Daly Smart BMS “Discharging” while charging???

    Could you explain how do you calculate the balancing delta on a given cell with 35mA? what would be the "rate" of change on a cell with a given capacity i.e. 120Ah? Thanks
  20. M

    BMS cut off , one unbalanced cell

    Is there a way to work out what the optimal float V is? I'm planning to live in the camper full time and will have fridge running 24/7 and other appliances as well? Is it only about keeping the cells at given voltage(the voltage they "settle at" and avoiding them getting them constantly...
  21. M

    BMS cut off , one unbalanced cell

    What would that equate to in terms of reducing the delta between that one cell and the rest of them being currently at about 0.35V?
  22. M

    BMS cut off , one unbalanced cell

    Thanks again for the extensive answer. If you don't mind me asking what are your settings for charging(absorption) and float? Do you see any advantage of having higher charging voltage / float voltages? . As far as I know a "standard" settings for LiFePo4 batteries is 14.2V absorption and 13.5V...
  23. M

    BMS cut off , one unbalanced cell

    Thanks, I've discharged it today to about 20% and charging it back up - it's the first substantial discharge cycle as it came at92% and was charged from there to 100%. Then I did couple of ones down to about 95%(I don't have much connected in my camper yet so it takes time unfortunately). If...
  24. M

    BMS cut off , one unbalanced cell

    Thanks guys, so what do you suggest then? The battery is brand new bought from a supplier not from Sterling directly and it is covered by 5 years warranty. I've contacted Sterling directly and they claim that the battery is well balanced and when the cells are at full capacity an one of them...
  25. M

    BMS cut off , one unbalanced cell

    Ah Ok now i understand, would you say something like 13.7v or 13.8v would be ok?(it trips at about 13.9V). Thanks
  26. M

    BMS cut off , one unbalanced cell

    I agree i don't have to use14.4v but at the same time i paid a lot of money for a brand new battery and I'm using parameters which are explicitly stated by the manufacturer (14.4v charge and 13.8v float). But of course i understand what you're saying. When it trips i have 13.9V ( 3x3.4 plus...
  27. M

    BMS cut off , one unbalanced cell

    I have tried that, the battery is in my campervan so I have two victron chargers, one DC to DC and one mppt solar on which i reduced the output initially to 1A. But then I realized the the balancing only works if it's more than 2A. So after settings it to 2A the same thing happened it just...
  28. M

    BMS cut off , one unbalanced cell

    The way it's set up in the BMS app(I can't change it without password which I don't know) is that the balancing starts when one of the cells goes over 3.5V. When this happens(on charging from anything less than 100%) it's a matter of minutes for that cell to go from 3.5 to over 3.75V and the BMS...
  29. M

    BMS cut off , one unbalanced cell

    So I've contacted the sterling and they basically claim that everything is ok, and it's a normal behaviour of the BMS to cut out the highest cell when the battery is fully charged (apparently 3.4V is a full state of the cells, and one with even the smallest deviation in capacity will reach the...
  30. M

    BMS cut off , one unbalanced cell

    Thanks guys, Makes sense, just thought I could balance it easy enough without going through the hassle of sending it back.
  31. M

    BMS cut off , one unbalanced cell

    I've just purchased a brand new Sterling 120ah lifepo4 battery and one cell seems to be quite severely unbalanced. On charging (14.4v as advised by battery data sheet) i have 3 cells at about 3.4 and one going over 3.75v which causes the BMS to cut off charging (see the attached). The difference...
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