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  1. electrodacus

    Yet another BMS

    This is a great project. I wast thinking I'm the only one working with ISL94203. My project is for my offgrid house and it suports up to 40A charge and 80A discharge. I even had a small kickstarter campaign for this project search for Solar BMS or SBMS4080 if curios. It is open source. I just...
  2. electrodacus

    LiFeMnPO4 charge and discharge

    I see this is almost two months old but have you seen my youtube videos there are also charge discharge curves for the 100Ah GBS cells. I also have a comparioson with the A123 Systems the 20Ah For an electric bike I will say A123 Systems are superiors by far do to their low internal DC...
  3. electrodacus

    BMS assumptions - have I got this right ?

    Thanks for this. It seems like a nice IC quite similar with what I use but mine is newer from a larger manufacturer and has some additional futures but I can see where they got their inspiration from. Not sure how I was not able to find this when I did my research last year. I fount probably all...
  4. electrodacus

    BMS assumptions - have I got this right ?

    This BMS is different form what I have found when I searched there. So I will need to apologise. That one had I2C and was called smart but the I2C was used just for monitoring and had fixed thresholds at 3.9v like the one OP has. I will take a look at this one but is clear that it has a...
  5. electrodacus

    BMS assumptions - have I got this right ?

    Most BMS/PCM on the market today sold as LiFePO4 are not design to charge LiFePO4 they are just sold as such is not true for those large one that have individual cell monitors mount on the cell and have programmable thresholds. I have two of them different models both use the same SOT23-5 chip...
  6. electrodacus

    BMS assumptions - have I got this right ?

    I was on that website and I cheeked the spec the smart one it was referring to dose not seems to have custom lvc and hvc and the limits are set at 4.2V. I also checked all other BMS on that website and did not found any that will work for LiFePO4. Can you provide me with a link or model of BMS...
  7. electrodacus

    BMS assumptions - have I got this right ?

    That BMS seems to be fine but is not for LiFePO4 is for LiCo so charge ends at 4.2V for that it will work as advertised I guess I did not try. But OP needs a BMS that works with LiFePO4.
  8. electrodacus

    BMS assumptions - have I got this right ?

    This BMS that OP uses has some small IC that detect over voltage at 3.9V and if you look at the spec of this IC you will see that they where designed for LiCo the military threshold for long life on LiCo. Get me a link to that Singlab or model number to take a look maybe that is better and uses...
  9. electrodacus

    BMS assumptions - have I got this right ?

    The shut resistor is only 70mA in order for that to be able to keep your cell at 3.6V the charge current will also need to be 70mA or less. I do not think you want to wait that much for a charge :) Actually this BMS that you have will work fine on LiPo with the exception that the cells will be...
  10. electrodacus

    BMS assumptions - have I got this right ?

    You are probably right but people should also read what is around the graph. Cell will get unbalanced especially in high discharge applications so almost always there will be one cell that will get to 3.9V especially with so many series connected cells and small capacity. I have 3 different...
  11. electrodacus

    BMS assumptions - have I got this right ?

    There is no solution at lest not a cheap an not complex solution to build a BMS for LiFePO4. The LiFePO4 is not mainstream except for a few DIY guys and two or three power tools there is not much use for this type of battery at the moment. They do not care that you will damage the battery in a...
  12. electrodacus

    BMS assumptions - have I got this right ?

    On eBikes you use high discharge rates so the cells will become much easier unbalanced. If you have very large packs with very low discharge rate like 100Ah 0.5C then that imbalance will not be so high. I think I mentioned but the fact that this 3.9V BMS exist is because the chip a small sot 23...
  13. electrodacus

    BMS assumptions - have I got this right ?

    What compromise ? At 3.9V the damage will be quite fast just a few charge cycles depending on battery and how tolerant it is to overcharge and how unbalanced the pack is. But with a good BMS that cuts the charging at 3.6V most LiFePO4 batteries will last for thousand of charges so at least 5 to...
  14. electrodacus

    BMS assumptions - have I got this right ?

    That so called BMS is not good for LiFePO4. I just looked at the spec and overcharge detection voltage is set at 3.9V and overcharge release voltage set at 3.8V this levels will damage quickly any LiFePO4 battery. Limits for this should be 3.6V / 3.5V
  15. electrodacus

    BMS assumptions - have I got this right ?

    Those stupid BMS are not designed for LiFePO4 even if they are sold that way. They use a small individual IC that is designed for LiCoO2 the military version for long life is set at 3.95V. This chips have fixed thresholds can not be modified. For LiFePO4 even 3.6V is a bit of a stress as it is...
  16. electrodacus

    iCell...New Bluetooth / cellphone cell monitor

    Well with the Solar BMS you do not even need to check the phone it will take care of charging, balancing and data logging. There is no alarm so you can sleep :) .
  17. electrodacus

    Cellog 8S display goes blank

    Those celllog 8s are quite bad. I have two of them BVM-8S. I made a video on how to reduce the power consumption by about 2.5x but is still bad. It also using power just from the first two cells so it will unbalance the cells substantially. It was using 31mA before modification that is huge. I...
  18. electrodacus

    iCell...New Bluetooth / cellphone cell monitor

    I see a lot of interest in bluetooth enabled devices. Dose it make sense to add bluetooth to my Solar BMS? The BMS already has an LCD where all info are displayed and data logging capabilities. Also not sure exactly how much it will add to power consumption. My BMS right now only uses 25mW with...
  19. electrodacus

    Is 24V (500W) enough for eBike?

    :) You should watch the 3D animation then EZt1oJ3n7jY
  20. electrodacus

    Battery comparison for energy storage. What bat to include?

    Shipping seems to be a real problem with Lithium. I got my A123 cells form China delivered by Canada Post. The large 100Ah 8 cell GBS where from a small company in Canada delivered with Canada Post in a heavy wood box. I think each city should have his own battery manufacturing plant same for...
  21. electrodacus

    Battery comparison for energy storage. What bat to include?

    Thanks for this. I did not know about this guys. Where can you get this cells?
  22. electrodacus

    Battery comparison for energy storage. What bat to include?

    Lead Acid will vent Hydrogen even the sealed ones so it not legal or safe to have them without venting in a house. Actually the price of the ones in your link is the same as what I have payed two years ago on my A123 20Ah cells you just get the charger that is of no value to me and I'm guessing...
  23. electrodacus

    Battery comparison for energy storage. What bat to include?

    Most build over sized Lead Acid battery banks for many reasons. One they do not like high discharge rates under 0.2C usually then they do not like high DOD usually much less than half the available capacity. So with a good deep discharge Lead Acid battery that can do 500 cycles at 50% DOD and is...
  24. electrodacus

    Windturbine: 6X More Efficient and Much Cheaper

    :) You can know from the title is just not possible. First a traditional vertical wind turbine will get over 40% efficiency and that is really close to the max theoretical efficiency Benz limit of 59% So not even 2x is possible. Then this turbine will be way less cost effective maybe by a...
  25. electrodacus

    Is 24V (500W) enough for eBike?

    Is there a need for 8S BMS for an eBike? Why do I ask? I have designed a 8S Solar BMS for my off-grid house. It is fully programmable so it can work with any type of Lithium cells (ex LiFePO4,LiCoO2....) It has an LCD so you can monitor all cell voltages, current, power, energy, remaining...
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