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  1. H

    Lishen 270ah-272ah cell group buy.

    I got my tracking numbers from Michael on 11-June (Fedex says the number was assigned on 9-Jun), and I see no movement yet.
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    Lishen 270ah-272ah cell group buy.

    I'm really confused how these power supplies go crazy like this. I've got four benchtop power supplies: 3 pretty cheap ones and one mid-range. I've not seen this happen. I was thinking though - I almost always have at least two of the four supplies in parallel for any charging I'm doing. I...
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    Batt go BG-8S issues

    Hooking the cells together is not top balancing. Search the forum resources for how to top balance. Top balancing makes sure the cells are all at the same state of charge near the highest. Cells can be at the same voltage but not the same SoC. It's pretty important to do top balancing (or...
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    Batt go BG-8S issues

    Does your multimeter indicate that cell #8 is not below 2V? If the cell measures fine except on the BG-8S, I would first suspect the connection of the balance lead to that cell. If that is not the problem (on either the cell end or the JST connector), it may be something wrong with the BG-8S...
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    Can anyone recommend a good mid-range bench power supply.

    Hopefully someone will notice what I posted a few back: Circuit Specialists sells the same power supplies as TekPower (or at least they look the same) and are much cheaper. At least the one referenced is much cheaper.
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    Can anyone recommend a good mid-range bench power supply.

    The TekPower power supplies seem to be re-branded versions of the Circuit Specialists ones (or vice versa). I have a different model from circuit specialists and it seems generally OK.
  7. H

    Danger Will Robinson, solar power can kill you!

    Well, in fairness, they could be only referencing the Netflix remake (circa 2018).
  8. H

    Lishen 270ah-272ah cell group buy.

    No, a balance charger is not going to top balance. At least not the ones I've seen. It will stop once all the cells get to the voltage you have set, rather than continue until the tail current drops down low. Like I said here...
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    Lishen 270ah-272ah cell group buy.

    Not to be to much of a stickler, but for doing balance charging, it DOES NOT matter much where you have your positive and negative leads. You are driving all the cells to the same voltage and the current will eventually drive to near zero. So no difference. People get confused because when you...
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    Difference between a full and empty battery is 1 volt ?

    One problem is that the voltage is not a very good indicator of SoC (State of Charge) for lead acid batteries. For flooded lead acid, checking the specific gravity of the electrolyte is considered to be the best indicator. If you don't have flooded lead acid batteries, there isn't such a good...
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    Question about fusing 2 battery’s in series

    I can't really tell much from the pics, but it doesn't matter. I would definitely put at least a fuse on the most positive post. Something like this would work, although you may want a 100A or 200A instead of the 300A fuse. If there is distance between the two AGMs and the lead from one to the...
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    Top Balancing "How to"

    The voltage displayed by these cheap power supplies is virtually meaningless. Do you have a good multimeter? If not, get one. If so: With everything disconnected from the power supply, set the voltage looking only at the multimeter. Ignore the PS display. Periodically check the voltage on the...
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    1 out 4 LiFePo4 cells is failing? Next steps?

    Like I said, to do a true top balance, you need to break up the pack and put them all in parallel. Then charge them at 3.65V (or 3.6V, or 3.55V if you wish), and continue until the current drops to near zero (maybe 1A in your case). A balance charger will try to get all the cells to the voltage...
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    1 out 4 LiFePo4 cells is failing? Next steps?

    I'm pretty sure he is talking about using a balance charger, like the iSDT Q8 or equivalent. These are chargers that also have balance leads, and they attempt to balance the cells in place (in the serial pack) while charging. My experience is that these would not be a good way to top balance...
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    can i upgrade a 280A battery bank with a 200A battery

    First off: : I may be misinterpreting your photo, but it looks like you have cells of different capacity in each row. That seems to be inherently a bad idea. You intentionally have a mismatch in cells. Things are going to charge very inconsistently. In your case I would definitely break that up...
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    Chargery Shunt Installed on Positive Lead?

    I should add: I was giving you a general answer about shunts. I know nothing about the Chargery shunt, but I would assume the sense leads to the shunt (for measuring the very small voltage across the shunt) would have to be in the right polarity, which would change between the two places you...
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    Chargery Shunt Installed on Positive Lead?

    For a regular dumb shunt, it really could be on either the positive side or the negative side. The standard is to put it on the negative side, primarily because many systems may have lots of paths out from the battery, but a common ground back to the battery. Think for example about a car. Most...
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    Chargery Shunt Installed on Positive Lead?

    I tend to think the same way. Shunt on the positive side just hurts my head. However, the Thornwave Labs Powermon-5s shunt (somewhat of a competitor to the Victron Smart Shunt) has to be put on the positive side.
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    BMS common port vs seperate port

    For LFP you should disable the temperature compensation. The RTS (remote temperature sensor) is used by the charge controller to raise the voltage in colder temps, as @HRTKD said. The compensation value (volts per °C above 25°) should be set to 0mV for LFP. The Outback charge controllers do...
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    Lishen 270ah-272ah cell group buy.

    Glad you said that. I was about to mention (as I guess I've mentioned lots of times on this forum): You can't assume "truth" in a difference in voltage of 3.279V and 3.272V unless you have a pretty good meter. If you don't pay the money for a good meter (>$200 not uncommon for a good Fluke), you...
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    can i upgrade a 280A battery bank with a 200A battery

    There's a pretty thorough discussion here about putting two packs of different capacity in parallel. I think the bottom line is that there are several people who are making such a parallel system work. My gut EE sense would be that it would be best to have the banks somewhat close to each other...
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    Why is mppt better than pwm?

    So you seem to be saying that partial shading doesn't lower the output voltage if you are using PWM? For PWM, the panel voltage needs to be close - but a little above - the battery voltage. So if partial shading lowers the output voltage of the PV, it seems to me that it would cause the the...
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    Lishen 270ah-272ah cell group buy.

    I don't want to cast dispersions on Overkill. Steve @ Overkill has been great, and I hope he gets back on his feet. However, right now things don't seem well there. He's not been responding to customers (there are some posts here, but I don't have the link), and when I sent him a note last week...
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    Why is mppt better than pwm?

    English is my only language. I'm not sure what you said. No offense, but... What are you saying?
  25. H

    Please help to decided Mpp solar or Schneider

    Sorry. I was just having some fun. Didn't mean to offend you.
  26. H

    Please help to decided Mpp solar or Schneider

    Hey @Leo777 - You should get a keyboard with a working period key. Just sayin. :)
  27. H

    Please help to decided Mpp solar or Schneider

    I've got experience with Schneider. On the plus side, Schneider equipment is rock solid and built to support professional installers and commercial applications. That results in the complaint that lots of people have with Schneider: They no longer are interested in supporting DIYers. Their...
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    the easy way to keep your cells balanced is...active balancing

    No, it wouldn't cause a spark. The underrating that @snoobler is talking about is that there is more than 5W going through the resistor, if only for a fraction of a second. For your 24V system, the resistor is getting a bit under 12W. If you did that continuously, the resistor would probably pop...
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    the easy way to keep your cells balanced is...active balancing

    Don't be hard on yourself - Your math was actually correct: 48 * 48 / 5 = 460 watts. So if you actually do use a 5 ohm resistor, it will be carrying 460 watts for a tiny fraction of a second. You just don't need to use a resistor that small. So Jim Beam did you good! (But use a bigger resistor...
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    the easy way to keep your cells balanced is...active balancing

    I don't know if that is a typo, but a 500 watt resistor is way bigger than is easily available. You can get them, but they are very costly. I think people over-do how small a resistor they use. The idea is to charge the capacitors in the front-end of the inverter, and that won't really take too...
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    the easy way to keep your cells balanced is...active balancing

    I believe that some people leave the BMS balancing turned on even though they have an active balancer. In my experimental hook-up, I've disabled the BMS balancing operation while testing the active balancers from QNBBM and Heltec, and that works fine. I think in my system I will leave the BMS...
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    the easy way to keep your cells balanced is...active balancing

    The OKS BMS (and most BMS's) is only a passive balancer. That means that it only burns off the power in the highest cell. In the case of that particular BMS (and again, most) it is not capable of burning off much. Something like 200mA max. That isn't enough to get these big 200Ah+ cells balance...
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    pwt versus mppt

    I assume you mean PWM rather than PWT. If you use PWM, the voltage coming in to the charge controller needs to be pretty close to the voltage of your battery. For MPPT, the voltage can be much higher than that of the battery. So with PWM you lose the ability to use the larger panels that are...
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    JBD BMS USA Inventory - Is there Community Interest?

    Dexter / @HighTechLab - A have a small suggestion. I know you have some highly accurate equipment. If you have a really good calibrated voltmeter, I'd suggest you calibrate each BMS. I have a rather expensive Fluke, and found that my BMS from Overkill was off a fair amount on two cells. Then...
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