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  1. J

    Cable Wire Resistance

    When I first started buying wire I was buying the cheapest which was usually copper clad wire CCA (they usually call it speaker wire), that wire corrodes easily, the one to buy is pure copper OFC wire (oxygen free wire) they call it welding wire or primary wire. Now I only buy OFC wire its...
  2. J

    Li-ion retirement?

    Some balance chargers will balance at too slow rate. I had an ISDT balance charger that balanced at 1 amp and it wouldn't balance my 220ah lifepo4, it would keep shutting down. I also tried the balance charger on a smaller 3s10p li-ion battery that was out of balance and it would also shut down...
  3. J

    Li-ion retirement?

    Something you can do is get active balancers and continue to use the pack that way. I been using a 220ah 4s lifepo4 for almost 5 years with active balancers. Without the active balancers 1 cell was always full before the other 3 cells, with the active balancers they reach full at the same time...
  4. J

    Why not just charge lifepo4 to 3.4v

    I been charging my 220ah lifepo4 to 3.65 everyday for almost 5 years. I prefer 100 percent everytime, it doesnt seem to affect anything on my battery which is still performing as when it was new. But I rarely use more than 50 percent of the battery. From my own experience charging to less than...
  5. J

    Charging cable off battery the thing that clicks into charger exploded

    can you post a picture of what exploded.
  6. J

    Active balancing need to be done while charging?

    I have a 4s active balancer on my 220ah lifepo4, I've kept them connected 24/7 for the past 3 years during charging and discharging. On my battery it goes out of balance quickly thats why I use the active balancer instead of trying to find the bad cells (160 cells total). This is the picture of...
  7. J

    Giant's "fire blocker" battery design

    I seen videos before of NASA also doing tests on lithium cell batteries being encased in cylinders holders similar to the ones mentioned. On the videos I saw, when a cell caught fire it was from the ends and the casing did prevent the other cells from catching fire. But on the test I saw the...
  8. J

    Could a cell explode?

    I always wear safety glasses when working on the cells, no need to buy expensive glasses even the cheap ones from the dollar store is better than nothing. The more expensive glasses have better clarity. The biggest hazard is flying pieces when taking cells apart, I once had a sidesnip cutters...
  9. J

    Cell Weight as a measure of quality

    for new cells I would just use an IR tester, that will weed out the weak ones. Some cells pass the capacity check, self discharge and still have high IR. Cells with high IR will cause balancing issues later on. I myself wouldn't waste my time building a battery pack without testing the IR. Even...
  10. J

    hi i bought a cellphone energy bank and they say charge it to 100 on first use?

    I charge my powerbanks to 100 percent and they have last me for years. You only keep them at half charge if you won't be using it for a long time. If you only charge them to 90 percent they might last longer but then you have to monitor while charging. To me its not worth the hassle, like my...
  11. J

    Charging a lion pack that has a BMS

    Any solar controller that you can adjust the bulk voltage setting is compatible with Li-ion, as long as the bulk setting can be adjusted to the voltage you need. All controllers are cv/cc which is what lead,li-ion and lifepo4 need. As far as voltage the only difference between li-ion and lifepo4...
  12. J

    Charging a lion pack that has a BMS

    Until everything is tested to work as advertised, the BMS, the solar controller, it would be a good idea to use an overvoltage protection relay to monitor the battery voltage and if the voltage gets to high, the protection relay will disconnect the solar panel. Thats how I run my solar system...
  13. J

    Charging a lion pack that has a BMS

    If you have a 10s li-ion 36 volt battery pack ( 4.20 volts x 10s = 42 volts) , 42 volts is the max you want the charger never to go over. In your situation you will use the "USER" setting of the rover controller and set the boost voltage to 42 volts or less, same with the overvoltage disconnect...
  14. J

    BMS and parallel batteries

    I would not recommend charging lithium with solar, unless it was a very slow rate where there is no situation where the BMS will ever activate. If the BMS ever activates while charging lithium, the solar controller will try to forcibly charge the battery, causing voltage surges which can damage...
  15. J

    How to charge an AGM battery without using an AGM battery charger?

    I have an odyssey 3 year old 16ah agm and also a 11 year old fullriver full throttle 27ah agm. I just charge them as a regular lead acid battery constant voltage/constant current at 3 amps. The only thing you need to pay attention too is the recommended bulk voltage. Some high performance agm's...
  16. J

    best order for cells with different voltage/ internal resistance

    The IR on your cells are all over the place. If they are from the same Manufacturer they will be very similar in milliohms. I also recommend one of the yr1030's they will give you more accurate "repeatable" results. All it takes is one bad cell (high IR) to give you balancing issues down the line.
  17. J

    What kind of safety measures do you take when building battery at home?

    For me the dangerous part is taking cells apart, thats when there is risk of shorting out cells. The only fire I had was when I was taking a battery pack apart and the cell shorted out causing a hole in the cell. This set off a fire. Pouring water was enough to to keep the fire from spreading...
  18. J

    My DIY 48V 16Ah battery cuts out at 47 Volts

    You have an issue with 3,4 and 5 those 3 are at about 4.00 volts, all the other cells are close to 4.20 volts. If you isolate those 3 cells you can probably charge them to 4.20 with the opus by running wires from the opus to the cells. That's how I charge large cells that don't fit on the opus...
  19. J

    My DIY 48V 16Ah battery cuts out at 47 Volts

    The problem with the opus when checking IR is that if you check the same cell 5 times you get a different result everytime, plus they also always read higher than they actually are. Also for a high discharge cell you should be aiming at under 40 milliohms (those would be high quality panasonic...
  20. J

    My DIY 48V 16Ah battery cuts out at 47 Volts

    When you built the pack did you check the internal resistance of all the cells before you put them together. If you got some High IR cells in there that will cause problems. When I first started building packs I never checked the IR of the cells and my packs usually had problems which I could...
  21. J

    Mystery charger performance ?

    are all the wiring for the engine shutdown detection correctly wired up? You can try and do the manual engine shutdown override, to see if you get power to the aux battery. I notice in the manual if the wiring isn't properly connected to detect if the engine is running, no current will flow.
  22. J

    cheap spot welder, moddable?

    The maletrics (version 1) I got about 4 years ago I paid 90 dollars for it. It has worked good. I had to buy my own 6 gauge cables (about 20 dollars) . It was an expensive purchase but I had to spot weld the nickle strip since the soldering wouldn't stick to the lifepo4 cells I was building. The...
  23. J

    cheap spot welder, moddable?

    One mod that you can do is probably use thicker gauge wires for the probes. When you do your welding do the probe cables jump around as you do the welds and get very hot? that would be sign the cables are too thin. I have a larger 12 volt malectrics spot welder and when I first got It, I was...
  24. J

    Does an MPPT solar controller have ripple in the output

    I charge 3s li-ion and 4s lifepo4 with my ecoworthy 20a mppt and also a makeskyblue 60a mppt. I never notice any ripple or pulsing, to me it seems like just any other charger. It won't affect longetivity, my lifepo4 is going on 4 years being hooked up and charged daily with mppt, the li-ion is...
  25. J

    what is the size ratio of li-ion vs LiFePO4

    here is a picture between a 10ah lifepo4 and a 31ah lifepo4. Both take up about the same space and weigh about the same. They are recycled cells, new cells would be about 15ah for lifepo4 and 41ah for the li-ion.
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