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  1. J

    Charge current for battery pack

    Charging at 0.25C definitely won't cause any harm. Honestly I'm really in no rush to charge, it's fine if it charges the whole day really as I'll pre-charge the day before use, while I am home. Yeah hopefully I don't get any bad cells :) I've let them sit for many days and they've all held...
  2. J

    Charge current for battery pack

    It would be 2C if my pack is 1P but it's 4P remember, so 0.5C. I won't be going any higher than that.
  3. J

    Charge current for battery pack

    Thanks for the info. My charge/discharge will be conservative. I will only be operating between 3.1v to 4.0v for now until I get a rough idea of how long this thing will last. As for charge rates, I will only be charging slow (well, recommended rates at least, 0.5c). The charger I have (x8...
  4. J

    Charge current for battery pack

    Thanks. This all makes sense. You are right, I should have used the full capacity charge rather than nominal. I'll be charging to around 4v or 4.1v max to prolong life, so total of 28.7v. Seeing I am only charging at 0.5c, then I think that means I will only need a PSU that does half the above...
  5. J

    Charge current for battery pack

    I have been looking more in to this and have came to the following conclusion: 4p = 12000mha (3000 * 4 Samsung 30q batteries are 3000mha) charge rate = 1.5A, or 0.5c, = 6A (1.5 x 4p) 7S = ~26v, so 26V * 6A = 156W Therefore as long as my PSU can output 156W then I'll be fine. Eg, I...
  6. J

    Charge current for battery pack

    Actually I just realised that the max charge current for that charger is 30A, so I'm pretty sure my calculations are incorrect.
  7. J

    Charge current for battery pack

    Hello, I have a question about charging current. Hopefully this is my last question regarding batteries(!) So I have two 7s4p batteries that I will be charging separately, and I'm trying to determine what current I should charge at. I have a hobby charger (icharger x8). All my cells are Samsung...
  8. J

    18650 vent at positive end of cell

    Ok cool, that's good (about the venting). I've weighed up the pros and cons of this setup and have not taken it lightly. The whole pack will be pretty tight. There will be hardly any vibration at all. It's for a (kids) quad bike which (he) will be going pretty slow. Once the magnets are all...
  9. J

    18650 vent at positive end of cell

    Hello, I am building (almost built) a battery pack (14s4p). I am using magnets to hold the nickel strips. To cut a long story short, how much of that "vent" can be covered up? I've seen battery packs have tape wrapped all around the battery and/or pack which looks like it has very little air...
  10. J

    Charging a 13s pack

    Thanks again. That gives me confidence. It's not the end of the world if it blows but will see how it goes anyway.
  11. J

    Charging a 13s pack

    Thanks amberwolf. I took some more pictures and had a look. It's still a bit hard to see. The black caps along near the fets it says 50v. There's a little red one near the battery that is 100v. There's also a 25v and 16v one but they're obviously irrelevant. I'll probably just try it and see...
  12. J

    Charging a 13s pack

    Ok I have opened up the controller and checked the FETs and capacitors. I will post pics. Is this something that could handle 14p?
  13. J

    Charging a 13s pack

    Yeah I can imagine. It would take some time to get over that completely, if ever. Hopefully there are no more unwanted events. Ok I understand. I have been looking in to this recently so I understand how they work now, how charging goes through phases, how it's constant current and voltage...
  14. J

    Charging a 13s pack

    Thanks for the reply. I went to bed after my last reply. I will reply properly later (don't have time at the moment), but I am 99% there, just my terminology on some things are lacking. Thanks. I always appreciate the time it takes for people to help out.
  15. J

    Charging a 13s pack

    Definitely new cells. I think I must have my definition of top balancing incorrect. I just thought that before they're all connected together, you want to get them all close to the same voltage as possible then parallel charge them to get them all roughly the same (balanced - I thought this is...
  16. J

    Charging a 13s pack

    Yeah I see you can get some cheap cell loggers for < $5, so I can put them on each group. I have a question about this though - so, lets say you set the low voltage alarm to be say 3.2v or something. If it goes below that, it will alarm. Ok that's great. But before you talked about when you have...
  17. J

    Charging a 13s pack

    Actually this guy https://www.youtube.com/watch?v=pljSZcEwc8Q explains exactly how I want my setup. Which is using the iCharger split up in to two separate batteries. Looks like it needs to be electrically isolated, so need to break the series connection. But that's no big deal, I can just have...
  18. J

    Charging a 13s pack

    Thanks again for the replies. Good point. I forgot that a fully charged battery outputs more voltage. I probably forgot exactly the same way I did in the other thread! I will double check this but yeah it's highly unlikely it's only 48v. I have already paired four 12v SLA batteries fully...
  19. J

    Charging a 13s pack

    So after all this I think the simplest thing to do is get one of these: https://www.ebay.com.au/itm/353154709819?hash=item5239a9393b:g:iX8AAOSwxONfM4qC these brands seem to be the most recommended around here and other parts, and are pretty cheap too. I will just get the 15A version as I won't...
  20. J

    Charging a 13s pack

    Thanks for the replies. I will try to answer them all. I have re-read this thread a couple of times and done some more research. It's slowly starting to sink in, I think... Sorry I meant to say that there aren't many that can balance charge. But yes plenty out there that will just charge...
  21. J

    Charging a 13s pack

    Hello, I am working on making a 13s4p pack for a quad bike. I understand how to make it and all that but when it comes to charging, I'm completely at loss. My plan was to just use a charger that can both charge and balance but then I realised there weren't really any (decent) chargers that can...
  22. J

    ATV conversion

    Yeah that looks good. I could work with something like that.
  23. J

    ATV conversion

    Oh yes I meant 14 in series, not 13. Yep will definitely need more in parallel. I haven't looked too much in to voltage sag. I might look in to some other batteries, probably the ones I mentioned will do for now. They're cheap... and the whole battery thing isn't complicated for me, compared...
  24. J

    ATV conversion

    Yeah regarding the batteries, I will just build it myself. I can get INR18650-25R Samsung Lithium Ion 3.6V 2.5Ah with 20A max discharge rate for about $5 each (about $3.65 USD), so 14s2p will give me 40A max current at 48v roughly fairly cheap. Hopefully they'll be ok. Might need to add another...
  25. J

    ATV conversion

    Actually doesn't matter. I think I'll just pick up four 12v SLA batteries and run them in parallel with the other four I have. It's pretty easy to find those powerwheels cars out in the rubbish collection so I'll snag their batteries.
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