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    What happened to the 24v DIY system web page?

    What you're saying is you can "right-size" each system to its use case. If you're NOT powering a whole house, or something that needs quite a bit of power by itself, then a 48v system might not be indicated. To better illustrate this point, Will wasn't using a 48v system back when he was...
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    Power Factor What Does It Mean

    Yeah, that's not the case, at all.
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    Power Factor What Does It Mean

    That is a very detailed response that I can only presume is accurate. The device I'm powering is a sonar unit on a boat. It is a 12v device and rated at 9W RMS. I'm presuming that means it draws about .75 amps, is all? What I'm really trying to understand is how long a battery of a certain...
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    4-pin or 16-pin?

    Thank you for confirming that. Is there a small, simple 4S BMS you would recommend? This is going to be a pulling no more than about 10 amps continuous.
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    4-pin or 16-pin?

    If I build a 4P-4S battery from 26650 cells, do I need to run a lead to every single cell (16-pin) or do I just need a 4S BMS with a 4-pin (5, technically?) balance lead configuration?
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    What happened to the 24v DIY system web page?

    I think you were being facetious, and rightfully so! :) Will put the page back up because enough people expressed an interest in that information. It's what I'm basing my small emergency backup system on...basically just enough to run the fridge, freezer and a few lights.
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    What happened to the 24v DIY system web page?

    Some things, like the trolling motor on my boat, run on 24v. I like having a dedicated 24v battery for it. Also, for a small backup system for home use, a 24v system is the "right size" for many folks. Just two batteries, the appropriate wiring, and a 24v inverter/charger is all you need...
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    Mixing Battery Capacities

    I have a follow-on question to this thread. I am looking to build a 4P4S battery from older 26650 LiFePO4 cells. They came in a 7P5S configuration, which I have broken down into 5 packs of 7P that are no longer in series. I then removed 3 of the cells from the 7P pack, to fit the space...
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    Jbd bms reading cell at 6v? Help

    12 and 13 are both showing crazy readings...I'd check your balance leads.
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    Power Factor What Does It Mean

    These are some amusing illustrations, but I have a question about "RMS". In some limited reading I did, this seems to be a measure of how many watts a given device consumes. The device I'm looking to power claims "Power consumption at full brightness •9W RMS". Does this mean it runs at just...
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    Splitting a liion battery in half for charging?

    There is possible, then there is prudent, and there's also practical. What you're describing is absolutely possible. You could design a pack where you charge each cell, individually, balancing each one every time before reassembling the pack for use. That's even less practical than what...
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    Anyone------can I safely STORE Lifepo4 battery in cold weather

    My question concerns the members who might use the cabin in January or February and "they use the lights etc." It's safe to store the batteries in truly cold conditions, but how are those members going to use electricity at the cabin if you have the batteries disconnected? Unless you're going...
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    Charging LiFePO4 Battery in cold conditions

    The larger batteries have a BMS with a low-temp sensor, but I have others (repurposed or unique stuff I have built myself) where they either don't have a BMS at all, or the BMS is a very small, simple unit. I will make sure nothing is getting charged when it is cold enough to be a concern, it...
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    Charging LiFePO4 Battery in cold conditions

    I turned on a small heater in the garage to ensure it doesn't get anywhere near freezing in there.
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    Charging LiFePO4 Battery in cold conditions

    If you have batteries in your house, at around 70 degrees, then take them out into an unheated garage where the temperature is near freezing, can you immediately plug them into a charger and rely on the heat generated during the charging process to keep them warm? Maybe a better question to...
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    DIY Portable Power Station using 2nd life LiFePO4 batteries

    I currently have one small, commercial PPS and we use it during power outages for lighting, running a small fan or charging devices. We also use it on camping trips, which is where I would like more capacity from the battery and inverter.
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    DIY Portable Power Station using 2nd life LiFePO4 batteries

    I have noticed more and more of the larger PPS units are coming out with LiFePO4 batteries, instead of NMC. Due to the increased weight many of these systems are coming with the battery in one box and the balance of the electronics in a separate box. I was wondering if anyone has built a DIY...
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    Backup system for practical daily use

    I am building a small backup power system that will keep the fridge and a few lights going for outages of no more than a few hours at a time. The initial thought is a 24v, 100AH, LiFePO4 battery, with a 2724 MPP inverter/charger and about 400w worth of solar panels. I already have the...
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    What BMS do I need for a 4S 7P 12v battery?

    I have purchased used scooter batteries from Jag35. I bought them for a different project I'm working on but when they arrived and I saw how they were configured, I realized that I could make a small portable power station with these pretty easily. They are arranged in a column of 5 packs...
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    I made big sparks! :O

    It's cool to have THE MAN respond to my post, and very reassuring to know even he has made this mistake. I now have the BMS wired up. I tested each lead on the BMS, ensuring it was adding ~3.5 volts with each successive tab on the cable end before I plugged it in. I then ran the B- wire to...
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    I made big sparks! :O

    So, I have my 60280 cells configured in an 8S, 24v arrangement. Long story short...I created a short...for a short period of time. It arced quite spectacularly, but I quickly broke the connection. I tested the individual cell voltages (3.3v) and the full pack voltage (26.4) and both were...
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    Shunt necessary?

    Your link also led me to find the 500A Victron Bluetooth shunt, which (oddly?) is about $70 cheaper and I can use my phone to check everything I need to know. No issues with android devices from that product, I'm sure.
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    Shunt necessary?

    That looks like what I had in mind, but $206 was rather eye-opening. :O I've only got about $400 into building the battery, including the cells, BMS and the case. Might have to come up with some other solution. Renogy offers what appears to be quite similar for $89. Any particular reason to...
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    Shunt necessary?

    I am building a new battery (8S, 24v, 55AH, 60280 cells) for my boat. My current batteries have a Daly BMS with bluetooth connection, so I can always check SOC with my Android phone. There is a BT dongle available for the BMS I am using on the new build, but from what I read, it doesn't work...
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    'New' MPP PIP2724, any users?

    D'OH! :O
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    'New' MPP PIP2724, any users?

    As long as your batteries are configured in a 24v array, they could be as large as you want, I suppose. If you bought two 12-volt, 280ah batteries and connected them in parallel, you'd have 6.7kwh of power, minus inverter losses...call it an even 6kwh, or a little less if you're not charging or...
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    Parallel battery wiring techniques

    OK, looks like I need to place another order, for some insulator pads, some pure nickel strip and a spot-welder. Can anyone recommend a spot-welder for $100 or less? Keep in mind I'm looking at doing a grand total of about 40 welds, unless this thing works out really well.
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    Parallel battery wiring techniques

    What do I need to do on the positive ends to join them in a parallel configuration, without shorting out against the case body?
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    Parallel battery wiring techniques

    I know this is an older thread, but I am working my way through several options for powering a small electric motor that runs on 3 volts, typically a pair of D-cell batteries, wired in series. Instead of two D-cell batteries, I'm using a single Li-NMC or LiFePO4 cell, at 3.7v nominal, and using...
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    3P charging

    I've been running a capacity test with these three 2200mah 18650 cells and after running the motor for 13 hours yesterday, it's been running for almost 9 hours today. If it makes it until 6PM today, that will be a total of 24 hours and I'll call that good enough. The pack has 6600mah, in...
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    3P charging

    OK, so this is getting more complicated, but if I placed the chip you have shown above into an 18650 3P battery pack, I would have both over-charge and over-discharge protection, correct? I presume the micro USB port can be used for discharging as well as charging the batteries in the pack...
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    3P charging

    So, if I bought that hobby charger, I see it has a place to connect a 3-cell lead. If I'm understanding correctly, that would be like the wires a BMS uses to balance cell voltages, in a series configuration. Is that right? Here's where I think I might be confusing myself: These cells are in...
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    3P charging

    The use case for this battery pack calls for it to be light and portable. It's in a 3P arrangement. Is there a BMS for that or are you talking about something else I don't understand?
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    3P charging

    This is the product I purchased. Does it have a protection circuit? https://www.batteryspace.com/smartcharger30afor37vli-ionpolymerrechargeablebatterypackstandardfemaletamiyaplug.aspx
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    3P charging

    OK, I have verified that the output from this charger is exactly 4.2 volts. What I don't know is if this charger is configured in some way to know when the cell is fully charged, and stop supplying any current. It came with very crude "Operating Instructions", which state that it has over...
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