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I'm looking for anyone to tell me if I'm going to set my boat on fire or if I'm going to end up electrocuting an unforturnate nearby diver. I ripped out a lot of electrical components and DIY'd a bunch of additions/replacements. Short version: I went from 2 12V FLA banks to a 48V 15KWh LFP...

@John Frum Thanks for your help. Now I just need to find the right fuses.

Obviously, the wire will not overheat and cause a fire if I use 2/0 wire and 200A fuse; but what of the equipment? If the inverter is capable of 3000W continuous (3000 / 0.9) /48 * 1.25 = ~87A, and I fuse the circuit with a 200A fuse because of 6000W (eh 180A) potential, what risk do I run when...

Main battery fuse will be 200A. 1/0 AWG wire to main distribution. Circuit length less than 20 feet Daly 16S 200A I had planned on sizing it for the surge power of 6000W. Fuse size was going to be 200A and I was going to repurpose some 2/0 AWG cable already on the boat. But I would opt for...

Correct. It's marketed as 6000W (2x) surge current. I could test it by hooking up my table saw. But I'm pretty sure I watched an independent review video of someone doing that with this unit already. In terms of sizing, I've planned my fuse and wire size on that 6000W surge. Am I putting...

I thought about using circuit breakers rather than fuses. In the case of the inverter, would it allow surge current (6000W @ 48VDC) to pass through without tripping the breaker? I've been sizing everything according to surge current (notably the wire), perhaps I shouldn't?

I'm thinking one feeder to the main distribution bars. On the main bus bars' large terminals, 1 terminal will be the input from the battery, 1 terminal output to the motor, and 1 terminal output to the inverter (only 3 in use). Using the smaller screw terminals, 1 will be output to the buck...

So, in conclusion, branch circuits do not need to be protected by class T fuses. Will automotive fuses suffice or is there another type that's recommended? I'm most interested in the higher current branches like the inverter and the motor.

Hopefully, this is not my ONLY option.

@John Frum Inverter: https://www.amazon.com/dp/B07JBC9Q5G?ref=ppx_yo2ov_dt_b_product_details&th=1 3000W continuous / 6000W surge. I'm trying to size everything for surge current. I do plan on having a pure 48V load. An electric motor for propulsion. Hopefully, some other components if I...

Battery Bank is LFP EVE LF280K Buck Converter: https://www.amazon.com/dp/B09ZNW2HSG?ref=ppx_yo2ov_dt_b_product_details&th=1 Input wires are 14 AWG rated for 105C (printed on the wire) ABYC reports that gauge ampacity as 35A Bus Bars: Mofeez Power Distribution Block Bus Bar, 4 x 5/16" Posts, 6...

I've built a 48V battery and am wondering about fusing branch circuits. If it is required that a class T fuse be used for 48V systems, does that apply to every branch circuit? Example: I have a 48V to 12V 360W buck converter that will pull (360W / 48V) * 1.25 = 9.375A. Does this mean I need a...

Did this and it worked!! I suppose I was too paranoid about stripping out those aluminum threads. I tightened everything as consistently as possible and pulled 53A from those batteries for more than 30 minutes. I will get that torque wrench!! I'm going to top balance these again since the...

I will do this. I will also pull out my benchtop power supply and hook it up to the balance cable leads to test for voltage consistency across those leads with my multimeter (to test my amateur soldering job). Thanks for your time today!

Under load, I'm well beyond 25mV delta. The max I've seen is 275mV difference. I even had cell difference protection set to 500mV, applied 50A load, and tripped the BMS.

I'm at the point where I just don't trust this Daly BMS. The meter reads good, but every time I try to pull 50A the BMS shuts the pack down instantly. Guessing due to cell voltage difference that it thinks is present. Can't show this problem outside of the BMS. But it's causing me problems...

Idle data: The BMS reads cell voltages slightly higher than the multimeter does. The multimeter reads 3.289V on all cells and the BMS reports 3.291V.

Additional Data: When checking with the multimeter, all cell voltages while under load were within 0.002V of one another, lowest reading 3.263V, highest 3.265V. So that falls within the range of your best practice number above. BMS saw completely different voltages. Screenshot below...

Additional question: What would be an acceptable cell voltage difference during high current discharges?

1. This pack is fully off-grid so it never sees 25A charge rate. The most it's ever seen is 8A with 443W PV input. I don't have a 48V charger so couldn't test it if I wanted to. 2. Without using a thermometer, it does seem that some bus bars are warmer than others. Nothing is hot. I will...

I have a 48V 16S pack oriented with cells 1-8 (top/right) and 9-16 (bottom/left). Cells 8 and 9 are connected by a perpendicular bus bar that doesn't make full contact with the cell terminals. I would like to know if I should get a custom bus bar to make full contact with the cell terminals...

That's good to know. I've been agonizing over not being able to get the current down to absolute 0 and cell voltages not actually reaching 3.65. However, 3.646 is close enough for me.

Is 100mA considered top balanced? I have 16 cells charging at 3.65V running at 40mA right now. It just won't drop to 0.

Thanks for the quick response. Currently, I'm only charging this battery for the first time, so the only components in the system right now are the panels, the SCC, and the BMS. I really hope that 1.8A is going into the battery even if the BMS won't show it. Otherwise, cloudy days will prove...

I have a Daly 16S Smart 200A BMS. I've noticed that the mobile app only ever seems to show charge current at greater than 2A. Does Daly BMS have an actual requirement of at least 2 amps to charge the battery? I wouldn't be asking this question had the battery (with no load) not dropped from...

So many videos on assembling a LiFePo4 battery pack. Now I need to know the proper way to disassemble one. Logically, I would think to disconnect things in reverse order of assembly. But, since I've dropped a good bit of money on this DIY 16S battery pack and 200A Daly Smart BMS, I'll ask for...

Thanks for looking out. I read that in a top balance procedure doc later on. I will not be doing that again.

No, you did not. I was thinking of a way to charge faster. @newbostonconst was keeping me straight and reminded me why doing that without a BMS is a bad idea.

That explains it. Thanks much. I'll have a 48V bank with absorption set to 56.4. So the maximum charge per cell will be 3.525, just as yours is.

Thanks, everyone for the help and the information. I've decided I will top balance with 3.55V because I do not want to get close to overvoltage. I have a question though.... If the indicator that cells are top balanced is that the current from the power supply drops to zero, why couldn't this...

Copy that. I guess I just need to let this little 5A power supply do its thing for a couple of weeks. Over the course of a couple of days, I've managed to increase each cell's voltage by 0.01V. Currently sitting at 3.303V. I'll set the power supply to 3.5V and let it go for as long as it needs.

Oof, this power supply only does 5 Amps and goes up to 30VDC. I guess I could create two 24V banks and charge them up that way. Then once those are done put them all in parallel again and let it finish out.

I've been trying to top balance 16 EVE LF280Ks for a couple of days now. All of the cells, when they arrived were reading 3.292-3.294V. I put them all in parallel and borrowed an OLD (it's analog) DC power supply from a friend. I hooked the leads to my multimeter and adjusted the pot until my...

The current motor is a Yanmar 3GM30F, 24HP continuous output diesel motor. When I use it, I run it between 1500 and 2000 RPM and usually for less than 1 hour. I have run it for longer when going upriver. But getting to open water is all it is used for under normal circumstances. I haven't...

The power draw is regulated by the motor controller which, in turn, provides variable amounts of power to the motor based on input from the throttle to control the speed of the motor. So is the load ever actually 450A peak / 179A cont.? I would think only if you maxed out the throttle would it...