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As promised, here are the results of the first round of capacity testing. All the cells were well within .02 V differential on delivery so no conditioning pre-treatment was applied. The procedure was as follows: Wire the pack in a 2P 4S 12V configuration Charge @ ~40A CC until 14V CV...

I ordered eight of the 150AH cells from BLS back on December 2nd and they just arrived. Very well packaged, and great looking cells. All brand new, with QR codes, and matched in voltage and (at least on paper) resistance. They were all labeled 3.29 V and 0.28M Ohms. They were all 3.29 V out...

To close this out... I top balanced the pack to 3.55 resting voltage on every cell, and was able to pull the full 300AH from this pack without going below the LVC. I am happy with this, and feel I got what I paid for so far. By the time I can comment on cell life, it will be irrelevant. Time...

A latching (AKA bi-stable) relay has two separate coils that need to be triggered by separate circuits. Let's say you have a NO latching relay that is currently in the open state. If you energize the "close" coil, then the relay closes, and remains closed even if you de-energize the close...

Bus bars - they are nickel plated copper, thickness is roughly .065", overall length = 3.1", holes will take up to .25" stud, slots will take on-center distances between studs from roughly 1.9" to 2.3". --mark

Ordered EVE 280s on Monday. UPS delivered on Thursday. Super smooth transaction. So far everything looks great. Thank you Jenny.

I messaged the reseller. Let's see how this goes.

Your raise two important points that have to be considered in lithium battery management: memory effect and calendar aging. Limited real-world experience that others have made available appears to indicate the memory effect can be reduced to insignificance with periodic (every 40 - 50 cycles)...

I'm in the US. The total bill for the eight cells was 850 USD delivered to the door including 50+ for sales tax. They shipped by Fedex. Yes, the shipping was a prolonged agony of waiting:eek:. I did ask RJ Energy for a quote and for 8 X 160AH cells they quoted me a "subtotal" of 1160...

Thanks for the kind reminder - I did let the vendor know that all is well. I was taken aback for a minute when they replied to me that they cannot view this forum that I gave them a link to. Then the bulb went on... We are so blessed to be privileged to live in freedom. --mark

I wish someone would build a LiFePo charger that would do exactly what you are trying to set up here- charge up to a user-settable target voltage and then STOP. Begin charging when bank voltage falls below a user defined setpoint. Repeat as needed. With a dedicated voltage sensing loop...

I'll admit I'm a reluctant battery tweaker - the price of admission to the DIY LiFePO4 arena. Once I determined the cells met capacity specs I I was done testing. I will say, the cell voltages stayed remarkably close (within .05 V) all the way down to 290 AH out. This is where the one weaker...

I used a Mean Well HRP-300-3.3 for top balancing 3.2 V cells in parallel. Worked perfectly for me. [Edit] One issue I had using the Mean Well was the lack of metering. A nice benchtop power supply offers the advantage of readouts, but I couldn't justify the $$$ for this use. I also realized...

@Grizzman - with that in mind I built in some excess capacity. Most 3.2 nominal prismatics are beyond 95% SOC at 3.45V and relatively little additional energy is stored as the voltage is pushed higher. I'm banking on trading a little per-cycle capacity for cell longevity. Laurie - when I came...

I decided to order one of these: Meanwell HRPG-600-15 power supplies and charge the pack directly from it. It has voltage adjustable range from 13.5V to 18V, dedicated voltage sensing with up to .5V voltage drop compensation, constant current limiting circuit, and inbuilt remote control...

The weak cell was still the first to go below LVC, but the remaining cells were close enough. The pack delivers its rated capacity. If the weak cell was replaced with a cell more equal to the others, then I could probably milk a few more AH off the pack. In real life I plan to live in the 30...

Help - I am trying to find a pre-assembled DF11 10-pin 2mm pitch Hirose female connector. Anyone have a board connector kit and willing to fabricate one for me? I've looked for one on ebay, Alibaba, and Amazon unsuccessfully. I tried to get a free sample from a vendor on Ali but no dice...

Awesome job. Thanks for sharing this. Do you find the Meanwell holds the voltage setpoint pretty tight? I plan parallel top balance my packs because I will avoid ever going below 20% SOC, but will occasionally push > 90% SOC. I will use a Daly BMS to shut down if a cell falls off the cliff...

Here is a rough schematic on how I plan to set this up using a dual coil latching relay (SPST NO Type) and a BMV 712. My converter (Mean Well HRPG -600-15) has a remote control pinout on an exposed header. When the RC circuit is open, the unit makes DC output, and stops output when the RC...

See this earlier post. A latching relay changes state when current is initially sent into the coil that opposes the current state of the relay - can be a pulse, many pulses, or continuous current.

UFF DA - looks like the BMV-712 will not fully support my use case. After studying the manual, it seems to be incorrectly engineered. The stated use case is using the internal relay to start a generator when the relay closes (NC is energized), but the response of the unit is only correct for...

Looks like I can order a few of these contact connectors from a few outfits and hand crimp them to some 22 ga wire. A hack job, but I only need 2 of the 10 pins wired. Thanks for looking. --mark

Use a negative bus from the P- on the BMS and wire all your load and charge negatives to the bus instead of to the battery. Think of the BMS as a fancy circuit breaker that cuts off when a cell-level threshold is exceeded.

There's debate whether or not it is safe to disconnect the battery when PV is hot. In the circuit represented by the OP's schematic, one way to terminate charging and avoid a hot drop would be to have an energized NO relay on the PV positive that is tied to the P- on the BMS. With this setup...

I'm going to take the gamble on exactly this deal. $772 right now with the BF deal. I don't have a good capacity tester set up yet, but I do want to put them through the paces. Ordering up some gear for that. Hopefully I'll have good news to report.

Hello, and thank you Will, and everyone, for this awesome forum. I am upgrading a small RV trailer to LiFePO and adding a solar array for boondocking. I plan to build a 12V 300 - 320 Ah pack with a Daly 4s 60 - 80A BMS, and I want to have solar, shore power, and generator charging...

My initial test was a little sloppy and not a very fair determination. I did not top balance initially, but that is in progress right now. For the initial charge, I just charged until the lead cell pair hit 3.45, charging voltage, not resting. At this point all cells were between 3.43 and...