Docan 230ah 16s Build

[willh]

Finally have assembled and started testing 16 230ah cells I got from Docan in the early summer. I assembled the pack in 48v series and let the JK bms do its work above 3.45v per cell. To my surprise it took less than an hour for the cells to get under 0.01v difference while slow charging at 2amps from Multiplus 2. I then discharged the cells fully until low voltage cutoff, based on my rough equipment and math I'm above the advertised 230ahs. I used a kilowatt meter and my dehumidifier running constantly as a load. Kilowatt meter read 11.22kwhs just before low voltage cutoff and this doesn't account for over 24hrs of inverter idle draw advertised at 13w.

My math goes like this:

11220w÷(0.93 Peak Inverter Efficiency)+(26hr x 13w Inverter Draw) = 12402w

12402÷51.2v = 242ah

Obviously not super accurate, anyone see anything totally off with this math? If roughly accurate I'm very confident I got what I paid for atleast.

Second full charge I set bulk to 3.5v/cell and 25amps. The cells were balanced enough that the delta stayed below the 0.01 trigger. The cells seem as if they arrived damn near balanced unless I'm missing something.

Very happy with what I'm seeing so far anyways, batteries shipped direct from China ordered from Amy Zheng at Docan.

 

[sunshine_eggo]

Math checks out.

Concerned to hear that Docan is shipping these nearly fully charged. Hazmat regs require they be no more than 30% charged. Additionally, LFP degrades when stored at high SoC, particularly at higher ambient temps (room temp will be negligible), but if they were stored in a warm garage for months, that would be a concern.

 

[willh]

Math checks out.

Concerned to hear that Docan is shipping these nearly fully charged. Hazmat regs require they be no more than 30% charged. Additionally, LFP degrades when stored at high SoC, particularly at higher ambient temps (room temp will be negligible), but if they were stored in a warm garage for months, that would be a concern.

Not what I meant at all, I do see how it would be perceived that way. Cells arrived all at 3.29v and took a significant bulk charge to reach 3.45v. I don't recall exactly how long but many hours charging at 25amps dc before reaching 3.45v where I reduced the current to allow balancing to keep up.

 

[willh]

Multiplus 2 just disconnected at 47v as planned after 19 days of running an all fridge/mini fridge used for beer/soft drinks on a single charge. I'm quite impressed. JK bms indicated 15% charge remaining which seems to compute with kwh meter + 11w inverter standby draw. I am more than happy with all components so far, can't wait to start charging with solar next spring. This system will be used at an offgrid cabin mainly for refrigerator power full time and small consumers while people are there. Initial tests with the system point to trouble free use in the future. I used information almost solely from this forum to plan/purchase/assemble and test this system and thankfully everything has been totally as expected! Thank you to all contributors and this forum in general!

 

[pauldnc]

Nice build with the box. I am looking to do something similar for the RV but 24V battery. What did you use for spacers between the cells?

Plan to use the same 230ah cells from Docan although disappointed that they no longer stock them at their Houston Depot.

Thanks

 

[Quattrohead]

Plan to use the same 230ah cells from Docan although disappointed that they no longer stock them at their Houston Depot.

Yeah those were great cells, my JBD BMS indicates they are at around 235ah for the set.

 

[willh]

Nice build with the box. I am looking to do something similar for the RV but 24V battery. What did you use for spacers between the cells?

Plan to use the same 230ah cells from Docan although disappointed that they no longer stock them at their Houston Depot.

Thanks

 

[willh]

Used that, is a foam/rubber type material. Just cut to size as needed. Box makes a nice snug fit so the material is just placed between the cells and stays there on its own.

 

[pauldnc]

Used that, is a foam/rubber type material. Just cut to size as needed. Box makes a nice snug fit so the material is just placed between the cells and stays there on its own.

I ended up getting my batteries from 18650batterystore (with the dual screws on each post). For separators, I was going to use these.

 

[willh]

I would think that would work just fine.

 

[Bud Martin]

I got mine from Dollar store, two for $1.25.
I am still waiting for the REPT 280Ah from 18650batterystore, I hope they will ship them out soon.

 

[DJSmiley]

I used the Ikea Finfördela Chopping boards

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