diy solar

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Our NEW GO-TO LiFePO4 vendor...09.20.21

I have had no problem changing my Docan JBD BMSs with the Android Bluetooth app. After you change the numbers on the setting page, touch the little check mark in the upper right to actually write them to the device.
 
GRBreaks said:
You have it about right.

But the JBD BMS from Docan has a factory default for enabling balance at 3.3v.
The only communication hardware they provided with my BMS was a bluetooth link.
The Android bluetooth app only allows you to monitor the BMS, not change parameters.
To change parameters you need to use a MSWindows PC program over a UART link.
Which is a PITA if you're like me and don't want anything to do with MSWindows.

As always, let me know if I have this wrong.
It's been awhile since I have looked into the various ways of communicating with a JBD BMS.
There are some projects to talk to the JBD BMS under other OS's,
but they would be a bit harder to get going.
Click to expand...
All of my JBD came set to only balance above 3.4v.
Side note, I found it hilarious when off grid garage used his JBD to top balance his cells, and then suddenly found that the balance capability of the BMS was more than adequate to keep them balanced. Always hard to tell what he is doing, but he is totally convinced you need an active balancer. No, you just need to top balance, leave the defaults set (in multiple videos he changes settings like 6 times in one charge cycle) and stop futzing with the settings.

Every version of the Android app I have used allows you to set the vast majority of the settings. Some calibration settings do require the PC software.

For IOS they have a pay version ($5 I think) that allows you to change settings, the free version does not.
 
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Dynoman said:
Possibly the app from Overkill solar will work? It is my understanding the BMS(s) are slightly modified JBD.

Manuals are good too...

overkillsolar.com

Support/Downloads

User Manual User Manual: Download Manual (6.5mb PDF) Simplified 4 Cell Assembly Ultra simple view of a complete 4 cell battery assembly. – Click for full resolution. Bluetooth Mobile Apps iPh…
overkillsolar.com overkillsolar.com
Click to expand...
No, they ARE a JBD BMS with better testing done, and actual support.
 
Same here for my Docan 200A “JBD” BMS, the overkill solar app allowed me to change every parameter I wanted. I was able to side load it on to multiple Amazon kindles.

That plus a couple free iOS apps on my phone and iPad that are read only it’s pretty handy to have multiple devices to check the BMS
 
justgary said:
I have had no problem changing my Docan JBD BMSs with the Android Bluetooth app. After you change the numbers on the setting page, touch the little check mark in the upper right to actually write them to the device.
Click to expand...
Ah, that was the trick.
Need to hit that magical checkmark in the upper right.
Way better than messing with a borrowed 12yr old MSWin Netbook.

Have been using the xiaoxiang Android app, version 3.1.1026
And that is the most recent version that Overkill has on their website: https://overkillsolar.com/support-downloads/

I like what Overkill is doing, their documentation is the best I've seen for the JBD BMS's.
Would have bought from them if they offered the 200A 16S BMS.
Worth a few extra bucks to get good support on this stuff.

Thanks!
 
GRBreaks said:
I like what Overkill is doing, their documentation is the best I've seen for the JBD BMS's.
Would have bought from them if they offered the 200A 16S BMS.
Worth a few extra bucks to get good support on this stuff.
Click to expand...

I don't have any insight into what goes on a Overkill Solar, but my guess is that he's selling the most reliable BMS that JBD offers. Fewer hassles that way. He got swamped really bad a while back when Will recommended his website. When you have all the business you can handle, why add to your stress by expanding the product line with items that require more after-sales support?
 
740GLE said:
Same here for my Docan 200A “JBD” BMS, the overkill solar app allowed me to change every parameter I wanted. I was able to side load it on to multiple Amazon kindles.

That plus a couple free iOS apps on my phone and iPad that are read only it’s pretty handy to have multiple devices to check the BMS
Click to expand...
One more puzzle here.

Have a JBD 7S-20S-200A BMS with 32 Eve LF280K cells in a 2P16S configuration, so 2*280=560Ah.
Using the xiaoxiang Android app, version 3.1.1026.
The "nominal capacity" is set to 560 Ah

The settings for the "Charge Overcurrent" and "Discharge Overcurrent"
both went to 300A automatically when I set the nominal capacity to 560A Ah.

But down at the bottom of the settings under "Hardware Over Current and Short Params"
the "Hardware overcurrent protection" cannot be set any higher than 100A with a max delay of 1280ms
and the "Hardware short circuit protection" has a max of 200A with a max delay of 400uS.

My Magnum MS-PAE4448 4400W inverter spec says it can deliver a 5 sec surge at 8500W, or 8500W/48V=177A
The Magnum PT100 PV charger can give a max of 100A.


Still somewhat on subject, as the BMS was bought from Docan along with the LF280K's.
 
GRBreaks said:
One more puzzle here.

Have a JBD 7S-20S-200A BMS with 32 Eve LF280K cells in a 2P16S configuration, so 2*280=560Ah.
Using the xiaoxiang Android app, version 3.1.1026.
The "nominal capacity" is set to 560 Ah

The settings for the "Charge Overcurrent" and "Discharge Overcurrent"
both went to 300A automatically when I set the nominal capacity to 560A Ah.

But down at the bottom of the settings under "Hardware Over Current and Short Params"
the "Hardware overcurrent protection" cannot be set any higher than 100A with a max delay of 1280ms
and the "Hardware short circuit protection" has a max of 200A with a max delay of 400uS.

My Magnum MS-PAE4448 4400W inverter spec says it can deliver a 5 sec surge at 8500W, or 8500W/48V=177A
The Magnum PT100 PV charger can give a max of 100A.


Still somewhat on subject, as the BMS was bought from Docan along with the LF280K's.
Click to expand...
Well, it is a 200A BMS, so asking it for much more could lead to trouble at some point. The BMS also comes with 4 gauge wire, which I don't think is really big enough. I'm changing mine to 2/0 instead. I prefer to keep cables cool under normal use.

Total current is the main reason that I bought two BMS units to run 16S2P. I have 4/0 cable to run from the battery combiner lugs to the inverter (also a PAE4448). A feature of two in parallel is that I can remove one battery for service if needed and still keep the power online.

Each battery has a 300A Class T fuse protecting it.
 
justgary said:
Well, it is a 200A BMS, so asking it for much more could lead to trouble at some point. The BMS also comes with 4 gauge wire, which I don't think is really big enough. I'm changing mine to 2/0 instead. I prefer to keep cables cool under normal use.

Total current is the main reason that I bought two BMS units to run 16S2P. I have 4/0 cable to run from the battery combiner lugs to the inverter (also a PAE4448). A feature of two in parallel is that I can remove one battery for service if needed and still keep the power online.

Each battery has a 300A Class T fuse protecting it.
Click to expand...

The 580 Amp-Hours of capacity should be fine.
I'm not asking the BMS to charge or discharge at over 200 Amps.
Weird that the "Hardware overcurrent protection" cannot be set any higher than 100A
on a 200A BMS.

Multiple BMS's mean more stuff to keep track of, and many more
wire connections that could fail. Not an obvious win.
I have redundancy in the form of a separate 24v system using some old lead acid batteries
and a cheapo modified sine wave inverter to keep the refrigeration and lights going.
 
Alkaline said:
Is Docan still going to sell the LF280K?
Click to expand...

They've been out of stock of the LF280K since the end of August.
I suspect they would sell them if they could obtain more.
Not currently listed on the Houston website: http://www.powerwholesale.net/Wholesale-Discount-battery-lifepo4-battery_c34.html
Note that only the first few items say "USA Stock", the rest are probably shipped from China.
The only US stock prisimatic cell is the 100AH Eve cell.

They do have CATL and Lishen at 280AH and 272AH for $110 listed toward the bottom,
plus shipping from China.

You could send an email to Jenny Wu: Jenny Wu <jennywu896@gmail.com>
or Amy Zheng <amy@docanpower.com> or any of the other Docan reps.
They can tell you if new stock is expected.
 
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Bleedingblue said:
Anyone know what the prices are currently?
Click to expand...
It is a moving target and I have no current quotes, The ladies in some of the previous posts can give you a current quote. I have done business with several of them and freight and prices are a constantly changing and volume matters
Several years ago I purchased cells for less than$125/kWh DDR to my home. I got a quote six months ago for a small volume from US stock but deferred until that project was better defined.
 
Ampster said:
It is a moving target and I have no current quotes, The ladies in some of the previous posts can give you a current quote. I have done business with several of them and freight and prices are a constantly changing and volume matters
Several years ago I purchased cells for less than$125/kWh DDR to my home. I got a quote six months ago for a small volume from US stock but deferred until that project was better defined.
Click to expand...


Couple years ago I paid around 90 shipped from China for 280ah cells. Last ones I bought I think they were around 110 shipped.

Right now I have 96 in use and I need to double my battery bank eventually. Trying to power a house uses a lot more batteries than you think. Especially in winter and no sun for days
 
Heating loads?
If so, I'd think H2O, SiO2, or NaCl would be cheaper than Li.
(power density depends on high vs. low grade heat. And optional phase change.)
 
Hedges said:
Heating loads?
Click to expand...
Yes, I use a heat pump. It has to work harder for the few hours that the outside temperature is around 32 F. Most of the time it is pretty efficient, only using 15 kWhs per day. That is the reason I run a deficit in kWhs for the first few months of my relevant period. However my Spring and Summer generation erase that and I am hoping to net out to zero at next true up.
 
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