Finally found a LiFePO4 BMS with Low-temp Charging Protection

[JoeHam]

I would think it best to take the time now to actually measure the current draw.

Once quantified you can decide if the switch is worth it or not. Until then we are all just guessing ?

 

[MrNatural22]

@Ljbezuidenhout The tiny amount of current drawn by the BT dongle is .003A when connected and LED on and .0003A when disconnected.

 

[chevymike]

I have this BMS installed on my battery. As it is used for camping and will be in storage inbetween uses, I want to be able to disconnect the BMS from the cells to stop any current draw (from the BMS bluetooth module mostly). Can I do this by installing a switch on one of the balance lead cables which I can mount on the outside of my battery box? I don't want to open up the battery box and pull out the balance lead cable connector every time. Thanks

If you look at my post from last week, I showed shots of my battery levels after 2 months of storage. This is leaving the BT hooked up but it appears there is very minimal draw when "sleeping". I could easily see this sitting for a year and never getting anywhere near drained. Here's the link,

Finally found a LiFePO4 BMS with Low-temp Charging Protection

Just wanted to give an update on the battery I put together using this BMS (thread here, https://diysolarforum.com/threads/my-new-diy-100ah-12v-pack-build.8288/ ) So it has been together for almost 2 months now but has not been used. I have not gotten my camper build to the point of installing...

diysolarforum.com

I would make sure you have a master cutoff switch between your battery and the trailer loads, so you don't get something in the trailer drawing power. I have zero concerns about the BT draw.

 

[heliwill10]

Is the setting for Balancer configuration “start voltage” a greater than or less than? Haha

So, let’s say just say 3400mV or 3000mV?

thanks!

 

[MrNatural22]

Is the setting for Balancer configuration “start voltage” a greater than or less than? Haha

So, let’s say just say 3400mV or 3000mV?

thanks!

On mine the setting is where it begins to balance. No balance operation below that. I have it set to 3200 and a 15 delta. ?

 

[Ljbezuidenhout]

Thanks all for your comments on the bluetooth draw whilst battery is in storage. Doesn't seem to be a problem then, so will just leave it all hooked up. @chevymike I do have a cutoff for the loads, so will be doing that when going in to storage for sure.

 

[heliwill10]

Andddd main battery terminal question. I have my cells arraigned in 2p4s (I think) and all the leads coming off one battery terminal.

My question is can I use the second terminal on the cell in parallel for something like the victron battery sensor?

 

[BiduleOhm]

Yes

 

[HRTKD]

Andddd main battery terminal question. I have my cells arraigned in 2p4s (I think) and all the leads coming off one battery terminal.

My question is can I use the second terminal on the cell in parallel for something like the victron battery sensor?
View attachment 20510

Is that a Victron shunt in the picture? If so, if you have a BMV device attached to it then the battery sense device shouldn't be necessary.

 

[heliwill10]

Not a victron.... it’s the 350amp Amazon one Will has on his site....

 

[HRTKD]

Not a victron.... it’s the 350amp Amazon one Will has on his site....

Ah, too bad. If you had the BMV-712 it would communicate the battery temperature with your Victron solar charge controller. Since you have the charge controller colocated with your batteries it shouldn't be a problem. The Victron 100/30 has an internal temperature sensor.

 

[heliwill10]

This is what I was planing to use.... So just to clarify I can use the terminals in parallel?

Thanks

 

[Xerxes]

SUPPORT HELP PLEASE

I have an old Samsung 7" tablet with Android 4.4 that I can dedicate to my battery box.

The lastest 3.1.1015 can no be parsed on the 4.4 but does work on a old LARGE SAMSUNG 10" Android 5.1 tablet dedicated for other use.

I did skimread through all the pages of this thread before I bought one of these suckers and recently searched, saw one fellow "AndreL" and reached out through IM here on how he got his 4.4 tablet bluetooth to work.

QUESTION:
Anyone know if there is an older version that works with 4.4 android?
If so what version number?
Any idea where to download that version?

Just trying to be another cheap after spending thousands on battery and buying BMS from overkill, instead of getting a Amazon 7" tablet for this project---just wanted to save the time of those folks who want to say this to me in a public thread.........TO LATE, ALREADY SAID!, be faster next time please!

Thank you in advance-

 

[Steve Swenson]

Deleted. Post moved to it's own thread.

 

[heliwill10]

I tried to search this thread but no to avail.

I’m not seeing my cells actively balance anymore. Even if I change the delta to 1mv.

 

[MrNatural22]

Maybe change balance start to 3200 and 10 delta? Could be 2000/2 is too low a voltage to register? ?
Just guessing here. ?

 

[lifeatthesharpend]

Spent the last few days and tonight testing BMS:

1. The "new" daly LiFePO4 BMS (that states in the data sheet that it has low temp charging protection) does not have low temp charging protection. And yes, it has a temp sensor attached. This disappointed me big time. Video to come.

2. Next, I programmed/tested this BMS for a couple of days:
View attachment 4222

And it failed. App would crash. Default low temp cut off was -5 degrees C. No manual and very difficult to work with. Had a lot of issues with it. Will cover every downside in my upcoming video. Avoid this BMS.


3. Then I tested the battery hook up 100A BMS that arrived this afternoon:
View attachment 4223
And low temp cut off was programmable and worked perfectly. Bluetooth connected perfectly as well. I was excited so I did a load test of 200Wh with 90-102A continious. Passed with flying colors, then pushed it passed its limit and it disconnected the loads. Heatsink stayed warm and did not heat up excessively.

I'll make a long video covering all these things and the testing methods, but I am going to go with this bms from now on. I am so tired of other bms failing. The battery hookup one is used on medical devices as well, which I need more information on.

The number one most important thing to know when using this bms is that you need the proper app. The app on the website is NOT what you want. You need the "enterprise" version:
Click Here for APK of enterprise BMS program app

Send it to your phone with an email (not gmail), then install in on your phone, then connect to bms.

Then go to parameter settings and change the low temp charging cut off to 2 degrees Celsius. Then the reconnect voltage to 5 degrees Celsius.

You can buy this bms by clicking here (my affiliate link) and the coupon code is "SOLAR" for 10% off. I am going to get a 8s model and build a big system with it. I like this bms a lot, so will be testing it like crazy. I also will make a DIY video on how to use it in the next couple days (possibly tomorrow if I get enough sleep tonight).

Biggest downside of this bms is 2x 10 gauge wires at P- and B-. But it has a hole and solder tabs for adding more wires.

Just wanted you guys to know about all this before you waste your money on the first 2 bms. I wasted $150 on those bms and they were a total rip off. The new bms seems to kick butt, so videos to come.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Have you been able to get the schematics of the board? not the system level wiring diagram?

I'm looking for the PCB schematics of a jbd-sp04s020 BMS as well which should be the same as this overkill board.

L

 

[_a1_]

I've been using my little 30a BMS on my 135ah 4s battery for a couple of months now and today saw my first protective events. One cell hit the high limit 3 times by the time I saw it. Very pleased to see it do it's job, not so happy about that cell being so different though.

I suppose I'll lower my DC to DC chargers target voltage a little. I only charge at 20a and discharge is very low. Not even managed a full charge/discharge cycle yet.

 

[wvansl]

I have a question about the temperature sensors in the app.
Temp_1 shows -30 (like it is not available)
Temp_2 shows some real value

I thought there were 2 temp sensors in the bms, one internally one externally. Which one is which and is maybe one broken?

 

[Roobarb]

got my 4 new 200ah cells wired up to the BMS, it seems one of my cells is always charging a lot higher than the others and setting off the over voltage protection. When left overnight without charge and some discharge they seem to go back to equal voltage. Any idea what is going on please ?