Finally found a LiFePO4 BMS with Low-temp Charging Protection

[chevymike]

I have been waiting for a solid BMS with low temp cutoff, so I can build up my 200AH pack. Can't wait for the video!!!

 

[astronom]

Will HAS tested the BMS, and the BMS passed the test. What then is the basis of your claim when both BMS's are from the same manufacturer and use the same programming software? Download and install the app and you'll see for yourself that the cut-off temps are indeed user adjustable.

I agree with you, it's great that Will could make it work properly, and apparently for that you need a specific "enterprise" version to set everything properly. I don't have an Android phone around nor the BMS so it's hard for me to fully test all this, that's why I'm very much looking forward to Will's video, as everyone here. I was just saying that the spec sheets you attached here don't show that you can do these settings, the 4s doesn't even mention an under temperature charge cut-off. By the way it doesn't look exactly the same than the one from batteryhookup, there seem to be more soldered pin-connectors on the link you gave, but maybe that's not an important detail. If this BMS can do low-temp cut-off, why don't they clearly state it in the specs? The more I look at BMSs and the more I feel they all look the same yet can have very important functional differences, so I'm just trying to double check before spending the money. After all maybe the 4s does low temp cut-off and not the 16s? Would be strange but hard to know with these cryptic spec sheets sometimes...

 

[Steve_S]

I feel I should add a word of Caution here folks... Not on the BMS per se, but the amperage ratings. Will has mentioned this before as well as others. BE AWARE that the Amp Rating is "optimal" and really should be used as a guide as a "maximum" it can handle. It is usually good sense to go a bit bigger to have elbow room for things... consider a fridge compressor or AC or Water pump surges. Also I don't think people really consider the Amperage @ the battery when your pulling loads.... IE: my 1500 watt coffer maker pulls 60A @ 24V on the battery when it runs (for 6-1/2 minutes) now toss on a light or two and maybe the microwave and well over 100 Amps, this of course INCLUDES the watts / amps pulled by the inverter as well, which is always on top. If that was on a 12V pack, double it. On a 48 Volt pack half it.

A common thing is people are used to seeing their AC panel which maybe 100A or 200A (most common) but that is at 240VAC Split Phase @ 60Hz (North America) and think Ohh wow 100A should be enough for my batteries, it isn't ! In fact, If I load everything up, all lights, nuclelator and trigger the water pump & have the fridge running too I can see 350A+ with surges on top. PLEASE take into account the Maximum possible load that your inverter "CAN" pull 12vdc/1000w = 83A @ 24VDC - 41.6A, @ 48VDC - 20.8A. And the "CAN" number is not the usual 3000W on the label but the Max Surge rate which in a HF (High Frequency) Inverter is typically Double while an LF (Low Frequency) can handle typically Triple, see your documentation. EXAMPLE: My Samlex 24V 4000W Inverter is LF and can handle up to 12,000W and even the AC breakers have to account for that.

I say this because if you buy an under powered BMS, not only can it trigger a shutdown of the battery but there could be potential damage as well and let's face it, no one wants to damage their gear, risk safety and waste money.

 

[Stupid Monkey]

Which is surely why its best to relay/bypass big loads like inverters from the BMS?

 

[Steve_S]

Inverter's are not loads as such themselves, without the inverter you get no AC. Some inverter's are dogs at 80% efficiency, other more expensive high end ones can reach 95% efficiency. Some BMS' with external relays can address that but now your talking about a more complicated setup and minimal reliance on mosfets. Like the Chargery BMS I'm installing has 2 relays & a delay board (to handle a monetary surge that can be set with the board) that works in combination to overcome some limits.

 

[Dzl]

Inverter's are not loads as such themselves, without the inverter you get no AC. Some inverter's are dogs at 80% efficiency, other more expensive high end ones can reach 95% efficiency. Some BMS' with external relays can address that but now your talking about a more complicated setup and minimal reliance on mosfets. Like the Chargery BMS I'm installing has 2 relays & a delay board (to handle a monetary surge that can be set with the board) that works in combination to overcome some limits.

Can you explain the purpose of the delay board? what specifically does it do to handle momentary surges better? Allow for a momentary surge beyond the limits of the BMS amperage without triggering the relay to disconnect?

 

[thedodgersonline]

@Will Prowse I hope you don't mind but I forwarded the info from here & your youtube channel to Jason Wang @ Chargery and suggested to him that they should send you some BMS Goodies to play with. I know your bored to death and twiddling your thumbs. I also suggested they consider adding a LOW TEMP Cutoff as that simple additional function would likely boost their sales by a significant margin. Half the world is subject to low temp issues, so it goes.

Hi Steve - do Chargery make a BMS with Bluetooth? I sent a query via their site and have not received a reply. Seems like you know them well
Thanks and Regards

 

[Max Bender]

I agree with you, it's great that Will could make it work properly, and apparently for that you need a specific "enterprise" version to set everything properly. I don't have an Android phone around nor the BMS so it's hard for me to fully test all this, that's why I'm very much looking forward to Will's video, as everyone here. I was just saying that the spec sheets you attached here don't show that you can do these settings, the 4s doesn't even mention an under temperature charge cut-off. By the way it doesn't look exactly the same than the one from batteryhookup, there seem to be more soldered pin-connectors on the link you gave, but maybe that's not an important detail. If this BMS can do low-temp cut-off, why don't they clearly state it in the specs? The more I look at BMSs and the more I feel they all look the same yet can have very important functional differences, so I'm just trying to double check before spending the money. After all maybe the 4s does low temp cut-off and not the 16s? Would be strange but hard to know with these cryptic spec sheets sometimes...

Oh, I see what you mean. I haven't bought the BMS yet either but I installed the app and found that the temp parameters can be changed, at least on the app, and so it makes sense that the temp parameters in a bluetooth BMS that uses the app can be changed as well (regardless of its omission in the specs).

I understand your confusion as well. The Chinese translation to English is bad enough and the pictures make it worse - they'll often show for example a 8s BMS and on the same page, pictures of their 4s BMS, 16s BMS, and others. I realize that the various BMS's of a particular manufacturer might share the same characteristics, but why put pictures of those others on the same page?

I have to confess that the process of deciding which BMS to buy has me so frustrated that I'm inclined to not even use a BMS - to just program the solar charge controller to my own preferences; monitor the batteries batteries myself; check the weather myself; and if I'm going to leave the house for any length of time, I can make sure that the batteries are charged and then just shut the system down before I leave.

Heck... even if I found a BMS that I like and put it in my system, what if it croaks or goes belly up in the middle of a winter's night or when I'm at my granny's house for Christmas?

I think what it all boils down to is that those who enjoy their solar system are going to monitor it regardless of whether they have a battery BMS or not. Building a system is fun... watching it work is entertaining.

 

[Steve_S]

Hi Steve - do Chargery make a BMS with Bluetooth? I sent a query via their site and have not received a reply. Seems like you know them well
Thanks and Regards

Unfortunately the Chaergery's do not come with Bluetooth but they do have an RS232 interface that a computer can communicate with via MODBUS. That's fine for me as I am building a Raspberry Pi with NodeRed, Grafana & InfluxDB to manage my Midnite Classic SCC, Samlex Inverter & the battery pack(s).

Jason Wang @ Chargery is a good fellow who is very helpful, I've sent him some recommendations and suggested they send some goodies to Will so he can review & play with them too. Communication is good BUT you have to account for the time difference, seems he sends me emails at 01:00 hours.

 

[thedodgersonline]

Unfortunately the Chaergery's do not come with Bluetooth but they do have an RS232 interface that a computer can communicate with via MODBUS. That's fine for me as I am building a Raspberry Pi with NodeRed, Grafana & InfluxDB to manage my Midnite Classic SCC, Samlex Inverter & the battery pack(s).

Jason Wang @ Chargery is a good fellow who is very helpful, I've sent him some recommendations and suggested they send some goodies to Will so he can review & play with them too. Communication is good BUT you have to account for the time difference, seems he sends me emails at 01:00 hours.

Hi Steve_S
Perhaps a Bluetooth could be one of those suggestions? Bluetooth is becoming a differentiator more and more as these batteries become more common in the RV and Mobile applications. To me (in sunny Qld) low temp cut off is unnecessary as our coldest (mid winter) barely drops below 20C
Regards

 

[Dzl]

Hi Steve - do Chargery make a BMS with Bluetooth? I sent a query via their site and have not received a reply. Seems like you know them well
Thanks and Regards

I just recently asked Jason Wang (of Chargery) this very question, below is the response (in red):

Is there a way to monitor the BMS via bluetooth or on a computer?

No, the present version don't support bluetooth, but the BMS can send out all data by RS232

(italics added)

 

[Steve_S]

Like everything else, improvements always follow. I wouldn't be surprised if Chargery has new versions available soon. Now if they come out with a Low Temp cutoff, Bluetooth, model, I'll upgrade then one I have. I'm hoping to get in 2 of those BYD Packs and want to use Chargery's on them as well. It's all in a separate heated powerhouse, but temp cutoff is still important "just In case"

 

[thedodgersonline]

Like everything else, improvements always follow. I wouldn't be surprised if Chargery has new versions available soon. Now if they come out with a Low Temp cutoff, Bluetooth, model, I'll upgrade then one I have. I'm hoping to get in 2 of those BYD Packs and want to use Chargery's on them as well. It's all in a separate heated powerhouse, but temp cutoff is still important "just In case"

Hi
Well, hopefully it is sooner than later. Hanging out for a decent BMS with Bluetooth.
Regards

 

[Steve_S]

Hi
Well, hopefully it is sooner than later. Hanging out for a decent BMS with Bluetooth.
Regards

Totally agree, I don't mind replacing (updating) one BMS but 3... rather not.

 

[Woggs1]

Got my batteryhookup BMS in the mail yesterday, no instructions, no wiring diagram and no video. Oh well, it should be straightforward. Like Will said, it only has 2 10 awg wires for the pos, and 2 for the neg so what is that like 60 amps max at 12V? (the online charts for amps for AWG are all different). I plan on running it through a relay to power a 2500 watt inverter to test it out. I would make a video but there is no need I suppose because Will should post his any minute

 

[Woggs1]

Ok, so I got it up and running and the bluetooth app connected without any issues. When I tried to change the low temperature cut off in the app it wouldn't take when I hit submit and went back and checked it. I played with it for a while and figured out you have to hit submit 3 times for it to take. The popup that you see when you hit submit has no clear meaning. Other than that its so far so good.

 

[_a1_]

I noticed that sometimes when submitting changes, I get a popup above the submit button saying mR:4 and the settings weren't changed. Pressing again gives the same message but also the mid screen message that seems to occur throughout the parameter screens that seems to be a loading thing, then the setting sticks.

Sometimes the app just seems to get stuck with the loading message. Restarting the app fixes it.

I'll take this over no control of the settings any day

 

[simple2010]

I noticed that sometimes when submitting changes, I get a popup above the submit button saying mR:4 and the settings weren't changed. Pressing again gives the same message but also the mid screen message that seems to occur throughout the parameter screens that seems to be a loading thing, then the setting sticks.

Sometimes the app just seems to get stuck with the loading message. Restarting the app fixes it.

I'll take this over no control of the settings any day

I've seen the same behavior. It got much better when I positioned the antenna for the bluetooth module in a more optimal location. Also, if you just tap the submit button 3 or 4 times in a row it tended to eventually go through.

 

[FilterGuy]

Can anyone post some screenshots from the app?

 

[lmwilco1]

Which is surely why its best to relay/bypass big loads like inverters from the BMS?

In this diagram where do you put the shunt for your battery monitor? In order for the low temp cutoff to work the charging power needs to go through the BMS and not direct to the battery. If you put the shunt between the battery negative and all of the battery connections including the BMS then the balancer will read the wrong voltage for the first cell.