Chargery BMS 8T power consumption.

[grizzzman]

There is a post on this site and they wanted to know how much power this BMS consumed at sleep. I disconnected the relays.(that would be dependant on what relays you used) with the system on with the control screen on was .13003. In storage mode .032018. I'm using the pack to power the BMS. If I switch to ext. Power then amps drop to zero. (perfect storage) It's got me thinking, what if I used external power to save the watt-hours while in "off mode". Hmmm

 

[DW SD]

Hi, thanks for this info!
How do you put the Chargery BMS in storage mode?
Maybe I'll buy a Chargery BMS. The one I bought is stuck in China w/o shipping movement.
Where did you buy the Chargery unit?

Doug

 

[grizzzman]

I have the Chargery BMS 8T. On the display, there is a "stop" button. This shuts down the display and disconnects both charge and discharge relays. This mode keeps the watt-hours and percentage stored. This is the .032018 Amp draw. I'm powering the BMS off the pack(4S) On the main unit there is a switch that allows int. (pack) power or ext. Power. If switched to ext. There is no Amp draw( you will lose watt-hours and battery percentage.) In my case, I'm running a CG2 bank with the LFP bank. I have a small DC to DC step-up converter that will be powered by the CG2 bank when I switch to ext power it will save the watt-hours and percent values.
I bought it ....well China.

 

[DW SD]

Thanks for that info!
Doug

 

[Steve_S]

Hi, thanks for this info!
How do you put the Chargery BMS in storage mode?
Maybe I'll buy a Chargery BMS. The one I bought is stuck in China w/o shipping movement.
Where did you buy the Chargery unit?

Doug

I buy mine directly from Chargery, Jason Wang can setup a PayPal, Visa or whatever invoice you like. They ship things out directly and quite quickly. It's also a bit cheaper to buy direct from Chargery, especially the relays.

 

[DW SD]

Hi Steve,
Care to share Jason’s email please?
Does the BMS8T have low temp disconnect?
Do I remember reading on the 16T and 24T did?
Thank you much!

doug

 

[Steve_S]

All the BMS*T's have it now, they did not until recently.
jasonwang3a@163.com

Here is the thread I started on Chargery way back when.... it's also in my signature but apparently people on phones cannot see the signatures.

Chargery BMS now with Low Temp Cutoff

Good Day Folks ! Note: I have no affiliation with Chargery whatsoever, I'm just a customer sharing info in the best interest to help others. I purchased a Chargery BMS8T a month or so ago as a replacement BMS for my ShunBin pack. Post showing installation on ShunBin Pack The installation has...

diysolarforum.com

 

[Super Fly]

Does anyone in USA sells these Chargery BMS?

 

[DW SD]

Steve, I sent Jason a note and mentioned your recommendation. I am hopeful of service levels like Amy's
Thanks!
Doug

 

[Steve_S]

Steve, I sent Jason a note and mentioned your recommendation. I am hopeful of service levels like Amy's
Thanks!
Doug

Jason is a really good and very helpful tech type. Keep in mind the time difference and he isn't English and has to use a translator which can be a bit 'interesting' at times.... because of the translator thing, keep your questions in simple clean English terms, no abbreviations of slang as that makes no sense and you'll be Golden.

 

[DW SD]

I have Chargery BMS 8T on the way. Jason hasn't been as quick as Amy (from Xuba) to update. I don't have tracking info despite paying for the BMS early last week.
I was doing some voltage drop calcs using online calculator thinking about wiring the voltage taps for the balance connector.
I used 4V and 1 amp (Chargery says up to 1.2 amps of balance for inputs on the voltage drop calculator. 18 gauge drops 0.64% with 2' (of wire. Is it fair to estimate 4V?
In thinking about it.... differential voltage at max is probably .1V. If I use .1V in my calculator, then the voltage drop is more like 25%.
Originally, I was going to use 22 gauge wire, which is WAY more pronounced. And the balance connectors I bought have 4" leads of good quality tinned wire, but still 22AWG.
Note, if I shrink those balance wires to 1', the loss is halved. Still high, though.

Am I over thinking??
Cheers,
Doug

 

[Steve_S]

Ummm, overthinking and getting caught in minutia, IMO. It's too easy to get into the niggly minutia and lose track of the bigger picture.

 

[DW SD]

Continuing to think things through... I emailed Jason. He said about consumption and procedure when I'm parked in storage and shut down (no shore power):
"in sleep mode, the lcd back light is off, relay controller is disable. BMS still detect cell voltage. and draw current from battery, it is around 5mA, depends on battery voltage. temperature and so on.
if battery storage over 1 months even 3 months, power off BMS and disconnect battery balance wire is suggested. and make the each cell voltage is in storage voltage, and charge or discharge once time every 3 months. to do so can avoid battery discharge and capacity loss."

@ 5mA consumption, I'd lose 3.6Ah / month to the BMS. Or 43.2 / year.
Then again, Grizz's numbers, above are 6 times that consumption!!
The most I'd ever leave the camper without use is 3 months. And that is rare. Usually once / month.
I'm planning on installing the battery in an accessible location, but one where it'd be inconvenient to disconnect the BMS.

1. Do I have a risk if I charge / discharge to say 50% to 60% SOC (280Ah) and leave it without disconnecting the BMS?
2. Does the BMS run off of just one battery pack? If so, they'd all be out of balance substantially after a 1 or 2 month hibernation.

 

[Steve_S]

Continuing to think things through... I emailed Jason. He said about consumption and procedure when I'm parked in storage and shut down (no shore power):
"in sleep mode, the lcd back light is off, relay controller is disable. BMS still detect cell voltage. and draw current from battery, it is around 5mA, depends on battery voltage. temperature and so on.
if battery storage over 1 months even 3 months, power off BMS and disconnect battery balance wire is suggested. and make the each cell voltage is in storage voltage, and charge or discharge once time every 3 months. to do so can avoid battery discharge and capacity loss."

@ 5mA consumption, I'd lose 3.6Ah / month to the BMS. Or 43.2 / year.
Then again, Grizz's numbers, above are 6 times that consumption!!
The most I'd ever leave the camper without use is 3 months. And that is rare. Usually once / month.
I'm planning on installing the battery in an accessible location, but one where it'd be inconvenient to disconnect the BMS.

1. Do I have a risk if I charge / discharge to say 50% to 60% SOC (280Ah) and leave it without disconnecting the BMS?
2. Does the BMS run off of just one battery pack? If so, they'd all be out of balance substantially after a 1 or 2 month hibernation.

The BMS can run from an external power supply and the plug is on the same side as the temp sensor & relay controller plugs. You could run a wire from the battery to a switch which you can easily access and back to the BMS power in. Otherwise you can just turn off the BMS with the power selector switch. I don't get the disconnect the balance leads part, doesn't seem to make sense if the BMS is off.

It's not a good idea to charge an LFP to 100% and store it full, most manufacturers recommend storing between 80-60%. If your going to store for 1 month or more, turn off the BMS and you should be good to go. * Turn off solar charging too, just in case ;-)

 

[DW SD]

Hi Steve,
Thanks. Again!
I have never touched a chargery BMS. So the controls will make more sense when I have it in hand.
Good idea on using a remote switch to the external power supply port.
Yeah, I'm aware of not charging the LFP to full unless I plan to discharge. The camper sits under a carport and everything is shut down when not in use, including the SCC.
I had planned to mount a remote LFP battery kill switch near the other related electronics (photo). And the Chargery remote screen nearby as well. But bury the battery up between the frame rails in an adjacent compartment. Storage is at a premium.