Battery BMS LED meter

I am using these 3S (12V) batteries with LED meter.  Normally, the LED meter shows SOC (State of Charge).  But when the SOH (State of Health) is low, the BMS cut off prematurely as low as 11V.  I can still by-pass the BMS and charge it to 12V.

I am wondering if it is doing that to alert the user to replace the unit.  Basically using a single meter for both SOC and SOH, just to save a few LEDs.

On 9/15/2022 6:54 AM, Ed Lee wrote:
> I am using these 3S (12V) batteries with LED meter.  Normally, the LED meter
> shows SOC (State of Charge).  But when the SOH (State of Health) is low, the
> BMS cut off prematurely as low as 11V.  I can still by-pass the BMS and
> charge it to 12V.
> 
> I am wondering if it is doing that to alert the user to replace the unit.
> Basically using a single meter for both SOC and SOH, just to save a few
> LEDs.

Does the indicator tell you when it is displaying SOC vs. SOH?
Or, does it simply determine both and "decide" based on a combination
of criteria that may not be visible to you?

On Friday, September 16, 2022 at 1:46:15 AM UTC-7, Don Y wrote:
> On 9/15/2022 6:54 AM, Ed Lee wrote: 
> > I am using these 3S (12V) batteries with LED meter. Normally, the LED meter 
> > shows SOC (State of Charge). But when the SOH (State of Health) is low, the 
> > BMS cut off prematurely as low as 11V. I can still by-pass the BMS and 
> > charge it to 12V. 
> > 
> > I am wondering if it is doing that to alert the user to replace the unit. 
> > Basically using a single meter for both SOC and SOH, just to save a few 
> > LEDs.
> Does the indicator tell you when it is displaying SOC vs. SOH? 

No.

> Or, does it simply determine both and "decide" based on a combination 
> of criteria that may not be visible to you?

Yes, that's what i am guessing.

There are only four LEDs.  I guess the user is expected to discard the unit when it cannot be charged up to all four LEDs.  So, when the SOH is low, SOC cannot be fully utilized as well.

The unit is 3S9P and usually 50% to 60% overall.  Some individual cells are at low as 30%, but no reason not to use them down to 0%.

On 9/16/2022 7:15 AM, Ed Lee wrote:
> On Friday, September 16, 2022 at 1:46:15 AM UTC-7, Don Y wrote:
>> On 9/15/2022 6:54 AM, Ed Lee wrote:
>>> I am using these 3S (12V) batteries with LED meter. Normally, the LED
>>> meter shows SOC (State of Charge). But when the SOH (State of Health) is
>>> low, the BMS cut off prematurely as low as 11V. I can still by-pass the
>>> BMS and charge it to 12V.
>>> 
>>> I am wondering if it is doing that to alert the user to replace the
>>> unit. Basically using a single meter for both SOC and SOH, just to save
>>> a few LEDs.
>> Does the indicator tell you when it is displaying SOC vs. SOH?
> 
> No.
> 
>> Or, does it simply determine both and "decide" based on a combination of
>> criteria that may not be visible to you?
> 
> Yes, that's what i am guessing.
> 
> There are only four LEDs.  I guess the user is expected to discard the unit
> when it cannot be charged up to all four LEDs.  So, when the SOH is low, SOC
> cannot be fully utilized as well.
> 
> The unit is 3S9P and usually 50% to 60% overall.  Some individual cells are
> at low as 30%, but no reason not to use them down to 0%.

So, the gauge is actually just a glorified "idiot light" -- not intended
to indicate anything NUMERICALLY but, rather a "feel good" sort of
display ("We're ALMOST charged...")

On Friday, September 16, 2022 at 8:27:07 AM UTC-7, Don Y wrote:
> On 9/16/2022 7:15 AM, Ed Lee wrote: 
> > On Friday, September 16, 2022 at 1:46:15 AM UTC-7, Don Y wrote: 
> >> On 9/15/2022 6:54 AM, Ed Lee wrote: 
> >>> I am using these 3S (12V) batteries with LED meter. Normally, the LED 
> >>> meter shows SOC (State of Charge). But when the SOH (State of Health) is 
> >>> low, the BMS cut off prematurely as low as 11V. I can still by-pass the 
> >>> BMS and charge it to 12V. 
> >>> 
> >>> I am wondering if it is doing that to alert the user to replace the 
> >>> unit. Basically using a single meter for both SOC and SOH, just to save 
> >>> a few LEDs. 
> >> Does the indicator tell you when it is displaying SOC vs. SOH? 
> > 
> > No. 
> > 
> >> Or, does it simply determine both and "decide" based on a combination of 
> >> criteria that may not be visible to you? 
> > 
> > Yes, that's what i am guessing. 
> > 
> > There are only four LEDs. I guess the user is expected to discard the unit 
> > when it cannot be charged up to all four LEDs. So, when the SOH is low, SOC 
> > cannot be fully utilized as well. 
> > 
> > The unit is 3S9P and usually 50% to 60% overall. Some individual cells are 
> > at low as 30%, but no reason not to use them down to 0%.
> So, the gauge is actually just a glorified "idiot light" -- not intended 
> to indicate anything NUMERICALLY but, rather a "feel good" sort of 
> display ("We're ALMOST charged...")

Yes, that's what i am guessing.  They don't want to explain the difference between SOH and SOC.  Depending on site policy, never use without 3 or 4 bars.  Also, replacing units before fully depleted.

On 9/16/2022 8:36 AM, Ed Lee wrote:
> On Friday, September 16, 2022 at 8:27:07 AM UTC-7, Don Y wrote:

>> So, the gauge is actually just a glorified "idiot light" -- not intended 
>> to indicate anything NUMERICALLY but, rather a "feel good" sort of display
>> ("We're ALMOST charged...")
> 
> Yes, that's what i am guessing.  They don't want to explain the difference
> between SOH and SOC.  Depending on site policy, never use without 3 or 4
> bars.  Also, replacing units before fully depleted.

Someone technically inclined would examine the batteries in more detail.
But, for a quick GOODNESS indication, "how many bars do you have?"

The batteries on many laptops have equally dismal (visual indicator) reporting.

On Friday, September 16, 2022 at 9:01:11 AM UTC-7, Don Y wrote:
> On 9/16/2022 8:36 AM, Ed Lee wrote: 
> > On Friday, September 16, 2022 at 8:27:07 AM UTC-7, Don Y wrote: 
> 
> >> So, the gauge is actually just a glorified "idiot light" -- not intended 
> >> to indicate anything NUMERICALLY but, rather a "feel good" sort of display 
> >> ("We're ALMOST charged...") 
> > 
> > Yes, that's what i am guessing. They don't want to explain the difference 
> > between SOH and SOC. Depending on site policy, never use without 3 or 4 
> > bars. Also, replacing units before fully depleted.
> Someone technically inclined would examine the batteries in more detail. 
> But, for a quick GOODNESS indication, "how many bars do you have?" 
> 
> The batteries on many laptops have equally dismal (visual indicator) reporting.

Yes, but EV owners are mindful of both SOH and SOC.

On 9/16/2022 9:09 AM, Ed Lee wrote:
> On Friday, September 16, 2022 at 9:01:11 AM UTC-7, Don Y wrote:
>> On 9/16/2022 8:36 AM, Ed Lee wrote:
>>> On Friday, September 16, 2022 at 8:27:07 AM UTC-7, Don Y wrote:
>>
>>>> So, the gauge is actually just a glorified "idiot light" -- not intended
>>>> to indicate anything NUMERICALLY but, rather a "feel good" sort of display
>>>> ("We're ALMOST charged...")
>>>
>>> Yes, that's what i am guessing. They don't want to explain the difference
>>> between SOH and SOC. Depending on site policy, never use without 3 or 4
>>> bars. Also, replacing units before fully depleted.
>> Someone technically inclined would examine the batteries in more detail.
>> But, for a quick GOODNESS indication, "how many bars do you have?"
>>
>> The batteries on many laptops have equally dismal (visual indicator) reporting.
> 
> Yes, but EV owners are mindful of both SOH and SOC.

Then I would suggest the chosen battery is not appropriate for that
market/use.

On Friday, September 16, 2022 at 11:36:28 AM UTC-4, Ed Lee wrote:
> On Friday, September 16, 2022 at 8:27:07 AM UTC-7, Don Y wrote: 
> > On 9/16/2022 7:15 AM, Ed Lee wrote: 
> > > On Friday, September 16, 2022 at 1:46:15 AM UTC-7, Don Y wrote: 
> > >> On 9/15/2022 6:54 AM, Ed Lee wrote: 
> > >>> I am using these 3S (12V) batteries with LED meter. Normally, the LED 
> > >>> meter shows SOC (State of Charge). But when the SOH (State of Health) is 
> > >>> low, the BMS cut off prematurely as low as 11V. I can still by-pass the 
> > >>> BMS and charge it to 12V. 
> > >>> 
> > >>> I am wondering if it is doing that to alert the user to replace the 
> > >>> unit. Basically using a single meter for both SOC and SOH, just to save 
> > >>> a few LEDs. 
> > >> Does the indicator tell you when it is displaying SOC vs. SOH? 
> > > 
> > > No. 
> > > 
> > >> Or, does it simply determine both and "decide" based on a combination of 
> > >> criteria that may not be visible to you? 
> > > 
> > > Yes, that's what i am guessing. 
> > > 
> > > There are only four LEDs. I guess the user is expected to discard the unit 
> > > when it cannot be charged up to all four LEDs. So, when the SOH is low, SOC 
> > > cannot be fully utilized as well. 
> > > 
> > > The unit is 3S9P and usually 50% to 60% overall. Some individual cells are 
> > > at low as 30%, but no reason not to use them down to 0%. 
> > So, the gauge is actually just a glorified "idiot light" -- not intended 
> > to indicate anything NUMERICALLY but, rather a "feel good" sort of 
> > display ("We're ALMOST charged...")
> Yes, that's what i am guessing. They don't want to explain the difference between SOH and SOC. Depending on site policy, never use without 3 or 4 bars. Also, replacing units before fully depleted.

You have not properly explained this.  How do you know there is both SOC and SOH, documentation?  Yet it says nothing as to  how to know when which is displayed?  

I'm not really following what you are describing.  I don't know why you worry with such a poorly designed product.  Why not use something that works properly? 

-- 

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209 

On Sunday, September 18, 2022 at 12:44:42 PM UTC-7, Ricky wrote:
> On Friday, September 16, 2022 at 11:36:28 AM UTC-4, Ed Lee wrote: 
> > On Friday, September 16, 2022 at 8:27:07 AM UTC-7, Don Y wrote: 
> > > On 9/16/2022 7:15 AM, Ed Lee wrote: 
> > > > On Friday, September 16, 2022 at 1:46:15 AM UTC-7, Don Y wrote: 
> > > >> On 9/15/2022 6:54 AM, Ed Lee wrote: 
> > > >>> I am using these 3S (12V) batteries with LED meter. Normally, the LED 
> > > >>> meter shows SOC (State of Charge). But when the SOH (State of Health) is 
> > > >>> low, the BMS cut off prematurely as low as 11V. I can still by-pass the 
> > > >>> BMS and charge it to 12V. 
> > > >>> 
> > > >>> I am wondering if it is doing that to alert the user to replace the 
> > > >>> unit. Basically using a single meter for both SOC and SOH, just to save 
> > > >>> a few LEDs. 
> > > >> Does the indicator tell you when it is displaying SOC vs. SOH? 
> > > > 
> > > > No. 
> > > > 
> > > >> Or, does it simply determine both and "decide" based on a combination of 
> > > >> criteria that may not be visible to you? 
> > > > 
> > > > Yes, that's what i am guessing. 
> > > > 
> > > > There are only four LEDs. I guess the user is expected to discard the unit 
> > > > when it cannot be charged up to all four LEDs. So, when the SOH is low, SOC 
> > > > cannot be fully utilized as well. 
> > > > 
> > > > The unit is 3S9P and usually 50% to 60% overall. Some individual cells are 
> > > > at low as 30%, but no reason not to use them down to 0%. 
> > > So, the gauge is actually just a glorified "idiot light" -- not intended 
> > > to indicate anything NUMERICALLY but, rather a "feel good" sort of 
> > > display ("We're ALMOST charged...") 
> > Yes, that's what i am guessing. They don't want to explain the difference between SOH and SOC. Depending on site policy, never use without 3 or 4 bars. Also, replacing units before fully depleted.
> You have not properly explained this. How do you know there is both SOC and SOH, documentation? Yet it says nothing as to how to know when which is displayed? 

There are only four LED bars.  The manual only says charge to 4 bars before use, and replace battery if less than 4 bars are shown.  So, the LED bars are really SOC, except when SOH is low.  The BMS will cut-off voltage prematurely.

> I'm not really following what you are describing. I don't know why you worry with such a poorly designed product. Why not use something that works properly? 

I guess that include all laptops, tablets and phones.  They don't really show you SOH.