Question Battery Low Indicator?

[Lab Minion]

I've got my N64 portable running on the bench with batteries now. I'm using this BMS (CX-74-2S):
https://www.ebay.com/itm/Intelligent...2S-Packs-18650-lithium-Satellite/311721987212 . It doesn't have a gas gauge nor battery low indicator from what I can tell.

I prefer not to use one of those pushbutton battery level gauges since it would be easy to forget to check when you are playing. My preference is to have a simple LED light up when the voltage of the battery drops below (for instance) 7V. This can be achieved with a voltage reference (EG: TL431) and resistors, but it tends to burn quite a bit of current due to resistors.

So, I was wondering what other's are doing to provide some sort of low battery indicator.
Thank you for the pro tips!

 

[Gman]

I've got my N64 portable running on the bench with batteries now. I'm using this BMS (CX-74-2S):
https://www.ebay.com/itm/Intelligent...2S-Packs-18650-lithium-Satellite/311721987212 . It doesn't have a gas gauge nor battery low indicator from what I can tell.

I prefer not to use one of those pushbutton battery level gauges since it would be easy to forget to check when you are playing. My preference is to have a simple LED light up when the voltage of the battery drops below (for instance) 7V. This can be achieved with a voltage reference (EG: TL431) and resistors, but it tends to burn quite a bit of current due to resistors.

So, I was wondering what other's are doing to provide some sort of low battery indicator.
Thank you for the pro tips!

Hello. The N64PMS board is for sale in the store. It eliminates the need for the BMS board and the PTH08080 regulator. It provides play/charge capabilities, custom regulators, a battery monitor for low battery indication, and other neat features.

 

[TodorSauce]

All credit to Daftmike and Mario.

 

[Lab Minion]

Thank you both! I tried out the circuit and calibrated R4 for 7.0V and it works nicely.

 

[Arceus]

This circuit seems nice, i definitively going to use it.

 

[Elen1441]

This circuit seems nice, i definitively going to use it.

Hello, I want to make that same circuit and I am interested in knowing what was the resistance that you used in R4 ?. Thanks a lot

 

[Stitches]

Hello, I want to make that same circuit and I am interested in knowing what was the resistance that you used in R4 ?. Thanks a lot

That post was a year and a half ago, and the dude is banned. To anser your question tho, 10k is a good number for the R4 pot.

 

[Elen1441]

That post was a year and a half ago, and the dude is banned. To anser your question tho, 10k is a good number for the R4 pot.

Thank you very much for the information, it is very useful. Thanks a lot