LEM DHAB hall effect sensors

Folks,

Has anyone dealt with those ? I'm thinking about using one for TinyBMS, which is originally intended to go with 750A version of LEM sensor (DHAB S/133). It is much cheaper to acquire 200A versions of LEM sensors, and it would be sufficient for my applications.

Now the way I understand it, that LEM puts out a voltage in the range of 2.5 - 5v, proportionately to the sensed current. So 2.5v at zero amps, and 5v at 750 amps or 200 amps, depending on the sensor. So in the absence of ability to change the calibration on BMS side, one would have to do some magic with the voltage conversion to get the correct reading ?

Are there off-shelf devices that can do that ? For DIY I was thinking it's possible to do the voltage conversion using op-amps, and also digitally with Arduino, but perhaps there is a more straightforward path.

Finally, perhaps there is a cheap alternative to DHAB DHAB S/133 ?

Hi cricketo,

Did you find an alternative to DHAB DHAB S/133?

Epm12 said:

Hi cricketo,

Did you find an alternative to DHAB DHAB S/133?

Click to expand...

No, I ended up buying S/133 through a distributor in Canada. If TinyBMS folks were a bit more friendly (I asked, they refused), they could have easily exposed the sensor range as a variable in the UI - there are lots of electrically compatible v1 DHAB sensors available for fraction of the cost, such as S/15 (600A) currently on Ebay for about $20. You can hook up that S/15, but all of your measurements will be reported with 12.5% error. If you only care for SoC tracking, you could technically just scale up the Ah value by the same amount.

Speaking of TinyBMS, I ran into another bug with it after EnergusPS provided an updated firmware to fix a different bug. Still need to report it... @circuit