search

bres55 / Smart-BMS-arduino-Reader

62 stars 16 forks source link

Discharge current is wild #5

Closed bkenn011 closed 4 years ago

bkenn011 commented 5 years ago

Using this code, if I'm putting 14.9 amps in to the battery I can see that value appropriately, 14.9. If I begin discharging at any amount, I get a number in the 6500 range that doesn't seem to respond appropriately whether my discharge goes from 0.1a to 10a.

Any idea what's up? This is a BMS with shared charge and discharge port FWIW

ckbliss49 commented 5 years ago

Is PackCurrent defied as an int or an unsigned int? Perhaps it is an issues with negative numbers. I am hoping to set up some kind of load so I can verify output of a load. Observation that the max for an signed int is 65,535. Looks a little like the 6500 you show.

ckbliss49 commented 5 years ago

I hooked up a 100 watt light bulb and the current correctly reads -0.75 amps. I changed the data type for PackCurrent from int to uint16_t and the current now reads a huge number like 654.32,

26Zoll commented 4 years ago

With a few additional lines it is working correct now.

// CURRENT highbyte = (inInts[2]); // bytes 2 and 3 lowbyte = (inInts[3]); int PackCurrent = two_ints_into16(highbyte, lowbyte); float PackCurrentf; if (PackCurrent <= 32768) { PackCurrentf = PackCurrent / 100.0f; // convert to float and leave at 2 dec places } else { PackCurrentf = ((65536 - PackCurrent) / 100.0f) * -1; } Serial.print(" Current = "); Serial.print(PackCurrentf);

bres55 commented 4 years ago

This was dealt with here https://github.com/bres55/Smart-BMS-arduino-Reader/issues/1