After a couple of weeks off with health issues and other distractions I am now looking to push on with this project.
The Murata 0.25% shunts from
@beanflying have arrived, thanks.
Learnings so far:
1) The 4W setups were poorly implemented. Docs supplied by Forum members will help here.
2) Too much heat in the load resistors. The test voltage will be halved to around 6v.
3) Orientation of shunts is important. Stability is improved if the shunts are mounted to facilitate natural air flow.
4) Tests will be carried out over 1 min instead of 4 min. (EDIT: 2min to allow for the PS and load to stabilize)
5) Shunt element temperature measurements and forced cooling will be considered if necessary.
The contenders below, from L to R:
- The shunt that started all this, 100A 0.5% form Bulgaria (white base)
- My home made 50A shunt (wood base)
- Murata 0.25% 10A, 100A and 500A (nice)
- 25A and 100A with 2002 calibration certificates
enut11