I may have mismatched my ammeter and shunt. I did an endurance test today, tied to the dock, ran at 10a for 10 hours. Should have discharged my 220ah batteries to about 55%, or a bit less due to Peukert. I am still showing about 63% charge. (calculated from resting voltage) With the system running at 10a I disconnected the ammeter and measured the voltage across the unmarked shunt... 6.5mv. Seems like it should have been closer to 5mv. The meter specifies a 50mv 100a shunt. So I think my recent current readings may be all erroneous. I have the batts on charge again, and in the morning I will look for a shunt clearly marked with the required rating, and swap it out. I think I might have a 75mv shunt installed because most cheap panel mount digital ammeters use a 75mv shunt and I have had a couple of them. So I will try to get to the bottom of all that, and regardless I will do another speed/current test. If nothing else, I will run it up to 100a, disconnect the meter and then measure the voltage drop of the shunt, and have a correction to apply. Meanwhile just for chuckles I ordered a 50mv 100a shunt from All Electronics but it will take a few days to get here. Their shipping is outrageous they should use USPS for small stuff instead of UPS.
| Reply via web post | • | Reply to sender | • | Reply to group | • | Start a New Topic | • | Messages in this topic (12) |
No comments:
Post a Comment