Amps Draw and Voltage Drop Question 2
Question 2 -17 Oct -------- There are no dumb questions--until now! If the furnace draws 8 amps and there is a 0.2v drop when it is on, and you change the positive wire to the furnace to a fatt...
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Tried to clarify the readings, but ran into not being able to get a good reading on the running 8531 unless I did! Can't find a for sure good place to get pos and neg contact points.
Knocked surface charge off the battery bank (four good 6s) and waited a bit, meter on the batteries 12.71v steady and Tri says amps 2.1 before starting the furnace.
Furnace on with heat coming out, where heat adds about 0.5a, now
12.64v meter on batts and 9.3 amps on Tri, so furnace amps 9.3 -2.1 = 7.2
I got 10.67v on the furnace outside using the best reading with one of the positive wires showing and neg to a frame ground BUT not confident I used the proper places to measure. Can't get at where it is "grounded" or where maybe the full 12v goes to. (anybody know how?)
So voltage drop was not that 0.2 I reported as seen while camping but was 12.71 - 12.64 = 0.07 I have no idea where the 0.2 I saw on the Tri came from unless it was rounding funny with its one-decimal place readings.
Anyway, that's what I just got. No plan to change the furnace wiring since it has worked this last four years we have owned this RV and for the 31 years since it was built I guess.
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DC-DC in thread about that last Spring it came out that if you used thin wire the draw on the alternator would be 30 amps for a 20 amp output, but if you used fat wire, that draw was much less, but still above 20 of course.
Knocked surface charge off the battery bank (four good 6s) and waited a bit, meter on the batteries 12.71v steady and Tri says amps 2.1 before starting the furnace.
Furnace on with heat coming out, where heat adds about 0.5a, now
12.64v meter on batts and 9.3 amps on Tri, so furnace amps 9.3 -2.1 = 7.2
I got 10.67v on the furnace outside using the best reading with one of the positive wires showing and neg to a frame ground BUT not confident I used the proper places to measure. Can't get at where it is "grounded" or where maybe the full 12v goes to. (anybody know how?)
So voltage drop was not that 0.2 I reported as seen while camping but was 12.71 - 12.64 = 0.07 I have no idea where the 0.2 I saw on the Tri came from unless it was rounding funny with its one-decimal place readings.
Anyway, that's what I just got. No plan to change the furnace wiring since it has worked this last four years we have owned this RV and for the 31 years since it was built I guess.
----------------
DC-DC in thread about that last Spring it came out that if you used thin wire the draw on the alternator would be 30 amps for a 20 amp output, but if you used fat wire, that draw was much less, but still above 20 of course.
