Question on charging batteries with Gen
We will be picking up our new to us toy hauler next week. It has a 23 CF residential refrigerator and an 80 amp converter. For the 1-2 times a year that I do not have shore power, Would my 2200 genera...
Forum Discussion
Bunch of numbers for those who like them! :)
Mr Wiz did his calculation using PF 0.7 but not converter efficiency of 85%. Sometimes you see these two things ttreated as being the same or at least where PF is part of the efficiency figure.
I think I can resolve this from using both and then comparing with what my Kill-A-Watt got in a real example:
Starting with the 75 amper doing 75 amps from a Honda 3000 with battery voltage seen as 14.08---
75 x 14.08 = 1056 output watts. Say 85% converter efficiency, input would be 1242w and with 0.7PF demand from the gen would be 1775VA
Kill-A-Watt said 123.8v, 13.64a, 1241w, 1690VA, 0.73PF so not so much VA being 1690 vs 1775. But the watts was close at 1241 real vs 1242 in theory.
Using just the input vs output watts ( how they do efficiency) it was
1056/1241 = 85% so that is on spec for the 75 amp converter (PowerMax)
Using 0.7 instead of 0.73 VA would be 1773 vs 1701--KAW said 1690.
So it looks like you should do the efficiency separate from the PF to get VA.
Another live measurement, this time with the B&S P2200 gen on the same 75 amper the Kill-A-Watt said:
119v, 13.67a, 1150w, 1626VA, 0.70PF. I do not have the battery voltage at the time, but using the 85% efficiency, output would be 1150w x85 = 997w and 997/75 = 13.3a (would be near the start of the recharge)
What comes up there is the different gens for loaded voltage and the results from that. The Honda 3000 was 123.8v vs the 2200's 119v but amps was still 13.64 vs 13.67. PF was different at 0.7 vs 0.73
The Ryobi's loaded voltage with the 80 amper would be a factor in whatever a Kill-A-Watt would say about it all, but the general idea seems valid for estimating about 1900VA as posted earlier in the thread.
Mr Wiz did his calculation using PF 0.7 but not converter efficiency of 85%. Sometimes you see these two things ttreated as being the same or at least where PF is part of the efficiency figure.
I think I can resolve this from using both and then comparing with what my Kill-A-Watt got in a real example:
Starting with the 75 amper doing 75 amps from a Honda 3000 with battery voltage seen as 14.08---
75 x 14.08 = 1056 output watts. Say 85% converter efficiency, input would be 1242w and with 0.7PF demand from the gen would be 1775VA
Kill-A-Watt said 123.8v, 13.64a, 1241w, 1690VA, 0.73PF so not so much VA being 1690 vs 1775. But the watts was close at 1241 real vs 1242 in theory.
Using just the input vs output watts ( how they do efficiency) it was
1056/1241 = 85% so that is on spec for the 75 amp converter (PowerMax)
Using 0.7 instead of 0.73 VA would be 1773 vs 1701--KAW said 1690.
So it looks like you should do the efficiency separate from the PF to get VA.
Another live measurement, this time with the B&S P2200 gen on the same 75 amper the Kill-A-Watt said:
119v, 13.67a, 1150w, 1626VA, 0.70PF. I do not have the battery voltage at the time, but using the 85% efficiency, output would be 1150w x85 = 997w and 997/75 = 13.3a (would be near the start of the recharge)
What comes up there is the different gens for loaded voltage and the results from that. The Honda 3000 was 123.8v vs the 2200's 119v but amps was still 13.64 vs 13.67. PF was different at 0.7 vs 0.73
The Ryobi's loaded voltage with the 80 amper would be a factor in whatever a Kill-A-Watt would say about it all, but the general idea seems valid for estimating about 1900VA as posted earlier in the thread.
