Actually the VA should be lower for running both 100 and 55 together than you get by adding each one's VA? The loaded voltage would be lower with the higher load. Also that would make for a lower input amps?
I did some math but not sure it is right but the VA was still above 2800 at around 3100 if so.
Looking at Mr Wizard's 75 amper's VA compared with mine, and his lower input voltage and amps for the same output amps. However mine was set to 14.8v while his was set to 14.4 if that counts as higher output making that much difference in VA required..
Another thing is the way converters can keep up their amps with a lower voltage input to some degree before amps out fall off with too low an input. This means a lower input would be a lower VA required for the same amps out within that range.
It seems possible from all these KAW results to get an idea what gen will run what converter, but you can't fine-tune it. The available gen specs and the converter specs are so broad brush, and also because each will operate wIthin a fairly wide zone "depending."
Hard to pin this down and come up with a rule of thumb like say, " 25 VA per Amp of output" My KAW results go from 19 VA/Amp for the PF corrected, 22-25 for PF 0.7s to 25-28 for PF 0.6s
Warning! The Kill-A-Watt P4400 P3 says do NOT exceed the specs on its label, which are 15a and 1800w.
So mine read 15.57a with the 100 amper but it did not fry the KAW, and it also showed 1854w but did not fry. (at 1910 VA)
Anyway, I don't think I should try to read the total VA etc from the 100 and 55 amper together!
Some specs seem to use 108V for the "max current" BoatandRv ad for the PM3-100 says it is max current 15amps at 108V. I have seen that 108v other places.
I got 15.57 amps showing on the KAW at 122.7 loaded voltage.
Looking at the 3000 again, it says 23.3 amps at 120v on the gen.
However it seems I can run the 100 at 15.57 and the 55 at 11.06 total of 26.63 amps by KAW! The KAW manual says it shows amps as "true RMS output current." Beats me.
The Honda 2000 says 13.3 amps at 120v. But what can it really do? :)
BTW don't forget all the KAW numbers are extremely sensitive to actual DC output of the converter, so if you are not at max rated output, but somewhere less than that, it will show as less VA required.
EDIT Last year there was a guy on here who had some sort of Honda 2000 somehow strapped to the back of his ?Van? ISTR. There was something funny about the way his Honda was rigged up. He bought a PM 75 amper and said it ran ok off the Honda 2000 he had. Forget who the forum member was, sorry.
Looking at what I have been able to do with the Honda 3000 at sea level, it seems to do more than its rated 2800VA no sweat according to the VAs I got.
EG, I have been running the PM3-100 and the PM3-55 for the past year and get 155 amps no problem doing a recharge from 50% SOC
That load is 1910 + 1383 = 3293VA
A few years ago I was often charging with four Vector chargers at 40 + 35 + 35 + 20 = 130 amps, but the Honda 3000 could not take 135 amps worth of Vectors--it would overload red light. So what is that in VA?
(I got 868VA for 35a and 511VA set at 20a on the 35 amp 1092A Vector)
So 1063 + 868 + 868 + 511 = 3310VA
Before I got the PM3-55 I used the PM3-100 and some Vectors together.
EG, 1910 + 868 + 511 = 3289VA for 155 amps which compares with the 3293VA for 155 amps using the 100 and the 55.
So the VAs from the Kill-A-Watt from various chargers come out right.
I am not able to run the 100 and the 75 together, it overloads the Honda (red light) but the 75 does not pop the 15a receptacle CB. The 100 goes in the 23.3a receptacle. So this is an "overload" and you have to shut off and then restart the engine to reset the power.
So, that makes me wonder what the "real" VA ratings are for the 2000 that is shown as 1600VA continuous. Maybe there is enough room above that for running the 75 amper at its 1693VA that I got with the KillAWatt.
Not sure but one time I was trying a higher combined load with the 3000, and it ran for several minutes ok but then the red light came on for overload. I suppose it warms up and gets too hot at the receptacles before quitting when it is over "continuous" rating? For that effect it must help to use fatter gauge extension cords and adapters? I was using 12AWG cords.
There is more to gen vs converter matching than just VA matching it seems?
Good news that got sorted out.
I added a post to that gen vs converter thread today with some more PowerMax numbers using my new Kill-A-Watt gizmo. One is for my 75 amper, same as Mr Wizard's, so comparison is of interest. (It matters which generator you are using it seems, or maybe what else you are running besides the converter to get a lower loaded input voltage.)
Got the Kill-A-Watt and tried it out with some chargers and trailer batts run down low to accept the amps no problem, powered from a Honda EU3000is (13 years young ) rated 2800VA Tests run at sea level
I was not able to capture the initial surge numbers like Mr Wizard did, but the gen was set to "eco-off' and was warmed up. Very slight increase in noise on start up, so go with Mr Wizard's numbers on surges
Lots of numbers--try to stay awake!!!! :) (unloaded AC was 127v)
Note- KAW numbers jump around some, so had to eyeball an average, but these numbers work out fairly well, so no nit-picking! :)
A. PowerMax PM3-100 (100 amper) "PF corrected"
122.7v x 15.57a, 1854w, 1910VA , PF 0.97
DC Output 102a converter set to 14.8v = 1510w /1854w = 81% efficient
OR using battery voltage 13.95 = 1423w/1854w = 77% efficient
B. PowerMax PM3-75 (75 amper---same as Mr Wizard's so compare the numbers in previous post. Note the higher VA when you use a different generator that has higher AC voltage--in this case it makes it doubtful a Honda 2000 can run a PM3-75 ????)
123.8v x 13.64a, 1241w, 1693VA (added on edit) PF 0.73
Output 75.0a converter set at 14.8 = 1110w/1241w = 89% efficient or using battery voltage 14.08 = 1056w/1241w = 85% efficient
C. PowerMax PM3-55 (55 amper)
124.7v x 11.06a , 980w, 1383VA (added on edit) PF 0.71
Output 56.8a set to 14.8v = 840.6w/980w = 85.7% efficient, or using battery voltage 13.7 = 778w/980w = 79.4% efficient
D. Vector (B&D) 1093DBD (40 amper)
125.4v x 8.4a, 680w, 1063VA (added on edit) PF 0.64
Output 40.4a (it does 14.8v so using that) = 598w/680w = 88% efficient or using batt voltage 12.8 (VEC readout) = 517/680 = 76% efficient
E. Parallax 7355 (55 amper but on long wire trailer plugged into Honda)
126.2v x 4.95a, 410w, 620VA (added on edit) PF 0.66
Output 25a converter fixed 13.8v = 345w/410w = 84% efficient
Anyway, there is some to add to the pot, so anybody got some Iota numbers?
Good info. Hard to know the surge allowance amount of the gen wrt the surge of the converter. I think most gens have some surge allowance. ISTR reading here that Yamaha also has a way to use their starting battery as brief additional support for surges?
Mainly we need to at least know how things would go using gen continuous VA ratings.
Anybody with a Kill-A-Watt and some other Brand converters and/or sizes in amps? So far we have WFCO 55 and PD 70 figures. I can get some PowerMax numbers when my KAW arrives next week or so, but maybe somebody already can do that? Also there is Iota and some others to check out.
I still think there might be something going on as to how to get the correct output voltage for the output watts figure. Hmmmm.
EDIT With MPPT solar controllers you do divide the output watts by the battery voltage to get the amps to the battery. So they are using the battery end of the wire pair, not the controller's end to take the voltage? So do you do the same with a converter, or go with the work the converter is doing from its higher voltage than the battery's? After all this is about the converter.
The Trimetric AH counter uses this factor when recharging. Good discussion of it in their owner's manual.
Note on P10 page 12 of 16 here
Are you factoring in the loss of power due to changes in altitude? If a Honda 1000i won't quite handle the load, try a 2000i. KISS
Yes, but we want a way to know if the generator will be able to handle the load before we buy it. I am assuming sea level for everything.
Perhaps every KAW does not show input watts equal to output watts.
Early in the thread we had these numbers for road-runner's WFCO 9855:
"DC volts 14.55, DC amps 41.2, DC watts 599
AC volts 119.2, AC amps 8.3, AC watts 706, AC volt-amps 992, pf 0.7
Crunching the numbers, efficiency in terms of watts is 84.8%,"
So in this case the KAW input watts was not the same as the output watts as seems to be the case with Mr Wizard's KAW and his PD70
Their PFs were about the same, 0.70 vs 0.68, so trying proportions on output vs VA required we get:
599 and 992 vs 918 and 1338 where 992/1338 x 918 = 680 (not 599)
So what are road-runner and Mr Wizard doing differently?
EDIT--Thanks for the KAW link. I used it.
More confusion? Do you use loaded or unloaded voltages for input and output?
When you measure output with the converter attached to the battery you get a lower voltage somewhere between the battery's voltage and the converter's voltage on that wire pair. Then with the current flowing you also get voltage drop. The converter would be putting out 14.4v but you might be seeing only 14.0 at its output terminals.
So do you use 14.4 as the output voltage or 14.0?
Meanwhile at the input end you also have the loaded AC voltage lower than the unloaded. You might read 122v and then with the converter on that might drop to 119v. So which voltage do you use for the VA?
On that, the KAW seems to read the loaded voltage.
(I didn't read all the Wiki stuff linked earlier, so if the answers are all in there, just let me know and I will read it)
If you use the loaded voltage, isn't that counting the load twice? The PF is in the load. Also is the waveform of the loaded voltage the same as the unloaded, where the PF is from waveform matching?
There is some mystery why the KAW shows input watts as being the same as the load's output watts, so I am wondering if the numbers would come out better if we used the unloaded voltages at each end.
Mumbo jumbo indeed :)
Try charging the power supply capacitors FIRST. Then use a power switch to the load. Once a generator's speed slumps - the game is all over.
The inverter type gen has an engine limitation and a circuit breaker limitation to go with the inverter part. It is hard to know what the real limit is-- engine or CB.
In cold weather, you can start the gen, plug in the load, and the gen motor will conk out. But you can be under the CB limit for VA.
After you let it warm up a bit, the engine can stay running with the same load, no problem with the CB popping.
With the engine warm, you can then add too much load so the CB pops and the engine stays running. You have to notice the red light of the CB, or the lower noise level, then you need to turn the engine off and restart it to reset the CB, so you can get back to work with less of a load.
I'll add to the brain puzzler
I just took my kill a watt
And my ac/dc Clamp on ampmeter and my line splitter for ac testing and made some
Output 64.7 DC amps at 14.2v measured
Kill a watt input reading's
122.4vac 59.9hz 917w
10.95amps 1338va PF 0.68
But the ac clamp meter reads 7.97 ac amps
3amps less than what the kill a watt says
64.7*14.2=918.74w almost a match for the what the kill a watt claims is input watts strange huh
122.4*7.97=975.52w that would be heat ? Conversion loss of 57 watts
122.4*10.95=1340.28 real close to the displayed 1338va
So here my guess va reading is peak power reading
Watts is the real apparent consumed power
The 7.97 amps reading of the clamp on amp meter is true RMS value amps consumed
And true power consumed is the 975w
917/0.68=1348.52 ... close to 1338va reading
The kill a watt is not perfect, its math works on some sort of curve
PF is the relationship between watts and va
Not a measure of power loss
VA versus volts kinda like dynamic force relates to static force
For our concern in this case 'charging'
We are interested only in power consumed versus charging watts
Pure efficiency aka power loss
With the KAW
917w/0.68pf=1348.52 va? Watts?
Am I consuming 1340w to create 917 input watts to create 918 ouputwatts
I'm running in circles
I know the PD does Not feel 400watts hot
Heat wise the output is very low
I'm inclined to believe the clamp on meter
7.97 amps real use aka 975w input 918w output
975w/1340=0.72xxxx pf ? , again it seems of is a relationship number not a power conversion use loss
And 10.95*0.72=7.884 amps.. The amp meter displayed 7.97 amps
Again real is about 8 amps not 10.95
At these numbers a 1000w generator would be right on the edge and could not handle the start surge but might carry the constant 8 amp load
So it won't start a 64 amp load but might carry a 40+ amp charge
This is all clear as mud, heh
(It takes me a while to hoist in what Mr Wizard is saying sometimes. He does know this stuff! So anyway, here is what I get from that. )
Ok, so we have output measured at DC 64.7a and 14.2v = 919 Watts and the KAW says input is 917 watts. So that can't be right. But if it is not right, the VA and PF wouldn't come out right.
But the 975w as obtained above would be 919/975 = 94 percent efficiency, which is at least possible, but it is over the claimed efficiency on the PD specs table.
So something ain't right and we are not out of the woods yet! :(
With PWM you get the Isc of the panels. So your two together can do 12.26 amps aimed at a high sun. You should allow some margin for panels when they are cold doing more than their rated amps, rated at 25C/77F
Flat panels don't get as much light as aimed panels, so do less than rated amps. A 15 amp controller should give you enough margin, but a 20 would be better for more margin.
From panels to controller should be #8 as stated above. However since you hardly ever do any off-grid, it is not worth the extra money if that is a consideration over #10.
In fact for that much off-grid you just need an extra battery for that trip, and no solar at all.
Some alternate HD antennae have small "wall wart" converters to supply the power up the coax to the amplifier in the antenna. These have a particular "12v" amount of voltage.
I asked Terk, eg, if their antenna I bought a few years ago when the bat wing died, would work on the Wingard booster "12v" which uses the wide range of 12v an RV has. Yes it does. So you don't have to use the wall wart if it is not convenient to use with the inverter you have on anyway to run the TV set.
One I tried had a 6v output from the wall wart instead of 12v so that was no use unless you used the inverter. Read the info on that before you take it home from the store.
Lately, after the Terk got water in it somehow, I got the Jack which has a way to mount on the Wingard mast ( I bet Wingard doesn't like that!) and it too has its own wall wart, but you can just use the Wingard installed 12v booster set-up in your RV and the various amounts of 12v voltage don't bother the Jack antenna amplifier.
If you do want the Wingman for your batwing, note the warning they have in the manual that it sticks out and may not fit on your RV roof when lowered next to say the A/C shroud. The Jack is one way around that. (It also works quite well :) )
For fun, I tried one of those coax power boosters you can get and it didn't work. You can't boost the booster like that.