Why 108 Volts for Watts Ratings?

BFL13 wrote:
The specs for various brand converters use 108 volts for their input ratings.

If a converter is rated as having a max input draw of 15 amps at 108v, for 1620w, what would be its draw using a Honda gen that is at 124 volts?

Which brand and model is this? The few that I just looked at don't list 108V as the nominal or min. operating input voltage. Off a nameplate perhaps? What rating of converter is that? That'd have to be a large one of 90 amps DC or more? Have never seen any electrical components or equip. rated at a nominal 108 volts (107, 110, 115 - yes).

The only manufacturer that seems to have detailed specs is PD. Their 9000 series have minimal specs but the 4600 series has these specs.

The PD specs (looking at the 4590 as an example) lists input voltage "tolerance" of 105-130V and maximum max. continuous input power of 1550 watts. Output is maximum 90 amps at 13.6VDC. Doesn't say what the input voltage is for max. input power or max. output current ratings. Peak inrush current is 80 amps (at what voltage and is that at max. output current?).

A converter doesn't make power so if the input voltage drops, I would expect the available output current to drop. For the PD4590, if the inrush current is at the 130 volt rating, that'd be over 10KW and you sure wouldn't size the generator based on that. The generator manufacturer should have tables/info. for sizing a generator but I would suspect not for loads with a leading PF.

1550 watts at say 120 volts would be 13 amps. 80/13 amps = 6.2 times normal full load current. (Similar to an electric motor if that means anything.) I believe the momentary inrush current comes from the capacitors that get charged up on initial energization and less to do with the load on the DC side. In that case if thinking about PF, that will be a leading PF, not lagging like in the case of motors.

I wonder if it would make a difference if you pulled the main DC fuse before starting the generator?

Used to design large generator installations in the 300 -500 KW range, but it's been way too many years and I haven't got a clue anymore and don't really want to. IOW, the above info. might be quite useless...

Best thing to do might be to call Randy at Bestconverter.com?

Never looked at converter inrush current specs before. I guess 80 amps would explain the zap and flash when you plug in a shore power cord with the power not turned off.