# Generator output to Grid Tie Inverter

## Main Question or Discussion Point

Guys,

I have a Lister generator that is capable of producing approx 5KW of power from an attached ST alternator.

I am in australia so our standard power is 240v at 50hz

I have a grid tie inverter for my solar panels - this unit accepts between 150v dc in to 500vdc It has a single input string only - what i would like to be able to do is to use the Grid Tie inverter as a load shed option for my generator.

When my Lister is operating at less than optimum (approx 80% of rated output is optimum) then i would like to dump power to the grid (we get paid 60c per KWH for this) and i run the lister on Vegoil/Lard so it is essentially free to run - maintenance costs on the lister work out to be approx 10c per KWH of electricity production.

Situation 1) - The Solar panels are putting out less than their optimum power output for whatever reason - early morning/late afternoon/cloud cover. - I would like to be able to add DC voltage in series to boost the Voltage coming out of the panels - all of the panels are currently connected in series and theoretically deliver around 270v to the Inverter.

I have access to server based power supplies that can generate 12vdc at 32amps in a very stable way - would it be possible to series connect a number of these to the DC output of the panels to add their voltage/current to the inflow to the Inverter ?

Situation 2) When the panels are generating no power be able to push out 150vdc from (say 13) of these power supplies into the panel - but to current limit it to a reasonable amount based on pwm or some such so that i was not overloading the lister ?

thanks for any input in advance

Craig

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anorlunda
Mentor
Sorry but you're thinking about voltage when you should be thinking of power.

Picking arbitrary numbers. Suppose I have 1 amp at 100 volts. That makes 100 watts. Now I add a power supply to boost the voltage to 120 V, still at 1 amp. Now I am making 120 watts. So the power supply needs at least 20 watts power input to the supply. 40 watts if the supply is only 50% efficient. Where does that power come from?

My advice is to plan using watts and watt-hours, volts and amps come later and are of secondary importance.