Can an inverter / generator (Honda EU200i) be modified to charge batteries directly?

[hwse]

The inverter / generator like a Honda EU200i has a gas engine that turns a DC alternator which creates DC power. It then runs that power through an invertor to produce 120vAC.
I have two of these generators, one of which is only use on my boat to charge by batteries through the Victron shore power charger.
The other one is an emergency backup that hasn't been used in 4-years.

On my boat, I burn dinosaur squeezing's to make AC power that is rectified to make DC that is then inverted to make AC so that I can transform it into DC. Seems rather wasteful to me.

That got me to wondering if I could modify one of them to just take the DC output before it goes to the inverter and sent it to my boats battery bank and skip the back half of the conversion nightmare.

 

[#40Fan]

If you wanted to, I don't see why not. Just intercept the DC before it hits the inverter part of the controls and install a voltage regulator.

If you're only dealing with 12V batteries, would it be easier to run a car alternator off of a small, efficient gas diesel engine?

 

[ElectricIslander]

Not a great idea - The Honda is finely engineered to create AC. Better to get a really good charger with power factor correction and high conversion efficiency. A good charger can be highly efficient and you won't lose much energy in the 120 VAC extension cord to your battery, compared to a long low voltage DC run between generator and battery to be charged.

If there was accessible DC in the generator it wouldn't be at the right voltage for battery charging (which changes anyways depending on what stage you are at in charging)

 

[hwse]

They are not actually Honda's, so I am not speaking sacrilege.
I got them from Costco for $475 each. The pro of this idea is that it would already have a case, engine, tank and alternator. I could possibly create enough room by removing the invertor to house the external regulator if it did not have one.

2000w is 153A at 13v and my shore power chargers are 30A each so in 12v I can charge at 60A and still have enough power to run the water heater but it runs at the high speed rather than eco mode. I have diesel fired hydronic heating so the hot water is not needed, but shorter runtime to refill my 560Ah LFP bank would be nice.

What I was looking at was being able to produce maybe 100A to 120A at 12v nominal to reduce the run time.

 

[Solarcabin Channel]

Does that 2000 have a DC direct port or DC trickle charger?

My old Champion has a direct DC output for small loads.

If you think that is funny I have solar connected to my All Powers power station and when it is full I use the inverter to run a DC 20 amp charger for topping up batteries and I recharge smaller power stations from that unit.

Hey it works and it is just excess power that would be wasted if I didn't use it!

 

[hwse]

Does that 2000 have a DC direct port or DC trickle charger?

My old Champion has a direct DC output for small loads.

If you think that is funny I have solar connected to my All Powers power station and when it is full I use the inverter to run a DC 20 amp charger for topping up batteries and I recharge smaller power stations from that unit.

Hey it works and it is just excess power that would be wasted if I didn't use it!

It has a 12v output, but it is only about 8A so not useful in recharging a 560Ah battery.

 

[Checkthisout]

You could but why?

So much work for no benefit

 

[hwse]

You could but why?

So much work for no benefit

Not sure it would be no benifit. The DC alternator is something greater than 2000w which is 158A @ 13v. That is way more than I can do with my 60A 120v chargers. I figure that I could connect it with 2/0 welding leads. If I decide that I do not want to go that high, I could also convert my LFP to 24v just by rearranging all of the current parts which would cut the amperage in half and require smaller wires. I could then run the boat off a Victron 24-12 converter. My fridge and freezer can use either 12v or 24 and they are the biggest users.

 

[AntronX]

120VAC Inverter generator has 200V unregulated 3 phase AC on stator windings. You can rectify it to 280VDC using diode rectifiers followed by bulk capacitors. Then wire it into DC bus of 120Vac input battery charger bypassing input rectifier or PFC. This should work in theory but in practice there may be some fireworks if something goes wrong.

 

[hwse]

120VAC Inverter generator has 200V unregulated 3 phase AC on the stator windings. You can rectify it to 280VDC using diode rectifiers followed by bulk capacitors. Then wire it into DC bus of 120Vac input battery charger bypassing input rectifier or PFC. This should work in theory but in practice there may be some fireworks if something goes wrong.

That helps. I could not find anything that talked about the voltage of the motor driven alternator. 200v is pretty hot.

 

[pollenface]

I plug a 20a dumb charger into my el-cheapo 1kva inverter-generator in times of need.

20a is pretty much the limit of what it's capable of.

 

[Checkthisout]

Not sure it would be no benifit. The DC alternator is something greater than 2000w which is 158A @ 13v. That is way more than I can do with my 60A 120v chargers. I figure that I could connect it with 2/0 welding leads. If I decide that I do not want to go that high, I could also convert my LFP to 24v just by rearranging all of the current parts which would cut the amperage in half and require smaller wires. I could then run the boat off a Victron 24-12 converter. My fridge and freezer can use either 12v or 24 and they are the biggest users.

The inverter controls the generator engine speed.

How do you plan on measuring output and controlling/governing engine speed if you're bypassing the inverter?

 

[Checkthisout]

If I was tinkering I would couple a small engine, like a GX50 to a GM single wire alternator or something bigger.

I wouldn't want gasoline on a sailboat though. Diesel, yes.

 

[AntronX]

That helps. I could not find anything that talked about the voltage of the motor driven alternator. 200v is pretty hot.

Ideally you would rewind the stator for lower voltage to get 60vac out then rectify and feed into input of solar MPPT controller. Here is good example using car alternator:

 

[hwse]

If I was tinkering I would couple a small engine, like a GX50 to a GM single wire alternator or something bigger.

I wouldn't want gasoline on a sailboat though. Diesel, yes.

I already have gasoline on the boat because the outboard is gas powered and I currently use one of the generators to power my two 30A Victron chargers. I am just looking at options. As for CO, I tie the generator into the inflatable and run the power cord into the mothership which removes all fumes and vibrations from the sailboat and greatly reduces the sound to me and other boats because sound travels mostly line-of-sight and the inflatable's tubes directs the sound upward.

I know that I could build a DC generator from scratch, but I have an unused suitcase generator which has a running engine, alternator, tank, and the suitcase. I like the idea of replacing the invertor with a MPPT. I have seen videos on how to change the stator wiring from a delta to a Y to double the voltage. It would seem possible that I might be able to do the same in reverse. Might need to look on craigs list for a non-working generator to do some an atopy on to see how it ticks.

 

[sunsurfer]

Ideally you would rewind the stator for lower voltage to get 60vac out then rectify and feed into input of solar MPPT controller.

I've been wanting to do this for so long now. Luck would have it, I just got a Ryobi INV gen that I can use. Just need some free time now. Should be very close to these windings but with less coils;

 

[wopachop]

On my boat, I burn dinosaur squeezing's to make AC power

I always thought that too. Its mostly from plant material on land or plankton at sea. The funny part is that you can almost consider it solar power!!!
The sun shining on plants is the source of the energy. They perform photosynthesis and then die. Get buried. Then millions of years later humans use the fossil fuel for energy. The energy which came from the sun. Thats pretty cool it means my 02 F250 diesel is solar powered!!!!

 

[Checkthisout]

I already have gasoline on the boat because the outboard is gas powered and I currently use one of the generators to power my two 30A Victron chargers. I am just looking at options. As for CO, I tie the generator into the inflatable and run the power cord into the mothership which removes all fumes and vibrations from the sailboat and greatly reduces the sound to me and other boats because sound travels mostly line-of-sight and the inflatable's tubes directs the sound upward.

I know that I could build a DC generator from scratch, but I have an unused suitcase generator which has a running engine, alternator, tank, and the suitcase. I like the idea of replacing the invertor with a MPPT. I have seen videos on how to change the stator wiring from a delta to a Y to double the voltage. It would seem possible that I might be able to do the same in reverse. Might need to look on craigs list for a non-working generator to do some an atopy on to see how it ticks.

So how will you control engine speed?


That is the downside of the inverter gen for such a project. You won't have any way to govern engine speed as they lack a mechanical governor.

From what I remember, the Honda inverter generators put out 130 Volts out of the winding. I assume other brands are the same.

That's why the inverter assembly is so compact.

 

[AntronX]

So how will you control engine speed?

Find out how inverter controls it and program an Arduino to do it.

 

[Checkthisout]

Find out how inverter controls it and program an Arduino to do it.

Ha ha.