Split loads between Battery and Generator?

[RossA]

Hey everyone! I am not sure if this is the right thread or not for this question.

I live in a school bus converted into a motorhome and when it gets hot outside, my solar doesn't quite keep up with my mini split AC...

Sooo, I bought a Predator 2000w generator with the idea that between the solar and the generator, I could power all of my loads and also have some excess to charge the batteries with. I have 1360 watts of solar panels on the roof.

Okay, to my main question. Is it possible to split my loads between the generator and the battery in the case that the generator can't supply all the power that I need in that instance?

For example, tonight we got home kind of late (after the sun went down) and the inside of the bus was still very hot. I cranked the mini split on and it was pulling a lot of power. More than the generator can sustain for a length of time. I'm wondering if I can change a setting on my MPP LV2424 Hybrid inverter charger to limit the power that it pulls from the generator and supplement any need with my battery. Ideally, I could control it to prevent more than 1600w being pulled from the generator and it would supplement with battery. Split the load.

It does this exact thing with solar all the time when the solar panels aren't producing enough for the full loads. Is there a way to have it do it with the generator input?

Thanks in advance! If I can get this to work I think the 2000w generator will get me by but if not, I'm afraid I wasted a bunch of money by not buying the 3500w generator.

 

[sunshine_eggo]

Okay, to my main question. Is it possible to split my loads between the generator and the battery in the case that the generator can't supply all the power that I need in that instance?

No.

What you are experiencing is normal and unavoidable. An inverter/charger can be both, but not at the same time. The same circuitry is used for both, but in opposite directions.

When AC power is supplied to it, it acts purely as a charger and passes through supplied AC power to loads. Thus, loads + charging MUST be less than the AC supply. YOU must manage the loads and charging.

If you need to run the mini-split, then you probably need to cut the charge current way down to whatever is needed to keep total power draw under 1600-1800W (you typically don't want to run a generator at 100%).

It does this exact thing with solar all the time when the solar panels aren't producing enough for the full loads. Is there a way to have it do it with the generator input?

This works because it's acting PURELY as an inverter, not an AC charger. It's providing DC to AC at all times, either from PV or battery, not AC to DC.

Thanks in advance! If I can get this to work I think the 2000w generator will get me by but if not, I'm afraid I wasted a bunch of money by not buying the 3500w generator.

Nope. Generators need to be sized 30-50% larger than the inverter power, so you can accommodate your loads and still charge.

You likely need to get an inverter-generator, not just a cheapo "regular" generator. The MPP Solar units like very clean input power, or they may not charge reliabily.

 

[DIYrich]

In SUB mode, the EG4 3000 has the ability to use solar first, and supplement with grid (generator).

In order to peak shave (generator first) you may need the 18kpv or sol-ark 15k, and even then generator peak shave (vs grid peak shave) may not be supported. I'm guessing generator peak shave on the grid line should work.

Use a chargeverter to charge battery directly, and run AC off the inverter. If inverter can't run the AC, then see if you can parallel a second inverter.

 

[Luk88]

As stated by post above there are devices that have this feature (another one is Victron Multiplus ii).

But most cheaper AIOs or inverter/chargers can't do it. They either charge and pass through the AC input to output (in which case you have even less than generator power available - as some power is used to charge batteries) or they provide power from the battery.

Another solution is to use a separate chargeverter type device.

 

[timselectric]

At this point the simplest option is to use a separate battery charger powered by the generator.
This would give you what you want.

 

[RossA]

At this point the simplest option is to use a separate battery charger powered by the generator.
This would give you what you want.

At least that's a solution... Thanks for the idea. Unfortunately anything that could handle the full generator output is expensive enough that I would probably trade in my 2000w inverter generator for the 3500w... I haven't opened the box yet but the 3500w was bigger than I wanted to lug around in my skoolie.

If I decide space trumps cost, I'll for sure just buy a big 24v battery charger.

 

[RossA]

As stated by post above there are devices that have this feature (another one is Victron Multiplus ii).

But most cheaper AIOs or inverter/chargers can't do it. They either charge and pass through the AC input to output (in which case you have even less than generator power available - as some power is used to charge batteries) or they provide power from the battery.

Another solution is to use a separate chargeverter type device.

Bummer... I bought the 2000w inverter generator from Harbor freight on sale for $550 thinking it would be enough and work as I was hoping... The same sale had the 3500w option for $630... I'm wishing I had gone for the larger option at this point but it had some drawbacks of being much larger and wouldn't fit in my storage as well...

I'll keep this in mind. If things don't go well maybe I'll get the bigger one or buy a separate battery charger... But the battery chargers that can handle 1600w are pricy...

Thanks a ton for the info.

 

[DIYrich]

Wen DF475t plus a Chargeverter.