Predator 3500 Replacement?

[brain007]

To start, I have a few different things that draw a good bit of power. One that's 1750w, another that's ~1100w, and some misc things that can sometimes add up to around 300w (all continuous).

I'd like to build something like a diy dolly/pelican case solar generator that could charge from solar, shore, and possibly car 12v. If I do it as one big system I'm thinking it forces me into at least 24v which makes charging from 12v trickier and my guess is that it'll cost more than 2 smaller 2kw systems. Ideally something like the Leoch or Bluetti AC200 would be ideal but they're either not available, super sus, or pretty expensive.

Any reliable plans/build videos out there for something in the 2kw+ range that meets my goals?

 

[Supervstech]

It depends on load duration. No portable battery system is going to have the runtime of a P3500...
but small loads, with occasional high demand is doable with many of the diy SG systems out there.
Will, David Poz, and many other youtuber have built hand truck builds that meet the requirements.
My system has a 160Ah 12V battery, with a 1000W inverter charge controller, and ac power supply, and it all fits in a small Milwaukee box, weighs in around 65Lbs. Handles most needs.
But my P3500 will run circles around it in both load, and duration.

 

[Supervstech]

Look at Will’s milk crate series...
And look here for the member builds based on it.

 

[brain007]

But my P3500 will run circles around it in both load, and duration.

Ah this is a very good point that I didn't think to mention. 1 hour would be ideal but I could get away with less certainly. In my mind I was thinking 2x 100ah 12v LiFePo4. A 36v all in one would be ideal there but I haven't seen anything at all in the 36v range.

Look at Will’s milk crate series...
And look here for the member builds based on it.

I've seen those and they look great but typically they're pulling smaller loads. I guess my question now is how much can I pull off something like a 2S 100ah SOK battery setup? Could I plug that straight to a 4kw inverter and call it a day on the power side?

 

[Supervstech]

Ah this is a very good point that I didn't think to mention. 1 hour would be ideal but I could get away with less certainly. In my mind I was thinking 2x 100ah 12v LiFePo4. A 36v all in one would be ideal there but I haven't seen anything at all in the 36v range.

I've seen those and they look great but typically they're pulling smaller loads. I guess my question now is how much can I pull off something like a 2S 100ah SOK battery setup? Could I plug that straight to a 4kw inverter and call it a day on the power side?

24(25.2V) 100Ah is good for around a 100AMPS draw, so that’s 2500W, some BMS or cells can surge 50% or more, so possible 4000W, but less than a few minutes.
Sustained 2500W would be a 1 hour duration... or a combination of smaller loads for 2500Wh over the course of the day. More if solar is feeding large watts in.

 

[brain007]

24(25.2V) 100Ah is good for around a 100AMPS draw, so that’s 2500W, some BMS or cells can surge 50% or more, so possible 4000W, but less than a few minutes.
Sustained 2500W would be a 1 hour duration... or a combination of smaller loads for 2500Wh over the course of the day. More if solar is feeding large watts in.

Ok so from the sound of things I'd either have to go with much larger Ah cells to pull more amps or split this into 2 using 4 batteries total and go down that road. Great food for thought! I'll try and get down a BoM and post it in here with a build if I can source good batteries quickly. Thanks for your help!

 

[OnTheRoadAgain]

Are we talking Harbor Freight.....Predator 3500 ?

 

[brain007]

Are we talking Harbor Freight.....Predator 3500 ?

Yup. Tired of blowing money on gas/oil when I only need it for an hour or so a day max.

 

[OnTheRoadAgain]

Yup. Tired of blowing money on gas/oil when I only need it for an hour or so a day max.

I have one. Great little genny. Took me a bit to find the cheap replacement starter battery for it (not that it's really needed)
Could you get by with a 2kw generator or do you need to run the approx 3100watts at one time?

A comparable setup with battery power would cost what? WAG......
Solar panels - $800
Charge Controller - $150
Inverter - $350
Batteries - $220 - $2000 (depending)
2 Gauge copper cable - $100

Even if you needed that for 2 hours you're only talking 6200 Watt hours to replace. (I think)
To replace that every day would require 6.2 kwh of solar charging. (I think)

6200watts / 6 hours of usable sunlight = 1,033 watts per hour needed to replace what you used ?

I could be so far off....I can't think clearly sometimes so forgive me if my math is stupid

 

[brain007]

Could you get by with a 2kw generator or do you need to run the approx 3100watts at one time?

The ~3100w is all at once but I'm certainly open to using 2 2kw systems as that means I can make a 3rd for redundancy/standby for a lot cheaper than making a 2nd 3kw system. Also it'd be easier to move 2 smaller units around than one beefcake >100lb monster.

A comparable setup with battery power would cost what? WAG......
Solar panels - $800
Charge Controller - $150
Inverter - $350
Batteries - $220 - $2000 (depending)
2 Gauge copper cable - $100

Even if you needed that for 2 hours you're only talking 6200 Watt hours to replace. (I think)
To replace that every day would require 6.2 kwh of solar charging. (I think)

6200watts / 6 hours of usable sunlight = 1,033 watts per hour needed to replace what you used ?

I could be so far off....I can't think clearly sometimes so forgive me if my math is stupid

I'm not entirely certain (I need to do the measurements to lock this down) but I think I'll only be able to get away with ~400w of solar due to space constraints. It won't be used at all on days it's threatening to rain so even if it's only a trickle of power those days it'll help top it up without shore power. Another thing is if things get crazy maybe it will be something closer to 10kw/day? That was one reason I wanted to have the option for 12v charging off the alternator. It's not the most efficient but it's also a rare event.

Would an all in one be cheaper to use for this situation? I've seen a few 3500w solar charger/inverters out there that I figure would work nicely with something like an array of SOK batteries. I think I'm running into the paradox of choice here.