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Discussion Starter · #1 ·
Doing some 12V re-wiring planning with my limited brain skills.
I use a little Shop Vac Hang-On frequently when doing projects aboard, but have only ever used it on shorepower. Haven't tried it with my 1000W inverter yet, but would like to have that option.

Shop Vac

Shop Vac says it's 1HP, and Google says 1HP = 745 Watts. So my inverter should have no difficulty running it.

If it were running in DC, 745 Watts / 12V = 62 Amps. That seems like a whole lot. Is that right? Must be. Just looking for a sanity check and further wisdom.
Inverter goes straight to battery at the moment, but if I relocate things it might go to my 12V system positive busbar instead. And assuming I fuse it, at 1000W/12V = 83A max, the ATC fuse format I plan to use for my other circuits won't work for the inverter since that stuff maxes out around 30A; I'll have to go with bigger stuff. Right?
 

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We have one of those, and 62A is about right.

Inverter should be wired very close to battery. If your bus bar is close, that will be OK. If it is on the DC panel, probably not OK.

You will need a larger fuse for the inverter, but I don't see your problem? Each circuit should be fused appropriately for that circuit/wire, and the inverter will be a separate circuit from the other stuff.

Mark
 

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Your math looks OK. One question I have is the horsepower rating of the shop vac. Those are generally only marginally accurate. Look for an amp rating on the nameplate or manual. Another thing to consider is that motors will typically draw more current at startup than they will at running speed. You may have trouble when initially turning the vac on.
 

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Startup can be MUCH higher than running power.
This ^^^^^^^^

The startup draw might exceed the capacity of the inverter. If I were buying an inverter with the intention of running something that draws 745 watts, I would probably want a 1500 watt inverter.

If you have a peak-reading meter you can check. If you don't, about the only thing you can do is give it a try and hope you don't do any damage.

Good luck.
 

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Freedom isn't free
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I'd say buy actually something like a 20V lithium vacuum... like the Dewalt Wet/Dry...

But your math is OK, but your practical experience is missing. The motor likely provides 1HP sure... but it'll overcurrent when spinning up, and it'll overcurrent when loaded (think sucking in water). Also a motor isn't perfect, it has losses in heat. Your inverter has losses in heat, and losses in efficiency, not to mention (as was mentioned earlier) the distance the inverter is from the battery, and of course the length/gauge of the wire involved.

Frankly I don't think I'm far off from doing the same. The one below caught my eye (someone had it at our club)... yep other brands out there (Milwaukee, Makita, Ryobi come to mind) I've just had good luck with DeWalt stuff, and I already happen to have the 20V Lithium batteries kicking around.

18/20V MAX* Cordless Wet-Dry Vacuum - DCV580 | DEWALT
 

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Suck it and see. You have both items. My guess is a 1kw inverter will run a 1hp shop vac just fine.

I found my shop vac to be a handy clean up tool. I only had my first as it was on the RV I had before moving on to the boat.

Mine is the micro 1 gall but my inverter is a 2 kw item. However I run it sometimes off a Honda 1kw genny and it seems to run the shop vac with out any signs of laboring.
 

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The OP wants a wetvac, and a dustbuster is about the worse boat vacuum we've experienced. I also haven't experienced a decent cordless wetvac that worked for more than small spills or pickups, but my experiences with these are rather limited.

That little shopvac is a real workhorse. You have nothing to lose by trying it on your inverter - it won't hurt anything. If the inverter is new, you might consider returning it for a 1200 or 1500W model.

Mark
 

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I was watching the ammeter yesterday when the wife was vacuuming w/our mini-shopvac. 64 amps of 12.4 volts.
 

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...........The one below caught my eye...... I've just had good luck with DeWalt stuff, and I already happen to have the 20V Lithium batteries kicking around.

18/20V MAX* Cordless Wet-Dry Vacuum - DCV580 | DEWALT
I've had this for several years and love it. I use it for general cleaning, contrustion dust and cleaning water out of the bilge. I use it on 120v most of the time, but the 18v DC battery creates exactly the same utility. No reduction in power.

Full disclosure, I also had the predecessor model to this and it died after about a year. The internal fuse blew and it wasn't replaceable. Obviously, this was redesigned and it's worked flawlessly for many more.
 

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I'd say buy actually something like a 20V lithium vacuum... like the Dewalt Wet/Dry...
18/20V MAX* Cordless Wet-Dry Vacuum - DCV580 | DEWALT
Looks nice.
I wonder what the chances are that the Ryobi 18 volt lithium batteries would work in this unit? A few years back I found a 12 volt high speed charger for the Ryobi batteries and it's like magic! 20 minute charge for hours of run time. But it was expensive and it is pretty big, therefore I wouldn't like to have to have a second 18 volt system aboard.
Did yours come w/the AC adapter or was it and added expense?
 

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I bought a kit for another power tool... an impact driver... it came with a 1AH battery and charger. the charger charges all the different AH batteries, and I got a bargain around Christmas for a package of (2) 5AH for $99 they are usually $99 a piece. I've since bought the bare tools to go with it, including a nice work light with 2 super bright LEDs. What I thought interesting about this vac, is it takes the older 18V DeWalt batteries AND the newer 20VMax batteries.

Again I've not purchased the vac, but I think its on my list now, since a boat neighbor had it and it worked better than a cruddy dust buster.
 

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Discussion Starter · #20 ·
it came with a 1AH battery and charger.
At 1AH, and 60+A current, it looks like we can expect about one minute of continuous run time before a recharge is needed?

I hadn't considered the DeWalt et al 18V Lithium options, but that could be a great way to go. Vacuum + batteries + charger we're looking at $200+ which is more than I'd like to spend, but it would remove any inverter setup contingencies and house battery drain.

I really like my little Shop Vac Hang On because it's so compact and it does stow securely on it's little holder that I attached to the hull ceiling in the head. The hose is long enough to reach into locker corners. Didn't know there was a 12V version, so that may be my final setup.
I've found the Dustbuster style vacuums utterly useless on a boat--and mostly useless off a boat.

Gonna try firing up the 120V Shop Vac off my existing 1k inverter and see what happens...I bought the inverter cheap and I need to replace the batteries anyway, so can't do too much harm...
 
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