Best practices electrical generator options for gas fueled V8

[The SnoBall Effect]

We will need to run our ice shaver(700W), a chest freezer or fridge/freezer combo along with some smaller electrical items. We purchased a gas powered generator from Tractor Supply that is spec'd to give us 4000 starting Watts and 3500 rated Watts. I would think that would be enough, but I have also been looking at power inverters to run off of the engine alternator. Does anyone have any recommendations for a power inverter instead of the generator?

We are already having concerns on where the generator will be located. On a bigger bus with more ground clearance, it may be able to go underneath. We were originally thinking of having it on a rear hitch carrier of some kind. We would be concerned about weather and possible theft. We have thought about possibly building a box for it where it would be secure and still on the outside maybe vented for exhaust and heat escape.

Any advice in this area would be appreciated.

[Tango]

I'm extending my rear bumper just enough to lock-box in my Honda 3000.

[Scooternj]

Depending on the size of the genny, you might think about doing something like this-



Or look for a MEP series tactical generator (either through eBay or government auction), either a MEP-831A 3kw or MEP-812A 5kw. They're both designed to be left outside, running, relatively quiet, but need to be grounded and run on diesel.

[The SnoBall Effect]

Originally Posted by Scooternj

Depending on the size of the genny, you might think about doing something like this-

Or look for a MEP series tactical generator (either through eBay or government auction), either a MEP-831A 3kw or MEP-812A 5kw. They're both designed to be left outside, running, relatively quiet, but need to be grounded and run on diesel.

That looks great! Is that something that can be purchased or is it something you built?

[Scooternj]

Originally Posted by The SnoBall Effect

That looks great! Is that something that can be purchased or is it something you built?

I just did a quick google search It may be able to be purchased. The originating address (Hayesequipment.com) doesn't show it. Or build something around a hitch carrier, just remember to provide enough clearance for intake and exhaust

[The SnoBall Effect]

Yes, we were considering a hitch carrier, but then I was looking at power inverters to see what options there were. I was not sure where to look for the capacity we would need. A power inverters seems to make more sense to me, but I would need to be sure it could handle the inrush current of the ice shaver startup. The specs for it say 700 Watts, but I am not sure if that means peak.

[bansil]

Your alt. may not put out enough power to help you, what size output and at what rpm?

I have a 200 amp on bus, and have several cobra 1575 inverters ($99 and mod/sine), run inverters at 85% for 1275 watts to use with surge ontop of that, these are inexspensive and have worked great for me for 8 years or so

I recommend a 12v battery to use as a "booster" for heavy load starts, we run a 900 watt microwave, fridge and rotisserie going down the road no issues

If money allows a true sine inverter is better, have not issues with digital timers or clocks that I know of

[The SnoBall Effect]

Originally Posted by bansil

Your alt. may not put out enough power to help you, what size output and at what rpm?

I have a 200 amp on bus, and have several cobra 1575 inverters ($99 and mod/sine), run inverters at 85% for 1275 watts to use with surge ontop of that, these are inexspensive and have worked great for me for 8 years or so

I recommend a 12v battery to use as a "booster" for heavy load starts, we run a 900 watt microwave, fridge and rotisserie going down the road no issues

If money allows a true sine inverter is better, have not issues with digital timers or clocks that I know of

Not sure on the output of the alternator. I will have to test. I was definitely thinking of adding a second battery if we were going to use an inverter. I wonder if the Cobras can handle the current draw. I saw an inverter in a video for a food truck, but not sure what it was and how they had it setup.

[family wagon]

I'd be worried plenty about theft of a generator that costs of one or more thousands of dollars new, and easily resells even well-used for 70%+ of the new value. I wouldn't worry so much about theft of a generator with new cost in the "a few hundred" range. If it's bolted down reasonably well, I would think most thieves wouldn't bother with it -- maybe no need to build a full steel plate doghouse for it.

It kind of sounds like you're doing some kind of concessions? (I personally wouldn't need very many sno-cones while driving!) I guess you would mostly use the ice shaver while the bus is parked, which implies the engine would likely be idling.. Whatever the rating of the alternator, it almost certainly won't perform anywhere near its rating while the engine idles. You'd have to rev the engine up to get full performance from the alternator. Even so, 700W (plus inverter losses etc) is a lot for an alternator unless it was specifically designed for continuously powering loads like that. However... it might be reasonable to build a big battery bank so that the inverter can power the shaver etc from stored energy, and deal with re-charging the battery later.

The Kill-A-Watt meter is a cheap and convenient way to measure power consumption of small appliances. It won't show peak/startup/inrush, but it's good for steady-state power.

[Redbear]

You are not going to want to run either the generator or the bus engine 24 x7 to keep the fridge cold. What you should do is get an inverter sized to start and run the fridge, and install a house battery bank. You may want to keep the fridge on a dedicated inverter, not used for any other loads. Other loads can be run on inverters that you turn on and off as needed.

Then with the fridge running on batteries, you can run the generator only a few hours per day (or less) as needed to top up the batteries.

Just my 2¢ . . .

[family wagon]

Originally Posted by Redbear

You may want to keep the fridge on a dedicated inverter, not used for any other loads. Other loads can be run on inverters that you turn on and off as needed.

That may be a good idea, especially if the fridge-only inverter has higher efficiency or lower power consumption (the inverter itself consumes power) as compared to a single inverter sized to do everything.

Something I may do on my bus is install an extra temperature sensor in the fridge so that it can call for the inverter to turn on when the fridge needs to run, and then turn the inverter off again when the fridge finishes its cycle. I haven't figured out yet how much power that would actually save as compared to just leaving the inverter on all the time.

[The SnoBall Effect]

We were thinking we would keep it plugged in on an extension cord overnight. I am going to test the generator with the ice shaver today. I could also plug in a fridge we have in the garage to make sure the generator can handle both. I have a Kill-A-Watt meter that I can also use. We may not even need to run the freezer while out selling our wares. It should have several ice blocks inside and it will be closed the majority of the time. These are things we are going to have to figure out as we go. I would prefer the inverter and batteries option rather than the generator. The generator is definitely in the few hundred dollar range and not thousands.

[Jolly Roger]

I would think house batteries and generator would be best so that you don't stress out the actual bus/van batteries or alternator? Then you don't have to worry about starting or moving the bus/van cause the concession/house requirement's drain it?
It is just an opinion but even if it takes more money and salvage time and work I want the two seperate that way if the bus don't start I know where to trouble shoot, if the house don't work then I can always crank up and go home to work on it if I can't solve it where I am at

[The SnoBall Effect]

Good points. The generator we have is supposed to run for 12 hours on a tank of gas. If we were at an event rather than off selling cold treats, we could have the bus not running and just running off of the generator or an extension cord. Run on sentence? Perhaps. I would possibly like the option of an inverter as well as additional power. How many batteries would everyone advise in a battery bank? I would like to have Optima gel cells, but that might be a hard sell to the board. Lol

[The SnoBall Effect]

I am also trying to picture how I would wire up the generator to the batteries. The generator puts out AC. Maybe it puts out 12VDC at a certain wattage as well. I would not think I would need to have an AC to DC converter from the generator to the battery bank and then DC to AC for the equipment.

[The SnoBall Effect]

I was also just looking at this.

Mobile Inverter | DC to AC Power Inverter | Mobile Food Trucks

[family wagon]

Originally Posted by The SnoBall Effect

How many batteries would everyone advise in a battery bank? I would like to have Optima gel cells, but that might be a hard sell to the board. Lol

Optima is a nice battery that does have its special place in the world.. but for this kind of application, I get the idea its dollars-per-available-amp-hour figure isn't very good. Plain old deep-cycle lead, or fancy new LiFePo are worth a look. Bank size is a very personal choice; it depends entirely on what you need to run (how much power is needed) and for how long. That said, it usually works out to "as many batteries as your bus and wallet have room for!"

Originally Posted by The SnoBall Effect

I am also trying to picture how I would wire up the generator to the batteries. The generator puts out AC. Maybe it puts out 12VDC at a certain wattage as well. I would not think I would need to have an AC to DC converter from the generator to the battery bank and then DC to AC for the equipment.

For some reason generators always have a battery charge output, but it's always useless because it's unregulated, there's no charge controller, and has a very low current capability. Instead, get a mains-powered charger and run it off the 120V generator output. In case you end up with a 12V bank, there's a Black & Decker branded 40 amp charger that nat_ster and myself are quite fond of.

You can buy the pieces separately (charger/converter, inverter, transfer switch) or integrated (hybrid inverter for example).

[Jolly Roger]

I can't afford the batteries and verter's I want right now but I am changing 120 to 12 on most and only a fridge and water heater on 120. If everything you are running is 120 then a generator on a good extension cord 10 guage is probably the best if you can run on a genny and need 12 without a verter and don't have money for batteries like me a good battery charger (50-60$) for me with a GFCI will work.

[Jolly Roger]

Snowball! Are you trying to do a food truck, ice cream? There are many option's depending on what you are attempting to do? I have references for a lot of HVAC equipment cause I do it commercialy? If I know your exact application I can give give you contact info that can help get it right once without guessing and less money in the long run. I think that is what we are all after

[bubb, the real one]

when using your house batteries you dont want to pull more than about 10% of their capacity, so if you have a single 100ah battery then you want your drain to be 10amps or less.
remember that 1amp Ac is equal to 10 amps DC, so see what your fridge pulls in amps then multiply by 10 to get its need in DC
if the fridge pulls 3 amps Ac, then its DC pull will be 30amps, then you will need a 300ah battery bank at the very least, 400 will be better, also you should only use 50% or less of your batteries so a 300ah bank should not be pulled down more than half.
so with the 30amp pull will last perhaps 4 hours on a 300ah battery bank, assuming it pulls 30 amps constantly, best to test it with a killawatt meter
the inverter needs to be within just a few feet of the batteries,