VikingTrad3r

hi guys, I'm asking this here in the general area of the C4 forum because I've gotten to know some of you guys fairly well and I really don't spend any time outside of the C4 section.

my question does involve engines so hopefully I won't get thrown off for this.

here is a description of my situation followed by a few questions. Appreciate any feedback you might be able to offer.

description: i have a few engines that run hydraulic power units off the crank shaft which are powering driveheads on oil wells. the engines run in shacks like the one pictured here. i have 3power shacks, a v6 chev, a 350 chev, and a 5.9 12v cummins. All have been provisioned for natural gas/propane fuel. The only belt drive "accessories" are the waterpump and the alternator to power the battery setup which is two 12v batteries connected in parallel to keep the 12v and give a bit longer run time ro some dc electricals that are powered by the second battery in the event of an engine shutdown.
There are some mission critical electrical items that run off the second battery.

my questions:

1. i would like to attach a 110 1500watt inverter on the system to power a few basic items and plug a car in overnight in the winter. How do i calculate if the draw from the items i want to plug into the 110 inverter is going to kill the batteries (like, maybe the alternator cannot keep up)

2. , can i just get a much bigger after market alternator to massively boost the output capacity to keep up with charging the batteries?


3. is it possible to bolt on more alternators to keep the system powered? through a seperate battery setup devoted to my 110 block and cab heater ?

i know this isnt a corvette question so if im offside asking no problem. im not really sure where else to ask and i though some of my c4 brothers (and sisters) may know the answer.

Cheers. pics attached.


this is a burner heating a 1000bbl tank. the controls are powered by the battery setup i mentioned.
this shack has the v6 in it. propane tanks are filled in case natural gas pressure is too low
the v6. she runs 24/7
alternator and waterpump are the only accessories. i see there is a blank pulley installed here on this unit
blank pulley
the v6 heads
the gas three that feeds the engine (couple ounces) and the burner when its on it takes a few pounds of pressure.
thats the drivehead powered by hydraulic fluid which is driven by the engines
that a well we drilled and awaiting being tied in
another shot of the shack

Benny42

The 12v to 115v conversion would probably make that hard, or quite expensive anyway.. The inverter will draw 110 amps or so on the 12v side to make 13 amps of 115v. Do the engines run continuously? A 5k generator belted to the engine and pullied to make it run at 60hz may be an easier option for plugging in the car. Interesting project

Patsgarage

I would think that you could run as many alternators as you could fit on the drive belt, you could even wire each one independent of the others. I would also talk to a local alternator/starter rebuilder about sizing a custom unit for whatever your load is. As for the inverter setup the genset Benny42 mentioned like a good idea, but the V6 might not be up to that much of a load.

VikingTrad3r

is an alternator just a really weenie generator?

if i could get three alternators on the belt, would they all get attached to the same battery and the result would be a very fast charging battery?

or would it have to be a unique set of batteries for each alternator to avoid over charging?

the genset i like the idea. if there was any question about load though, i wouldnt be able to do it as the primary function (turning the oil well pump) cant be compromised.

Patsgarage

I am not sure how you would calculate the load of the genset, the inrush would be the biggest draw, but I would only consider it with the Cummings diesel.

Benny42

I am amused at the names, alternators make DC and generators make AC (for our purposes). A 5k genset may be too big, it would need about 7 HP to run at full load (40 amps @115v). If you don't have that HP to spare, limit your load and the HP requirement will be less. 750 watts per HP is going to get used if you use a genset or an alternator and an inverter in a perfect world. The inverter route will use more power in the real world.

crowz

If you want ac then I would recommend 24 volt over 12 volts. All you have to do is wire at least 2 12volt batteries in series and then add a 24 volt alternator to motor you have. Everything else stays the same. I use a lawn more with a 24 volt truck alternator hooked up where the deck was to charge the batteries for my home (solar setup) if its storming outside. My daughter rolled a 1999 dodge 1500 pickup I sold her 2 weeks ago so Im converting it to be my homes backup charging source since when I had it before and wanted to get bad gas out of it the thing ran 13 hours showing empty on the tank. With a full tank I should be able to run it for a solid 130 or more hours easy.

Anyways the reason for the 24 volt vs 12 is efficiency. It takes much smaller wiring to make large wattage output from an inverter the higher your dc voltage is to start with.

I use aims inverters. This is one of the inverters I use :


I recommend not cheaping out on the inverter. Go for a sinewave for instance since that will be safer on electrical devices. They cost more but are generally are more efficient and more stable than the cheap Chinese models.

The alternator I use cost $80 I think off amazon.

Tod Stiles

OK lets straighten this out a little. An alternator creates A/C which is then sent through a rectifier where the output is nominal 12v DC but really is around 13-14vDC. Generators create DC current directly. Alternators are used now because they can maintain output at a lower rpm and are lighter among other things.

I'd bet the alternators you have are probably the lowest rated available 50-60A. A 1500 W inverter will draw usually around 140A max. and around 1A no-load. Check the specs of the inverter you're interested in, that'll tell you the draw. Anyway you're talking 230-250A 12V alternator to be bullet proof and have everything loaded down at once.

As crowz already said you could go 24V system. You have to change the alternator anyway. My only thought on that is if people are expecting a 12V system because of who knows - other 12V installs or whatever. And yeah get sine wave not modified sine wave. A little more expensive but you don't have to worry about screwing up a piece of equipment that expects sine wave.

Paul Workman

Interesting project.

Maybe I can condense this a little?

For critical equipment, it might make sense to keep its power source separate from non-critical stuff. You can build in as much backup (redundancy) as is critically necessary for the operation.

Then you'd want to consider the noncritical AC load.

Both the critical and noncritical circuits can be power by the same battery/inverter, as long as there is a redundant inverter covering the critical devices.

The total AC load determines the base generator capabilities. And, just because an alternator/rectifier is rated at (say) 100A @ 12V isn't the same as what the unit can deliver on a continuous basis.

And, as some have already pointed out, certain kinds of equipment, especially motors or transformers or battery chargers that are designed to operate on sine wave voltage sources can over heat and or draw excessive current when powered from a square wave inverter - causing it too to fail prematurely.

The kind of equipment your dealing with, I'm guessing is not just a "hobby" question; a situation where a goof is just a leaning experience. , true? To do it right, it is going to require a bit of engineering, either on your part, or someone that does this for a living.

So, regardless of who does the "noodling" you might want to first start by laying out a schematic picturing what is connected to what, and where the critical items are. Then gather all the load data; how many watts or volt/amperes the AC equipment requires, AND what kind of equipment it is (that pesky "square wave" thing again, e.g., inductive loads may not do as well with square wave, whereas incandescent lights don't care. (As some mentioned, you may need to specify a true sine wave inverter!)

Now, if you're comfy with kludging together your own system, more power to ya. But, if you do, there are things that are likely to become issues you may not have considered. One that sprang to my mind was you asked if you could "gang" alternators* together to share the load.

*automotive alternators have inherent full-wave rectifiers built in to produce a DC output.

Well, technically it is possible, but if you don't consider load balancing, whichever alternator is putting out the higher voltage may inherit the bulk of the load resulting in a load unbalance and cooking first one alternator, and then like dominoes, the rest will fail in turn!

A lot to think about, especially if this is important (i.e., critically important!). Without knowing more of the particulars, or even when you have them all figured out, the people I found very helpful when designing UPS for remote microwave repeater sites (back when I used to work for a living) are the people at La Marche, for example. They've been in business for many decades, designing and building custom and turn-key UPS systems for all sizes of applicaitons. Good people. You'll learn LOTS, even if you don't end up buying any of their stuff.

Oh, and BTW, you'll learn some tricks on ganging and series circuits which can save money and still use, for instance, 12V alternators and DC inverters to charge 24 or 36v battery banks...

Several options, but it starts with gathering all the particular information, beginning with that layout, aka "schematic"!

Benny42

You know, a propane carburetor on a 5K campsite type generator may be easier and cheaper. Even getting 1 per site may be less than modding the well pumps.

VikingTrad3r

i like this concept. would i have to pull heads and put hardened valves and heads due to propane? i know thats done to all the oilfield lrime movers.

confab

And they make propane and natural gas gensets.

If this well head is mission critical, why add points of failure to it when you have a gigantic gas supply right there?

Benny42

That likely depends on the expected run time. Long periods of high load, yes. Intermittent light to moderate loading, no.

crowz

If you do the gas or propane generator method remember to get one large enough. Someone mentioned well pumps when I was skimming thru the replies and I prefer at least an 8000 watt generator for a well pump. They don't take much power to run its the starting them that's tuff on the generator. Most cheap generators give very inflated results for what they can do. 5k in my experience wont start a decent size submersible pump. 8k is a safe minimum. Pumps are normally 220 volt too not 110.

The main reason for the 24 volt setup is to lower the amps needed. A 100 amp 24 volt alternator will power 2000 watt inverter like it isn't even there.

A 100 amp 12 volt alternator doesn't make enough power to feed a 2000 watt inverter at idle normally. If it does its under a massive strain. My 24 volt inverter for instance pulls about 40 amps maxed out normally. My 3600 watt 12 volt inverter in my f150 for instance pulls 80 to 100 amps at around 2000 watts load.

Making 40 amps at idle with a 24 volt alternator is easy, doesn't heat the alternator up and doesn't choke the motor down that's powering it.

12 volts doing 100 amps at idle on any alternator is very hard on the alternator and can roast most of them for long term use. Alternators get very hot under high loads and at idle there isn't much in the way of cooling for them.

By adding a 24 volt alternator just for this project and leaving the current charging system intact at 12 volts means you have the 24 volt for the inverter and the 12 volts you had already for any 12 volt needs you have.

Throw in a few 24 volt solar panels with a cheap controller and you wont even need the motor during the daytime

yd328

Would an alternator similiar to a Delco Remy 55si work?

Gary

crowz

Yep but its going to cost a fortune compared to one of the 24 volt old fashion truck alternators.

This is what I went with.


Shows to be $100 now. I paid $80 when I bought mine best I remember. It self excites so no special wiring needed. Just hook up positive to the lug on the back of the alternator and then ground to the case and your good to go.

When it hits 500 rpms it starts charging.

ghoastrider1

would having one of those huge bus battries help?

VikingTrad3r

thanks guys.

so the truck i want to park overnight is a kenworth pressure truck we use for loading and desanding and pushing flowlines.

apparently the draw from the block heater on trucks this size are huge and no 12 or 24 v alternator could keep up.

so that puts me to the idea of adding a belt drive genset on the pulley. i cant suck any more hp off the 350, the v6 wont do it, which leaves the cummins.

anybody know if i can get a cummins crank pulley with a v-belt groove in it? i could have a groove machined into the oem pulley if there is enough room, or, could weld and balance it. rather go off the shelf part though.