Alt Power Source

A

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
So we are on a job where we had to abandoned shanties in the building and use trailers outside. They have no power available and say we have to use gas generators for trailers. It's costing us a fortune and we did not figure in the bid. Is there any other practical way to power these without any electric nearby..lol? :mad::mad::mad:🥹🥹
 
Hmm, solar and wind are free but are obviously not great choices. Any nearby buildings where you can get temp power? You might be able to make a deal with a building owner on a short term basis.
 
infinity said:
Hmm, solar and wind are free but are obviously not great choices. Any nearby buildings where you can get temp power? You might be able to make a deal with a building owner on a short term basis.
Click to expand...
Nope wide open at JFK airport. no building nearby.
 
In any 'off grid' situation, the first question is 'how much power and energy do you need?'

You may be using generators in a very inefficient fashion, if you aren't using much power but have the generators running to maintain power availability. Batteries and intermittent generator use, or batteries and solar could be a good choice. You might even use an ev, charge it off site then drive it over and use it as the power source. The key here is that you want power availability but aren't actually using much energy.

But if you are actually loading the generators significantly, then they are probably the cheapest source of temporary off grid power.
 
Alwayslearningelec said:
Wonder if any of these would work. Probably not as you have to plug in the loads and we'd need to feed a trailer panel.
Click to expand...
I'm thinking that the solar panel associated with the battery system will not fully charge the battery. Shanties have electric heat in the winter and AC in the summer running 24/7.
 
winnie said:
In any 'off grid' situation, the first question is 'how much power and energy do you need?'

You may be using generators in a very inefficient fashion, if you aren't using much power but have the generators running to maintain power availability. Batteries and intermittent generator use, or batteries and solar could be a good choice. You might even use an ev, charge it off site then drive it over and use it as the power source. The key here is that you want power availability but aren't actually using much energy.

But if you are actually loading the generators significantly, then they are probably the cheapest source of temporary off grid power.
Click to expand...
I appreciate your insight and do really need the help as we are using about 350 gallon of fuel a month right now in the winter for two trailers. It's running about 8-9 hours day.
How could one implement batteries along with generator.
 
Alwayslearningelec said:
I appreciate your insight and do really need the help as we are using about 350 gallon of fuel a month right now in the winter for two trailers. It's running about 8-9 hours day.
How could one implement batteries along with generator.
Click to expand...
You may already be doing the cheapest thing. Off grid power is expensive no matter how you slice it.
 
How much power is being used max, and what is the average per day? You could get this and plug it into the generator to charge it, or take it home each day and plug in to recharge. They offer a transfer switch with this one which you'd probably need if you want to connect the trailer in and not just be using extension cords all over. If you need 3 phase for the trailer panel, then it will be even more expensive. Solar charging is probably not cost effective for this, especially if you can move it and plug in to recharge or even if you have to use a generator to charge it.

is 7000W enough for max use and 5KW-hr's enough for the day? You can add more battery if needed, but cost and weight just goes up.

www.jackery.com

Jackery Explorer 5000 Plus | Whole-home Backup Power

5-60kWh Capacity & 7.2-14.4kW Output for reliable home backup power lasting up to 2 weeks. 120V/240V dual voltage enhances compatibility, supporting more loads like dryers, water pumps, ovens, ACs, EVs, RVs, etc. Fully charges in 1.7 hours, compatible with AC, high-voltage PV (4000W, 135-450V)...
www.jackery.com www.jackery.com

Another factor is to assess the generator. Is it way over sized? If so, consider a smaller one, but if you're using it days on end you probably want a commercial one and they only go so small.
 
The power source should have been in the contract documents, of addressed by an RFI. It can be a big issue.
 
suemarkp said:
How much power is being used max, and what is the average per day? You could get this and plug it into the generator to charge it, or take it home each day and plug in to recharge. They offer a transfer switch with this one which you'd probably need if you want to connect the trailer in and not just be using extension cords all over. If you need 3 phase for the trailer panel, then it will be even more expensive. Solar charging is probably not cost effective for this, especially if you can move it and plug in to recharge or even if you have to use a generator to charge it.

is 7000W enough for max use and 5KW-hr's enough for the day? You can add more battery if needed, but cost and weight just goes up.

www.jackery.com

Jackery Explorer 5000 Plus | Whole-home Backup Power

5-60kWh Capacity & 7.2-14.4kW Output for reliable home backup power lasting up to 2 weeks. 120V/240V dual voltage enhances compatibility, supporting more loads like dryers, water pumps, ovens, ACs, EVs, RVs, etc. Fully charges in 1.7 hours, compatible with AC, high-voltage PV (4000W, 135-450V)...
www.jackery.com www.jackery.com

Another factor is to assess the generator. Is it way over sized? If so, consider a smaller one, but if you're using it days on end you probably want a commercial one and they only go so small.
Click to expand...
Most construction trailers that I hooked up had between 10 and 20 kW of electric heat, and when the temperature dropped below 25 or so, the heat ran pretty much all the time.
 
Alwayslearningelec said:
I appreciate your insight and do really need the help as we are using about 350 gallon of fuel a month right now in the winter for two trailers. It's running about 8-9 hours day.
How could one implement batteries along with generator.
Click to expand...

First, it is unlikely that you really have a situation where batteries will save you money. Batteries are very expensive and don't store much.

Generators have an efficiency curve; they are less efficient (fewer kWh per gallon) when lightly loaded, and more efficient when heavily loaded. If you have highly variable loading, then your generator might be sized to match your peak load, but spending lots of time at partial load. A battery could help here by 'shaving' the peaks.

But if you have a fairly constant load, then you don't get any benefit from the battery. Adding a battery also won't help if you don't also change the generator.

The first thing you need to do is actually figure out what your electrical loads are, and how variable they are. Until you have this information, all other discussions are pointless.

As others have mentioned, if these are construction trailers, you probably have large significant heating loads. If you are using a generator to run electric resistance heating, then before looking at fancy/expensive tricks to make the generators more efficient, you should look at ways to make the heating cheaper.

-Jonathan
 
You must log in or register to reply here.
Top