Battery charging service?

There's no reason why you can't charge during the day while you're also using power from the battery. Get a 2000w generator (Yamaha or Honda is super quiet), a good AGM battery charger and a dc volt meter (even one that plugs into a power port if you've got a spare). Try running 30 minutes a day, 60 minutes a day, etc. and keep an eye on the final voltage to see how much run time is needed to get a decent charge. Try to do your other heavy uses while the generator is running.

using jumper cable from your truck to the trailers batteries will work but over the long run will be expensive in gas and wear and tear on the truck. (not to mention leaving your truck running for hours in the city.)

I can make a 250w range solar setup for around $500 each. I use two while camping for up to 34a of charging whenever the sun is out. Then again I use them out in the middle of no where and they don't grow legs. Installing them will cost some and make them safer but you will lose some of the power because they can't track the sun.

A small Champion 2000w inverter generator would be as quiet as any and cost around $500. With it you could charge when needed and use much less gas than the truck would. Even with solar you need a means of charging when the sun doesn't play well so getting the generator first may be prudent.

My first choice if I had one would be a small inverter type generator (Yahama EF-1200i or Honda EU-2000i) powering my converter for at least six hours during daylight hours, Not very noisy, and I would double chain it to the RV's hitch.

Alternate is the ONAN on board with a Gen-Turi to keep exhaust fumes above the roof where they do no harm. (The Smaller portable is preferred due to fuel consumption)

A 3rd alternative, which I have used, and I like it as much as the Honda 2000 is a Genrac 1000, this is a traditional generator (not an inverter model) but enclosed so the weight, fuel consumption and sound levels compare with teh Honda 2K, but.. only 1K out, but it is a true 1K out so it will run my Progressive Dynamics 9180 at full boost mode, And has.. Too bad it grew legs and walked off.

Invest in a Honda generator. I don't have one, but I was at a cookoff a while back where several of the contestants had them. They are so quite I didn't realize that any of them were actually running till I was within 10-15 feet of them.

Not difficult, Not terribly expensive to go solar.
Assuming self install it should be about same as a Honda 2000 or slightly more depending on size and equipment.

If the area is basically secure you could just lean them against the RV to get started.

But you do need sun. If you are parked between a large hotel and a high rise office tower shade might be an issue.


This may give an idea what is involved:
Forum Members Solar Installations With Pics

We used to charge $7.50 for a battery charge back in the '80s.
That was minimum labor charge back then for a corner gas station.

Good to know.

What do repair shops, garages, etc., generally cost to charge up a large battery overnight?

100AH in AGM batteries can be replaced to 90% in a couple of hours with a 50 amp or bigger charger. My truck has a 130 amp alternator and would have them back to 90% in a couple of hours or less. Otherwise, auto repair shops have chargers.

I see I should have explained more :).

We don't have a standard RV -- it's a self-built project, and we don't have a generator. Didn't think we would need one :/.

We'll be in a dense city. Not a place where people have lawns or lawnmowers.

The batteries are AGM, so no concerns about gassing. They are 2x50aH and 1x100aH, so they need quite a few hours to charge.

We could get a generator, but I really don't think it's realistic to run it for 5+hours...and it would have to be at night, mostly, as we will be using the batteries during the day.

It's not a construction job; I don't know what gave that impression. Some auto work and stuff, running hoists, etc.

@smkettner Is that a typo? Did you mean INexpensive? Or not?

Time to go solar. 400 to 600 watts is not all that difficult or expensive.

Otherwise a local gas station that does service can do a recharge and I think you will find it expensive.

Your built in generator.

Why do you question not being able to run the generator because you are in a city? That seems weird, and it is no more noise than a lawn mower.. .

You should be able to run the generator during the daylight hours.

What do you plan on powering?

If it is a skillsaw, it can draw 15 amps per hour at 120 volts, or more than 20 AH per day - even with only a few dozen 30 second cuts!

Do you need to also recharge cordless drill batteries?

My suggestion is to plug in all the cordless drill batteries and run the generator during lunch or shortly before or after, and also run power tools at the same time. The RV charger should put out around 35 - 45 amps per hour, but usually only the first hour is at the full rating, then it will drop off quickly.

While your battery has a "Lab" rating of 200 amp hours, don't expect to get more than about 100 AH out of them.

What is the largest load that you plan to run? That will dictate the inverter size. You need to locate the inverter near the battery, but not in the same compartment, as the battery gives off hydrogen and that is explosive and also can corrode the inverter circuit board material.

Most construction sites do have a 120/240 volt electrical panel to run the construction equipment. Normally they would also have a bunch of extension cords running everywhere.

What about the neighbors? Can you get power from them? It might be possible, but you probably will not find out until you get there, perhaps invite them to a Saturday BBQ to get to know the neighbors, and spread some good will. This can do a lot to help improve the site security, as after having a BBQ with you and the construction group, they might be more likely to call the cops if they hear someone packing up the construction materials onto a truck at midnight!


If you really could not use the generator, then consider at least 500 watts of solar panels. Try this website. SunElec.com You can write back about the size and number of tools, and perhaps get a idea of how much power you will really use each day. How large of a project? Remodeling 500 square feet or building a 2,000 square foot home? It makes a huge difference!

Home Power Magazine has written articles about construction site solar generation to power all the construction tools and equipment. They used 6 golf cart batteries and a 1,000 watt solar system. As the house was getting closer to completion, then the main house 2,500 watt system was also connected to the batteries, and all worked together to run the tools. This eliminated the need for running a generator.

Good luck on your project.

Fred.