The Roof Cleaning Institute Of America Training & Certification Forum
"Find A Certified Roof Cleaner Directory"

Ben Harville · Guest

Battery hook up question for 12V system

Guest

Believe it or not, it is much more complicated than you think.

It is very easy just to say you are going to use the 12v accessory terminal on a 7 pin trailer connector, but the connections quickly build up high resistance and the wire gauge is far too small to give any effective charging of 2 deep cycle batteries.

You really should isolate the trailer battery from the tow vehicle battery using an isolator. If you do not, you will try drawing current from the tow vehicle's battery through that same connection you are using to charge the battery.

My question to you would be, have you ever run into a scenario where the batteries went dead in the middle of the day when you were roof cleaning? I'm going to guess the answer to that is no?

There is a much easier way to make charging your batteries painless. Just take an automatic battery charger, place it inside another battery box, mount it close to your batteries on your trailer and connect it to your batteries. Every night when you get home, plug the automatic charger in and let it charge until the next day when you go out work.

If you park the trailer close enough to a garage, just mount the charger inside the garage and entend the cables to reach the batteries on the trailer. Use some type of quick connection device to easily connect or disconnect the wires when you return from or are headed out to work.

The automatic chargers have built in circuitry to maintain the proper charging current levels. Having the proper charging current levels helps keep batteries from sulfating. Sulfating causes premature battery failure.

The biggest draw back to the trailer/tow vehicle system is the expense associated with really doing it the right way. To get what you want out of this hook up, you will need to use very large gauge wire (6 or 8 minimum). You will need somewhere around 25 to 35 feet of that large wire and that is NOT cheap! The isolator will be necessary for your batteries in parrallel and a heavy duty connection device between the vehicle and trailer will be needed to handle the current capacity. Those connectors are not cheap either. You will also need some sort of circuit interruption device (AKA fuse or circuit breaker) that will have to be mounted close to the vehicle's battery and another mounted by each trailer battery. If you do not install these and have a wire get crushed (and it will happen eventually) the short will cause a severely overheated/melted wire, a damaged battery and possibly a fire.

There are a lot of other variables that can come into play. I know I made something that seems simple look very complicated, but that is because I have extensive experience with trailer wiring and battery charging systems. I have been in the automotive repair field for over 15 years and I am an ASE certified master technician. I spent 4 years working on a fleet of tree service truck and equipment and had extensive time into repairing and reconfiguring the electrical systems on both the trucks and chippers/stump grinders.

I personally do not try to charge my batteries through my truck's alternator. I hook the charger up when I get home from the jobs.

Brian

Algae*Free Roof Cleaning · Nov 20, 2009

That`s what I do also. Why would you have 2 batteries? I run my Fatboy on a 875 cranking power & I`m able to clean at least 3 roofs before I charge it. Kipp

Ben Harville · Guest

Thanks for your insight. I already have a charger mounted on the trailer, but we store our trailer in a storage unit that does not have power, so to charge, we have to take the trailer to one of our houses and let the charger run.
You do make a good point about battery failure, though, because I have done 7 roofs with my setup without needing a charge.

Redfisherman · ETERNAL MEMBER-RESTING IN PEACE

Ben,

I have searched this forum for months and read, read, read before I joined, I always wondered why this question was not answered, hopefully no one takes offense to my reply.

It is easier than you think and not as difficult as has been posted. Sorry guys being new I don't want to wet on anybodys campfire, or a PITA.

I the fishing business which I know quite well, we have a system that charges our trolling & cranking batteries on the way to and from the boat ramp. It hooks directly into the towing plug on the car or truck. Now before anybody starts to beat me up, I have used it for 5 years "successfully", towing my boat ($50,000 plus) a few miles or a thousand miles for a tournament and be completely charged and ready to rock and roll. It works for 12-24-36v systems. Your tow vehicle must be 1999 or newer and have the factory wiring for the tow connector, if not a newer vehicle the wiring kit contains the proper gauge wire and very detailed install instructions. Surely if you can put together a soft wash unit from the parts you buy, you can run 2 wires from the battery of your tow vehicle to the connector on your trailer to connect or disconnect your pump battery. I don't think anyone is running trolling motors on their trailer so the high $$$ unit is not needed only the standard wiring and connections very inexpensive cheaper than 10 gal of SH.

Should you have a self contained vehicle and not a trailer, just run the wiring to the area of your units battery and have the connection point there being able to connect while you are on the move or crank the vehicle if you notice a drop in battery charge while using the pump for work.

Additional information; your 1999 or newer vehicle already has the proper gauge wiring if you have a factory installed harness for towing all you need is to put a fuse in the main fuse box. If not what you are adding is the proper wiring and fuse so you won't burn your vehicle to the ground or overload the existing vehicle wiring harness causing damage.

For all that are interested drop me a line and I'll help you out.

Eric · Guest

i put a reminder in my phone to go off, every evening! it helps to remind me!

Feb 12, 2010

I agree that there is no need for two batteries at once on the fatboy. I use only one keeping a charged one on the truck just incase. I hump the battery home each night for a charge only because there is no electric by me. This year I am trying the compressor,I will keep the delvans on the truck incase of emergency.

RCIA Founder

The Roof Cleaners of Chester County Pennsylvania 610-842-2104 wrote:

Believe it or not, it is much more complicated than you think.

It is very easy just to say you are going to use the 12v accessory terminal on a 7 pin trailer connector, but the connections quickly build up high resistance and the wire gauge is far too small to give any effective charging of 2 deep cycle batteries.

You really should isolate the trailer battery from the tow vehicle battery using an isolator. If you do not, you will try drawing current from the tow vehicle's battery through that same connection you are using to charge the battery.

My question to you would be, have you ever run into a scenario where the batteries went dead in the middle of the day when you were roof cleaning? I'm going to guess the answer to that is no?

There is a much easier way to make charging your batteries painless. Just take an automatic battery charger, place it inside another battery box, mount it close to your batteries on your trailer and connect it to your batteries. Every night when you get home, plug the automatic charger in and let it charge until the next day when you go out work.

If you park the trailer close enough to a garage, just mount the charger inside the garage and entend the cables to reach the batteries on the trailer. Use some type of quick connection device to easily connect or disconnect the wires when you return from or are headed out to work.

The automatic chargers have built in circuitry to maintain the proper charging current levels. Having the proper charging current levels helps keep batteries from sulfating. Sulfating causes premature battery failure.

The biggest draw back to the trailer/tow vehicle system is the expense associated with really doing it the right way. To get what you want out of this hook up, you will need to use very large gauge wire (6 or 8 minimum). You will need somewhere around 25 to 35 feet of that large wire and that is NOT cheap! The isolator will be necessary for your batteries in parrallel and a heavy duty connection device between the vehicle and trailer will be needed to handle the current capacity. Those connectors are not cheap either. You will also need some sort of circuit interruption device (AKA fuse or circuit breaker) that will have to be mounted close to the vehicle's battery and another mounted by each trailer battery. If you do not install these and have a wire get crushed (and it will happen eventually) the short will cause a severely overheated/melted wire, a damaged battery and possibly a fire.

There are a lot of other variables that can come into play. I know I made something that seems simple look very complicated, but that is because I have extensive experience with trailer wiring and battery charging systems. I have been in the automotive repair field for over 15 years and I am an ASE certified master technician. I spent 4 years working on a fleet of tree service truck and equipment and had extensive time into repairing and reconfiguring the electrical systems on both the trucks and chippers/stump grinders.

I personally do not try to charge my batteries through my truck's alternator. I hook the charger up when I get home from the jobs.

Brian

Me 2 Brian, back when I ran 12 volt pumps, I simply plugged in my automatic battery charger at night.
Most roofs I ever did in a day with a 12 volt pump was 4.
I have regularly cleaned 6 roofs a day in the past with better pumps.

I don't think he neeeds to overcomplicate things with invlving the trucks charging system ?
Hell, 2 deep cycle marine baterys should be fine all day.

Guest

Apple Roof Cleaning Tampa FL (813) 655-8777 wrote:

The Roof Cleaners of Chester County Pennsylvania 610-842-2104 wrote:

Believe it or not, it is much more complicated than you think.

It is very easy just to say you are going to use the 12v accessory terminal on a 7 pin trailer connector, but the connections quickly build up high resistance and the wire gauge is far too small to give any effective charging of 2 deep cycle batteries.

You really should isolate the trailer battery from the tow vehicle battery using an isolator. If you do not, you will try drawing current from the tow vehicle's battery through that same connection you are using to charge the battery.

My question to you would be, have you ever run into a scenario where the batteries went dead in the middle of the day when you were roof cleaning? I'm going to guess the answer to that is no?

There is a much easier way to make charging your batteries painless. Just take an automatic battery charger, place it inside another battery box, mount it close to your batteries on your trailer and connect it to your batteries. Every night when you get home, plug the automatic charger in and let it charge until the next day when you go out work.

If you park the trailer close enough to a garage, just mount the charger inside the garage and entend the cables to reach the batteries on the trailer. Use some type of quick connection device to easily connect or disconnect the wires when you return from or are headed out to work.

The automatic chargers have built in circuitry to maintain the proper charging current levels. Having the proper charging current levels helps keep batteries from sulfating. Sulfating causes premature battery failure.

The biggest draw back to the trailer/tow vehicle system is the expense associated with really doing it the right way. To get what you want out of this hook up, you will need to use very large gauge wire (6 or 8 minimum). You will need somewhere around 25 to 35 feet of that large wire and that is NOT cheap! The isolator will be necessary for your batteries in parrallel and a heavy duty connection device between the vehicle and trailer will be needed to handle the current capacity. Those connectors are not cheap either. You will also need some sort of circuit interruption device (AKA fuse or circuit breaker) that will have to be mounted close to the vehicle's battery and another mounted by each trailer battery. If you do not install these and have a wire get crushed (and it will happen eventually) the short will cause a severely overheated/melted wire, a damaged battery and possibly a fire.

There are a lot of other variables that can come into play. I know I made something that seems simple look very complicated, but that is because I have extensive experience with trailer wiring and battery charging systems. I have been in the automotive repair field for over 15 years and I am an ASE certified master technician. I spent 4 years working on a fleet of tree service truck and equipment and had extensive time into repairing and reconfiguring the electrical systems on both the trucks and chippers/stump grinders.

I personally do not try to charge my batteries through my truck's alternator. I hook the charger up when I get home from the jobs.

Brian

Me 2 Brian, back when I ran 12 volt pumps, I simply plugged in my automatic battery charger at night.
Most roofs I ever did in a day with a 12 volt pump was 4.
I have regularly cleaned 6 roofs a day in the past with better pumps.

I don't think he neeeds to overcomplicate things with invlving the trucks charging system ?
Hell, 2 deep cycle marine baterys should be fine all day.

I agree. It's not necessary to overcomplicate the set up. It ultimately comes down to personal preference, but I always thought that keeping it simple is best.

I don't even use a marine, deep cycle battery and I have cleaned 4 roofs in one day multiple times without having any performance problems. Before anyone comments about my battery choice, I look for certain criteria in a battery. I have training classes through Deka and Interstate Battery Companies and that training dictates which battery I choose.

It is hard to clean more than 4 or 5 different roofs in one day using a 12 volt system, so two batteries should never be a problem during the course of one day.

The key to battery life is very low amperage charging. That is why the battery maintainers put out such low amperage. It only takes a few extra minutes to hook up the low amperage charger when you call it quits for the day.

Again, everyone has their own methods that they think are the best. This is just my personal opinion about the subject.

Brian

Redfisherman · ETERNAL MEMBER-RESTING IN PEACE

Well, it's good to know all posts unless they please everyone you get beat up. I too have had all the battery training classes, I DO use Deka and Interstate batteries in my boats NOW. Just excuse me for even wanting to help answer a question. It's not brain surgery, if you have trailer brakes on your trailer you are already wired, so why not... Never mind it's like spitting in the wind. Look at the picture below all you need is wires from your pump battery to the extra plug. Charge it on the way home, and just pump and scrub all day long to your hearts content, leave the wires curled in the trailer until your done. I only wanted to answer the mans question.

-- Edited by Redfisherman on Saturday 13th of February 2010 05:24:06 PM

Guest

Fred,
I wasn't trying to critisize you or your answer. You obviously know what you are doing with respect to your battery set up. What may seem easy to you or me may not be so easy to others. There are some on here that don't want any parts of building their own rigs. They want to buy a turn key set up because this stuff is too complicated for them. I just try to keep it simple for them. Sorry if I offended you. I didn't intend to do that. Text doesn't always translate the way it was intended.

Just an FYI about the trailer wiring on 99 and newer trucks. General Motors trucks/SUV's have multiple levels of trailering packages. All of the new trucks come with the 7 way connector, but the levels of wiring can be very different. Some have all the wiring right to the connector. Some have the stop, turn, marker and ground wire to the connector, but the electric brake, 12 volt accessory and back up light wires are taped off short of the connector and have to be manually installed in the 7 way connector in order for them to work.

If the vehicle didn't come with a hitch from the factory and the dealer installs the hitch at the dealership, the possibilities are endless for how the wiring came from the factory. I have seen them come with wiring front to back. I have seen them with wiring that stops shortly after it goes through the firewall and may not have all of the wires you need at the connector. Believe it or not, I have even seen wires exiting the firewall, wires completely connected to the 7 way connector, but nothing between the firewall and connector. Don't ask me why they would make a truck that had 2/3 of the wiring and not add the last 1/3, but I have seen many trucks come through that way. When a customer would come in and ask for a hitch to be added to their new truck they bought, many times it would be a crap shoot as far as what wiring was actually there. I have worked for GM for many years as a technician and a service manager. These are the types of things that really make you scratch your head when you see them. You have to wonder if this type of thinking in GM is company wide and that philosophy is what has led to their massive mismanagement of money and assest confuse

Brian

Redfisherman · ETERNAL MEMBER-RESTING IN PEACE

Brain,

Thanks for the reply, guess I let my usually thick skin get the better of me on this one. Well not so thick as when I had lead going through it. But that is another story....

Around 2004 time frame, as a Professionial Fishing Guide, I took 2 GM Engineers on a charter, well long story, short version, we fished hard ran the boat everywhere, ran the trolling motor all day, at the end the batteries were about gone. Back at the boat ramp they invited me out to Outback. That night, we (they) discussed, drew pictures on napkins etc,etc., a way to build a circut box, that could use the big motor to charge when operating and use the wiring from my tow vehicle to charge, top off batteries on the way home or to the ramp, at the same time isolate the unit from the on-board charger if I plugged it in. To me it was "like a hog looking at a wrist watch", I had no idea what they were talking about. Well...., they went back and built the circut box, and wiring diagrams, as you say there are things not so simple with truck and auto wiring harnesses. They also started a company from this idea, I keep waiting for my 1st royalty check, until then guess I'll keep working.

There are a few companies making this system now big $$$ for a roof wash system to add on as a convience, but only for boats. I have the originial design and schematic I was sent and use it on my stuff now, it works for me. For the older vehicles or vehicles that are not with all the extras in the tow harness, I can see where, just another wire added to your vehicle can be a scarry thing.

Best to just use the trickle charger at home. Only wanted to pass helpful info for those that put trailers away in areas that do not have electic to charge batteries. Some charge is always better than oops, off to Wally World or somewhere else to buy a battery for the job when there's pooped out at the customers home or job site.

I'll stick to reading more before I comment and not over complicate the issue.

Roof Cleaning Raleigh NC · Aug 27, 2010

Redfisherman wrote:

Well, it's good to know all posts unless they please everyone you get beat up. I too have had all the battery training classes, I DO use Deka and Interstate batteries in my boats NOW. Just excuse me for even wanting to help answer a question. It's not brain surgery, if you have trailer brakes on your trailer you are already wired, so why not... Never mind it's like spitting in the wind. Look at the picture below all you need is wires from your pump battery to the extra plug. Charge it on the way home, and just pump and scrub all day long to your hearts content, leave the wires curled in the trailer until your done. I only wanted to answer the mans question.

-- Edited by Redfisherman on Saturday 13th of February 2010 05:24:06 PM

Thanks for the picture. I know what you are saying now. David like pictures..pictures goood.

The Roof Cleaning Institute Of America Training & Certification Forum "Find A Certified Roof Cleaner Directory"

The Roof Cleaning Institute Of America Training & Certification Forum
"Find A Certified Roof Cleaner Directory"