Relocate batteries to reduce tongue weight

[RTBabich]

I would like to reduce the tongue weight of our 2009 WW FB2100. There are currently 2 6v batteries mounted on a rack on the tongue. There is enough depth at the rear to mount them under the bed of the trailer in the center near the spare tire. I can make access plates in the bed of the trailer for 2 drop in battery boxes. The boxes would be vented underneath and I know the requirements for cable sizing. I've been searching for an in-floor mount/drop-in style battery box, but haven't found much. Has anyone seen anything like that? In a few weeks I'm going to set up a lever scale to measure the tongue weight and shift the batteries to the rear for a second measure before cutting any holes. I'm thinking moving the batteries from 11ft in front of the wheels to 4ft behind has got to have some effect. It would be a more secure location for the batteries and still be accessible.

[Bedlam]

Maybe this would work on your trailer frame rails:

http://www.torklift.com/index.php/products/auxiliary-battery-storage/hiddenpower

[RTBabich]

shooted wrote:

Strabo wrote:
Your towing with a '03 Ford Expedition, what did you expect? Its a Mid Class SUV.
Buy a real truck, any flavor will do. Problem solved.

I fail to understand how replacing the expedition with a "real truck" or any other tv will reduce the tongue weight of the trailer. The op did not mention a "problem", only a desire to reduce tongue weight.

Thank you, shooted.
I'm just trying to dial in the trailer for how we are going to use the trailer.
I rebuilt the battery rack under our class-C when I upgraded from a single 12v to 2-6v and it worked just fine.
I'm not expecting the towing to be noticeably improved, I'm just looking to lighten the tongue weight for the Expy.
The batteries would be more secure from tampering/theft/sun heat if caged underneath.
Running the + cable from the batteries to a master cutoff switch near the power distribution block wouldn't complicate the wiring that much. There are 3 wires connected to battery + terminal now. Moving those to the master cutoff switch will help keep them all from corroding. Yes, I will need one rather large/long cable.
I'm not sure the fire department really cares where the batteries are, but is it a good idea to have essentially an arc welder right next to the propane?
With access plates in the floor I can still easily service/check the battery's water levels. It's a good idea to check the water level regularly.
I was originally asking if anyone has seen an undercarriage mounting rack, but I think making a custom one will do. I'm also thinking of adding a second spare tire on the left side. The batteries would still fit between the spares.
When I get the trailer all loaded with our normal stuff I'll weigh the tongue. Then I'll take a second measure with the batteries sitting in the back and see what it does.

[shooted]

Strabo wrote:
Your towing with a '03 Ford Expedition, what did you expect? Its a Mid Class SUV.

Buy a real truck, any flavor will do. Problem solved.

I fail to understand how replacing the expedition with a "real truck" or any other tv will reduce the tongue weight of the trailer. The op did not mention a "problem", only a desire to reduce tongue weight.

[RedRocket204]

souraider wrote:
You could always transport them in the back. Then when you get to your destination hook them up.

Uh, you mean disconnect them to transport? How will the mandated emergency trailer brake system work? There needs to be an available and charged battery hooked up to the system while in tow.

[Strabo]

Your towing with a '03 Ford Expedition, what did you expect? Its a Mid Class SUV.

Buy a real truck, any flavor will do. Problem solved.

[1L243]

Tongue weight should be between 10 and 15% of gross trailer weight. Your fine where you are now without moving the batteries. If you reduce the tongue weight you may make your problems worse. If your having sway issues you can add anti sway devices. If the TV is not handling the weight you can address that too with air bags.

[souraider]

You could always transport them in the back. Then when you get to your destination hook them up.

[Oaklevel]

It is not worth the trouble & will not be that noticeable. I would leave them on the tongue. It would be better to have them accessible to the fire dept. in case of an accident.

[otrfun]

RTBabich wrote:
The TV is a 2003 Expedition, 5.4L, 2WD, 3.73L, Class V factory tow package, 8900lb trailer, 880lb tongue, Equalizer 1K/10K hitch.
The trailer is a WW FB2100 5600lb, 9K max, 815lb tongue.
It will be lightly loaded for short camping trips.
I would think a 750lb tongue weight would be enough to keep sway under control.

Assuming everything remains *static*, 750 lbs. is 13-14% of 5600 lbs. That's within the typically recommended 10-15% tolerance for tongue weight.

To be prepared for *dynamic* situations, have you run the numbers with your waste/water tanks and fuel/propane tanks empty and full? With potentially unexpected toys/gear behind the TT's axles?

[phemens]

For what it's worth, I did this a few years ago on our trailer, moving 4 T-125's to the extreme rear of the trailer (vented in the rear garage) to reduce tongue weight as well. I ran that way for a few seasons, but in the end, I moved them back to the tongue, as it didn't make that much difference and ended up being more complicated for other wiring.

[RTBabich]

The TV is a 2003 Expedition, 5.4L, 2WD, 3.73L, Class V factory tow package, 8900lb trailer, 880lb tongue, Equalizer 1K/10K hitch.
The trailer is a WW FB2100 5600lb, 9K max, 815lb tongue.
It will be lightly loaded for short camping trips.
I would think a 750lb tongue weight would be enough to keep sway under control.

[otrfun]

I agree with your calculations. IMO, there's good chance you'll reduce your tongue weight at least 100 lbs. Removing the batteries from the immediate tongue area decreases tongue weight 100 lbs. Plus, there's an additional reduction by having 100 lbs. of counterweight behind the TT's axles. Depending on the amount of work involved it may be worth the effort. IMO, battery access and ventilation are the key points.

For those that worry about sway, numbers speak loudly. Reducing excessive tongue weight by transferring more weight on top of or behind the TT’s axles is absolutely a win-win situation (assuming the TT's GAWR is not exceeded).

Curious, what is the current length and gauge of cable from your converter to your batteries? Will the length increase or decrease by moving the batteries? FWIW, cable size (gauge) is typically undersized (restrictive) on most OEM installations. If you’re going to rerun the cable I would consider using a larger gauge cable. This could reduce electrical losses and decrease charge times.

[N-Trouble]

What is your tow vehicle? 1/2 or 3/4 ton?

I agree on moving the batteries wont accomplish much. What is your WD hitch setup and is it undersized?

[coolbreeze01]

Toys reduce tongue weight and enough tongue weight is important to eliminate sway.

I'd leave the batteries alone.

[calamus]

All that work to save 100 lbs?? Not worth it IMHO