Move battery to rear bumper???

[WIBadger]

skylarkva @ post #14:

I just finished moving a pair of golf cart batteries to the rear bumper of our 264BH. In our case I couldn't get the tongue weight down to a comfortable range without moving those 2 heavy parts to the rear. I had a shop fabricate a tray out of angle iron to fit the bases of the two boxes, used square d-rings to hold it in place, and strapped the batteries around the bumper. .... I also reinforced the bumper "just in case" with the brackets from mount-n-lock.

I realize you have already spent some money on the fabricated battery tray. However, I would have recommended that you NOT do that. As I understand from your write-up, the bumper is supporting the tray and batteries. If my understanding is correct, a couple of things to note. The bumper is the weak link in your setup. Many folks think (incorrectly) that the bumper is a solid, durable support mechanism for carrying bikes, generators, and the like. It is not. The other problem is that anything attached to the bumper is subjected to a lot of road shock/vibration, thereby helping to destabilize the bumper attachment/weld points. For example, next time you see a trailer with bikes mounted to the rear bumper, make a note of the amount of stress subjected onto the bumper (and trailer frame in general) from road shock/vibration as the bikes are "thrown" upward and downward.

Also, the batteries may have a shorter life span due to damage of the lead plates inside the batteries from the road shock/vibration.

I guess my point is that since you are unlikely to redo your battery tray so that it is attached to the frame (but that wouldn't solve the potential damage to lead plates), you may want to closely examine the bumper welds as a periodic maintenance item as opposed to never examining simply because it appears "rock solid" when the trailer is stationary.

[WIBadger]

ctbailey1 @ post #15:

As for the electrics... just determine the gauge of the wire running to the battery right now. Buy the next size heavier gauge wire (cable) and use that heavy stuff to run to the tail of the camper.

"just determine the gauge and buy the next size heavier gauge wire???" WRONG. BAD ADVICE TO SOMEONE WHO KNOWS "NEXT TO ZIP ABOUT WORKING WITH ELECTRICAL DODADS. (see post #17)

There is a proper/correct way to determine the correct gauge size for a DC circuit and it involves knowing the length of the circuit and the amp flow so that one has a 3% (or less) voltage drop.

[bono]

Did anybody install a battery tray in the back of White Hawk which would be attached to the frame? Would using gel batteries on the back tray be a better option? Or they can be damaged similar to batteries with lead plates?

Additionally, what kind of bike racks do you use in the back of the trailer? I read that Thule and Yakima do not recommend / warrant their racks when use in the back of the trailer.

thanks!

[33 RLDS]

How about using a sealed AGM and mount it inside. Or use a conventional battery and vent the vents to the outside like many cars do. My Olds has the battery under the back seat and vented to the outside through the floor.

[Ottawasteve]

I would also be interested in seeing some pictures or rear mounted batteries if anyone has them.

Recently installed my deep cycle batteries which will not fit on the tongue mounted tray so I installed them on rails that run under the propane tank cover (pictures: search 284 BhBE Extra Batteries). Not happy with how the Group 27 batteries in their boxes sit, so looking for an alternative. Mounting my 2 Honda 2000 generators to tongue and moving batteries rear bumper would be an excellent solution. As long as proper gauge wire is used and aside from aesthetics, I do not see a downside.

IMHO, batteries mounted on top of trailer bumper would not compare to bikes mounted on the fulcrum of a bike rack. Having observed my camper from the rear, I do not believe there would significantly more vibration or bouncing at the back of the camper than on the tongue and if this was a concern, this could be mitigated through the use of an AGM battery. For that matter, everything on your camper and tow vehicle will last longer if you leave them stationary and do not subject them to the rigours of road travel.

[skylarkva]

Originally Posted by WIBadger

skylarkva @ post #14:

I realize you have already spent some money on the fabricated battery tray. However, I would have recommended that you NOT do that. As I understand from your write-up, the bumper is supporting the tray and batteries. If my understanding is correct, a couple of things to note. The bumper is the weak link in your setup.

This is a valid concern, but not that I did reinforce the bumper using the Mount-n-lock brackets. The welds are now reinforced by a steel bracket bolted to the frame.

But, the usual failure point on bumpers has more to do with torque applied to the bumper than lateral forces pressing down. Bike racks and storage trays hang out behind the bumper, so as you bounce down the road you are getting the weight of your cargo on the end of a lever trying to twist the center.

In this case the batteries have a 7 inch base, on a 4 inch surface. They are slightly offset to fit, so about an inch overhang on the camper side and 2 inches to the rear. Being strapped down tightly, they don't bounce the way a cantilevered load would, and they are applying force directly downwards, so it's a completely different set of forces at play. I've also positioned them at one side, over the frame attachment point.

Originally Posted by WIBadger

skylarkva @ post #14:
Also, the batteries may have a shorter life span due to damage of the lead plates inside the batteries from the road shock/vibration.

Also something I thought through. As above, the batteries aren't bouncing in the same way that a cantilevered load would, being firmly attached to the bumper/frame. There would be a small difference in this case between vibration at the front and vibration at the rear. I decided that the added beefiness of the golf cart batteries I'm using over the standard marine hybrid battery is enough to offset that. Ask me in 5 or 6 years!

A couple pics-




Note the Mount-n-lock bracket around the bottom & back of the bumper.


You can just see the breaker for the positive side in there. Negative is attached to one of the bolts for the support bracket, behind the frame rail in this shot.

[ctbailey]

Originally Posted by WIBadger

ctbailey1 @ post #15:

"just determine the gauge and buy the next size heavier gauge wire???" WRONG. BAD ADVICE TO SOMEONE WHO KNOWS "NEXT TO ZIP ABOUT WORKING WITH ELECTRICAL DODADS. (see post #17)

There is a proper/correct way to determine the correct gauge size for a DC circuit and it involves knowing the length of the circuit and the amp flow so that one has a 3% (or less) voltage drop.

I'm not entirely sure it matters, we're not building a nuclear power plat, right? The normal draw for a stock RV battery setup would be what? 10-15 amp hours? You're correct about a 3% voltage drop for running alternating current to a motor. But by going up a size from the current gauge, for an additional 25 feet of run, common sense says that will be totally sufficient.

I'm not sure why a fellow forum poster would use YELLING and jump up and down stating my post was WRONG without providing any further answer.

Have a nice day. I wasn't able to respond till now, simply because I was camping this weekend. You all have a nice day, and I hope this internet "discussion" between total strangers actually helps the original poster, but I'm afraid it has just served to confuse them due to a bunch of Internet urban legends (the bumper not being string enough) and a bunch of self-important "expert" RVers who instead of actually camping, spend their time trolling the Internet forums.