Battery Box Mod for 6 Volts

[kscherzi]

My new trailer is now three years old. Not so new anymore. Frankly, I've made so many changes Airstream would hardly recognize their trailer anyway, so what's one more, which is to cycle out the stock Interstate Group 24 batteries and modify the battery box to accept larger capacity batteries. I've been reading much about the lithium batteries and their advantages, frankly think they're great. I was almost starting to go that route when reality hit, the work to redo all the existing wiring, the complexity, and then there's the price tag. Ouch. I need a new truck, my son is in graduate school ($$$), I just spent a lot on a new Trek road bike..... Maybe later.

In reality we are mostly weekenders and long week'rs. I never imaging full timing, but can imagine some long duration camping. If I'm hot, I'll probably pay to stay in RV park to plug in, but mostly stay at National and State Parks. Might boondock some, but I like to travel to tour, to experience different places and people.

So decided to go old school, lead acid battery upgrade. On my trailer the battery box is outside. No need for AGM's. I'm intrigued by the Trojan T-165 260 amp hour battery (130 usable). Not sure this is what I'll get but I know I need to modify the stock battery box as its only 10" deep and cannot hold any normal 6 volt (golf cart) battery.

Knowing this would require welding, and to make this even more adventurous, since I've never welded before, I bought a Harbor Freight welder figuring this should be just fine and of course I can do this. What a disaster. As I practiced with this new welder I discovered I could not make a weld to save my life. So what to do? Ahh.. watch a YouTube video. I learned the welder uses AC current and DC is what's required for decent welds. So after modifying the welder by rewiring and adding a rectifier and large capacitor to bridge the sine gap I ended up with a decent DC welder that works okay. After practicing on various metal bits I think I'm ready.

My stock Airstream 2013 external battery box was 10" deep. Most 6 volts are 11" to 12" tall. Their other dimensions are okay for the existing battery box. Using a straight edge I figured I could lower the battery box up to 3" and still remain in line between the jack and lowest point on the spare tire. The idea here is a object on the road over a hump would still clear the modified box if it cleared the spare tire. Since I've never dragged the jack nor spare tire, I figured this drop should be okay. I decided to drop 2.5" just to be safe.

Major tools used, a grinder with a cutoff wheel and sanding disk. A Sawsall with metal blade. My modified welder. Here's some photo's.



In the above photo I've cut the bottom off the battery box. No going back now!


Not trusting my welding skills I embrace a hybrid approach. I cut four 1/8" steel straps extending the bottom 2.5", securing it all with 3/8" bolts. I then weld them solid, including the bolts and nuts.



View from top.



Viewed from underneath.



To be fair, butt welding thin steel sheet is hard. I managed to weld enough to get complete connectivity along the length, but not 100% all the way. Burn through spots were hard to avoid. Ended up running a paste of JB Weld to fill in the gaps. After it cured I sanded it smooth.





After sanding and paint this is the finished result. Not too bad. You too can do this this with enough persistence. Just don't set your front yard on fire as I did when grinding off excessive weld splatter.

[Steamy1]

Nice job!
I am curious why you decided on this mod as opposed to just raising the lid as most of us have done, which involves considerably less work, I think.

[kscherzi]

Thanks. I have the 27FB trailer. The storage door is at the trailer front, directly adjacent to the battery box and opens downward. It would be impossible to raise the battery box even a tiny bit without impacting the storage compartment door. I think the 25FB's also have the same design and inherent battery box conflict.

[AWCHIEF]

I did it the easy way with the two inch extension. Like the finished results of yours better. Looks very clean and well executed.

[KJRitchie]

You are tenacious. Purchase welding equipment, modify welding equipment, experimenting with the welding equipment etc. Wouldn't it be easier to get a welding shop to have done the work?

I wouldn't be able to lift a 72lb battery into my A frame box.

I'm afraid if I ever need more than 220ah capacity the only choice would be a lithium upgrade but no chance unless the price comes down at least 50%.

Kelvin

[gandttimes]

Originally Posted by kscherzi

Thanks. I have the 27FB trailer. The storage door is at the trailer front, directly adjacent to the battery box and opens downward. It would be impossible to raise the battery box even a tiny bit without impacting the storage compartment door. I think the 25FB's also have the same design and inherent battery box conflict.

Luckily the 25FB does not have this issue as the access is on the side, but I like your mod anyway. Looks neater from the top.



George

[mfrez]

Just bought 2 Trojan T-105-RE's for $400 total. 220 amps should be enough for me with the Zamp factory solar. I have the 25FB and agree that raising the lid was easiest since there is no front storage to interfere with. I had a local metal fabrication shop build me a 2 inch tall aluminum C-channel frame attached to my lid for $60. Got it back in 2 days.
I just have to paint it now.
Some things are easier to farm out, but I like what you came up with given your storage compartment issue.

[casarodante]

Originally Posted by mfrez

Just bought 2 Trojan T-105-RE's for $400 total. 220 amps should be enough for me with the Zamp factory solar. I have the 25FB and agree that raising the lid was easiest since there is no front storage to interfere with. I had a local metal fabrication shop build me a 2 inch tall aluminum C-channel frame attached to my lid for $60. Got it back in 2 days.
I just have to paint it now.
Some things are easier to farm out, but I like what you came up with given your storage compartment issue.

Do you have an pictures of this addition? I am looking for some type of extension on the top for the taller batteries but I would also like some sort of short storage area for my Equal-i-zer parts.

Thanks!

[OTRA15]

Possibly a parallel threads FYI:

http://www.airforums.com/forums/f37/...es-150077.html

http://www.airforums.com/forums/f37/...5s-149505.html

[gecko]

When we purchased our 28' International new in 2009, we immediately sold the 12 volt AGM's and replaced with four six volt AGM's for a battery; bank of 440 amps, which is 220 amps usable if you only run down to a max of 50%. This has worked very well for us, boon docking up to a couple of weeks as early as March, even with maybe 35-45% of the time having cloud cover or fog. We did all of this with our dealer, and placed two of the new 6 volts in the battery box, and two in the L of the gaucho, where the converter-charger, circuit breaker fuse/panel, blue sky solar charger, hot water heater, subwoofer, and grounding "bus" for the BlueSky all live. So very little relocation, and just used huge gauge wire for the short distance from the battery box to the front of the coach.

The box modification was to add a 1" lip all around--this did the trick for the slightly higher size of the Lifeline AGM six colts over the stock 12 volts.

Our only challenge is 4 6 volt AGM's are A LOT of weight on the front of the trailer! We are now considering lithiums to change the battery weight from about 280-300 lbs down to 84 lbs, with almost all coming directly off the trailer tongue! So it did get expensive after all.

[greghoro]

Originally Posted by gandttimes

Luckily the 25FB does not have this issue as the access is on the side...

25FB Queen does not have front external storage compartment but 25FB Twin does.

Greg

[gandttimes]

Originally Posted by greghoro

25FB Queen does not have front external storage compartment but 25FB Twin does.

Greg

Wrong. Our 25fb queen has one side external compartment. The twin I believe has one on each side.


George

[SSquared]

Originally Posted by gandttimes

Wrong. Our 25fb queen has one side external compartment. The twin I believe has one on each side.


George

My 2013 25FB Flying Cloud came with three external storage compartments. The biggest one is at the very front. As was said previously, raising the height of the battery box would interfere with the compartment cover.

The other two compartments are one on each side, under the beds.

[greghoro]

Originally Posted by SSquared

My 2013 25FB Flying Cloud came with three external storage compartments. The biggest one is at the very front. As was said previously, raising the height of the battery box would interfere with the compartment cover.

What I was trying to convey, wasn't clear in my use of the word "front".

Thanks for the help SSquared


Greg

[kscherzi]

Originally Posted by KJRitchie

Wouldn't it be easier to get a welding shop to have done the work?

Yes it would, but I'm just strange about these things. Suppose also looking for an excuse to try out welding.

Originally Posted by KJRitchie

I wouldn't be able to lift a 72lb battery into my A frame box.

Not looking forward to that part. I may wait for my strapping young son to come back home from college this summer.

[gandttimes]

Originally Posted by SSquared

My 2013 25FB Flying Cloud came with three external storage compartments. The biggest one is at the very front. As was said previously, raising the height of the battery box would interfere with the compartment cover.

The other two compartments are one on each side, under the beds.

My 2014 FB international Queen has one external compartment on the awning side.


George

[Chucke]

I used aluminum tubing and flat straps with a diamond plate cover all purchased at Home Depot. Everything is held together with pop rivets including a piano hinge.

[Chucke]

Here is a photo of the new box lid.

[greghoro]

Originally Posted by mfrez

Just bought 2 Trojan T-105-RE's for $400 total.

Looks like a very good price, where did you buy them?


Greg

[gandttimes]

Originally Posted by Chucke

I used aluminum tubing and flat straps with a diamond plate cover all purchased at Home Depot. Everything is held together with pop rivets including a piano hinge.

One question I have is whether you can open the lid of the battery cover without removing the propane tank cover?


George