How much support to do batteries need?

booster · 11-01-2015, 01:01 AM

I have been searching for quiet a while to try to find out how much support batteries need from the battery tray. Obviously, they need to handle the weight, but does the tray need to have a full and strong bottom to support the bottom of the battery? I noticed Wincrasher's second battery upgrade had just the perimeter supported on slotted angle, did the original have the same method?

I ask as I am working on the battery upgrade on our van and there are several ways to do things, which would give varying support to the non edges of the battery case. Right now it appears that the best way to mount things is for the batteries to sit on one end, with the terminals on a vertical surface. Lifeline says this is an OK orientation, but don't say anything about support. The frame I built will totally support the edges, but the center areas would be only supported by whatever I use for a floor in the frame, and I would like to stay thin, like .08" aluminum, which is not all that strong.

Anybody ever heard or seen any information about this, or do I need to try to get through to Lifeline, which can be a bit of pain.

wincrasher · 11-01-2015, 01:14 AM

The more support the better, I am sure, but I think supporting from the edges is good enough.

The stock tray in my van is not a solid sheet - it has big holes in it.

AK49er · 11-01-2015, 01:52 AM

Would adding aluminum angle to the bottom plate add strength without too much additional weight and clearance? I like the idea of a plate instead of just perimeter support, maybe it's just for peace of mind.

wincrasher · 11-01-2015, 01:55 AM

You can buy galvanized metal pieces of various sizes at your local Lowes or Home Depot. Get a metal cutting blade for your chop/miter saw and a heavy vice to bend your pieces. Make anything you want.

booster · 11-01-2015, 03:55 AM

I don't have any problem getting anything I want to use as a bottom plate, as we have Discount Steel in town, so that is not an issue. Very reasonable to get anything you want. For me it is a question of added weight and height for whatever I use as a bottom for the battery tray. Leaving it open is probably not a good idea from a road damage standpoint, but minimal would be good, but with adequate battery support. Right now I am leaning toward 1/8" aluminum or .048 stainless for the tray bottom, which will just be a drop in. I don't want to get lower than the rear swaybar with the battery tray, so any amount of height I can eliminate is a good thing, but I also want to do what is best for the batteries. With nearly 300# of battery, things need to be pretty strong.

wincrasher · 11-01-2015, 04:12 AM

A tray assembly should probably be steel if you are mounting underneath. Thickness can be the same as you had for your generator supports. 300# may seem like alot, but it really isn't when the tensile strength of steel is in the 1000's of lbs.

I'd avoid mixing metal types - especially pairing aluminum with other metals. That can open another can of worms. I'd stick with steel if you had the choice, and powder coat it if possible.

Boxster1971 · 11-01-2015, 04:36 PM

I would agree that steel is the preferred metal for a battery tray. I recently took some photos of the way Airstream now mounts two 12V batteries under the Interstate B-vans. They use a heavy gauge sheet metal box to mount their Lifeline AGM batteries under the van short side down with terminals facing inward. Here is a photo of their battery box.

Boxster1971 · 11-01-2015, 04:52 PM

After looking at how Airstream mounted their batteries I chose to mount my battery upgrade in the same area with two 6V AGMs on each side of the van. I built racks from 1-1/4" steel angle welded to form a platform that supports the entire perimeter edge of each battery. They are mounted with the long side down which keeps the battery entirely above the lower edge of the van body sheet metal. I had to built an elaborate attachment system because I did not want to drill any holes in the Sprinter van frame members. Here is a photo of rack before painting and final installation.

Boxster1971 · 11-01-2015, 04:56 PM

I'm using my iPad and just discovered that it only lets me attach one photo to a post so here is a shot of the rack with batteries in my shop.

Boxster1971 · 11-01-2015, 04:58 PM

... And here is a shot of how the racks are installed on the van.

booster · 11-01-2015, 05:14 PM

Nice pics Boxster. Our frame material is all angle iron and steel tubing. The big question is not the strength of it, but of the bottom sheet that I am going to put on top of the frame. The setup is similar to what you have, but is for four batteries in a row, on end, with the terminals pointing out. In your pix it shows the battery area as open on the bottom, with the support only on the edges of the case, and that is what I wonder about, especially with the batteries not sitting on the normal bottom of the case. Every manufacturer case or tray I have seen has a full bottom of some sort, which may or may not be to support the "middle" of the battery.

Boxster1971 · 11-01-2015, 11:50 PM

booster - you've brought up a good question. I could add a piece of sheet metal under the batteries later if needed. I've seen a lot of edge only battery trays over on the Sprinter-Source forum when I was looking for ideas on how to build my battery trays. I finished installing batteries today. Now I'm building the connecting cables. I'm using 4/0 wire as the cables are about 3 feet long. I used a copper bar to connect the two 6V batteries on each tray. Also added an edge clamp to hold the batteries in the tray. The top side of the batteries are wedged against a frame rail under the van floor with a piece of rubber flooring pad so the are solidly held in place. Here is a photo of final installation.

eric1514 · 11-02-2015, 12:05 AM

That's a VERY nice install, but, IMHO, that solid bar connecting the two battery poles looks scary. If there is any movement between the batteries, even just vibration traveling down the road, that movement will be transferred to the guts of those batteries, perhaps loosening them up. I would use a flexible cable. I'm probably wrong, but rigid just seems wrong.

Eric

booster · 11-02-2015, 12:11 AM

Quote:

Originally Posted by Boxster1971

booster - you've brought up a good question. I could add a piece of sheet metal under the batteries later if needed. I've seen a lot of edge only battery trays over on the Sprinter-Source forum when I was looking for ideas on how to build my battery trays. I finished installing batteries today. Now I'm building the connecting cables. I'm using 4/0 wire as the cables are about 3 feet long. I used a copper bar to connect the two 6V batteries on each tray. Also added an edge clamp to hold the batteries in the tray. The top side of the batteries are wedged against a frame rail under the van floor with a piece of rubber flooring pad so the are solidly held in place. Here is a photo of final installation.

Looks nice, and a tight fit to get them in place! We have quite a lot of horizontal space for and aft, but side to side is limited by a frame member on the top that tapers in as it reaches the van floor. If we want width we have to go lower and the other way around. We are also a long ways from solid mounting surfaces, so it will probably be made with hanging bars and kind of trussed.

I have also seen some of the perimeter only mounts, but they were always homebuilt, and never factory, and that is what brought up the question in the first place. It seems odd to have all the plates (which will be parallel to the base in our case) pushing on the plastic end with no support in the middle, but maybe the plates are held in place so they don't hit the end. I think I will try to get a hold of Lifeline and see what they say about it. Can't hurt to see if they care or not.

Sounds like you are just about ready to go.

avanti · 11-02-2015, 02:04 AM

Quote:

Originally Posted by eric1514

that solid bar connecting the two battery poles looks scary. If there is any movement between the batteries, even just vibration traveling down the road, that movement will be transferred to the guts of those batteries, perhaps loosening them up. I would use a flexible cable. I'm probably wrong, but rigid just seems wrong.

I'm not sure how big an issue it is, but it probably would be good practice to fabricate such a bus bar with a U-shaped section bent upward a bit in order to make it springy.

Boxster1971 · 11-02-2015, 04:41 AM

Quote:

Originally Posted by eric1514

That's a VERY nice install, but, IMHO, that solid bar connecting the two battery poles looks scary. If there is any movement between the batteries, even just vibration traveling down the road, that movement will be transferred to the guts of those batteries, perhaps loosening them up. I would use a flexible cable. I'm probably wrong, but rigid just seems wrong.

Eric

Thanks Eric - I hadn't considered the vibration impact on the battery internal structures. I'll have to consider changing the connector to 4/0 cable. I have enough extra to do just that.

booster · 11-02-2015, 06:45 PM

I agree on getting rid of the solid bar for stress reasons.

I heard back from Lifeline, and they are good with perimeter support in all approved orientations, which is everything but upside down. Most have the plates oriented in the strong direction, so that makes sense, and in our case of the plates parallel to the floor of the battery case, they said the compression in the assembly is enough to make it a non issue.

Sounds like everyone is good to go. I will still be putting a floor in the case, but more from a debris and damage prevention standpoint, so it can be pretty thin and light.

Crank · 03-30-2016, 09:00 PM

Old thread now: but a new issue. My coach battery just sat, terminals up, on the steel floor of my Roadtrek. I don't know the steel thickness. There is some "random" supporting structure below the floor. I had been thinking about the support issue as I prepared to add an extra battery a few inches away from the original. They are both Lifeline GLP- 27T, 62lb each. I have decided it is not a problem (although I will sit them on rubber mats).

Crank

briancummings · 04-01-2016, 04:12 AM

Aluminum is easily corroded by battery acid, galvanized would be better.

Crank · 04-01-2016, 04:34 PM

Quote:

Originally Posted by briancummings

Aluminum is easily corroded by battery acid, galvanized would be better.

A good point Brian.

The floor of my original battery box looks to be galvanized. The second battery will be on enameled steel, and both will have a rubber mat under them.

I neglected to mention that I am putting in AGM batteries, which being sealed, are very unlikely to cause any acid problems.

Crank

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