Material thickness for this battery rack?

[Crawford]

So I have a question for you guys. The project is to try and create a battery rack on the cheap and I'm wondering what I can get away with? I need it to hold four batteries inside the two pieces of channel:

length of green channel is 33" 2" spacing on batteries.

height of red tube is 16"

batteries L 7" x H 8" x W 12" Weight: 65-70lbs each.

original design was

red tube: 2x2x3/16"
light/dark green angle: 1.5"x1.5"x1/4"
Yellow plate feet: 4x4x3/16"

The feet will bolt to concrete when weight is on them.

Now that I'm getting a rough cost, I'd like to make it a little cheaper and save some weight where I can without getting too technical in braces and cutting angles.

I'm thinking now:

red 1x1x.120 or 2x1x.120
green: 1x1x.120
yellow: 3x3x3/16

Any suggestions? Kinda wondering if the above smaller/thinner material will still hold 200lbs without destruction.

Disclaimer: this is not for me otherwise I'd build it and play around with differing thicknesses.

[DSW]

The angle is where most of the support will come from the way you have it drawn. I'd go with taller angle if you go lighter. Also you will want some braces to connect the angle across the bottom. The big thing when loading angle is that it will want to twist, and as soon as it twists, the load vectors will change and things go sideways from there often. The temptation would be to use the angle in an L fashion. However it will be hard to brace unless you run the braces between the batteries out of flat stock. In reality the batteries will partially act as the bracing also, but that can cause issues when on battery is remove if things are too light and it starts to twist. A better way would be to flip the angle so the leg goes down rather than up, and then run angle between the rails for support. The down side is that you loose the natural "rack" effect that angle gives used the other way. A set of center legs will also go a long ways to allowing you to lighten every thing.


As far as the legs, the way you have them drawn, it appears they will be very short. If so light tube will support quite a bit of weight over a short span. If the legs are taller, then you will have to enlarge or beef them up to prevent buckling from the eccentric loading.

Keep in mind that the batteries you appear to be showing will most likely be acid filled. Expect corrosion on a metal frame. Just look at the brackets in a car that are steel and near a battery. Thats a good reason for staying with heavier materials.

Note: If this was actually designed by someone, be very careful making alterations without written approval. Should something go wrong it will be on you, regardless what was said or suggested. I can't count how many times someone has wanted "cheap" then been unhappy with the predictable results. At that time they won't care how much you saved them back then, they'll just want you to fix the problems that "you" created. Just CYA.

[MarkBall2]

Ask Joker about battery racks. His job uses batteries for back up & they are clamped tight in the rack. Side to side & the plate are tight. This prevents the batteries from swelling & breaking the cases.

[Crawford]

Originally Posted by DSW

The angle is where most of the support will come from the way you have it drawn. I'd go with taller angle if you go lighter. Also you will want some braces to connect the angle across the bottom. The big thing when loading angle is that it will want to twist, and as soon as it twists, the load vectors will change and things go sideways from there often. The temptation would be to use the angle in an L fashion. However it will be hard to brace unless you run the braces between the batteries out of flat stock. In reality the batteries will partially act as the bracing also, but that can cause issues when on battery is remove if things are too light and it starts to twist. A better way would be to flip the angle so the leg goes down rather than up, and then run angle between the rails for support. The down side is that you loose the natural "rack" effect that angle gives used the other way. A set of center legs will also go a long ways to allowing you to lighten every thing.


As far as the legs, the way you have them drawn, it appears they will be very short. If so light tube will support quite a bit of weight over a short span. If the legs are taller, then you will have to enlarge or beef them up to prevent buckling from the eccentric loading.

Keep in mind that the batteries you appear to be showing will most likely be acid filled. Expect corrosion on a metal frame. Just look at the brackets in a car that are steel and near a battery. Thats a good reason for staying with heavier materials.

Note: If this was actually designed by someone, be very careful making alterations without written approval. Should something go wrong it will be on you, regardless what was said or suggested. I can't count how many times someone has wanted "cheap" then been unhappy with the predictable results. At that time they won't care how much you saved them back then, they'll just want you to fix the problems that "you" created. Just CYA.

I drew that finger pant there.. Thank you for the input, I plan to add some tube to keep it from twisting out then, the batteries are 100% fully sealed with tabs for lugs, they aren't your average car battery so the corrosion issue should be pretty low.

Originally Posted by MarkBall2

Ask Joker about battery racks. His job uses batteries for back up & they are clamped tight in the rack. Side to side & the plate are tight. This prevents the batteries from swelling & breaking the cases.

Normally my boss buys racks for customers (we're into repeaters and 2 way communications) but this will be for his house and a super expensive/nice battery rack is not in his vocabulary. the plan is to weld some tabs to the outside and install some studs, bend up some 1/8th strap and add some little rubber feet to hold the batteries down. Sadly I'm open to suggestions however my boss is pretty closed minded but we'll see what I can work with...

[Boostinjdm]

I'd just double the size of everything you listed and you'd be close. Even doing that, the cost of materials will likely be less than the cost of one battery.

[Crawford]

Originally Posted by Boostinjdm

I'd just double the size of everything you listed and you'd be close. Even doing that, the cost of materials will likely be less than the cost of one battery.

I wish that were true. cost of this pallet was 85 dollars total. It only has to hold 4 batteries and 200ish lbs total

[jman]

Considering the 'short distance' across the length of the Angle Iron, my feeling is that it will be PLENTY strong. How high are you going though...? Is this something that you'll be stacking more than 2 high?

Cheers,

[BCRD]

I don't know if this is within design parameters, but I would price out some welded bar grate (do a google image search if you are not familiar with it). Local shop might even have some offcuts lying around...

Jason

[dave powelson]

Originally Posted by Crawford

So I have a question for you guys. The project is to try and create a battery rack on the cheap and I'm wondering what I can get away with? I need it to hold four batteries inside the two pieces of channel:

length of green channel is 33" 2" spacing on batteries.

height of red tube is 16"

batteries L 7" x H 8" x W 12" Weight: 65-70lbs each.

original design was

red tube: 2x2x3/16"
light/dark green angle: 1.5"x1.5"x1/4"
Yellow plate feet: 4x4x3/16"

The feet will bolt to concrete when weight is on them.

Now that I'm getting a rough cost, I'd like to make it a little cheaper and save some weight where I can without getting too technical in braces and cutting angles.

I'm thinking now:

red 1x1x.120 or 2x1x.120
green: 1x1x.120
yellow: 3x3x3/16

Any suggestions? Kinda wondering if the above smaller/thinner material will still hold 200lbs without destruction.

Disclaimer: this is not for me otherwise I'd build it and play around with differing thicknesses.

1- "length of green channel is 33" 2" spacing on batteries."

.....ummm..... 4 x 7 = 28" , 5 open spaces @ 2" = 10", 28 + 10 = 38"

The support angle for the batteries needs to be stiff.
1 x 1 x 1/8 angle is going to bow with 280+ #

2-your first selection of steel sizes was more reasonable.
2 x 2 x 3/16 angle wouldn't hurt.
You're not talking that much money for the steel-anyway.
Do yourself and the customer a favor by building it stout
enough--the first time.

[Crawford]

yeah bit of a typo, 1" spacing between batteries, with .25 on each end =31.5"

heres the revised design.

Angle on bottom serves as a support brace for the angle tray, as well as an anchor for a battery clamp out of a length of angle. This is what my boss, who is also my customer wanted...

everything will be 3/16ths and 2x2"..

verticals are 12"

[Boostinjdm]

your clamp isn't going to work as is. Look at how close the posts are to the edges of the batteries. Why do you need to clamp them anyway?

[Crawford]

Originally Posted by Boostinjdm

your clamp isn't going to work as is. Look at how close the posts are to the edges of the batteries. Why do you need to clamp them anyway?

He wants them clamped down for some reason unknown to me..... I believe he mentioned "earth quakes"........

How would that not work? single bolt in the middle pulling in on top bar and bottom anchored bar? He wanted it angle....

What about "how close the posts are to the edge of the batteries"? the angle tray will be laid down on top of the tube legs like a table then welded in. Batteries are sitting in the tray as they appear in the pic.

[Boostinjdm]

I guess I glanced at the pic and assumed there would be two pieces of angle for the clamp. One down the middle would be OK. If you get a big enough quake to make those batteries jump out of a 1 3/4" deep tray, I think ya got bigger problems than backup power.

[farmersamm]

When designing anything it's a good idea to get a concept of the total effect of the load.

The 1.5-2" angle is plenty strong over the span.

Keep in mind that the two rails SHARE the load. You're not puting 300lbs on just one rail.

The tubing sounds more than adequate. By my reckoning it corresponds to 11ga tubing, which I use a lot. It's very strong.

If you're concerned about racking, or sway, just add a few gussets in the corners to stiffen things up and reinforce the stress raisers.

[DesertRider33]

2x2x1/4 angle would be the minimum size I would use for the support tray. 1x1x1/8 is too flimsy. The legs could be built with the same angle as the tray, to simplify materials used.

A clamp bar down the center of the row of batteries between the cell caps would miss all of the post connectors and hold the batteries down fine. Of course, I really don't see how they could jump out of there if this is a stationary rack.

[Crawford]

Originally Posted by Boostinjdm

I guess I glanced at the pic and assumed there would be two pieces of angle for the clamp. One down the middle would be OK. If you get a big enough quake to make those batteries jump out of a 1 3/4" deep tray, I think ya got bigger problems than backup power.

Funny, we shared the same thought.

[Crawford]

Originally Posted by DesertRider33

2x2x1/4 angle would be the minimum size I would use for the support tray. 1x1x1/8 is too flimsy. The legs could be built with the same angle as the tray, to simplify materials used.

A clamp bar down the center of the row of batteries between the cell caps would miss all of the post connectors and hold the batteries down fine. Of course, I really don't see how they could jump out of there if this is a stationary rack.

Thanks desert, I was thinking of doing angle too but he has spoken and wants tube so that's what he gets i guess...

[jman]

Originally Posted by farmersamm

When designing anything it's a good idea to get a concept of the total effect of the load.

The 1.5-2" angle is plenty strong over the span.

Keep in mind that the two rails SHARE the load. You're not puting 300lbs on just one rail.

The tubing sounds more than adequate. By my reckoning it corresponds to 11ga tubing, which I use a lot. It's very strong.

If you're concerned about racking, or sway, just add a few gussets in the corners to stiffen things up and reinforce the stress raisers.

Exactly what I was thinking....