Reverse-mount 12V alternator

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kdiqq
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Reverse-mount 12V alternator

Post by kdiqq » Tue Jul 02, 2019 8:07 pm

After seeing the thread for the alternator solutions, I decided to start up something different.

I wanted to add a common, off-the-shelf 12V alternator to the Pinz, but currently the only solution is something over $1000. Rather than just try to do the same thing cheaper, I wanted to get the alternator up higher and away from the heat of the exhaust . Unfortunately, the only other place is blocked by the distributor.

Unless! You go with a reverse mount like so! I found an 80A 10SI alternator from Tuff Stuff that is fully rebuildable and has an awesome case size. Supports a 1-wire install, but I plan to do an OEM-style 3 wire.

Here's an image of what I want to do. After looking over the math for belt engagement, I plan to go higher than what's shown in the pic, but I have the exact number I need calculated.
Image

In addition, I wanted to change the belt tensioning method to be a more tradition style versus the shims. This also makes the belt sizing easier.

So I designed this bracket that supports the reverse mount of a 10SI and uses 3 mounting locations on the motor. I made sure it could be made from a bent material, no machining. It gets waterjet cut, bent, and then I will weld up the mating faces to make it nice and rigid. I ran some analysis and with A516 (because I get it for the same price as A36) and my minimum factor of safety is >10 with the stress of alternator weight, belt tension, and torque transmitted through the V-belt. I have a prototype that I'm having printed to make sure measurements are okay.
Image

I definitely didn't have to actually engineer the thing, but... it's what I do.

This is what it looks like all mounted up.

Image

It obscures a corner of the fan, furthest from the cylinders, about a 5%-ish obfuscation, but clears the doghouse and lower shroud just fine.

Wanted to run this by the community and get some feedback and make sure there wasn't any issues I was overlooking. I appreciate the feedback in advance!
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Merrick
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Re: Reverse-mount 12V alternator

Post by Merrick » Wed Jul 03, 2019 10:41 am

Please keep us posted on testing and let us know if you decide to do any production. Looks real cool! MM
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kdiqq
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Re: Reverse-mount 12V alternator

Post by kdiqq » Wed Jul 03, 2019 1:04 pm

Merrick wrote:Please keep us posted on testing and let us know if you decide to do any production. Looks real cool! MM
For sure! I'd love to be able to give back to the community. If I can get through a couple of weeks of use without drama and finalize my bill of materials, I'd be happy to run a batch of them.

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Re: Reverse-mount 12V alternator

Post by Hotzenplotz » Thu Jul 04, 2019 2:25 am

kdiqq

an excellent design !
which alternator have you decided to use ?
I guess they have more or less standard housing sizes, so I could find a suitable one from eg. Bosch ....
Cheers
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Re: Reverse-mount 12V alternator

Post by kdiqq » Thu Jul 04, 2019 6:55 am

Hotzenplotz wrote:kdiqq

an excellent design !
which alternator have you decided to use ?
I guess they have more or less standard housing sizes, so I could find a suitable one from eg. Bosch ....
Thank you!

You are correct, the housing is known as 10SI and there are tons of options. I wouldn't run higher than 90A though through this single v-belt.

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Hotzenplotz
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Re: Reverse-mount 12V alternator

Post by Hotzenplotz » Fri Jul 05, 2019 3:31 am

kdiqq

As far as I can tell your design is based on a single laser cut part, that will be folded and tack welded in the following steps.
What is the material you intend to use ?
Cheers
Albert
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Re: Reverse-mount 12V alternator

Post by kdiqq » Fri Jul 05, 2019 7:49 am

Hotzenplotz wrote:kdiqq

As far as I can tell your design is based on a single laser cut part, that will be folded and tack welded in the following steps.
What is the material you intend to use ?
You are pretty much correct! I intend to waterjet instead of laser, just because it's cheaper, but the finished product is the same.

I'm planning to use A516 Gr 70, but A36 would work fine as well.

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Re: Reverse-mount 12V alternator

Post by tgreening » Sat Jul 06, 2019 9:43 pm

Is this adding a 12v alt to the system, or replacing the 24v?

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Re: Reverse-mount 12V alternator

Post by kdiqq » Sat Jul 06, 2019 9:50 pm

tgreening wrote:Is this adding a 12v alt to the system, or replacing the 24v?
The original intent was to add a 12V alternator, but you can get a 24V alternator in a 10SI housing, so either could be done.

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Re: Reverse-mount 12V alternator

Post by kdiqq » Wed Jul 10, 2019 8:33 pm

So the first model of the bracket came in today. For hand measurements, it came out awesome. Basic fit was solid. I need to adjust the belt alignment and drop the alt a little to better clear the doghouse. That will affect belt engagement so I will likely add an idler.

I have a lot of confidence this will work but the crudeness of my hand measurements for sure dictates another flimsy 3D print before the steel version gets banged out.

Here's to optimism for rev 2!ImageImage

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Re: Reverse-mount 12V alternator

Post by VinceAtReal4x4s » Thu Jul 11, 2019 12:10 am

Very nice work. Can you mention why you are adding this to the Pinz?
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Re: Reverse-mount 12V alternator

Post by kdiqq » Thu Jul 11, 2019 5:08 am

VinceAtReal4x4s wrote:Very nice work. Can you mention why you are adding this to the Pinz?
Yeah! I just wanted a dedicated 12v system for running a winch and whatever else. I could run a converter but I feel like this is a little more robust and provides a lot more amperage.

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Re: Reverse-mount 12V alternator

Post by VinceAtReal4x4s » Thu Jul 11, 2019 5:49 am

I can understand if you have a lot of 12v items in the truck but when it comes to winches, 24v ones are available from most brands and work better than a 12v winch as well.
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Re: Reverse-mount 12V alternator

Post by kdiqq » Thu Jul 11, 2019 5:58 am

VinceAtReal4x4s wrote:I can understand if you have a lot of 12v items in the truck but when it comes to winches, 24v ones are available from most brands and work better than a 12v winch as well.
That was actually plan A, but I found the cost of 24v winches was about equal to doing this project and buying a 12v winch. Nothing wrong with running a 24v winch, I just saw this project as being able to give me a few extra options, tax the Pinz alt less, and scar the truck for running whatever 12v accessories I want.

Just helps give choices when shopping electronics.

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Re: Reverse-mount 12V alternator

Post by pinzi » Thu Jul 11, 2019 12:05 pm

Or you could go for a second 24v alternator :wink:
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