Fuse box upgrade (prototype)

[Ezz]

Hi,
my fuse box contacts had some corrosion and fuses were mostly bad. So i looked at different solutions and came up with PCB mounted fuse holders that fit in the original fuse box.
I solder the fuse holders to the PCB and soldered copper strips to each side of the fuse holder then soldered that to the fuse box contacts.
Looks like working well.
Also, working on a more professional looking replacement to the whole fuse box that would have the same quick connect terminals and would be a direct replacement.

 

[Bmachine]

Any improvements on the flimsy existing fuse system would be most welcome

 

[x_atlas0]

Nice! I have seen a couple replacements for other BMWs and Porsches, so this kind of upgrade for our cars would be fantastic.

BMW E28 Blade Fuse Box Upgrade Kit

Upgrade your flakey, melty, and unreliable E12, E23, E24, or E28 fuse box. Address one of the biggest causes of electrical problems in your classic BMW—the ancient and unreliable torpedo fuses. Our kit upgrades your E12, E23, E24, or E28 to modern, reliable blade-style fuses. Lower total...

www.holygraillabs.com

 

[Ezz]

Just got the PCB and components
Looks good so far!
I am excited to put it together and test it out!
I am also working on a design for an enclosure that I will 3D print.

 

[coupesport]

Thanks for your effort. Great idea. Just want say the solder tabs of the fuse holder piece appear to also be the mechanical fastener of the fuse holder. If so... not good. Maybe you already have it on your design list.
I like where you are going with this and will follow. Cudos!

 

[Ezz]

I appreciate the feedback. They make those fuse holders through hole as well so I will look into using them in the next design while keeping the whole thing compact.
Thanks again
Ezz

 

[x_atlas0]

Are the E3 and E9 fuseboxes similar enough such that your part would be cross-compatible? Based purely on the part number cross-referencing, the E3 and E1 share a fusebox but not with the E9.

E3:

E9:

I have a spare E9 fusebox I could send you if you'd be willing to make an upgraded version of it.

 

[HB Chris]

They are very different.

 

[Ezz]

Are the E3 and E9 fuseboxes similar enough such that your part would be cross-compatible? Based purely on the part number cross-referencing, the E3 and E1 share a fusebox but not with the E9.

E3:
View attachment 168076

E9:
View attachment 168077


I have a spare E9 fusebox I could send you if you'd be willing to make an upgraded version of it

That is kind of you to offer. As a start if you send me some pics (front and back) and the schematic if you have one, that might be enough that I can design one.

Are they all 10 fuses?
I can potentially design one that is configurable and can be used on multiple vehicles. Size would be the main limitation but i think there is enough room where the fuse box currently sits….

I would appreciate anyone else posting pics here of their fuse box if different from the above.

 

[Ezz]

Enclosure concept:

 

[Ezz]

Note that this is a low quality 3D print for fast prototyping
Also, the fuse holders accept the low profile mini fuse (shown above) and the standard size fuse

 

[Ezz]

Found some info regarding the E9 vs E3.
This is only for the 10 poles/fuses boxes. At some point I will work on the 12 poles fuse box as well (i have schematics). I have looked for the 16 poles fuse box schematic but couldn’t find it on my Bentley manuals.

This is only according to the manuals . If anyone can confirm this info that would be helpful. I do plan on making early E3/E9 and later E9 boxes. 10poles only.
I will also at later time look into the 12 poles boxes.

 

[Bmachine]

Some awesome work you are doing there!

I don’t know if this is of any help, but here is a pic of my 1974 fuse box

 

[Ezz]

Thank you!
Yes, this is helpful as it confirms post 1973 E9s still use the 10 poles fuse box.

 

[Ezz]

I made some design changes and created two fuse PCBs that will use the same enclosure:
1. Early E3/E9
2. Late E9

I would like to have both PCBs made but I want to confirm the late E9 (post 1973) connections. I think I got it right based on the schematic in the manual, but it would be nice if someone has the late model fuse box can provide a picture of the back where the terminal connections are.

 

[x_atlas0]

I'll pull out the harness I have (I think it's from a 73, not sure of the month) and take a pic of the front/back for you when I get back from a business trip.

Any chance you can add a LED per fuse to the PCB? Most of these updated units I have seen include a light to indicate if the fuse is blown or not. It's pretty hard to tell since it's buried close to the firewall under the dash.

 

[Ezz]

sounds good. safe trip.
I thought about adding the LED indicators, but I did not look into it since I found fuses with LED indicator built in. https://www.mouser.com/ProductDetail/Littelfuse/0ATO010.VPGLO?qs=6kmNHVaEmPimNKgxxyM2IQ==
However, it is not that difficult to add. I will start to look into that.

 

[Bmachine]

Here are a few pics of the rear of mine (December '73 build, '74 MY) with the wires attached if that is helpful. As you can imagine, it is very difficult to bring a camera and some lighting back there with all the wires still attached. So Ansel Adams will not feel threatened today. But maybe some of this will help

That seems to match the "E9 from 9/73 on" schematic you posted above

 

[Bmachine]

PS: A light indicator is an awesome idea. Really makes this upgrade that much more useful

 

[Ezz]

Thank you for the images! That is very helpful
What I am looking for are the connections between fuses. I circled an example shown in one of your images (a connection between #3 and 4):

There should be one between 5&6 right under your finger in the image above and also 9&10