Redesigned Fuse Block

Thanks everyone for your patience. The assembly jigs were being mfg'd as a favor by a friend--and, well, they were prioritized accordingly. I ended up machining the jigs myself (after waiting for so long), which meant the whole process wasn't as quick as we were hoping.

First article is complete (still need one more minor tweak on the base plate). Also still need to put together some installation notes. Below are some shots of the entire assembly.

A quick recap on the features:
- Uses modern mini-blade fuses (ATM)
- Single fuse block replaces the two block solution from the OEM
- Spare fuse holder for three extra fuses
- No fuse splitters required; all OEM connectors should have a direct connection to the board
- Works with all generation 308s (GT4, GTS/GTB, GTSi/GTBi, QV) and likely 512BB
- LEDs to indicate working fuses, enabled with push-button (fuse supply-side must be powered)

A fuse cover is still in the works, but given demands on time, it's likely at least another month before I'll have that design ready to test out. You'll note that cylinder in the center of the board (w/yellow Kapton tape on the top) is the planned mount to provide positive retention for the cover.

I'll send out another note in the next couple days with pricing and contact info (didn't have time to put up a webstore, so we'll start off doing this 2010-style: email + paypal). In this first run, I only ordered ten boards so if demand outpaces supply, it'll be a bit before the next run.

 

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Hey all,
Finally ready to start shipping out the design to folks. As mentioned before, this will just be the fuse board itself--cover is still in development.

Pricing is set at $325 + shipping. Working on a website, but for now please email me directly: jstinson1 at yahoo.com

I'll need to get address, model + year and other info--will use Paypal for transaction.

As mentioned before, this first run is only ten (well, nine, since one of them goes in my car), so if we go thru them quickly, I'll need to order more.

Thanks,
Jason

 

Oh, almost forgot. I'd wanted to perform some validation tests on the design, which I finally was able to get into the shop to perform last week. Everything passed fine, but some of the results might be of interest for those folks that still have the original fuse blocks in their vehicles.

One of the tests was to validate the resistance of the design with an accurate milliohmeter. This is a piece of equipment that very accurately can measure the resistance of a circuit. The test setup used a lab calibrated HP 4338B milliohmeter with a 4 point test setup to do the measurements:

• New design: average resistance was 15mohms with a variance of 2mohms across all fuse circuits on two separate boards. The fuse itself measured out to ~12mohms, so the design itself is only adding ~2mohms of add'l resistance. The design target was less than 5mohms.
  
• Original Ferrari fuse blocks (my fuse blocks are still in very good shape): average resistance was 300mohms with a low of 100mohms and a high of 1.2 ohms.

Or, put more simply, for a load such as a window motor (let's call it ~5A @ 12V):

• The new design has approximately a 0.075V voltage drop across the circuit -- meaning your window motor (or any other load) would see near battery voltage (if it weren't for the crappy wiring harness and downstream connectors....).
• The original design would generally have a 1.5V voltage drop across the fuse block (or even as high as 6V) -- meaning your window motor would be very sad. This also means the original design would be dissipating 7.5W (or as high as 30W) in the fuse block itself for just this particular fuse circuit (other fuse circuits will also be dissipating power), which is why these blocks tend to melt over time cuz power dissipation = heat.

This shouldn't be news to anyone, of course, as all of the other replacement fuse block designs over the years have pointed out the weakness in the original design. But thought you'd be interested in the numbers.

Here is the setup for the new design:
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And the setup for the original design (note this particular circuit was at 530mohms--there was a lot of variance from circuit to circuit):
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Catching up on responses:
- @Saabguy : Milliohmeters are pretty standard equipment in battery design/development where internal resistance is a critical test parameter. And, yeah, I've spent a lot of time around batteries.
- @Dr Tommy Cosgrove : Please send me an email (jstinson1 at yahoo.com) if you'd like to place an order for a fuse block. It's easier for me to track orders and handle the transactions thru email (vs. fchat)
- @absostone : Cover is still in design; my day job has been a bit crazy last few weeks, but hoping to find some time to complete in coming weeks.
- @2cam : Thanks for the kind words and let's see how the 308 process goes. From what I've seen on the Mondial, it's a full PDU (power distribution unit) including both the relays and the fuses as well as power routing. The existing aftermarket designs look quite well done; while it might be nice to move to mini-blade fuses, it's not clear that would be enough value to warrant yet another aftermarket design.

 

@skipgt4 Thanks for the kind words, good luck this weekend and let me know if you run into any issues!

@kiwiokie Still have a couple left. I re-responded to your PM, but the short of it is to send me an email (jstinson1 at yahoo dot com) with the request. It's much easier to track than thru fchat.