43 – Vertical Power PPS & EarthX Battery

Vertical Power PPS

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The Vertical Power PPS (Primary Power System) combines the functions of multiple high-current, electro-mechanical components into a single, solid-state device.

I decided to locate it using the existing nutplates which had been installed on the firewall. These were for attaching the Battery/Starter mechanical contactors.


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I used 2024T3 3/4″ x 3/4″ x 1/16″ Angle to make two “Z” brackets, which proved to be a perfect size to match the PPS holes and the original nutplate spacing.


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Having researched where various components were to be located on the firewall, I decided to mount the PPS diagonally.

This is an acceptable but not perfect orientation for the PPS. The interior components of the PPS are thoroughly encapsulated for complete sealing from the elements, but the back panel includes “weep” holes to allow any excess moisture to escape. There are two weep holes close to each corner, but obviously in this orientation there will be a small triangle for potential moisture to collect.

Bearing in mind the internal encapsulation, I decided it was an acceptable compromise.


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Since the PPS had to be mounted slightly off-centre on the nutplate doubler, I added another doubler the same thickness and drilled two holes in the firewall for two bolts … this will prevent any wobble due to the flexibility of the firewall.


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I riveted on nutplates for easy attachment of the PPS.

ProSeal to seal around the holes.


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Here’s the finished bracket ready to attach the PPS.


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This has produced a nice secure location for the PPS, hopefully not causing interference with other components.


EarthX Battery

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I decided to fit an EarthX Lithium battery.

The stock Odyssy PC680 battery weighs 15.4lb (7kg), whereas the EarthX ETX900 weighs just 4.9lb (2.2Kg), a saving of over 10lbs.

I’m hoping this will not impact the CofG too much … we have several avionic boxes in the avionic bay to help with the forward CofG.

Anyway, we’ll see … fingers crossed.

The ETX900 is the same size as the smaller capacity ETX680, and only weighs 0.8lbs more.

Talking of size … the kit battery box is designed to fit an Odyssey PC680. The ETX680/900 is 0.1″ deeper, and just over 0.5″ shorter in width. Height about the same.

The depth issue means that the ETX900 would sit on the battery box lower lip, rather than on the box bottom.

Hence packing pieces are required …


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… which I made from hard foam covered in aluminium foil. The foil will provide some heat insulation I hope.


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I also made a restraining strap to secure the battery bottom, due to the ETX sitting on the lower lip rather than behind it.


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This picture shows the ETX sitting on the foam packing piece and hence not being constrained by the battery box lower lip.


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The kit supplied Battery Box Angle FF-01403A fits well, but because the battery is 0.1″ deeper than the Odyssey, I made some little spacers … see arrow.


With a few mods the EarthX fits well, and I’m pleased with the result.

Anyone reading this who has not yet attached the kit supplied battery box may be interested in an EarthX battery box, which I believe may match some of the firewall rivet holes for attachment.

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