Homebrew, open source, repurposed, hacked, software defined, open hardware

Tuesday, 27 November 2012

Final implementation of the OZroll roller shutter battery replacement

Just as an epilogue to the OZroll roller NiMH battery pack replacement with 12V SLA batteries, I thought I'd upload the photos of the final approach taken.

I ultimately decided against DC barrel connectors for the power feed to the OZroll roller shutter controller, as they are

1) ugly
2) supposedly rated at only 3 Amps
3) have only two conductors, making remote up/down button signalling difficult in future
4) flimsy

I opted for 4 pin microphone connectors. They are rated at 10 Amps per pin, are nice and shiny (improving wife acceptance factor), and have a screw collar for positive and secure engagement. I went with white sheathed 6 core cable. One pair carrying 12V DC, one pair carrying Ground, and the remaining pair kept spare for later used in remote signalling of roller shutter up/down commands.

Here is a front and rear view of the connector mounted in a blank wall plate



It turns out that they have 0.2 inch pin spacing, making a breakout board easy with veroboard and terminal blocks:



And here's the breakout board soldered into position:


Labelling is always good, in case you don't remember what you did in 5 years time. See also the jumbo Clipsal wallplate to cover the SLA battery compartment:


And here's the hole in the wall with custom sheet metal glued into position, drilled and tapped for screws to accept the clipsal wall plate (I couldn't find suitable mounting brackets from the electrical supplier).



The drilled out tongue depressors were invaluable in maintaining alignment of the sheet metal while being glued and clamped.

In summary, the nominal 12V, 3.3AHr, SLA batteries I have installed to replace the OZroll NiMH batteries last a few weeks before needing charging again. This charging will be automated in due course. The batteries have very low demands placed on them and should last many years, unlike the OZroll NiMH battery packs, all of which among my six roller shutter controllers have long since died.

12 comments:

  1. This comment has been removed by a blog administrator.

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  2. Is there anything against merely cutting the NiMH battery wires and connecting the 12v external battery to the battery connector plug? I am not very interested in stopping the flashing LED since the units are all installed in my loft.

    This would save me having to desolder etc.

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    Replies
    1. It should work, but if someone plugs a charger into the controller's charging socket (which I removed to make way for the new cable going in), things could get a bit strange. Maybe hide the charger plug packs. Also, make sure the wires going from the battery to the controller aren't so beefy that the controller struggles to notice a voltage drop as the roller shutter reaches its end limits.

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  3. Further to the above, I have connected the first three of ten shutter controllers to my superfluous 12v golf buggy SLA battery which now sits in my workshop, via a 2 pole switch and a 5A inline fuse. (That might have to be replaced with a 10A one as I add those shutters that have failing batteries - it depends on the instantaneous start current when several are triggered at once.)

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    Replies
    1. Maybe a big 20 or 30 Amp fuse at the battery, and 5 Amp fuses for each of the power feeds going to each individual controller? It would depend a bit on your overall layout - i.e. star topology vs main bus.

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    2. I have now wired another two up: their batteries hadn't yet given up the ghost so I put their batteries into a couple of small windows which *had*. I now have all five which are controlled from one remote now wired up: the other five from a different remote are still battery driven and will be connected up as they fail.

      The 5A fuse seems perfectly happy even when all five shutters are lifting together, although sometimes one or two halt halfway and have to be restarted. I can live with that if it means I don't have to climb into the loft every few weeks to replace a battery!

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    3. If the fuse ain't broke, why fix it. Most of my shutters are 5m^2 each, which may account for my higher measured current draws.

      Anyway, Good stuff. Sure beats paying $80 for a new battery. I'm glad you've found this useful.

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  4. I am grateful for your insight into the way the controller stops the motor by sensing the change when the shutter reaches the top or bottom of its travel. I had assumed that it was by means of microswitches.

    That explains why, even with a large golf buggy SLA battery, if I run all five shutters essentially concurrently, sometimes one or more will stop moving. The battery is obviously well able to power this number of motors but as a controller senses another one or two starting and momentarily pulling down the voltage, it must think "stop". That solves one puzzle!

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  5. PS - Can you consider eliminating the captcha entry when trying to post? Like all sites you can spend hours trying to get the entry to match the pictures!

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  6. Final post!

    I now have all ten OzRoll shutters operating from an ex golf buggy SLA in my garage: this is permanently connected to a Matson charger to keep it topped up.

    Each controller (they are the remote variety) has had its charging lead cut and isolated, the individual chargers being removed.

    Each controller's battery has been removed, and since I couldn't source the tiny connectors, I milked the mouse and managed to remove them from each battery pack to re-use.

    Carefully checking the polarity, the tiny connectors have been wired to the "bus" that carries the 12v from the SLA.

    No problems with the 5A fuse blowing, even when all ten shutters are run at the same time: sometimes one or two will halt because - as Erich says - they sense a voltage change, but that would often happen anyway when the individual batteries began to fade.

    The red LEDs flash but they are in the loft, so who cares?

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    ReplyDelete
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    ReplyDelete