Today's mystery object

[Graham W]

Its purpose?

[Peter Cockerton]

Shock collar, self-incrementing. Prefer to slap the back of my hand and mutter "you silly boy" when i get things wrong.

Peter

[david]

Looks like some kind of fancy connector for your towing lights?

David.

[Michael Rogers]

No, it's part of an electronic device which, linked to a tiller pilot, looks after one of the sheets. With one per sheet and the help of GPS and an onboard computer, the aim is to have the boat sail itself, the time and effort saved being put to better use exploring the depths of a bottle of worthwhile plonk while admiring the maritime view.

Michael

[Graham W]

Good replies all but not even close yet. It is nautical.

[Peter Cockerton]

Gas detector
Strobe or light controller
Bilge pump controller

Peter cockerton

[Graham W]

Imaginative ideas but no.

The upper device with a bungee on it may be a bit misleading and can be exchanged for another more obviously identifiable piece of kit.  The important bit is the lower dark-lidded enclosure with part of a retractable biro sticking out of the lid.

[EDWIN DAVIES]

It is a timer!

[Graham W]

Edwin,

You spotted the LED inside the enclosure but no, it's not a timer.

[Matthew P]

Torqeedo battery monitor?

Matthew

[Peter Cockerton]

Can we play "eye spy" instead, this is to hard.

Peter

[Graham W]

Torqeedo battery monitor?

Matthew

Close enough but probably too Heath Robinsonesque to be guessed with complete accuracy! The misleading gadget in the upper part of the photo that looks like a van de Graaff generator is in fact a plug that attaches to a 5-pin 26v 18aH lithium battery normally used on an electrically-assisted bike. The plastic cosmetics jar splash-proofs the innards of the five-pin plug.

The dark-lidded box lower down in the photo is a voltage step-up controller in a Spelsberg waterproof enclosure. This boosts the bike battery's 26v to the >30v needed to fast charge a Torqeedo outboard battery. The blue retractable biro top in the lid switches the LED display on the step-up controller between voltage input from the bike battery and voltage output towards the Torqeedo battery. The output voltage (which is adjustable) has to be higher than the Torqeedo battery's voltage for the charge to be effective. The whole idea, of course, is to increase the Torqeedo's range on the go without paying £450 for a second Torqeedo battery. Photo of the apparatus in action below.

Of more general use, the whole apparatus can also be connected to a 12v battery and will similarly boost that voltage to >30v. Photo with this much less misleading connector below.  As a third alternative, the Torqeedo can be charged directly but very slowly at 12v without the step-up apparatus. All three alternatives need to be fused at 4A.

This is the cheap as chips step-up controller from Hong Kong http://www.ebay.co.uk/itm/3-35V-3-5-35V-100W-Adjustable-DC-DC-Step-up-Boost-Voltage-Converter-Module-/271254847313?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3f280c7f51

[Matthew P]

I like it - using retired cosmetic jars and biro mechanisms to save £450 is my sort of technology.

Can you do something similar to reduce costs on the European particle accelerator project?

Matthew

[Peter Taylor]

I like that Graham! I did buy the 12v to 32v controller you had previously mentioned but I haven't actually used it yet because of the potential loss of power due to (1) the 85% efficiency of the conversion process (2) the loss of capacity due to discharging a lead acid at reasonably high current.  Using your new method with the electric bike battery sounds much preferable - it can handle the discharge current and the DC converter efficiency is higher. It almost gives one a second battery so I'm planning to copy you and implement it to provide reserve power.

Having said all that, I am presently managing well just using the lead acid battery to "trickle charge" the Torqeedo battery. For example, on Saturday I set off before the wind had woken up and therefore motored the 3 miles down the River Itchen before tacking up Southampton Water and round to Gilkicker point near Portsmouth. By the time I sailed back to Southampton and needed to use the Torqeedo again on the river the battery was showing 95% charge having been charging all the time I was sailing. For anyone who only uses the outboard at the start and end of a trip, recharging from a 12v lead acid is well worth considering.

Peter

[jonno]

I've been following closely this discussion about 'Today's mystery object'.  We should all get out more.

Jonno