Battery for Tacktick Micro Compass

I still stand by my comment of being reasonable. A 10 year old sanav would be useless now. There is nothing else I would use on a boat for 10 years. Sails £600 min -1 year, 2 if looked after well for championships. Wetsuits £150 - 2, maybe 3 years. Ropes - cheap but 2/3 years.

Someone is salty!! 

I think the Micro Compass is a great product and reasonably priced. Mine is the old white one, so 10+ years old and still works...! How many other boat products have I got that old that I would still use... NONE.

Could pay even more for a Velocotek with less functionality! 

I don't have access to the internals of my TackTick any more, since it's gone AWOL somewhere in the English Channel.

But, as far as I can tell from what other people are saying, you're looking for a nominal 3V Lithium-Manganese Dioxide cell.

There are some of these on ebay UK e.g.

https://www.ebay.co.uk/itm/192542818586?epid=1905713369&hash=item2cd472411a:g:zHQAAOSw~zdgYX~2

but these are smaller cells, lower capacity. Which may matter if you want your tacktick to have the claimed 180 hours of battery life in the dark. For those of us who sail dinghies in daylight, we probably only need a small battery capacity for when we are in the shade?

AIUI, Lithium Manganese is kind of old tech, let's face it, the TackTick was designed about the time of the Alto? But these cells are still in use in things like BMW car keys.

Personally I am mildly grumpy about the tacktick not having a proper safety leash kind of thing and for personal reasons I loath the concept of giving actual money to Raymarine, so, I am looking at an Arduino homemade replacement. Processor £5, Compass IC £6, couple of LCD's £8, small solar cell, 3D printed case and a tube of gorilla snot, parts bill of £40 tops? OTOH my former employers could flog that kind of thing to the MOD for about the price of a Merlin Rocket.