I was at the london cycle on thursday. A bit disappointing as usual. I did speak to a guy about garmins on the blacks stand i think?

He said if i took batteties out of my touch 35 and set system to usb garmin then i could run the garmin all day off dynamo hub / though sinewave.

Apart from exposing socket. To elements it seems a good idea in dry weather.

Anyone ever done it on any gps.

Any draw backs??

What happens when you stop moving? Or are you planning to use a cache battery between the dynamo and the GPS to keep it switched on?

Good point didnt think of that one. With a cache battery inthe loop. It shud work. .

Then you need to find a cache battery that will charge and discharge at the same time.

I managed to find one but it switches the discharge circuit off when I slow down/stop, which sort of defeats the purpose

The B+M USB Werk AC to USB converter has a small battery built in so it will keep a garmin off that annoying 'power lost' message during brief stops or slow climbs. ~£50. Mine's been great. I could use a cache cell with it also but haven't needed to so far.

jameso wrote:The B+M USB Werk AC to USB converter has a small battery built in so it will keep a garmin off that annoying 'power lost' message during brief stops or slow climbs. ~£50. Mine's been great. I could use a cache cell with it also but haven't needed to so far.

So you ride with your garmin diectly powered ?

I like to think of the setup as a flow of water. To keep most Garmins sweet, you need an uniterrupted flow of power, direct power from a dynamo will only work whilst you are moving, in most cases over about 8mph. A power bank is a reservoir that the dynamo keeps topped up, allowing juice to flow constantly to the gps. The tricky bit is finding a power bank that allows pass through charging and doesnt stop sending out power when the dynamo is putting power in. Ive found 2 that work, 1 is called a juice cube and only costs a fiver from Maplin, the problem is it seems to have been discontinued. The second is a Portapow 10200mAh capacity which should last forever. These are available direct from them or via Amazon for £15-20.
Hope this helps.

pistonbroke wrote:I like to think of the setup as a flow of water. To keep most Garmins sweet, you need an uniterrupted flow of power, direct power from a dynamo will only work whilst you are moving, in most cases over about 8mph. A power bank is a reservoir that the dynamo keeps topped up, allowing juice to flow constantly to the gps. The tricky bit is finding a power bank that allows pass through charging and doesnt stop sending out power when the dynamo is putting power in. Ive found 2 that work, 1 is called a juice cube and only costs a fiver from Maplin, the problem is it seems to have been discontinued. The second is a Portapow 10200mAh capacity which should last forever. These are available direct from them or via Amazon for £15-20.
Hope this helps.

Yes it does thankyou. Is it common practice to run a garmin this way ?

So you ride with your garmin diectly powered ?

Hub>USB Werk>Garmin 800. Standard way of keeping a similar GPS powered. Sinwave etc will do similar, just the battery just helps smooth out the power into the Garmin. I leave it plugged in on long rides, when the battery is full is draws now more current anyway and stays full, unplug it if I need to charge the phone or if weather's poor.

I use a powermonkey explorer 2 in-line between my plug 3 and garmin/mobile.

This cache battery also allows an uninterrupted flow to the garmin (old edge 800) irrespective of losing dynamo power when I stop/slow down. This way, I can ensure I can charge phone, gps camera etc while moving and still be topping up the cache when nothing else is charging.

It's had a lot of use both on the bike for a couple of years and when backpacking and has been very reliable. Only problem is that it's robust aluminium construction means it's relatively weighty for a 6000mAh cache.

Ive just ordered a. Portapow cache battery. Hub / sine wave/ cache / garmin touch 35

On wet days good old rechargeable batteries.

From what iv read it should work