dynamo question

[Doo]

Hi Folks,

Not sure if I'm posting in right place, but here goes...

I have a dynamo SPV8 and am wanting to use it to charge Garmin and/or battery pack. Can anyone suggest a suitable cable or 'thing' that I will require/could use please.

Many thanks,

Doo

[oggy]

You need to convert the ac dynamo output to dc

Busch Muller do one called a USB Werk

The SP dynamo might not be powerful enough to charge the garmin and run the lights so charge a power pack and use that when garmin needs charge

[Whitestone]

They tend to get called USB chargers though converter would be a better name. There's quite a few, ranging in price from reasonable to ridiculous.

This page https://www.cyclingabout.com/list-of-hub-dynamo-power-supplies-for-usb-devices/ shows a few of them - US Dollar prices but the UKP prices are roughly the same numbers. I've an Igaro D1 and a Cycle2Charge but haven't as yet used either so can't comment on their suitability or otherwise. No doubt others on here have experience with those and others.

[LittleWheelsandBig]

Quite a few here have the Igaro and like it. HK is looking to get a second one sometime.

[fuaran]

Or you could get a light with USB output built in. eg B&M Luxos U.
Maybe worthwhile, depends on what lights you already have.

[LittleWheelsandBig]

The reliability of the Luxos isn't great IMHO. There are similar alternatives but they tend to be fairly big.

[Tillapaw]

I use the Sinewave Revolution. It starts charging at about 12km/h so if your doing a hilly route it's worth having it trickle charge a battery pack and have your devices plugged into the battery.  Make sure the battery has pass through charging.  I made it through LEL without having to plug my phone or Garmin into the mains.

https://www.sinewavecycles.com/products/sinewave-revolution

[Somnolent]

The reliability of the Luxos isn't great IMHO. There are similar alternatives but they tend to be fairly big.

The early Luxos U were indeed failure prone. Later ones much better.  No probs with mine 3 years in - although in fairness my mileage is somewhat more moderate than HK or LWaB.

Have an Igaro too but was underwhelmed by the current available from it - significantly less than from the Luxos based on my testing with an inline ammeter.

[yoav]

From experience, the SP Dynamo doesn’t have enough output to power both the lights and a Garmin via USB at the same time. At my nighttime riding speed of 12-15 mph anyway. So I used a small mobile charging battery between the Igaro and the Garmin. Other dynamos/riding speeds may differ.

[Kim]

The electrical performance of 3W nominal dynamo hubs is pretty much identical, except when you build a dynamo designed for small wheels (SP 'S' series, SON Delux, Shimano Capreo) into a full-sized wheel, which reduces the output for a given speed, or vice-versa, which increases it.  There are a some models that are specifically designed for a 1.5W nominal output, but that's just silly for charging.

What really matters is how fast you ride.  And all that device-specific USB charging nonsense - sometimes you have to sacrifice efficiency with a buffer battery in order to convince a given device to charge at a decent rate.

[Dave_C]

There are a few to chose from, depending on your budget. My budget was low when I sought one of these. I chose the Kemo USB converter from Maplin. It is cheap, robust and has not let me down in the 3 years I have been using it. It is not the smallest, but does what I need it to do. To house it I bought an Alpkit Medium Tri/frame top bag. The manufacture claim it can be zip tied to the frame but I didn't want it scratching my frame.

Top tip - generally in the past I have found cables brake before the charger. If your USB charger has stopped charging try replacing the cable first.

Dave C

[Whitestone]

I chose the Kemo USB converter from Maplin. The manufacture claim it can be zip tied to the frame but I didn't want it scratching my frame.

Helicopter tape, basically a clear protective adhesive tape can be used to prevent frame scratches. I've not used it under zip ties though, only "soft" bikepacking bags.

[Kim]

A Mk 1 bit of old inner tube is traditional for providing protection and elasticity when zip-typing arbitrary things to bike frames, surely?

Helicopter tape's more for protecting them from cables etc rubbing.

[igarocom]

The reliability of the Luxos isn't great IMHO. There are similar alternatives but they tend to be fairly big.

The early Luxos U were indeed failure prone. Later ones much better.  No probs with mine 3 years in - although in fairness my mileage is somewhat more moderate than HK or LWaB.

Have an Igaro too but was underwhelmed by the current available from it - significantly less than from the Luxos based on my testing with an inline ammeter.

It has a battery in it, same charging circuit as the USB-werk (charges the battery then dumps it out).



https://www.igaro.com/res/measurements.ods

[Kim]

The USB-werk uses a LiFePO4 battery.

[quixoticgeek]

The USB-werk uses a LiFePO4 battery.

Have one of these on my bike, it was charging my battery pack quite happily at -2°C-0°C at xmas. You only get about 500mA out of it, no matter how fast you go, so it may not be suited to devices that need more current, but to feed into a bigger battery it's just fine. I get 500mA out of it even when I'm running the light too (Edelux II, no rear).

J