Velocharger?

Discussion in 'Touring and Adventure Cycling' started by Blue Hills, 1 Jan 2018.

  1. aegis

    aegis Senior Member

    B & M do two different models of chargers btw.

    The original is the e-Werk which doesn't have a cache battery built in but has the advantage of variable output so you can charge 9v devices like some cameras.

    The cheaper USBWerk only outputs USB friendly 5v. It has a very small cache battery in it which it charges first before supplying to the external device. Your first 5-10 minutes or so charges the cache battery. The cache battery is useful for devices where they pop an alert up on the screen every time you connect/disconnect a charger. I used to have a different charger without the cache and I'd be endlessly pressing OK on my phone screen at every junction or when pedalling slower than required to charge. The cache battery solves that issue. It still works even with a dead cache battery. I'm on my second USBWerk having killed the first in cold weather after about 3-4 years and found this out by experience.

    If you're just using the device to charge a power pack to charge your phone later, you don't need a cache battery. Be aware some external power packs do not charge unless you press a button to start charging. Some also allow you to charge the powerpack at the same time as discharging it; in effect acting as a big cache battery.

    If you do have a camera that needs a 9v charger, there are third party battery chargers that run off USB supplies. I have one for my Olympus camera. It's also smaller than the Olympus official charger which is a bonus.

    I don't have a Garmin as I just use my phone and Komoot but from what I gather with some Garmins they think they have been attached to a PC if you attach them to a powerpack that puts out a voltage over the two data pins (the middle two) in the USB socket. Many powerbanks do this because Apple stupidly decided that it wouldn't follow the USB charging standard. Apple USB chargers output different voltages over the data pins to tell the iPhone/iPod/iPad if the charger is a low of high power charger. In this case, get a cable which shorts the two middle data pins or has a resistor across them and the garmin will not see a voltage across the data pins and assume it is connected to a dumb charger.

    In theory, charging the device directly is the more efficient way of charging. If you're charging a powerpack you're going from 6v AC to 5v USB DC to 3.7v DC (in the cells in the powerpack) and then back to 5v USB when charging the device later which probably has a 3.7v battery in it. All those conversions suck efficiency. In practice, it probably doesn't matter over the course of a day's cycling.

    Personally, I find the USBWerk reliable and predictable. The one complaint might be that it never outputs more than 1A no matter how fast you cycle where some of the newer devices do. But, they're about £50 from Germany so quite a bit cheaper than the others.
     
    Blue Hills, mjr and raleighnut like this.
  2. OP
    OP
    Blue Hills

    Blue Hills Guru

    Location:
    London
    Thanks for that detailed reply aegis. I didn't know the usb werk only outputted 1A? Ewerk the same? Anyone know if an improved model might be on the way?

    I suppose as important as the output is the speed you need to be going to get a charge, especially when heavily loaded possibly over challenging terrain. And the thought of having to pedal pedal harder than you feel like just to get a charge might spoil a tour.

    So can I ask aegis how fast you need to be going to charge?

    Do the B&M units output enough power reliably to allow you to go off power lines for a week or two or do you think that you will need occasional/regular recourse to a power socket?

    Apologies for all the questions :smile:
     
  3. psmiffy

    psmiffy -

    Location:
    Midlands
    I use a B&M USB-werk - its function is primarily to charge the Lion batteries for my camera - which it does quite happily - always have a charged one - after that I charge a power bank - typically once a week i buy electricity (usually <€4.00/night) or quite often these days it tends to come with the pitch when i'm in Europe - to my mind tho the big advantage of the dynamo is the light - while mid-summer night cycling is not something that happens very often and I have a rule about cycling in the dark (never works out) - early and late doors having a good light so that i'm able to get to that campsite without stress is a godsend
     
    Blue Hills likes this.
  4. OP
    OP
    Blue Hills

    Blue Hills Guru

    Location:
    London
    to clarify smiffy - you keep the powerbank charged up via the dynamo or do you rely on your weekly hook-ups for that?
     
  5. woodenspoons

    woodenspoons Über Member

    Location:
    North Yorkshire
  6. psmiffy

    psmiffy -

    Location:
    Midlands
    Mainly the latter
     
  7. OP
    OP
    Blue Hills

    Blue Hills Guru

    Location:
    London
    mm - thanks for the reply but that maybe makes the werk sound not so good?
     
  8. psmiffy

    psmiffy -

    Location:
    Midlands
    not so good as what? - I think these things are good for say - charging a phone - does my 7" tablet OK - but you have to have to have a bit of realism - prioritise what you want charged - simple charging dynamics of most USB devices limits you - in three months last year i didnt run out of electricity in what i consider to be my core devices - camera, tablet, mifi dongle - GPS doesnt count as it will run off AA - but back to my original comment having a very good light was a very big plus
     
    Blue Hills and raleighnut like this.
  9. aegis

    aegis Senior Member

    The eWerk can output 1.5A. I've not used an eWerk. IMHO 1.5A isn't really useful. You're not likely to reach it at touring speeds unless you've a long downhill. It's this which annoys me about the USBWerk. I've probably spent the best part of the day riding up a mountain with it generating 200mA but then coasting down the other side it stops at 1A. It's only a small annoyance. But, I know it could be generating more!

    Bear in mind that hub dynamos output 6v 3W at around 15kmph. That's 500mA. It varies slightly per brand but not much as the German standard says they have to reach 95% of output at 15kmh. The hubs are current limited. What happens when you go faster is the voltage increases.

    To get 1A out of the hub you'll need to be doing north of 25-30kmh.

    That all depends on how much electronic guff you're carrying, how much riding per day and how hilly.

    Generally I've got an Android smartphone attached on my bars for GPS and music in constant use. GPS eats batteries in phones. On a flat day, It's charged up a bit past lunchtime. (4 hours ish). I'll then switch to charging the powerpack for a bit perhaps and then back to the phone for a few hours. I also have an 8" tablet and a 4/3rds DSLR with me which I charge from a powerpack in the evening. Those aren't on all the time so how long they last depends on your use pattern. The tablet does 10 hours out of it's built in battery (4400maH I think) so to recharge that it would "cost" over a day's worth of cycling.

    Generally, 8-10 hours a day cycling and I'm power neutral and can keep that going indefinitely.

    However, if miserable weather makes me resort to a hotel, everything gets charged up. If I'm sat at a cafe, I'll ask if they don't mind me plugging in a phone charger and I have been known to sit next to a vending machine or two. :whistle:
     
    Blue Hills likes this.
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