Old 01-05-18, 05:23 PM
Tourist in MSN
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Join Date: Aug 2010
Location: Madison, WI
Posts: 5,250

Bikes: 1961 Ideor, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, Perfekt 3 Speed -age unknown, 1980s Bianchi Mixte on a trainer. Others are now gone.

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Originally Posted by Flounce View Post
Tourist in MSN - I was wondering - which cache battery do you use?
Pass through cache battery - I should define that, if I plug my GPS into a pass through cache battery and then plug that pass through cache battery into the charger, it works if your dynohub powered USB charger charges that battery simultaneously with that battery also supplying power to your GPS. In other words, power is going into it and also coming out of it at the same time. But, many battery packs will not do both simultaneously.

I bought some cheap cylindrical power packs on Ebay, shipped from China that had Li Ion 18650 batteries inside that worked great as pass through batteries. But eventually they quit working, so I ordered some more. But the newer ones did not work that way anymore, they would either charge the GPS or they would accept a charge from the charger, but not both. <Major bummer.> At that time I tried all the power banks that I had to see if any would work the way I wanted them to, I had two small powerbanks that also had solar panels on the side of the powerbanks that actually worked the way I wanted them to but all of my other powerbanks did not work that way.

I suspect that the solar charger power banks are wired so that they can accept a charge while also discharging simultaneously so that the power bank can be providing power and also continue to accept a solar charge. The ones that I have that work are the Brunton Ember 2800 and a small solar charger/power bank that came with a Steripen that I have. Neither of them are available for sale any more.

Unfortunately, nobody that sells powerbanks will tell you if their product will simultaniously take a charge while providing a charge because only a cyclist with a dynohub would really care about that.


For AA and AAA, I only use NiMH rechargeable batterys, not disposable. For AA in a GPS, I have the best luck with Eneloop batteries and the low discharge version of rechargeable batteries sold by Ikea (they name them Ladda and they are white with black print). Ikea also sells some non-low discharge ones that cost less, I recommend the low discharge ones. I bought some of the Ladda Ikea ones last month for $6.99 for four cells.
LADDA Rechargeable battery - IKEA

Eneloops, I usually bought them from amazon, I won't bother with a link here, anyone can find amazon.


Now let me tell you one problem with using a Garmin 64 if you are not plugging it in for power. The screen can be configured to shut off to save battery life. I have no idea how long the battery will last if you have the screen permanently turned on, I have mine set to turn off after 30 seconds. You need to touch a button to turn the screen back on. But, while it is plugged into a power source the screen stays on. If your plan is to only power your Garmin 64 from disposable AA batteries and keep the screen on, you should test it first to see how long the batteries will last, they might not last as long as you planned.

The other thing I do not like about the Garmin 64 is that when the screen is off, there is nothing telling you that it is still turned on. Several times at the end of the day I assumed it was off, but it was on and then I had dead batteries the next day at the start of my ride.

In the photo I was using one of my remaining cylindrical pass though cache batteries on a tour last February in Florida (before Irma), the battery is copper color and on top of my handlebar bag bracket. (This is on a different bike than the one pictured above.) On this bike tour for two weeks, I was fully self sustained for power on my dynohub, never had to plug in elsewhere. But my phone was almost always off. I occasionally used it for weather forecast, but that was pretty brief. On this trip I used a Sinewave Revolution but I needed the separate pass through cache battery to be able to charge the AA batteries in my Garmin 64.

As I mentioned above, the Luxos U has a built in pass through battery that plays well with my Garmin 64, I can just plug it in and it works great without needing anything else. I bought my Luxos U from Star Bike in Germany last spring, also bought another SP hub from them at the same time.
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