onesmalldrop

I'm doing some research for an upcoming cross-country tour, and I've been surprised by how little information seems to be out there about charging battery packs with a dynamo hub. No matter how I phrase my search, this discussion from two years ago is all that seems to come up. I guess maybe it's an unconventional approach - most people do a dynamo hub or a battery pack, but not both, I guess? - but I was wondering if anyone else has experience with doing this. My concern is that the low power flow from the dynamo will be insufficient to charge a high-capacity battery pack. The above linked discussion suggests that this is true and I'd have better luck with a low-capacity battery pack, but yeah, just seeking wisdom/experiences/advice

DanBell

Most people I know with dynamos also use a battery pack. I use a 20,000mAh Xiaomi battery. It charges fine from the dynamo. The problem with charging your phone directly from the hub is that if the power drops out when your speed drops your phone will wake up everytime. So I really think the battery is necessary. I haven't heard of anyone having the problem you're suggesting, but maybe I just got lucky. I'm quite ignorant about electrical matters.

fietsbob

probably https://www.peterwhitecycles.com/b&musbwerk.php ... / ... https://www.peterwhitecycles.com/ewerk.php

https://www.peterwhitecycles.com/tout-plug.php

I managed to tour Europe, etc. 3X , before any of this stuff existed..

Tourist in MSN

There are people that charge up a big powerbank and then at night use that to charge up their other devices.

I am more inclined to charge my devices directly off the hub, but usually using a low capacity pass through cache battery. More on that here:
https://www.cyclingabout.com/best-dy...fer-batteries/

Regarding capacity, I see nothing wrong with a larger powerbank, other than weight. But it becomes a question of how much power do you need? I think I get about 2 to 2.5 watts of power out of my USB charger on my hub for each hour of rolling. That of course depends on speed and amount of slow hill climbing. If I am rolling for six hours, that becomes 12 to 15 watt hours. If you are putting that power into a power bank, there will be some losses when that power is withdrawn later, if I put 12 to 15 watt hours into a powerbank, I would expect to get maybe 10 watt hours back out later. I have no data on this, it is strictly a guess. When you charge up a battery, it gets warm and when you discharge it later it gets warm again. That warmth is evidence of wasted power that you lost.

You might need to start thinking about how many watt hours of power you need each day.

Rolling, my GPS (2 X AA) is on, one or two taillights (2 X AAA) is on in flash mode. My phone (Li Ion) would be either off or in airplane mode, likely to have all apps shut off. If I brought a tablet, it would be off. I would also have a camera (Li Ion), a second taillight (2 X AAA), possibly a headlight for the bike which most likely is off, and a headlamp (4 X AAA) to use in camp on my head. All AA and AAA batteries would be NiMH rechargeable batteries and I would charge those off the hub too.

Are you doing this cross country trip with a group like ACA? If so, they could comment on power availability at the campsites that they use.

My last tour was two weeks, I was self sufficient on power, never plugged into an outlet.

Most powerbanks can either be charged or discharged, but not both at the same time. But a small number can function as a pass through cache battery. If you can find one that can function as a pass through cache battery, that would be better so you can charge things off the hub while you are rolling.

Some devices are picky about their power supply, my Garmin 64 is very picky about power supply and some of the pass through cache batteries that I have bought do not charge that GPS while the battery pack is also being charged. Everybody has to learn the hard way what works and what does not.

Good luck.

gauvins

1. You can charge your battery pack from your dynamo. I've done it (forum slader -> Anker). If it is crucial for you, test it before you go.

2. You'll lose 25% energy with this intermediate step. Much much better, if you can, to recharge your devices directly. If your dynamo doesn't have a cache battery, you may not be able to charge your phone - phones typically require stable voltage or will stop charging altogether. Note that a cache battery is NOT like charging your phone from your generator. Current flows through the battery to the device, and the cache takes over when voltage drops. If you can, get a dynamo that provides a cache battery.

3. Usual scenario would be to charge/top-up bike computer, smartphone, headlight with your dynamo. If there are more kilometers to ride, top-up your bank. Recharge your bank from a wall outlet whenever you can. Be sure that your bank can digest 2.4 amps, that your USB cable is of good quality, and that your wall charger outputs 2.4. test your system at home.

Have fun

Rick

You can find pass through battery packs at places that sell portable solar panels. I have one made by Voltaic. It is not large enough to do a full charge of the 4900 on my phone but will charge the phone while I am charging it with my Sinewave Reactor. When you go to purchase from any of the companies that make these pass through batteries. Make sure they have the minimum current/Amp output that your device requires.

Tourist in MSN

One more thought, if you go with the big powerbank that does not function as a pass through cache battery, it might be a good idea to have a second small power bank too. Then if you had a device you were relying on during the day, such as if you were using a phone with a GPS app and your phone started to get low, if your phone did not want to charge directly off of the dynohub you could use one powerbank to charge the phone while continuing to charge the other powerbank off the dynohub.

Thanks for posting. I looked it up.
https://www.voltaicsystems.com/battery-packs

One of the reviews of the V15 at their website said they could charge the powerbank while also charging their Garmin from an SP dynohub, that confirms what you were saying too. I did not check the other batteries they sell, they might do the same thing too.

The pass through cache batteries that I am currently using are no longer sold. And I did not want to buy one of the high priced ones specifically sold for cycling with a dynohub. I do not need to buy one right now, but I am glad to find out where I can find one later. It is interesting to note that the two pass through cache batteries that I am currently using have a built in solar panel.

HobbesOnTour

Zendure is another brand that allows pass through charging. I do not have one but have read positive reviews from other cycle tourists.

I second the idea of charging a powerbank, then charging devices from that. My Cycle2Charge unit does not have a cache battery.
I also second the idea of carrying 2 smaller capacity powerbanks rather than one large one. For redundancy if one is damaged and to optimise opportunity if you can top up at an electric outlet.

I've used RavPower powerbanks for the last couple of years and can't fault them.

On a typical day's touring my powerbank is connected for most of the day. Near the end I will connect my Wahoo directly and it charges very quickly (A previous Garmin did not). Off the bike I will charge, as necessary, phone, kindle and rechargable batteries for camera/lights.

It works for me.

Trevtassie

The Forumslader that has the big battery pack doesn't need really a secondary battery bank as it already has batteries inside, the smaller steering stem version probably does,because the batteries would fill up quickly. The way ours are set up is in a PVC tube similar size to an old school bicycle pump, with a plug to connect to the hub wiring and with a switch in that wiring to switch between the light and charging. The PVC tube clips into a couple of Bluemels pump clips that mount to the water bottle bosses on the down tube, so we can take the tube in the tent at night to charge stuff.. We have the USB boost charger to recharge the Forumslader from AC power if needed. We carry a 60W AC charger that can charge everything we have, all at once really fast. If you do decide you need a power bank, find one that charges with USB-C, it's much faster than standard USB.when charged from AC power with the right adapter.

Rob_E

There might be more discussion in the electronics section of the forum. It's kind of a niche case. Some of us do it, but not enough to generate tons of discussion, and, as far as I know, there isn't a huge issue with incompatible batteries. Maybe the reason you're not seeing lots of posts about batteries that don't work is because that's not a huge issue.

I've used two batteries in recent years for this. This one: https://www.amazon.com/gp/product/B01422TC14/
It's the higher capacity and it works the best. The issue with higher capacity for me has not been that I can't get it to charge. It's that I have to have it plugged in for a long time before I see a change in the charge. There are only lights to indicate 4 levels of charge, so you need to increase the battery level by as much as 25% before you see any change in the charge level. On a high capacity battery, that might be a good amount of pedaling. But then I only carry a higher capacity battery because I sometimes spend days at a time with no pedaling. Otherwise it doesn't make much sense to carry a battery that you can't fully charge on a day's ride.

The other battery: https://www.amazon.com/gp/product/B00RVIGY1I/
This one is actually a little more finicky. I can charge it, but sometimes it doesn't like the inconsistent power output of the dynamo. But it's handy to have because I can create a local wifi network and transfer files between devices.

My advice is to estimate your daily power needs, maybe double it for your days off, and look for a battery to match. Read the reviews. Probably there are no reviews saying, "I was able to charge this with my bike hub." But there may be reviews about charging it with solar power, which is also a good indication that you can use an inconsistent source of power. Good luck.

Tourist in MSN

Resurrecting a dormant thread from a few months ago.

I just wanted to say thank you for posting that. Soon after this thread was posted, one of my vintage external pass through cache batteries died. That pushed buying a new one up higher on my priority list.

I bought the V44, although the V15 might have met my needs. I am very very happy with it. It functions great as an external pass through cache battery with my SP hub and Sinewave Revolution to charge my Garmin 64 GPS. My Garmin which I run off of rechargeable NiMH AA batteries appears to be more picky about its power source than any other device I have used. But the Voltaic and Garmin play very well together. I leave in a few weeks for a five week trip and will be using the Voltaic.

I decided to get the V44 which will have excess capacity instead of the smaller V15 so that I do not have to think very hard about the status of the charge in my devices. Cost a bit more money and will make the handlebar bag 175 grams heavier than the V15 would have, but after using smaller battery packs over the years I decided to get some extra capacity this time. With 44 watt hour capacity, that will be plenty of capacity.

I found the "always on" mode to be a bit confusing, but I got it figured out. I am leaving that mode disabled to reduce drain on the battery. That made this powerbank a bit more complicated than most other powerbanks but now that I am up on the learning curve, I anticipate no difficulties with it. By leaving that "always on" turned off, all it really means is that when I start withdrawing power out of it to charge something, I just have to remember to press the power button to turn it on.

I bought a spare 5.5mm barrel connector coiled cable that is a bit longer to use with it for charging. Bought it on Ebay from Asia, shipping can take a month.

Thanks again for posting.

ason

Rick,

I am looking at the same system (Voltaic plus Sinewave). I am wondering if I can use the two inputs (USB-C and Mini-USB) on the Voltaic cache battery to take power from the Sinewave and the other from the solar panel at THE SAME TIME. Any luck with this?

Thank you,

Andrew

skookum

You didn't have any problem charging it? Alee Denham doesn't recommend cache batteries of more than 3000mAh, because he says the internal resistance of larger capacity batteries is too high.
I have no idea, I'm just going on what others recommend.

Tourist in MSN

No trouble at all. The V44 battery pack I used is no longer listed on Voltaic website, they have larger and smaller ones.

It worked very well for me on a five week bike tour. During the first couple weeks I was slowly depleting my batteries until I discovered that a high resistance cable had gotten into my collection of cables and I was not getting as much of the current from my Sinewave into my V44 as I should have been. Charged everything up from an outlet in a laundry room on a rainy day at a campground and finished the tour with out a power problem. Besides using a better cable, I also was more careful about my screen time on my phone and I was careful to avoid using a cold phone. Checking the weather forecast on wifi in the morning with a 40 degree phone could consume a lot more power than with a 70 degree phone.

On a different forum I described in great detail what worked for me on that bike trip as far as electrics go, the link to that is at:
Electrics that I use for bike touring - what works for me.

skookum

Thanks. I haven't been looking at the thorn forum much, its a pretty quiet place.
I'm just setting up a nsystem so all this is relevant.
Thanks again.

Tourist in MSN

Just to reinforce one point, when I have to assemble my bike after flying somewhere with it packed in an S&S case, I decided to quit installing a headlight on the bike, instead just carry one that I can strap onto the handlebar in case I need it.

But, if you are not frequently disassembling and reassembling the bike, that is not a problem. Thus, you could certainly leave a light on the bike. When I am not touring I put my Sinewave Revolution USB charger on my rando bike and also have a dyno powered headlamp on that bike, works well.

I just find that I use a bike headlamp so rarely on a bike tour that I felt it was not worth the time to install one on each trip. But if the bike is used for other purposes besides touring, it makes sense to have one installed.

If you are new to dynohub lighting, be advised that dyno powered taillights do not flash. I mostly use flashing taillights when I tour, thus I consider a dyno powered taillight to be a secondary light with my primary taillight(s) battery powered.

rifraf

Yeah if you've not found a campsite by dark, a headlight is unlikely to help.

Mines permanently on my bike as its now my only form of transport, having given up driving. but is rarely utilised on tour.

Saying that, I do feel my dynohub and charging system is the best investment I've made in my cycling outfit.

Such a relief to have a great fit and forget system that offers light on demand and keeps my phone and garmin units topped up.

rifraf

Great tip as a cold phone offers much less power than a warm one.

Discovered this the hard way after relocating from Western Australia to New Zealand (a much cooler clime)

Tourist in MSN

I do not put things in order of best investment, second best, etc., but I agree that it is worth it if you are mostly camping.

Built my first touring bike in 2004, saw no need for a dynohub.

Then built another in 2010 but did not have anything that charged with a USB, again no dynohub.

In 2013, built up another touring bike and this time got the dynohub. I expected to use it mostly for charging, not much for lighting. At that time my flip phone did not use USB for charging, but I knew that the time would come.

In 2017, built another touring bike and did not even consider not getting a dynohub. By then everything electric I used on tours was charged by USB. When I say that, my AA/AAA NiMH battery charger was also USB powered so I am including AA and AAA batteries as being USB charged.

Pratt

As Dan pointed out, phones complain when the hub output drops below a certain level. In my case that level is right around cruising speed in New England. Rechargeable AAs, for the eTrex, however, charge very nicely from the hub with a Sunjack charger. The old phone would charge on long downhills, e.g. Kankamagus, or off my Wanker solar panel.
Haven't tried the new phone with either yet. Also have to see if the phone likes my cache, old one didn't, and if the cache likes the hub and solar panel.

Tourist in MSN

I think that the range of phones is quite huge. It is my experience (which is admittedly quite limited) that the cheaper the android based phone, the less picky the phone will be about the power source. And Apple phones appear to be the most picky about where they get their power.

.

3speed

When you all say you use a cache battery, is this referring to a specific type of battery, or just that you plug a power-bank type battery in-line with your charging system? Also, is there a difference in electrical losses between charging a power-bank and then charging the phone, vs charging the phone through a cache battery? To me it doesn't seem like there should be a difference since it's running through a battery either way, but I'm no electrical expert by any means. I have a 5,000ma battery that will charge my phone while charging itself. Will that serve as a perfectly decent cache set-up?

Oh, phones... I think it's just all over the place. I have a friend with a cheap android. That thing will only charge with the charging base that it came with, or weirdly, my kindle charging base. No regular old charging base will work to charge his phone. My iphone has never complained about anything, but it is an old one by today's standards. I hope I don't have issues if I get a new one this year.

Tourist in MSN

If it works for you, great. And if it serves your needs, you are set.

Some powerbanks can only be charged or used to charge something, but not both at the same time. Sounds like yours can be charged while also charging another device like your phone at the same time, which I think is good.

I am no expert on battery stuff, but it is pretty clear that if you put some power into a battery, that you do not get all of that power back out again, there are losses.

If a power bank can be charged simultaneously with being used to charge something else, I refer to it as a pass through cache battery. In this case the phrase "pass through" means that the power will pass through it.

When touring, I use mine in "pass through" mode to charge my GPS or to charge my phone. But to charge AA or AAA batteries or my Li Ion camera batteries, I do that in the campsite in the evening when my hub is not charging things up. There is no best way to do this stuff, just personal preference.

stardognine

Interesting thread. I’m another electricity idjit, but slowly learning. 😉 I recently went to a Walmart for groceries, and got sidetracked in the electronics area. I ended up grabbing a Blackweb (their house brand?) 20,100 mAH battery pack, for $30.00, because the price seemed like a pretty good deal to me. It takes a long time to charge, alright, but you get a lot of power back out, obviously. 😎

Now I think I’ll look into a portable solar charger. I ride too darn slow, to rely on a dynamo, I think. 🤔😁😉