Pass through charging. Grrrrr.......

[rufus748]

I've previously used aukey and anker but find they have a tendency to shake themselves to bits internally.
I recently bought a zendure following reviews on here and it appears to be well built
Having just completed by latest wheel build, a son 28 with a K-Lite top cap switch and light also an Igaro D1 to charge gps and battery.
First test run last night and it's pumping out just under 5v at 10kmh.
On today's ride it drove me nuts. Both gps and battery were fully charged to start with. Battery initially wasn't allowing pass through. I could charge the gps or battery separately/directly using the Igaro but as soon as I tried passed through the garmin kept shutting down telling me i had lost power. It then sorted itself out and was fine.
Then when I was moving slowly and the battery should kick in it again shut down. Again sorted itself until it would run on battery at slow speeds but when I built up speed (in excess of 12kmh) it then said I had lost power and wanted to turn off, a drop in speed or turning the switch to light rather than battery and it kicked it again running off battery power.
Tried different cables, no change.
Thoughts? Battery issue?

[Bearbonesnorm]

As much as I like my Zendure battery, I'm not convinced by its pass through capability ... which would cause your problems Andy. Seems odd that yours is intermittent though, mine simply won't allow the gps to function when set up - dynamo > regulator > battery > gps.

[rufus748]

That's reassuring Stu thanks. I was hoping it wasn't the switch system, hub or Igaro.
So, which battery do I go for now? Anyone have any recommendations?

[Mr Arbuckle]

Have you tried the goalzero? It charges batteries from solar whilst charging device too, may be worth a bit more investigation on their site and the have good qna section.

[Wilkyboy]

It may also make a difference exactly which GPS you're using — I understand from the audax crowd that the Garmin Edge 810s have a tendency to do some weird switch-off stuff when it loses external power, that neither the 800 nor 820 do. If that's the case then you're on a hiding to nothing, unfortunately, since all batteries will "gap" the power at some point, causing the 810 to switch off. The solution would be to charge the battery to full and just run the GPS for as long as you can from external power, triggering the switch-off issue only when you need to charge the battery.

Then again, could just be the battery.

[Blair512]

I bought a couple of cheapy 8400mah batteries out of b&m for £7 each which pass through charge from my PC to my garmin ok so would assume they will work with a dyno as well. Details on the bargain alert thread

[ianfitz]

Not convinced on this but if the device is charged then surely it won't pull any current from the battery.

Also on some garmin devices you can tell it via the menu how to respond to a USB lead.

Some of them prefer a power only, rather than a data lead. I use a power only lead with no issue. Even when the garmin (800) is fully charged.

No idea if that's any help.

[rufus748]

I'm using an Oregon. It's worked in the past with pass through however batteries have effectively 'fallen apart' mid ride (Tuscany Trail and Turino-Nice) hence the pursuit of a replacement.
The zendure works fine as a pass through when running off the mains, just not from the Dynamo, I assume it's to do with the power input?
Problem was Ian it was shutting down saying it had lost external power when in reality it should have even been running off its own power (if full) or the pass through. I hadn't considered the data cable though, interestingly I used it for the garmin this time whereas I haven't before only due to the length of it (I need a longer cable this time). I changed the the power cable but not this one.
Just off for a ride, I'll swap it out and see how it goes, thanks.
I've ordered a 'jackery' battery last night after much research, all their range supports pass through.

[ianfitz]

Is it also worth seeing if the battery terminals inside the GPX are loose? That may account for the unit shutting down

[SixPotBelly]

I don't know if it's relevant but I tried using another brand power pack with pass through as if it were a cache battery and had the same result. What it seemed to be doing when connected between my e-werk and my Garmin was just passing through the output from the e-werk, so when I slowed too much the voltage dropped and the garmin reported loss of input power - same as if I had connected the e-werk directly to the Garmin. In the case of the power pack I tried, at least, the vendor's claim it could "simultaneously charge and be charged" was misleading.

edit - just thinking about it again now, it may be that when the bank is full that's what's supposed to happen. The bank doesn't need any more juice so routes whatever it's fed directly to the output. Would that explain your results?

[Asposium]

I have a goal zero Sherpa 50
large, heavy, and expensive
however, it does have pass through charging, and a 12v output ((useful for charging a garmin GPS via its powered mount, and for charging camera batteries via a 12v car charger))

[Wilkyboy]

I don't know if it's relevant but I tried using another brand power pack with pass through as if it were a cache battery and had the same result. What it seemed to be doing when connected between my e-werk and my Garmin was just passing through the output from the e-werk, so when I slowed too much the voltage dropped and the garmin reported loss of input power - same as if I had connected the e-werk directly to the Garmin. In the case of the power pack I tried, at least, the vendor's claim it could "simultaneously charge and be charged" was misleading.

edit - just thinking about it again now, it may be that when the bank is full that's what's supposed to happen. The bank doesn't need any more juice so routes whatever it's fed directly to the output. Would that explain your results?

My understanding is you can do pass through only on power banks that have two independent sets of cells in parallel, i.e. 5000mAh+ — bigger and heavier units. Then you can be adding charge to one cell while charging from the other (this all happens automatically). The electronics in the pack switch between them based on voltage at the terminals, probably with a bit of hysteresis to prevent rapid switching. When both sides of the power bank are full then I would expect the power from the dynamo to be presented at the USB output — albeit possibly with some cleaning up.

There's also thermal cascade to worry about, since these are lithium packs — when I quizzed Ankher on it, they said they'd had difficulty managing this and so had removed the pass-thru feature from later power banks.

The problem you're experiencing appears to be when switching between pass-thru from the dynamo and running from the battery — the Garmin needs, say, 4.5V to charge or else it goes to sleep, but the battery doesn't switch over to delivering from stored power until it's down lower, say 3V — that gap is enough to shut the Garmin down. I think the only solution would be to find a power pack that switches back to stored energy at a higher voltage, or to not bother with pass-thru and just charge batteries or charge direct.

Then again, it is definitely possible that the switch-off is caused by a USB data cable being used, instead of a normal one — that's the quickest and easiest thing to try to see whether it fixes the issue.

FWIW, I've toyed with pass-thru charging before and came to the conclusion that it's too unpredictable and the pass-thru batteries required are cumbersome. Instead, on my audax bike at least, I charge as much as possible directly from dynamo, and also charge up a couple of lipstick-sized power banks for overnight riding, which are small enough to be much easier to handle. On my off-roader then I'm batteries all the way (no dynamo) and so will have a clutch of them to get me round WRT (five: one per device per day, plus one).

And, while being a fully signed-up member of the geekery club, I do recognise the limitations of electronical solutions to navigational problems and almost always carry a battery-free, paper-based (waterproof paper) backup, and that's usually clipped to my stem, readily to hand. Compass, too

[DoctorRad]

I've never charged my (1st Gen) Zendure with a dynamo, but I have from a solar panel, which has similar output in as much as it's 'variable'. What I found was that after solar charging, the Zendure would get itself into a state where it would never show more than 2-of-4 lights lit until it was plugged into a fairly high-current charger (such as a car or mains charger) capable of giving a steady current. It would then charge as normal and eventually show 4-of-4 lights without an issue.

My PortaPow batteries seem to take trickle or variable charge better, but they have the disadvantage that they have an on-off switch. However, when they are receiving enough power, the electronics get switched on, and therefore the battery will provide output even when there is low input current. Of course, if the attached device is pulling more current than is going in, the USB battery will be discharging. It's therefore best to keep your devices as topped-up as possible, so they pull as little current as possible from your USB battery. The latter is then available to charge devices in case of emergency / dynamo failure etc.

[rufus748]

Tried the non-data cable today, still not operating properly.
I'll wait for the jackery to arrive tomorrow in the increasing futile hope it will solve my issues before I consider alternative methods for keeping the gps charged.
Appreciate all the advice

[Bearbonesnorm]

Andy, can't you simply have two batteries to run the gps - one charging from the dynamo while the other's plugged to the gps ... although that might be defeating the object slightly?

[In Reverse]

I bought a couple of cheapy 8400mah batteries out of b&m for £7 each which pass through charge from my PC to my garmin ok so would assume they will work with a dyno as well. Details on the bargain alert thread

These are very good tbf. Ran Garmin and phone off one on last weekend's bivvy (about 29 hours, no dynamo) and it had only lost half its charge whilst keeping both devices topped up to 100%.

I'll be taking two of these to Spain I think (they're pretty light) and hoping to get an occasional bit of charge out of an SP dynamo.

[rufus748]

Andy, can't you simply have two batteries to run the gps - one charging from the dynamo while the other's plugged to the gps ... although that might be defeating the object slightly?

I can Stu yes. But as you say that's defeating the object and that pigheaded side of me doesn't want to give in. just yet anyway...

[ScotRoutes]

This sounds a wee bit familiar.

I'm using a SP dynamo, a Kemo 172 and a Garmin Oregon.
I bought a wee battery that was supposed to charge and discharge simultaneously.
Plugged it into my Kemo and then the Garmin into the battery. Switched on the Garmin and the battery. - All good. Garmin shows external power is being supplied.
Went for a ride. Still good.
Stopped at a junction. Not so good. The Garmin pops up a message saying that external power has been lost and I need to hit a button to stop it powering off - despite there being a pair of fully charged AAs in it.
Start riding again (within 30 seconds) and the message goes away.

Now, having to hit a key to continue on internal battery power isn't a major issue, but it seems that the cache battery is switching off its output circuit when it shouldn't. If I just leave the cache battery and Garmin connected without the dynamo feeding it all, it carries on powering the Garmin until the battery is discharged.

I've been planning to skip the cache battery altogether, stick a wee bit of card in the Oregons battery slot to initiate the charging circuits and just have the dynamo keeping the internal batteries topped up.

[Mariner]

Rufus

I have an e-werk USB which has a built in cache battery which I am not using at present.
Will be passing through Exeter next week twice and can lend it to you if you want to experiment.
If you blow it up its yours though price tbd.

[journeyman]

Not sure if this will help but the way I stop blowing a gasket is with the following set up - cycle2charge charges a zendure a3 off of an sp dynamo (switch to revo light in eve) . During day garmin 64s runs off its own garmin rechargeable battery. At camp I then use the zendure to charge the garmin, phone etc via charge only lead. ( I found out that Pass through doesn't work on zendure and iharbot at low ( <12kph) speeds and garmin used to countdown to switch off - and often unnoticed). The routine works with the zendure in a gas tank; no gps crashes, but probably lose some efficiency charging battery to battery, although it hasn't been noticeable. I like the brick like 64s due to buttons rather than a touch screen. I have had problems with my rough handling causing the micro usb port on the zendure to have a loose connection caused by bending cable to fit in gas tank - hopefully resolved this with a right angled usb cable...

[Wilkyboy]

... but probably lose some efficiency charging battery to battery, although it hasn't been noticeable ...

I'm running a long-term test on all this at the moment — it's over a year now. Empirically, if you charge everything to 100% then losses battery-to-battery appear to be about one third, i.e. 30-40%. This is consistent with the charging-profile of lithium batteries, where the first 80% of the charge goes in quickly and then the final 20% "saturation charge" takes an age. There's a fair bit of heat produced, hence the losses. If you stick to just charging to 80% of Li batteries then your stored-energy will last longer.

The old article is here — http://www.16inchwheels.uk/2016/04/11/p ... ong-rides/ — although it's due a complete rewrite, due to observations such as the above. I need more warm-weather data, though, as batteries behave much better at warmer temperatures.

[rufus748]

Rufus
I have an e-werk USB which has a built in cache battery which I am not using at present.
Will be passing through Exeter next week twice and can lend it to you if you want to experiment.
If you blow it up its yours though price tbd.

Michael, really appreciate the offer but if the battery solution doesn't work I'll just carry 2 and charge independently.

The 'Jackery' arrived today. So far so good...
At slow speeds the battery kicks in and charges the gps. When the speed increases it appears to swap to pass through. I say 'seems to' as rather than see the battery symbol on the garmin display I now get what looks like a green plug, I haven't seen this before nor can I find it's meaning online. An in-line display shows the same power going to the GPS (4.77v) as when running off the Jackery.
When slowing down to sub walking speed I get the 'external power source lost' flash up but instantly the Jackery appears to kick in and the battery sign on the GPS appears again.
Anybody know what the green plug means?
Needs a proper ride tomorrow anyway.

[ScotRoutes]

The green plug means external power is being supplied.

Without that, it's running off the internal battery.

[rufus748]

Cheers Scott. So it could be sorted!
When it's being charged from the mains or through a standalone battery though I get a battery symbol that shows the charging state and a lightening bolt.
Is it due to the way the power is being supplied?

[ScotRoutes]

OK - here's how my Oregon seems to work.

Green plug icon - an external power source is present.

Flashing/lightning battery - an external power source is present and is recharging the internal NIMH batteries. Once these are fully charged, it becomes the green plug again. After a while ( the batteries have lost a bit of charge), it'll do the flashy thing to top them up, then back to green plug.

If an external power source is present and is then removed, the Oregon will flash up it's 30 second warning. If I hit a button in that time it'll carry on on battery power.