Dynamo AA battery charger - do they exist?

[Tigerbiten]

I think this route may be my only option. Plus I don't know how well those USB AA battery chargers would hold up to the vibration / abuse of off road cycling? I think I need something pretty rugged.

My experience from doing long tours with usb chargers is that they are pretty rugged.
What kills them is either damp or the usb socket breaking, same with cache batteries.
What can be tricky is keeping the batteries in place when the going gets very rough.

[Sweep]

That last is a pretty high price.

I do have a set of 4 7day shop thingies which are supposedly 2900. I use them in my Lidl £6.50 light.

Not used them enough to say how they might last but they get good reviews and I am hopeful if I charge them at a low rate.

Must get another set.

I got through the Dunwich Dynamo with a single set of those batteries and that light.

Here:

https://www.7dayshop.com/products/7days ... a29004case

I don't think they are low self discharge but that isn't a big issue for the above type of use.

[MikeF]

Probably because AA rechargeables are going the way of the dodo. Lithium batteries are taking over the rechargeable field and for bicycle equipment the USB charger can be easily set up for a dynamo.

The problem with Li batteries is that they deteriorate from the day they are produced and have a lower number of recharge cycles than NiMH. Also they have a higher self discharge than LSD NiMH cells. I went to use a camera this week only to find, when I started to take a photo, that the Li ion battery had self discharged almost completely. The main advantage of Lithium cells is that they have a higher power density, but they are not the "bees knees" in every respect, and there aren't safety issues with NiMH cells .

[Sweep]

I thought I'd offer an update on the USB AA/AAA battery charger from IKEA I linked to above.
I haven't actually used/tested it yet but first impressions on unpacking all £1.80s worth of it are better than I expected - no information at all is visible on seeing it in the shop.

I had expected that it would effectively be a fast charger and that the batteries would get warmish/hot, rapidly degrade in the process as with the Maplin fast charger I stupidly bought a few years ago - charged AAs in an hour but rapidly fried them.

But it appears that it's not so.

According to the specs in the mukltilingual book that weighs as much as the unit.

AAA 900mAh takes 9 hours and AA 2450mAh takes 12 hours.

This means that in theory it can be left to recharge batteries overnight in the tent without waking to find that your batteries have fried/too much been sucked out of your powerbank.

It also claims to terminate charging via twin minus delta voltage sensors which I understrand is a good thing.

On checking it out in the shop it appeared to have no indicator light, which concerned me, but in fact it does, beneath the surface. An LED shows that charging is in progress and goes off when charging is complete.

The LED even flashes to indicate if cells are damaged - something it did with an aged set of mine, showing that it has a certain amount of rudimentary intelligence.

So on short, if you don't expect wonders from it, and perhaps don't put your best batteries in it, this may be a goer. Am hopeful that it will provide a handy means of charging the batteries for my Etrex 20 - those batteries don't need to be premium low self discharge ones as they are not by definition sitting around unused for long periods.

Will try to report further when I have tested it overnight with a variety of batteries.

And look forward to impressions from anyone else.

Yes I realise that this isn't a post about charging AAs directly from a dynamo, but from a powerbank. But that can of course itself be charged from a dynamo if you are so inclined. Me? I may possibly be veering away from the technical complications of dyamo charging and power conversion.

[tommydog]

I thought I'd offer an update on the USB AA/AAA battery charger from IKEA I linked to above.

Thanks for that update. I am very tempted to buy one myself. Although it is not a fast charger, it may work very well for topping up the batteries. You could just plug it in overnight and forget about it. It's great that it has the termination circuit.

I am very interested to see how you get on with this on a real tour.

[tommydog]

Me? I may possibly be veering away from the technical complications of dyamo charging and power conversion.

Have you seen the latest post from Darknewt on this thread:

viewtopic.php?f=5&t=120392&start=60

He seems to being having great success with charging a powerbank from a dynamo. It's very encouraging and I think I am going to go that route.

[Sweep]

yes I saw darknwewt's post tommydog.

Agree that it is positive but still a tad wary at the mo.

After all it strikes me that there shouldn't be any debate about this thing at all - surely it should just be a matter of plugging in and stuff works?

Have given the Ikea £1.80 jobbie a test run though not on tour.

It did indeed appear to take 12 hours or so to charge up two AAs of about 2500 capacity.

Used it connected to my Anker 20100 powerbank.

The light went out, indicating that it had judged the batteries to be fully charged and I noticed that it was no longer warm.

The lights were flashing on my Anker powerbank - something I haven't seen before with stuff plugged in - not sure what that means.

Have put the batteries in my Garmin and it shows them as fully charged. Will see how long they last. They are actually pretty old/trashed batteries - will try to test it with some better condition non low self discharge batteries in the near future.

By the by, if looking for this thing in the maze that it is your average Ikea, it should be near the rechargeable batteries near the lighting department.

[tykeboy2003]

I am looking for a solution to charge AA batteries from a dynamo.

Have a look at this. http://www.14degrees.org/diy-bicycle-dy ... ery-packs/

Maybe it could be adapted to charge AAs?

[tommydog]

yes I saw darknwewt's post tommydog.

Agree that it is positive but still a tad wary at the mo.

After all it strikes me that there shouldn't be any debate about this thing at all - surely it should just be a matter of plugging in and stuff works?

I think the main uncertainty comes from the Ewerk as it does not put out an exact 5v. Why don't you try the forumslader? That is reported to put out a stable 5v and is the most efficient charger on the market.

[andrew_s]

The problem with Li batteries ... have a higher self discharge than LSD NiMH cells. I went to use a camera this week only to find, when I started to take a photo, that the Li ion battery had self discharged almost completely.

That may well not be the batteries.
Most modern electronic devices don't have a physical on/off switch that breaks the electrical connection between the battery and the circuit board(s). Instead, they have a soft switch that effectively puts the device to sleep, but some current is still used to monitor whether the switch has been pressed to turn the camera back on. That may only be 0.5 mA, but it's still enough to drain a battery over several months or a year.

[MikeF]

The problem with Li batteries ... have a higher self discharge than LSD NiMH cells. I went to use a camera this week only to find, when I started to take a photo, that the Li ion battery had self discharged almost completely.

That may well not be the batteries.
Most modern electronic devices don't have a physical on/off switch that breaks the electrical connection between the battery and the circuit board(s). Instead, they have a soft switch that effectively puts the device to sleep, but some current is still used to monitor whether the switch has been pressed to turn the camera back on. That may only be 0.5 mA, but it's still enough to drain a battery over several months or a year.

In some cases you are right, but I've have had it happen with batteries charged and left out of the camera.

[Sweep]

I thought I'd offer an update on the USB AA/AAA battery charger from IKEA I linked to above.

Thanks for that update. I am very tempted to buy one myself. Although it is not a fast charger, it may work very well for topping up the batteries. You could just plug it in overnight and forget about it. It's great that it has the termination circuit.

I am very interested to see how you get on with this on a real tour.

Update - have used it on tour and - all £1.80s worth of it - works fine - I tend to use it to recharge my Garmin AA batteries overnight from a powerbank - the powerbank is recharged from a dynamo.

I did a bivi trip recently and although the forecast was for a dry night I thought it best to put the Anker powerbank and the Ikea charger with the batteries being recharged inside a semi transparent light dry bag. I could see the light on the Ikea thingy so charging was going ahead just fine (the light goes out when it figures that the batteries are fully charged). I awoke in the middle of the night to see the light on the charger flashing which indicates an error. I think that maybe this was due to overheating, so maybe not such a good idea to put it inside a bag on a fairly warm night. Have used it since and it seems to be none the worse for wear.

I decided to buy another but it appears from looking online that Ikea no longer sells it, at least in the UK. I also checked ion my local Ikea in the usual place and, yep, it seems to be history.

I had to get another new one from ebay from a chappie selling new ones for just under £4.

[Jdsk]

What a helpful resurrection, I had no idea such things existed.

Could you post a photo of yours now that it's known to work, and a URL for the one you've found, please?

Thanks

Jonathan

[Sweep]

What a helpful resurrection, I had no idea such things existed.

Could you post a photo of yours now that it's known to work, and a URL for the one you've found, please?

Thanks

Jonathan

Pictures here, along with lots of technical stuff that is somewhat beyond me..



https://lygte-info.dk/review/Review%20C ... %20UK.html

If you were interested I could type out the typical charge times quoted in the manual for charging various capacities of AAA and AA cells.

Essentially though I would use it overnight and just check on it if you wake during the night. It charges slowly, which is good I think.

I suppose you could also use it for micro charges when stopping in the likes of spoons - some have USB ports at tables, if no USB ports just plug the ikea device into a mains/USB adaptor.

On discovering that they are discontinued I bought my second one the other day from here:

https://www.ebay.co.uk/itm/IKEA-VINNING ... 2749.l2649

I was expecting it to come by royal mail but that seller actually sent it by courier and I got an email alert to tell me it was coming with a 2 hour delivery slot.

If you search for Vinninge you will maybe find other sellers.

I have no idea why Ikea discontinued it in the UK - I have the impression that they are still selling it in other territories.

Great thing - saves me from carrying a mains AA/AAA charger and in any case sitting in a spoons for 12 hours, even for me, might be a challenge.

It weighs next to nothing.

[Jdsk]

Thank you very much.

For us this would probably be a case of only needing to know that it works. : - )

...

I've posted before about how we manage electrical stuff while we're touring. That has involved swapping all of the AAA and AA batteries from rechargeable to disposable before setting off. This might offer another option.

Jonathan