Author Topic: Solar gadgets + AA's (Read 14882 times)

mrcharly-YHT · « **Reply #50 on:** 04 April, 2011, 02:37:42 pm »

I used a similar buckpuck to run an LED from a variety of battery packs. The model I had took 6-32V and output a constant current of 3A.

Tried it with a bridge rectifier and the AC output from a bottle dynamo, but the dynamo didn't really have the oomf.

Very good devices, if a tad expensive.

If you look on http://uk.farnell.com/power-management there is a great system for searching for power control.

~~What's the voltage output from a hub dynamo?~~6V hmm.

http://uk.farnell.com/maxim-integrated-products/max1672eee/converter-dc-dc-step-up-down-smd/dp/1379767
or
http://uk.farnell.com/texas-instruments/tps62750dskt/ic-step-down-converter-2-25mhz/dp/1755706

Greenbank · « **Reply #51 on:** 04 April, 2011, 02:45:16 pm »

Quote from: mrcharly on 04 April, 2011, 02:37:42 pm

What's the voltage output from a hub dynamo?

A hub dynamo is a constant current device. Output is 0.5A. The voltage will be proportional to speed.

Some sites quote 6W at 15mph, so that would be 12V at 15mph but it all depends on the load placed on it.

Bicycle Hub Dynamos

Valiant · « **Reply #52 on:** 04 April, 2011, 04:48:29 pm »

I'm currently working on a unit. Mains/Solar/USB > 12v 14ah Li-on pack > 2x USB outs. With the added complication that I want to be able to bulk charge the batt, and connected devices when plugged in via the mains.

Kim · « **Reply #53 on:** 04 April, 2011, 04:55:55 pm »

Quote from: Valiant on 04 April, 2011, 04:48:29 pm

I'm currently working on a unit. Mains/Solar/USB > 12v 14ah Li-on pack > 2x USB outs. With the added complication that I want to be able to bulk charge the batt, and connected devices when plugged in via the mains.

Have you seen the MAX1737? It has a rather spiffing input current limiting feature (intended so that wall-wart rating doesn't have to equal max system load + charging current). Add a bit of circuitry to adjust this according to power availability, and you're winning.

andygates · « **Reply #54 on:** 06 April, 2011, 12:57:09 pm »

Quote from: mrcharly on 04 April, 2011, 02:37:42 pm

I used a similar buckpuck to run an LED from a variety of battery packs. The model I had took 6-32V and output a constant current of 3A.

Was that a commercial device?

mrcharly-YHT · « **Reply #55 on:** 06 April, 2011, 01:07:50 pm »

yup - 'buckpuck' is a trade name.

I had a luxeon led - erm I said 3A output, that was wrong, it was 1A. the led was 3W.

Had a couple of battery packs - 7.2 and 9.6v - just plug them into the buckpuck and it drove the led at a constant current.

andygates · « **Reply #56 on:** 08 April, 2011, 11:10:07 am »

Cunning stuff! Alas constant current isn't what I want, but they're clever.

Shifty pointed me to this at Farnell:
MURATA POWER SOLUTIONS|LSM2-T/6-W3N-C|CONVERTER, DC/DC, 6A 5V VARIABLEL | Farnell United Kingdom

...it looks ace, but it also has confusing specs, listing output voltage twice, once as a range and once as 5v. Any ideas?

mrcharly-YHT · « **Reply #57 on:** 08 April, 2011, 11:19:11 am »

I think this is what you need:

http://www.farnell.com/datasheets/74506.pdf

"This device provides a constant output voltage for
inputs that vary above and below the output voltage. It has
a 1.8V to 11V input range and a preset 3.3V or 5V output.
The output can also be set from 1.25V to 5.5V using two
resistors."

Output is only 0.3A, but that's ok for charging.

http://uk.farnell.com/maxim-integrated-products/max1672eee/converter-dc-dc-step-up-down-smd/dp/1379767

redshift · « **Reply #58 on:** 08 April, 2011, 12:05:28 pm »

Mrcharly is probably nearer the mark - albeit you'll need to put a little board together. On closer inspection the Murata seems to require a different range from that shown in its headline spec - for 5V out, you need 8.3-13.2V in which is outside your working range - the 2.4-5.5V in range is only for 3.3V out. It's more for CPU supply than ad hoc chargery.

Although - if you've already got the clever charger end, and you're only looking for regulation of the output from the panel, then maybe the Zener idea is the simplest?

I'm definitely out of the loop on this one - I haven't needed to fiddle with components for so long now that I'm way out of touch with what's out there. I think I'll go back to my leather work - at least this year's products are similar to last year's...

andygates · « **Reply #59 on:** 08 April, 2011, 02:06:57 pm »

The problem I have with the Zener is that it wastes that high sunny-day power. I'd rather use that to charge batteries!

andygates · « **Reply #60 on:** 10 April, 2011, 05:03:35 pm »

Heh. The Y-shaped cable that came with the charger is a perfect fit for the panel that arrived Friday (Lady Ada = FAST). What's the worst that could happen?

andygates · « **Reply #61 on:** 12 April, 2011, 09:09:34 am »

First pass says that whoever said "don't worry about overpower" was right.

Now, I need a South Pointing Chariot and a phototropic gimbal!

frankly frankie · « **Reply #62 on:** 12 April, 2011, 10:07:18 am »

Quote from: andygates on 10 April, 2011, 05:03:35 pm

Heh. The Y-shaped cable that came with the charger is a perfect fit for the panel that arrived Friday (Lady Ada = FAST). What's the worst that could happen?

Wrong polarity?

andygates · « **Reply #63 on:** 12 April, 2011, 10:28:41 am »

Apparently not. Instead the standard UK solar experience -- "is it working?" and vague disappointment!

andygates · « **Reply #64 on:** 12 April, 2011, 02:03:43 pm »

Why, Ambassador, with this little green "charged" light, you are spoiling us!

andygates · « **Reply #65 on:** 19 April, 2011, 07:31:47 pm »

Learning curve: The Awesome Charlotte Charger [tm] has a big fat button that gets bumped from charge to discharge mode in bags unless you're lucky or careful. Bombing descents down lanes upset careful packing schemes, so several times I've found that my cells aren't charged because I'm in discharge mode.

The solution? A molly-guard to prevent the button being pressed by accident quite so often: Twitpic - Share photos and videos on Twitter

(yay Dremel, hot glue and a bent spoke

)

Kim · « **Reply #66 on:** 19 April, 2011, 08:42:58 pm »

The less than awesome Kim charger has the same problem, as I mentioned upthread:

Quote from: Kim on 22 January, 2011, 02:52:18 pm

I discovered the SCH600F charger [...] It needs minor fettling to make it touring-ready, in the form of disconnecting the 'refresh' button internally, as that's just going to get knocked and waste all your valuable charge, and the addition of a Mk 1 elastic band to hold the battery compartment flap shut.

Our different approaches to this problem probably say something about our respective fettling psychologies.

andygates · « **Reply #67 on:** 19 April, 2011, 10:13:02 pm »

Not exactly: my button needs to be up, not down, or I'd be using the Mark I Postie Special elastic band as well!

(plus I'd been looking for an excuse to unbox the mini glue gun, and Firefly prop guns must wait until I get back from LEJOG

)

Kim · « **Reply #68 on:** 20 April, 2011, 01:54:44 am »

Quote from: andygates on 19 April, 2011, 10:13:02 pm

Not exactly: my button needs to be up, not down, or I'd be using the Mark I Postie Special elastic band as well!

So does mine. The elastic band is to stop the batteries falling out.

Feline · « **Reply #69 on:** 20 April, 2011, 02:10:37 am »

I had the same problem with my Dahon Reecharge when it was in my bar bag, and unfortunately it's charge on/off button is of the little round button you press once for on and again for off kind, so no elastic band pingfuckit fettlage would do the trick. Having it strapped to my head tube has worked though, it hasn't got knocked at all as yet. I would really like to disable the button internally, because there is really no reason to ever turn it off. If there is no current coming in anyway then it doesn't matter if it is on or off, but if there is a current coming in and it is off then the modulator gadget thingy down the line can get fried.

The switch is a bit of a liability, and to make matters worse the green led light that is on when it is charging can hardly be seen at all in daylight, which is when I need to see it because I run my light instead during the night

andygates · « **Reply #70 on:** 20 April, 2011, 06:53:41 am »

It's odd that these portable rufty-tufty chargers don't come with a little sliding door to secure the buttons away, eh?

Charlotte · « **Reply #71 on:** 20 April, 2011, 08:06:10 am »

Genius idea, I'll be effecting a similar molishment on my battery pack at some stage as I've had the swichy-onny-innada-pannier problem already.

Yet another use for Sugru, I think.

thing1 · « **Reply #72 on:** 20 April, 2011, 12:40:09 pm »

Quote from: andygates on 22 January, 2011, 01:46:15 pm

Aha! A Freeloader add-on Freeloader AA/AAA Battery Charger ... but the Freeloader's construction shouts "break me! drop my bits in the road!" to me.

Correct. It has several serious drawbacks:
1/ the oh-so useful built in torch has a whopping great push button that is bound to drain the batteries if left at the bottom of a bag (stupid when it *also* has a slide switch for the LED)
2/ the power out connector is a proprietary easy-to loose cable
3/ the power out connector fairly quickly worked loose and became unreliable
4/ attempting to open the case to fix the above points was a fairly destructive process
5/ it won't reliably charge and be charged at the same time
6/ the battery compartment is a bit tight for the new-school oversized rechargeable AAs (but this is really the battery's fault)
7/ it gets very hot when charging.

On the plus side it is very small and (point 3 & 4 notwithstanding) fairly robust.

I've just received a Powerboost pro2 charger. So far so good, it seems to not suffer most the issues above (but not yet tried 4 or 6!)

EDIT: I do also have the Extreme 4 battery charger. Not so keen on that one for touring as it's so much bigger, the batteries don't stay in when shaken, and again uses a strange USB cable.
All these chargers suffer the problem you have to charge in pairs; not ideal when all head torches seem to take 3 AAAs.

Kim · « **Reply #73 on:** 20 April, 2011, 01:38:30 pm »

Quote from: thing1 on 20 April, 2011, 12:40:09 pm

All these chargers suffer the problem you have to charge in pairs; not ideal when all head torches seem to take 3 AAAs.

Hence the SCH600F.

It's naff, but it'll charge cells independently.

thing1 · « **Reply #74 on:** 20 April, 2011, 01:44:36 pm »

Quote from: Kim on 20 April, 2011, 01:38:30 pm

Quote from: thing1 on 20 April, 2011, 12:40:09 pm
All these chargers suffer the problem you have to charge in pairs; not ideal when all head torches seem to take 3 AAAs.

Hence the SCH600F.

It's naff, but it'll charge cells independently.

O! I C.

I didn't realize they had two models. I have this one Extreme SCH500F AAA/AA Battery Charger

on balance I decided for the head torches I could probably make myself live with buying new batteries. We never needed to change them once in over 2 months on the road..... (but a lot of that was mid-summer with 18+ hours daylight...)