iPhone 3Gs does not work with my minty boost 2.0

[paulbeard]

Hmm, I just built my first one of these and it seemed to work (with an iPhone 3G) and then started cutting in and out (the phone would chirp as if the charger was being disconnected/reconnected). I decided to leave it overnight once it said it was charging: got up this morning to find about 5% of the battery left.

I need to go over the connections and check the voltages: it looked fine but I want to doublecheck. Which of these post-factory modifications are recommended? I see a lot of stuff being thrown around but I don't understand all of it.

EDIT: aha, I see part of the problem via the FAQ. Don't leave it plugged in overnight

It really sounds like I need to go with three batteries, since my plan is to use rechargeables.

[paulbeard]

OK, replying to myself, maybe, but I'm sure someone else will read this.

I just went over my kit and it all checks out, with just under 3V at the battery holder and right around 5V at the USB connector. So that's all good. Curious about additional batteries. Since ideally, I should push 3V in (with 2 1.5V alkalines) but I want to use rechargeables, it's been suggested I use three and get up to 3.6V. Where's the cutoff? 6V -- what you get with 4 alkalines or lithiums -- seems to be too much, but 4 rechargeables would be 4.8V. I'm reluctant to test this on the iPhone without some banned it will work

Any issues there, other than a need for a bigger tin?

[adafruit]

http://www.ladyada.net/make/mintyboost/faq.html

[paulbeard]

http://www.ladyada.net/make/mintyboost/faq.html
I want better performance, should I attach 3 or 4 AA batteries? How about a 9V?
If you are using rechargeable batteries (NiMH or NiCad) then 3 batteries is better than 2. However, if you are using Alkalines, you won't get significantly more run time this way. In fact, with 4 batteries, the output voltage is 6V which is too high and could theoretically damage your device! The charger is optimized for about 3V input. For longer run time, use 2 C or D size batteries.

Yes, I saw that. The mention of 6V as a theoretical maximum was what I was concerned about.

Part of the trouble I am seeing is that on/off charging state which may be attributed to rechargeables vs disposables. And the drain of the iPhone battery into/because the MintyBoost doesn't make it very useful.

[LHOON]

It worked from the first time with the 2 100k resistors as instructed, for my new iPhone 3GS.
No-load current is 0,18 mA
The current taken from the batteries (2 x NiMh) during charging reaches 1,5 A however!
AA's wont take long this way, hence I go for two 11000 mAh D-cell NiMh's.

Will have to look for a larger box however...

[Parlex]

I've read and understand the FAQ. (At least I hope I did.)

To recap: 4 Alkalines in series provides far too much voltage. What I don't understand is why can't 4 be used in a series parallel configuration? It will still provide 3v but the current draw will be split across all the batteries. Or am I missing something?

Would I be able to use 4 in a parallel series configuration if I want to power an Arduino along with the GPS shield and the EM-406A, as opposed to an iPhone? Obviously for this the Data lines won't be used, as noted in http://www.ladyada.net/make/gpsshield/power.html

Sorry if this has already been covered, I'm happy to just be pointed in the right direction.

[Len17]

To recap: 4 Alkalines in series provides far too much voltage. What I don't understand is why can't 4 be used in a series parallel configuration? It will still provide 3v but the current draw will be split across all the batteries. Or am I missing something?

It can be done. Here's one example: viewtopic.php?f=15&t=10151

You have to be a bit careful with batteries in parallel. If their voltages aren't the same, one will try to shove electrons down the other's throat, which is bad. Use matching batteries and make sure they all start out fully charged, and you'll be OK.

[LHOON]

It worked from the first time with the 2 100k resistors as instructed, for my new iPhone 3GS.
No-load current is 0,18 mA
The current taken from the batteries (2 x NiMh) during charging reaches 1,5 A however!
AA's wont take long this way, hence I go for two 11000 mAh D-cell NiMh's.

Will have to look for a larger box however...

It worked indeed, as long as the NiMh's are fully charged ! Well before the discharge, the pullup voltage (taken from the NiMh voltage) drops too low (< 2,4V), and the iPhone switches off.

I have measured the voltages of the standard iPhone charger: it gives 2,7 V and 2 V on the data lines. Removed the resistors R4 and R5 and replaced them with voltage dividers to get approximately these voltages, fed however by the 5V.

This works well now for charged NiMh, will see how much energy I will be able to get out of it.

[semicolin]

What resistors did you use for the voltage dividers...also could you possibly post a picture of the finished product

[barduck]

I got a brand new iphone 3GS (week 45) and I am unable to get any charge at all from the MintyBoost, takes a few seconds before I get "charging is not supported with this accessory". It use to perfectly charge my itouch before. I went over this thread and other posts on the forum and it's still not clear to me whether there is a reliable solution for this issue and if there is, what are the exact steps to implement it.

So, from the various theories raised here, were any of them confirmed and is there a solution?

Help! I rely on MintyBoost for charging my devices when I am out cycling and don't have access to power for few days so finding out that it doesn't charge my new iphone 3GS was really bad news for me.

Thanks
- barduck

[adafruit]

the 3Gs doesnt work well, which is why we put

Tested works with: iPod nano/mini/photo/video/shuffle, iPhone (except 3Gs),

on the product page at http://www.adafruit.com/index.php?main_ ... ucts_id=14

[barduck]

the 3Gs doesnt work well, which is why we put

Tested works with: iPod nano/mini/photo/video/shuffle, iPhone (except 3Gs),

on the product page at http://www.adafruit.com/index.php?main_ ... ucts_id=14

I wasn't complaining at all, I bought the MintyBoost long before I knew I would ever own an iphone 3Gs, it served me well for my itouch and other devices and I love it. But it's always comforting to know that one's problem is legally covered

Anyway, I was simply reading on these forums that people had their speculations why it doesn't work with iphone 3Gs and some suggestions how this may be solved and I just wondered if there is any collective consensus about what can be done to fix it.

Thanks
- barduck

[adafruit]

hi, its not an issue of legality or not, we just try to keep our customers informed of what devices currently work well so they know what to expect
if we find a good solution we'll post it on our Big List of Devices here: http://www.ladyada.net/make/mintyboost/

[LHOON]

What resistors did you use for the voltage dividers...also could you possibly post a picture of the finished product

47k/68k and 47k/39k

Put the whole thing in a box, together with a device to charge the NiMh's: transformer (from old halogen lamp), and current source charger (800 mA), even a fan to keep it cool!
Works fine now: I get nearly 3 full charges of the iphone 3GS out of the D cells. The mintyboost is very efficient, the charger however a bit less, but this way I don't have to take the thing apart to charge the D's.

See here the assembled box (charging), with ventilation holes (and a trace of the soldering iron on the corner of the plastic...)

bilde.jpg (127.36 KiB) Viewed 5459 times

Some interior fittings were removed for clarity. The interior of the box, on the left the transformer, above it the rectifier and regulator. The fan blows on the latter's heat sink (it is shown a bit to the right of its actual position in the picture) as well as on the load resistor below. The mintyboost is on the right, on top of the batteries.

bilde(2).jpg (104.33 KiB) Viewed 5459 times

(Photos taken with the iphone itself)

[jpstaub]

Hello,

I was having significant problems making the MintyBoost v2.0 work with 3.7V LiPo batteries. For most here the LiPo batteries aren't relevant. However, you might follow the discussion at this location: http://forums.adafruit.com/viewtopic.php?f=15&t=13206. Since making the modification I've had success charging several iPod versions as well as iPhone 3G and iPhone 3Gs.

Best wishes,
Jake