Is there a car charger that will work with the Touchpad?

[whitty]

My boating cohorts turned me on to this site:
Powerstream

I haven't bought anything yet, but this looks like the place for all 'yalls needs!

[Wheel_nut]

Originally Posted by bdbr

Probably a dumb question, but I'll ask anyway: Is it that the chargers aren't sending 2A, or the TouchPad isn't accepting it (somehow)?

I bought a two-USB port car charger (the one Wheel_nut recommended earlier then realized was wrong). It has 1A x 2 ports. If I get one of those cables with the two USB power inputs (like the ones being discussed for the USB host), would that send 2A to the TouchPad?

Not a dumb question at all! The Charging current taken by the Touchpad (within the capability of the PSU to supply it) is controlled by the state of the D+ and D- lines of the USB port. This is both voltage and impedance sensitive as has been discussed earlier in this thread. If you want to use the USB Cable supplied with the TouchPad, the D+ and D- line state has to be adapted inside the Bullet PSU.

My apologies for your purchase, however, you can still adapt it externally by putting the circuitry in a USB Male to Female asapter. I think I have already suggested this earlier in the thread.

Originally Posted by whitty

My boating cohorts turned me on to this site:
Powerstream

I haven't bought anything yet, but this looks like the place for all 'yalls needs!

Specifically what are you recommending here? I don't see anything that will work directly with the TouchPad.

[whitty]

DC/DC Converters, to convert voltage up or down, retail, wholesale, off-the-shelf and custom, DC/DC 5 watts to 1500 watts, voltage from 1.5V to 72V looks good...

[Wheel_nut]

You would be wasting your money. Better RTFT first ....

[whitty]

Sorry for the botched message above, this is what I was trying to post:

Universal plug adapter for international travel includes surge protection



Specifications:
Parameter Value Notes
Input Votage 12V to 24V
Output Voltage 5V
Output Current 2A
Size 100x48x48mm
3.9 x 1.9 x 1.9 inches
Ports 4 each USB sockets
1 each extension socket
Protection Removable fuse

[Wheel_nut]

OK, I give in ....

[BBooDoc]

Or you could buy a Ford truck with a 110AC outlet and just plug in and enjoy the ride!

-- Sent from my HP TouchPad using Communities

[TPBuyer]

Originally Posted by sidewinder33625

anyone try these dual usb chargers with one port for 2.1 amp and another for regular 1amp?

Black 2A Dual USB Car Charger For iPad iPod iPhone 4G | eBay

Click to view quoted image

I tried the 2.1A output and it does Not charge the TP. You get the TP warning message.

[RICKV]

Just be extremely careful with inverters, especially low costs ones.
If you are not using a "Pure SIN" wave inverter you run a great risk of damaging your devices in the long term. It will work... But the real question is for how long?
I have owned a few Inverters and after a few events I would not even run a power drill off of a non "Pure Sin" wave inverter. I have seen electronics do some weird stuff due to this, and considering the TP is almost a piece of museum at this point I'll take every precaution to not give it any abuse.

I have modified a 3$ griffin car charger with 10 cents worth of material, and 20 minutes worth of time and now have a fine working car PSU that powers both my TP and pre2 at the same time. Much cheaper and safer than any low cost inverters out there.
You can see my mods earlier in this thread based on some other contributors designs.
Unless you are a complete un-handy person, this mod is quite easy to achieve.

-- Sent from my HP TouchPad using Communities

[gergev]

Originally Posted by Wheel_nut

Not a dumb question at all! The Charging current taken by the Touchpad (within the capability of the PSU to supply it) is controlled by the state of the D+ and D- lines of the USB port. This is both voltage and impedance sensitive as has been discussed earlier in this thread. If you want to use the USB Cable supplied with the TouchPad, the D+ and D- line state has to be adapted inside the Bullet PSU.

My apologies for your purchase, however, you can still adapt it externally by putting the circuitry in a USB Male to Female asapter. I think I have already suggested this earlier in the thread.

I also jumped the gun, purchased (and received) the dual USB car adapter you mentioned originally.

eBay - The UK's Online Marketplace

If I order the USB Male to Female adapter you mentioned in the earlier thread:

"If any of you are considering hacking a PSU, it may be easier to add the Bridge and potential divider externally by splitting one of these and adding the circuit in it.
eBay - The UK's Online Marketplace
"

and put one of these at the end of the Touchpad USB cable, then into the USB adapter, will it charge the TP, without further modification?
Is it the "B" port on that dual USB car adapter which provides the 2.1A ?

Thanks for your work on this.

[Mutoidi]

Originally Posted by RICKV

Just be extremely careful with inverters, especially low costs ones.
If you are not using a "Pure SIN" wave inverter you run a great risk of damaging your devices in the long term. It will work... But the real question is for how long?
I have owned a few Inverters and after a few events I would not even run a power drill off of a non "Pure Sin" wave inverter. I have seen electronics do some weird stuff due to this, and considering the TP is almost a piece of museum at this point I'll take every precaution to not give it any abuse.

I have modified a 3$ griffin car charger with 10 cents worth of material, and 20 minutes worth of time and now have a fine working car PSU that powers both my TP and pre2 at the same time. Much cheaper and safer than any low cost inverters out there.
You can see my mods earlier in this thread based on some other contributors designs.
Unless you are a complete un-handy person, this mod is quite easy to achieve.

-- Sent from my HP TouchPad using Communities

But surely the AC from a square wave inverter is anyway rectified in the standard TP wall-charger, as it is brought back to 5v DC?

Otherwise I totally agree.. a pure sine wave is probably MUCH 'prefered' by modern mains powered micro-electronics.. and also to do the Car charger job 'properly' by bridging and adding the correct value resistors in order to work with the Touchppad's own system of charge sensing/limiting for maximum efficiency!

Good work!

[Wheel_nut]

Originally Posted by gergev

I also jumped the gun, purchased (and received) the dual USB car adapter you mentioned originally.

eBay - The UK's Online Marketplace

If I order the USB Male to Female adapter you mentioned in the earlier thread:

"If any of you are considering hacking a PSU, it may be easier to add the Bridge and potential divider externally by splitting one of these and adding the circuit in it.
eBay - The UK's Online Marketplace
"

and put one of these at the end of the Touchpad USB cable, then into the USB adapter, will it charge the TP, without further modification?
Is it the "B" port on that dual USB car adapter which provides the 2.1A ?

Thanks for your work on this.

NO, NO, NO, I should have been more explicit. You would need to split that adapter and put the two resistors and the bridge inside it. I suggested this because I have not (yet) found a way to open that Bullet Adapter without breaking it. Also, if someone wants to make and sell the Female to Male USB adapter, the postage would be less.

The B Port will supply 2.1A .... and the D+ and D- terminals are Bridged .... but the pull-up and pull-down resistors are ~ 27K rather than the 300K required by the TouchPad. However, the B Port charges my Nokia N900 SmartPhone perfectly. I believe that the standard for chargers is still evolving and maybe one day we will beable to travel with just one charger for all of our toys!

[wilywyrm]

Hi guys, long time no see.

Just came back to check if anybody else was having problems with the mod, but it looks like we've moved backwards to asking if X charger or Y doohickey will work again? :/
I swear, you could make a fortune from selling adapters with the resistor divider built in.

Anyway, Wheel_nut, I haven't forgotten! I just need to get ahold of a decent camera and remove some capacitors that are blocking view of some tracks on the charger's PCB. I'll probably be able to get them up here in a day or two.

[noseph]

Originally Posted by Wheel_nut

Whereas it would be very easy for me to produce these for under $10 a pop, the postage cost from the UK would be $14 for Tracked Delivery or $6 for non-Tracked.

I don't think the market would stand a price of around $25 Delivered.

The advantage taht the Hong Kong and Chinese sellers have is that the cost of postage is heavily subsidised for exports.

Wheel_nut - are you taking orders? If so I would like to be put on your list, your pricing is more than fair.

[Wheel_nut]

Noseph, Please PM me. I don't want to fall foul of the Forum guidelines.

I am making a batch of six, mainly for my friends here so will have a couple to spare...

[Wheel_nut]

Originally Posted by wilywyrm

Hi guys, long time no see.

Just came back to check if anybody else was having problems with the mod, but it looks like we've moved backwards to asking if X charger or Y doohickey will work again? :/
I swear, you could make a fortune from selling adapters with the resistor divider built in.

Anyway, Wheel_nut, I haven't forgotten! I just need to get ahold of a decent camera and remove some capacitors that are blocking view of some tracks on the charger's PCB. I'll probably be able to get them up here in a day or two.

Hi Wilywyrm, No need to go through the bother of stripping the charger down to take the pictures. I have done some more calculations and can rationalise the measurements I am getting on my Charger with the Resistor values you quoted. Only difference is the because 250K is not a preferred value, I am using 240Kto +5V ang 300K to Gnd. This works fine.

Many thanks for sacrificing your charger in the interest of Science.

[Finally Pre]

Pick THIS inverter up for 17.00. It supplies more than enough for the TP's A/C plug to work. On the ride home of about 15 mins the TP went from 50% to 64% battery.

[Mutoidi]

Originally Posted by Finally Pre

Pick THIS inverter up for 17.00. It supplies more than enough for the TP's A/C plug to work. On the ride home of about 15 mins the TP went from 50% to 64% battery.

80Watts.
Remember when the 'going price' for an inverter was about $1 per Watt?

Good value, but personally I still prefer the compactness of a correctly mutated 12v --> 5v cigarette lighter socket --> USB unit. Slick.

Beats me how HP can rave on about 'mobility' and yet produce TouchPads that apparently are to be tethered both to local Wifi and mains AC only!

Duh!

[Wheel_nut]

Originally Posted by Mutoidi

...... but personally I still prefer the compactness of a correctly mutated 12v --> 5v cigarette lighter socket --> USB unit. Slick.

Wot, Like this but compatible with the TouchPad Charging Spec ....

[Mutoidi]

Originally Posted by Wheel_nut

Wot, Like this but compatible with the TouchPad Charging Spec ....

HEAPS like that.. exactly yes!!