Auxillary Power Supply

[900supersport]

I have a cube U30GT Mini that I am really happy with. However once in a while the battery life is a little limiting. My solution to this has been to build myself an axillary power supply. This is sufficient to give me two or three full charges.

Thought I would share my solution here.

Before I go into any detail just a note of warning on lipo cells used in the tablets and also in my power supply. If misused these cells present a significant fire risk. There is circuitry in consumer devices to protect the cells from over charging and over discharging. I'd advise a little research if you intend to go further.

The cube mini comes with a 5v 2amp power supply so I've constructed my solution to match that. I've also sourced an appropriate connector for my power unit and checked the polarity of a working charger and confirmed that the polarity of my charger is the same.

Because I'm a geek I brought individual cells and soldered these to give the pack I require. The component list below is for a cell pack readily assembled. You will need basic soldering skills and tools and a multi meter.

Ok enough of the pre-amble here's my solution. You will need to source the following, I've included links to an on-line store I've used as the prices are good and I've been in no rush. You may be able to source better.

• ZIPPY Flightmax 5000mAh 2S1P 20C ($13)
• Turnigy 3A UBEC with Low Voltage Buzzer ($4) low voltage buzzer will alert me before excessive discharge, sized for 5v and suitable amp draw.
• connectors ($3) these match the charge cables I have
• heat shrink tubing
• IMAX B6 AC Charger Discharger 1-6 Cells ($40) versatile mains powered charger for lipo cells
• cable
• power connector to suit your device

I already had a suitable charger that is safe for use with Lipos so total cost for me was about $20 plus postage.


Lipo


UBEC


Connectors


charger

Remember to put heat shrink tubing on cables before soldering.
I had to set a jumper on my ubec to select between 5 and 6 volts

Assembly instructions:

• if you need to change the connector on the cells then cut one cable close to the existing connector and solder to one of the connectors you have sourced using correct male/female connector (it should be female) on a cell and checking polarity (compare with a charge lead from your charger). Now do the second cable.
• Solder the input cables from the UBEC to a connector (male) checking polarity. Do not connect to the lipo pack just yet.
• Solder up the outputs from the ubec to the cable you are using for your auxiliary power supply
• Solder this cable to the power connector sourced for your tab checking polarity
• Check all your soldering and that all joints are heatshrinked so you cannot get shorts
• connect the ubec to the lipo. The led on the ubec should be on, if you have the polatiry wrong or the lipo is not sufficiently charged the alarm may sound.
• Using your multi meter check the voltage ouput at the power connector for the tab. You need the same polarity and similar voltage 9a few tenths will make no difference) to your mains power supply.
• Check the polarity and voltage again as if you have it wrong you could damage the tab
• If all checks out then connect to the tab and check its charging

Will be uploading a few pictured and hopefully a link to a Finless tutorials on soldering shortly.

UBECs are available that output between 10 ans 12 volts so if you need to you can get a 3s1p (three cells in series) lipo and appropriate UBEC and recharge your tab. Fot a Cube u30gt h you would need a UBEC outputting 10 v

[900supersport]

And here's my prototype. Works a charm though I don't think I will be taking it on any planes.


and I think this link should help with some soldering technique.


Finless soldering 101 (30MB)

[Guest]

Thanks for posting this info 900. You should be able to run for a week on one of those large packs~!!

[900supersport]

Re: Auxillary Power Supply

I wish, does give me some useful additional run time:-)