Cut the barrel connector of a 12V .5A wall wart and got my truck started. Gotta love dumb devices.
So then for the non-electronics-geniuses, what is a good DIY smart charger to put 6 good batteries in? The problem with these off the shelf chargers is that they are universally nowhere near their stated capacities from what I’ve seen.
I can highly recommend 4x18650 Coolook PB-2000.
I bought 2 from Fasttech. My android tablet and phones, my iPod, all Apple devices I tried charges great with this unit. My friends are using it when they come over and it newer fails to charge. It charges my picky Galaxy Tab 7.7 with same current as original Samsung charger. It can supply more that 2A without problems. By the way, I’m using some old laptop pulls in the power bank and I’m sure it’ll be even better with nice new batteries. Another thing I like is that battery voltages are nicely balanced when discharging. That’s not the case with some 3x18650 ENB power banks I’ve had. HKJ tested this power bank some times ago, here’s the review: Review: USB battery box 4x18650 Coolook PB-2000
Thanks for the recommendation, Noki. Looks like a nice charger. I have a Ruinovo I like, and it has 4 green Sony cells from a laptop pull. The 4 cells all tested about 2000 mAh but I could do way better with 4 Panasonic, and I like the Ruinovo too much to mess with it, though it can be a little picky about what it charges.
The Ruinovo is a nice, brushed aluminum but it’s killed a few devices by scratching glass/plastic with its sharp edges.
The smart DCP Anker and RAVPower power bank do not appear to lie about battery capacity.
LGABB41865 inside the previous 2600mAh model of the RAVPower power bank. LGABB41865 is indeed a 2600mAh cell. 
I haven’t seen teardown pictures of the newer higher capacity models yet.
Now be aware that all power banks I have ever seen quote the battery capacity not the output after 5v boost losses. You should get 80-90% after losses. And then there are losses inside the charging circuit of your device as that 5v is dropped down to 3.0-4.2v (or up to 4.35v) during a full charging cycle. These losses are unavoidable and vary some depending on how efficient charging circuit in your device is.
A 3000mAh power bank will never equal a full 3000mAh charge of your device’s battery.
Here is two 6 cell power banks with smart DCP
Anker 16000mAh 2nd Gen Astro E5 $37
RAVPower 16000mAh 3rd Gen Deluxe $36
I’ve never seen a DIY (bring your own cells) power bank with smart DCP.
Is there anywhere else then Amazon you can get Anker power banks? Tried to order from Amazon Norwegian site, UK site and US site, and the two first site stated that they would send to Norway, but it stops and tells me that I can’t get the Anker PB to Norway.
Just to add my 2cent to the discussion, try also different usb cable…
Don’t ask me why but with chinese product (car charger, battery pack,…) not all the cable work correctly.
For example my car charger should not charge my android phone without an old micro-usb cable…
For phones etc, that could work. For my PDA, it has a another connection, so I have to use on of two cables I have to it. No one worked.