How can I get 12V 1A charging voltage from USB?

[karabiner98k]

12V batteries are available in all sorts of capacities.

They are certainly much more expensive. Could you please show me the picture of one of them?

The original factory charger charges my battery in 1 hour 15 mins (wall socket adapter), so I have no problem if charging the battery with the converter takes an hour or so.
1 hour delay between flights is good for the helicopter too because the motors have time to cool down.

 

[Borek]

1 hour delay between flights is good for the helicopter too because the motors have time to cool down.

You've made that up, haven't you? No need to wait that long, several minutes that you will spend just replacing the battery with a spare is perfectly enough. Make it 15 if you want to be super cautious.

Heat is usually not a problem with motors, but with regulators (ESC, Electronic Speed Controller, thing that runs the motor, in your model probably combined with UBEC - Ultimate Battery Eliminator Circuit - as that is the cheapest option these days). I have seen several models bursting in flames - it was always regulator that was source of problems. Motors reach their maximum temperature in several minutes and they don't get any hotter then, they are often designed in such a way they force air flow just by working. ESC/UBEC are more problematic, as unless they are by design placed in a position with a forced air flow they get hotter and hotter all the time.

To paraphrase an old saying: you are looking for a solution that is cheap, working and reliable - but you can pick only two at the same time.

 

[sophiecentaur]

They are certainly much more expensive. Could you please show me the picture of one of them?

The original factory charger charges my battery in 1 hour 15 mins (wall socket adapter), so I have no problem if charging the battery with the converter takes an hour or so.
1 hour delay between flights is good for the helicopter too because the motors have time to cool down.

Look on eBay for lead acid battery and you will find many 12V examples. I saw a Yusa 12V 7Ah at £14.69. Search yourself and find what's available in your area. A charger (motorcycle application) can be obtained for about the same cost. Buy some thicker wires than you initially think you need and you are in business.
If I were out in the field, I would find waiting one whole hour for my next flight could be a real pain in the butt at times. The problem is that the 'USB' power source is not really 'Universal' as its name suggests. There's often a mismatch between the requirements and the capabilities although, give them credit, they do allow many peripherals to work seamlessly. But a model helicopter is in no way a Computer Peripheral and something has to suffer if it's treated as one.
I do sympathise if you are finding this all more expensive than you planned. Your solution to this may well be a bit of cheap DIY but you run the risk of needing to do it all 'properly' later on and finding you need to spend even more money. What if you decide to get a bigger and better aircraft, for instance. In that case your present marginal solution could be inadequate,

 

[karabiner98k]

If I were out in the field, I would find waiting one whole hour for my next flight could be a real pain in the butt at times.

It's not a problem because I have two other helicopters to fly in the mean time.

 

[Rive]

Well, for three drones: maybe first you should sum up all the Ah you wanna' burn in a day and check if your powerbanks meets the demand?
I think it would answer some questions you forgot to ask so far...

 

[russ_watters]

Standard when charging LiPos is to use "1C" current - "C" meaning same current as the capacity of the battery (so if it is a 2200 mAh battery, you will charge it with 2.2 A),

So perhaps the way it is shown is a lazy way of saying 800ma to charge an 800mah battery.

 

[russ_watters]

12V batteries are available in all sorts of capacities. A Voltage converter from your existing USB Power block is, in my opinion, no more logical. How many times do you need to recharge your helicopter battery 'in the field' per day? A (cheap) 5000mAh 12 volt battery will give you around twice as many charges as your 5000mAh power bank.
Only if you are doing this on a shoestring would the DC voltage converter solution be worth doing.

I agree. I was thinking of something like this:
https://www.amazon.com/dp/B00935L44E/?tag=pfamazon01-20

 

[Borek]

So perhaps the way it is shown is a lazy way of saying 800ma to charge an 800mah battery.

Cheap chargers don't let you change the current so you have to use whatever they are capable of delivering. As far as I am aware it is not a problem for large batteries (other than it takes forever to charge 12 Ah monster), but using too large currents for charging shortens the life of the smaller ones.

To add to that most chargers let you balance the battery, which is another way of saying "charge each cell separately till they have the same final voltage". It is not like they really charge cells separately (cells are in series and most current goes through the main connector, one that is capable of surviving huge currents), but they do some tricks with charging them and discharging through additional balancing wires (standard in LiPo packets, often used also for powering some additional gadgets that need currents well below 1A).

Now that I think about it I have no idea whether they keep the current by changing the voltage throughout the process, or by keeping the voltage constant but switching the current on/off to keep the average as requested. My charger initially shows the current to be that I set up, but the closer it gets to the end the lower the current is - but at this stage it is typically balancing cells, not really charging them.

 

[donpacino]

To add to that most chargers let you balance the battery

To add to this, you SHOULD NOT charge LiPo batteries with a charger that cannot balance charge

 

[karabiner98k]

Problem solved!
I bought this DC-DC Step-Up Module today and tested it:

I increased the output voltage of my powerbank (5.0V) to 14.5V by connecting it to this little but handy device and connected the output poles of the device to my Lipo Charger:

I managed to charge my battery in about 45 - 50 mins (about 8.50V fully charged) and good news is that the module didn't get hot during the charging process (just a little warm).
I also flied with the charged battery and flight duration was excellent!

Thanks everyone for your help!

 

[jim hardy]

Good for you. We learn faster by doing than by reading about doing.