step up converter efficency doubts

[digik]

I basically need to run a 30-34V led from a 14.8V Lithium-ion battery pack, so i need a step up converter. I found this on aliexpress:

http://www.aliexpress.com/item/DC-DC-8A-Solar-Wind-Energy-Automatic-Step-Up-Step-Down-Constant-Current-Voltage-Adjustable-Power/32509748157.html?spm=2114.01010208.3.11.JSTZ6u&ws_ab_test=searchweb201556_8,searchweb201602_3_10017_10021_507_10022_10020_10009_10008_10018_10019_101,searchweb201603_6&btsid=ce55ac45-568e-4ff0-91cf-e8e25ff26581

But since I need to double the voltage i'm concerned about the efficiency of this thing. The led need 1A of current. What do you think? Will i loose too much energy? I'm not into the step up technology, so every suggestion will be appreciated

[uncle_bob]

Hi

Without buying one of the specific parts and testing it, there is no way to be sure of it's efficiency. There is no basic reason why a properly designed converter would *not* be above 80% efficiency. If you need better than that, shopping for random parts is probably not the best way to get the job done. To me the bigger issue is that you say you need 34V and the unit you are looking at is only good to 30V max....

Bob

[zlymex]

I bought something similar in 2013, here is the photo and test result at that time. I use HP34401A DMM, IT6122 power supply and IT8512 e-load.

[QuantumLogic]

I've used this converter in my project to charge Li Ion cells (4S) and to power an adjustable power supply control unit.
12V input and 16.8V output at 1A for charging.  Works great.
And for the main supply, it takes the 12V to 16.8V battery as input and outputs 23.25V at around 2A.
Totally adjustable voltage and current.  Just don't short it out to set the current (it needs a real load like a high-power resistor).
www.ebay.com/itm/DC-DC-250W-Constant-Current-Boost-Step-up-Module-Mobile-Power-Supply-LED-Driver-/251715894855