Lipo dc-dc step-up to high current loads

Thread Starter

rollebollen

Joined Aug 3, 2017
2
Ive been trying to get a step-up for my LiPo's that can boost to high voltages (>15V) with high current as well (around 2A). I found and tried this one based around the mt3608, but it does not deliver close to 2A as promised. Instead it starts giving off a buzz and limits the current around 1A when connected to a 10 Ohm load at 18 V. Why is this, and what alternatives should be considered for step-ups in this range? Sorry if this is a noob question, quite new to electronics.
 

tcmtech

Joined Nov 4, 2013
2,867
Assuming you are starting with a typical 3.7 volt battery voltage and going up to 15 volts the battery would have to produce around, 15/3.7 =8 amps not including andy conversion losses which at that low of voltage could push the number up to more like 9 - 10 amps.

Is your battery capable of supporting that amount of current draw to begin with?
 

Thread Starter

rollebollen

Joined Aug 3, 2017
2
Assuming you are starting with a typical 3.7 volt battery voltage and going up to 15 volts the battery would have to produce around, 15/3.7 =8 amps not including andy conversion losses which at that low of voltage could push the number up to more like 9 - 10 amps.

Is your battery capable of supporting that amount of current draw to begin with?
Thanks. Its a 800 mAh, 25C battery, so I think yes. But you mean the 2A rating refers to the "converted current", for example, stepping up from 3.7V to 7.4V would mean a max current of 1A?
 

bertus

Joined Apr 5, 2008
21,861
Hello,

The limitation is in the MT3608.
The internal switch has a current limit of 4 Amperes:

MT3608_max_ratings.png

When you want an output current of 2 Amperes, you can about double the voltage.

Bertus
 

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