LiPo Battery with voltage regulator

I am trying to use this battery: … ipoly_Pack

but it is giving me a voltage of ~8.4V currently. I would like to regulate it to ~6V and so I purchased However, when I connected it to the battery it started to smoke and flame. I think there is too much current coming from the battery. What is the best way to regulate this voltage?


What caught on fire? What is your load, and what kind of current are you expecting?

- Jan

The chip on that voltage regulator caught on fire. I hadn’t hooked up a load yet, I was about to use my multimeter to adjust the pot for an output of 6V when it started smoking.

That doesn’t sound good. Are you sure you didn’t hook it up backwards or with power to the wrong pins?

- Jan

I only had the battery wired up to the Vin and GND. I was about to use my multimeter on the Vout and GND to see what the pot was currently set at. I didn’t have the SHDN wired to anything yet. Would that make a difference?

Thanks for your help

SHDN should be optional. It would be good to verify that your load is reasonable first, but we can give you a coupon for a replacement one if you email us.

- Jan

Sorry to resurrect an old thread but I have just had exactly the same occur to me.
I had one of these reg06a - Pololu item #: 2120 - hooked up to supply a mini camera with clean 5V from a 3.7volt lipo…
I had used this arrangement before and it worked - today it would not power my camera - upon checking voltages I couldn’t get any reading from the vout pin - just stayed at 0v - vin was at 4.1v… strange.
I had another #2120 sitting here so I hooked it up to a lipo and multimetered the vout so I could adjust it to 5V out.
It was at 3.0v so I adjusted it to 5v and was about to unplug it all when the multimeter spiked to read 11.2V and then fell to 0 and the little square chip let some smoke out - I wasnt quick enough to catch the smoke so I dont think I can fix that one!
Any ideas what could have gone wrong here - should I have limited the current coming from the lipo? if so how would you recommend it be limited? I also wonder why one of them worked a couple of times and then wouldnt power up and the other just went pop during setting the voltage…

I am currently using a #798 5V boost reg without trouble but my intention was to run from a 2s lipo which is too high a voltage for that boost reg (and my camera) and the reason I went for the #2120 instead.

Thanks for any help.

Batteries, and other power sources, do not “push” current. Load “pulls” current. If you need current limiting, you need to make sure your load does not “pull” more current than the regulator can handle.

If you want to limit current, you can use a fuse of the right rating. Make it fast-blow if possible. The one draw-back of this is that fuses aren’t very precise in their protection, so you have to specify things conservatively. If you need 500 mA of current, get a 600 mA or higher fuse, and then make sure your power regulator can deal with up to 1 A, as the fuse may (at least temporarily) let more than rated current through.

Another option is to get a PTC “resettable” fuse, which is a temperature-dependent resistor that will go from “low” to “high” resistance at a particular heat point, which it reaches faster the more current flows (and is guaranteed to not reach under a certain level of current.) PTCs don’t need replacement, and are nice “just in case” protection. After tripping once, though, they will have higher resistance in the un-tripped state than before, which is something to watch out for.

Hi, leachy.

I’m sorry you’re having trouble with your #2120s. When you were adjusting the regulator, did you have a load across the regulator in parallel with the meter?

- Ryan

Thanks for the replies

The first one was always connected to my camera and just seems to get warm but outputs no voltage now. But no I had no load connected while I was setting voltage on the 2nd one.

Hi, Leachy.

Unfortunately, it sounds like both of your regulators are damaged beyond repair. Here are a some practices that can make it more likely that your regulators will keep working in the future:

  1. avoid drawing more current than they are rated for
  2. place a light load on the regulator when adjusting the output voltage
  3. avoid shorting wires together or anything to the board
  4. avoid touching or shocking the board

If you’d like to try again, please email us, referencing this thread, and we might be able to get you a discount on some replacement regulators.

- Ryan

I read this old thread today - 6/4/2015 and am posting the following warning about spikes upon power connections. This is a cut-n-paste from the product page:

LC Voltage Spikes

When connecting voltage to electronic circuits, the initial rush of current can cause voltage spikes that are much higher than the input voltage. If these spikes exceed the regulator’s absolute maximum voltage (16 V), the regulator can be destroyed. In our tests with typical power leads (~30" test clips), input voltages above 10 V caused spikes over 16 V. If you are connecting more than 10 V or your power leads or supply has high inductance, we recommend soldering a 33μF or larger electrolytic capacitor close to the regulator between VIN and GND. The capacitor should be rated for at least 25 V.

More information about LC spikes can be found in our application note, Understanding Destructive LC Voltage Spikes.