Profoto B2 Dead Battery Fix

In General Stuffby Patrick

Imagine my dismay when I setup my Profoto B2 lights to test them for an upcoming shoot and the battery was dead. Even more disturbing for me was it did not even want to charge when plugged in. I use these lights on a regular basis so it was not a matter of never charging them and they have not sat for a long period of time fo it was even more frustrating. So now my task was either buy a new battery or figure out how to bring a dead battery back to life. I post this so other photographers can use this and hopefully it will help someone save some money.

The option of buying a new battery was not something I was crazy about. As of the writing of this post, the battery lists for $236.00 USD. Pretty steep price tag. The battery is a Lithium Ion battery and should be able to be recharged, but it would not even start charging.

So let’s get to the point of the matter, how did I fix it. After a few Google searches I found that the Li-on batteries have a minimal charge, something like 0.3v, they have to maintain to be recognized by the charger before it will even start charging. The problem was how to perform a parallel charge from a Lion battery to the B2 Li-on battery that was below the minimal charge value. Below is my solution.

Captured with iPhone X

This is an old USB cable that I had an I no longer use. I used the wire cutters to clip off the opposite end to the USB portion. I then stripped back the casing to reveal the copper wires. There are usually 4 wires in a USB cable, the two you need to be concerned with are the red and the black. This is your basic positive and negative. Once the copper wiring was exposed, I used some basic scotch tape to hold the red positive to the positive post on the B2 battery (these are clearly label with a + and -) and the the black negative to the negative post. I plugged this into a portable Xuma Portable Power Pack. I have had this for several years and I believe they are discontinued, but any portable pack will do.

I let this charge for about 20 minutes, removed the USB wires from the B2 battery posts, plugged the B2 battery charger in and saw a green light. I let the battery charge to full capacity (mine took about 1.5 hours) and then tried it on the B2 Air TTL pack and it work. It has been working ever since. This simple and safe method brought my dead battery back to life.

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