Subtronic Batteries

[atus]

Hi all, I own two Subtronic Alpha 160 pro fusion, which I really love because of its power, light quality and size. for me the handicap of this flashes is its batteries, they are dedicated and I don't really like it. The main thing that I don't like about it it's the charger, only a red or green led to know if they are charged or not. Several times I have noticed issues with the charger, I connect the batterym switch the power on and after 15 minutes turns green, It feels strange, so I restart the procedure and this time  the battery is charging for 2 hours. If i don't notice I'll run out of batteries in 10 pictures the next dive, Presumibly just before you find an Orca having sex with a whale shark. 

So as I was tired of the situation I planned to do on myself new battery packs that I can control the cells individually in a normal charger. Then I noticed than the original battery packs are simple as two 18650 cells connected in series, so they give 7,4 volts (nominal). So I decided that if I am going to do it I want to not charge batteies in a day during a trip, tipically 4 dives. So I made my packs with two packs of two 18650 batteries connectd in parallel, so I double de mah. resulting in this packs you can see in the pictures.

I made the design and went to a turner to make the pack with the threads and the o'ring channels, I bought the cables with the conector already welded from Subtronic and I bougt the battery holders from Aliexpress, sended the alluminum pack to anodize and I got the cable penetrators from BlueRov  which i had to modificate a little bit in order to hold 6.5 mm cable. 

It's been a bit expensive, around 300 euros each plus my time and my job, but I can control every cell one by one, but everytime I go to the water I am absolutely sure they are perfectly charged, if any of the cells it's damaged i can change it for a ridicculous price comparing with a wole pack, and I can do on myself in seconds. The contra is that this battery packs are big. So now I am planning to make another packs with only to cells in serial connection, ir order to make it thinner, to use it when at home and tipically dive once or two a week.

The connector is an S4, so if Seacam uses the same voltage this would also work with them