An adapter to power Yongnuo flashes using lead acid batteries.
Yongnuo flash units are relatively inexpensive and are ideal for camera trap setups. Powering these flashes using AA batteries however is expensive and the flash charge time between shots increases noticeably.
The adapter allows a 6 volt lead acid battery to be placed into the battery compartment. This dramatically increases the number of flashes between recharge and also significantly decreases the recharge time between shots.
Beware! Lead acid batteries like the one shown above are capable of delivering a huge amount of power. Extreme care needs to be taken if you attempt to replicate this setup. Allowing the contacts to short is a real fire risk. Inserting the contacts incorrectly has the potential to damage your flash. You copy this at your own risk! You have been warned.
Here you can see the construction of the adapter. There are two 3d printed parts, one to fit snugly into the battery compartment and the other to isolate the bolt heads and keep the from moving. Due to the power draw of the flash it is essential that the correct gauge of wire is used to prevent the wires from melting.