We’ve had our E130 Retrofit Smart Lock for almost 3 years now. It works well, though we rarely use the features. It’s on our back door, and we are most always manually locking/unlocking.
It’s been bothering me that it goes through a set of 4 CR123A batteries roughly every 3 months. I’ve investigated CR123A rechargeables, and the capacities are pretty low - much lower than the non-rechargeables. I looked more and then decided I could DIY a higher capacity external battery. In the Smart Lock the CR123As are stacked end to end in two sets (2S2P) for 6V each set.
I found a small LiFePO4 6V pack on Amazon - 6V 6AH. Each CR123A I was using is 3V 1600mAH (2S2P = 6V 3200mAH = 3.2AH). So, this pack should give me twice the life with each charge.
I just got everything together, quickly threw together an alpha test, and it works! Now I just need to solder the leads to the contacts in the lock, cut a small notch on the side of the battery back plate for the wires to go through, and velcro the battery pack to the back of the door (or fashion a holder of some sort). The LiFePO4 batteries came as a 2-pack for $23 and the cable going to the F1 terminals was $7. So, I’ll have one battery installed and the second charged and ready to swap when the first gets low. The CR123As cost anywhere from $1.50 to $3 each depending on what’s on sale. The other problem with the CR123As is that in general, quality of what’s out there is pretty poor. Figuring $2 each it’s costing $32/year in disposable batteries. I should recoup my cost in just under a year, and not have to replace the battery as often - yet to be seen with these unproven packs, but I’m hopeful.
