Sunday, January 18, 2009

Making a Charging Timer

I wanted to make a timer so that I could charge the car for a specific amount of time to prevent over-charging the AGM batteries with the Belktronix charger. The only timer I could easily find that would charge for several hours was a wall-socket mount like the one shown above. I found a weatherproof box with weatherproof cover and mounted the timer in the box. There were also special cord protectors that screwed into the holes in the box. I simply cut a 25 foot 14-gauge extension cord in the middle and wired in this contraption to limit the time on my charges.


Too Many Parts said...


I thought one of the primary benefits of the Belktronix charger was that, via the Batmons, it would not overcharge AGM batteries. Is this not the case?


TimK said...

Hi Jesse,

The charger has two modes of operation. If enabled, it will go into "float mode" after it sees the first OVP light go on. This works but extends the charging cycle. The second mode just dumps in current while all the Batmon boards bypass the fully charged batteries. This mode charges faster but can overcharge the system if left on too long.

In reality, I added the timer for peace of mind, since there's not a lot of mileage on the Belktronix system and I want to be able to limit the charge cycle, if needed.