Battery Charging Rig

Hi all,

It’s been a while since I last posted what with holiday’s and all, but I got the itch for a project that has been lurking in the back of my head for a while now.

The SLA battery on my little battery box needs a desulfurization charge, a process that could take some time.  I have a charger that has a setting expressly for this project, but I have one reservation.  The process will take some time—possibly days, and I am slightly nervous about the possibility of someone accidentally knocking the large alligator clips from the charger and inadvertently have them touch while charging and short-circuit.  My solution is to make a little charging rig that will keep the leads separate throughout charging.

I used some leftover lumber and screws, but needed to buy 2 feet of 4 gauge bare copper wire, some red electrical tape, black shrink wrap tape and wire nails.  Overall, the purchase was pretty cheap and I have leftovers for another project.

I ended up cutting a piece of 1x12, placing the smaller, cutoff piece vertically along the center line so as to physically separate the alligator clips and the two circuits.  The 4 gauge wires are insulated with either red electrical tape or black shrink wrap (I wanted red shrink wrap, but couldn’t find it locally—electrical tape will do).  The “charger” ends are bent over 90 degrees to make attachment easy.  The 4 gauge is attached to a 4” piece of 2x4 with about 3” bare leads sticking out.  I may adjust the length and angle of those leads later on.  The rig also has a platform for a battery to sit easily.

I am about to start giving my battery its first recovery/recharge.  I will definitely be using the rig.

Feel free to offer commentary or suggest improvements.  I am just starting out with this idea.

Eric

I added a couple more pictures

desulfurization charge, a process that could take some time.

What happens and why is it necessary?

John,

When an SLA battery over discharges, the internal chemistry can be disrupted.  I did once slightly over-discharge the battery and I wanted to see if it were possible that I had a reduced capacity.  I went ahead and ran it through the repair cycle twice.  It seems to be working fine, though I don’t really know if it works any better than before—I have not really done a thorough stress-test.

Eric

If you don't use the charger for other uses I'd suggest replacing the large clamps with female terminals that fit directly onto the battery terminals. Might be tricky due to the large wires & small terminals.

It seems the rig you made could still be disturbed in such a way that the wires could touch. If one of the smaller alligator clips slipped of the thick copper wires for example. Consider shortening &/or securing those jumper leads so that if one does pop off it can't physically reach the opposite polarity.

I'd put a different plug on the desulphator.
One that can't short if disconnected.
I'd probably even put a plug on it that allowed me to switch end connectors so I could still plug the clamps back on if needed.

Mike,

I do use the charger for other purposes, so I want to keep those alligator clips still attached.

You are right in that the battery side could still have an unintended contact/short.  I am thinking about shortening the 4 gauge leads, maybe bending them down like the ends on the charger side.  Additionally, I am planning on making some more custom fitted cables to minimize the overall cable length and maximize the likelihood of a connection staying put.  In particular, one set of cables may have one end as an alligator clip to fit the lead, while the other has spade connector to attach to the battery.  I also may extend the divider.

I will update as I make changes.

Eric

Craig,

As I stated above, I am thinking about making some specialized clips.  I have some XT60 connectors (lots of electronics use these) and may make interchangeable and swappable connector ends.

Eric

Good plan.
XT60 connectors are used on a lot of the battery stuff.
And they can't be connected with the wrong polarity.

Thanks Craig,

I chose XT60 connectors because they seemed so common and seemed so flexible.  Also, as you point out, it can’t be accidentally connected backwards.

I do have a couple of minor changes I might make to the rig.

First, I might extend the divider a bit forward to help ensure that an accidental clip snapping loose doesn’t accidentally connect and short out.

Secondly, I am thinking about bending the leads on the battery end sideways so they run parallel to the base plate.  They might even bend towards each other, but of course would be separated by the divider extension.

But these are just ideas and I am open to suggestions.

Eric

Maybe put an inline fuse in there while you are making connections.
That should help protect against shorts.