View Single Post
Old 07-08-2012, 06:25 AM   #1
Canine_Rescue_Pilot
Getting Wild
 
Canine_Rescue_Pilot's Avatar
Club Car
 
Join Date: Dec 2011
Location: Dunedin, FL
Posts: 78
Default DIY - 4 x 12v to 6 x 8V Conversion (Part 1)

When I started doing a complete overhaul of my Precedent, I knew that when the batteries finally needed to be replaced I would probably bite the bullet and do the 4x12 volt to 6x8 volt battery conversion.

That time came. And just like Driver33b in a post dated from 2009, I could not fathom paying over $480 for a conversion kit, which in my opinion, looks like crap when it's done. So here is my story about doing an *Almost Free* conversion. I created it on a separate thread to make it easier to search, though I will tell you I did everything that Driver33b did in his conversion with very little change. The tools I used were about the same, though I did not use a hack saw, I found that a Dremel with a cutting disc attached worked better for me in the delicate cuts.

Because the cost of 2 new (additional) battery cables was only $4.95/ea, I decided to just buy two additional cables. I also decided on replacing my batteries with Crown CR-190 batteries. I'm a HUGE fan of Crown batteries mostly because I have a lot of experience with them in industrial machines.

Tool List...
Small angle grinder
Dremel tool with a cutting disc
Chalk
Standard Pliers
6-inch Flat blade screw driver
Paper templates
Flat metal or wood file
Bench Vice, Vice grips, and a Propane Torch (all for bending the hold-down hooks)

The jist of this whole conversion is that you are cutting into the battery tub on the front-facing side to allow the batteries to protrude into the space between the tub and the body panel. Only one battery per side will protrude from the tub into the body cavity.

1) Flip the RUN/TOW switch to TOW.
2) Remove all of the battery cables, tape up the positive terminal connected to the OBC to prevent discharging the capacitor in the OBC.
3) Remove your old batteries.

Make three paper templates, or footprints, the size of your new batteries. Use these to determine your placement. A short block of wood, or short level will help determine if the "floor" of the battery tub has been sufficiently cut/ground down properly - use this as your check to determine that you have flattened the floor of the tub where it needs to be flat.

On the rear interior of the tub there are two molded-in angles, each about 2 to 3 inches long and about 1 inch high. One angle is on the rear, bottom. One is on the side, bottom. These have to go. As Driver33b pointed out in his article, there is a wiring loom running along the front and sides of the tub, between the tub and the body wall. Be careful, cut shallow.

Along the inner side on the floor of the tub, next to the center “console”, there are two protrusions that used to serve as the retainers for the 12volt batteries. Both of these have to go. Grind them down flat with respect to the floor of the tub. In all, there really isn’t a whole lot you have to cut on the rear and the sides of the tub.

Turning to the front of the tub, you will cut a window just slightly larger than the entire long side of the battery. Mark your cuts in chalk first. Because there is a wiring loom on both sides of the battery tub front, I decided to just cut the first 3-4 inches from the top... then across the battery length. This gave me the chance to reach down through the area I cut and safely move the wiring loom out of harm’s way. Then continue to cut down the remaining amount and across. Grind your cut as flat to the floor as possible. Here is where I found the Dremel tool (with a cutting disc) was great for the tough to reach areas. If you’re using an angle grinder, be careful of how deep you cut, you don’t want to touch the inside of the outer body panel with your cutting disc. Use a file to clean up and rough edges.

Repeat all of this for the opposite side.

On the passenger side, there is a large wiring loom between the tub and front panel. There are also molded features on the rear of the actual body panel that prevent the wiring loom from sitting flush. You will need to cut notches into these molded features, just enough to allow the loom to sit flush within the notches you cut. Using the Dremel here makes these cuts a snap. Cut carefully.

Shop vac the whole mess. You will be covered in sticky plastic dust... but it is worth it.
At this point I cut up thin pieces of wood trim to place on the bottom of the tub to level out batteries that would otherwise not sit flat. I suppose I could have ground the heads off of bolts but I didn’t want to cut any more than I had to.

Place the new batteries in, positioning the front batteries first. For simplicity of wiring, and getting all of the battery poles lined up properly, you will want to position the front batteries with the posts closer to the front wall. It seems counter-intuitive, but you’ll see why when you go to wire it all back up.

If you cut both sides of the battery tub properly, there will be plenty of room between the batteries to not only reuse the hold down hooks, but also the same plastic keeper from the 12V cells. So let’s modify those...

Bending the hooks is a snap. You’ll need a large pair of vice grips, a bench vice and I used a torch. Mount one hook in a vice, hook-side up. Using your torch, heat the area just below the hook until it glows cherry-red. Then using your vise grips while the metal is cherry-red, gently and carefully twist 90 degrees. Plan ahead. You want the kink of this hook to point to the rear of the cart, and you want each hook end facing the outer side of the cart. That means one hook is bent 90 degrees to the left, the other is bent 90 degrees to the right. Heating the metal cherry-red before bending makes bending them effortless, it also causes much less stress on the metal. Allow them to cool after you bend them. Brush off any scale with a wire brush. I gave both of mine a shot of fresh enamel paint to prevent rusting.

For the two plastic battery retainers (I call them “keeper bars”), I flipped each one over and cut the protruding rib flush about 1/3 of its length. This will be the portion that contacts the top of the front battery. The remaining portion of the rib sits between the two rear batteries. That one little mod will allow the keeper bar to sit between, and Flat on top, of each 3-battery group.

Now stop for a moment...
Did you have any 12 volt accessories that were powered by just one of your 12 volt battery before? How about your lights? If you did, you can’t just simply hook it up. I have seen a few people suggest that you could wire it across two of the 8-volt batteries, and that most things will tolerate 16 volts. I HIGHLY recommend against this idea. When you charge the battery pack the voltage will rise even higher than 16 volts across any two of the batteries. Sorry if I’m insulting anyone... but that idea is just “hack”, and very amateur.

You have choices. You can choose a 16 to 12 volt converter, a 48 to 12 volt converter, or a separate 12 volt battery just for accessories. In my mind there are only two real choices: the 48 to 12 volt converter or a separate battery. Remember this: unless you wire an on/off switch for the converter - it will draw a slight amount of current even when no accessories are on. It’s negligible, but it is a draw.

If you choose the converter route, choose a converter that has enough current. Twenty (20) amps would be a minimum in my mind. If you power lights and a horn, possibly a stereo... 20 amps will be plenty **except** when you draw short bursts of current... like using the horn, at night with your lights on. (amazing how much current a horn draws momentarily!) Some stereo systems are sensitive to a current sag, and may “reset” if you use the horn and there is not enough current available.

I have a deep-cycle 12 volt battery on board just for accessories, mounted up under the space behind the battery tub. Sure, It’s a bit of a pain to use two separate chargers (one for the cart and one for the accessory battery) but we’ve gotten used to it, and I’ve installed a second charger plug, just to make it simple.

Back to the pack...
Rewire the whole pack, pay special attention to polarity.

<Continued in Part 2>
Canine_Rescue_Pilot is offline   Reply With Quote