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-   -   DIY - 4 x 12v to 6 x 8V Conversion (Part 1) (https://www.buggiesgonewild.com/showthread.php?t=66901)

Canine_Rescue_Pilot 07-08-2012 06:25 AM

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
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 07-08-2012 06:28 AM

DIY - 4 x 12v to 6 x 8V Conversion (Part 2)
5 Attachment(s)
<Continued - Part 2>

Did I change my OBC?
No. Here’s why, and it’s a long story so hang on...

The dealers will tell you that anything less than version 5.0 is really designed for the 4-12V pack setup and will cause charging problems.

The amateur builders (I’m one of them) will say that 48 volts is 48 volts, it still has the same number of cells.

We’re both wrong - sort of. True, 48 volts is 48 volts, and the batteries still have the same number of cells, BUT the cells have a larger plate area and are capable of a bit more energy storage (hence the higher amp-hour rating). As for the rest of the "sort of" - read on.

It took me close to two weeks of contacting different people at Ingersoll Rand, I was honest during each call explaining my background and looking for information. To make a long story short I was finally put in touch with a programmer that works on the team which supports the code in the OBC eeprom. Persistence pays off. Here was the bottom line...

(some of it maybe you knew, some of it maybe you didn’t)
His story:
The OBC controls the charge rate of the battery pack both with the PowerDrive charger, AND with the Regen feature. Where the programming of the version 5 or higher OBC will make a difference in charge is if you have not disabled the regen of the motor/controller. It has a slightly different algorithm for the Regen when you have the (6) 8-volt batteries as opposed to the (4) 12-volt batteries, mostly to control current and HEAT that can be realized when in the brief periods of Regen. With regard to the A/C PowerDrive charger; when you first plug it in to a pack that needs to be charged... the charger runs at max regardless of the (4) 12v or the (6) 8v set up. And will continue to charge at the normal rate, but may hold that rate slightly longer with the (6) 8-volt batteries than with the (4) 12-volt batteries. The “taper charge” at the end, switches to a constant voltage anyway.

His words:
You’ll not notice any difference in charging with the A/C PowerDrive charger. Unless you are using the Regen feature (meaning, if you have not modified your cart for high-speed and disabled the Regen feature), there is no difference. The changes affect the algorithm and charging of the Regen function. There is no significant difference between the version 3 and the version 5 or higher OBC that affects the A/C Charger. There are, however, some slight differences for the computer with regard to fleet management - but those don’t affect functionality of the A/C charger.

I know, I know... As I write, I know there are going to be people arguing about this. All I can say is: It’s your choice, believe what you choose. I don’t care. I’m not Moses. And this is not Mount Sinai. This guy’s explanation at Ingersoll Rand was good enough for me. I’m just sharing what I learned, do with it what you want.

So what’s it like? How does it work?
Break in your batteries following the advice that is repeated on this forum and by many dealers and experienced “modders”. Carefully use them for the first 25 or so cycles, never going beyond 50% depth of discharge. What you are actually doing is “growing” the plates with each charge, as the substrate becomes a little more spongy. This is a good thing, as it is creating slightly more surface area on each plate. It is by design.

The first full charge is a little odd... it appeared my OBC had to re-learn what was considered “full charge”, though I don’t really know what it was actually doing. The charger ran much longer than expected. However, after that the performance has been outstanding. The charger operates normally after the initial charge. Since I’m a big math freak, I also calculated out what my actual increase in capacity has been (using a hygrometer as my point of reference... a volt meter or state-of-charger meter does not have that fine of a resolution.) I have obtained about a 21% increase in overall range. What is important about that is NOT that I can go 21% further, although I can, ... but is that with each use, I discharge the pack 21% less deeply. This means you will realize a much longer overall battery life, given the same distance travelled.

I have zero regrets. I saved a ton of money, and a lot of work. Cutting the tub carefully is actually less work than removing rear seats, the body panel, the tub, rewiring harnesses and mounting electronic assemblies. With the money I saved, I bought the brand new, high quality batteries I wanted. And I’m thrilled with the performance. I would recommend this type of “garage” conversion to anyone who is handy and mildly knowledgable. As with any handy work... the quality of appearance and performance is directly proportional to the care you put into it. Think first, plan it out.

Pictures are attached, though I did forget to snap a shot of the front tub cut-outs prior to installing the batteries. But look carefully at the "finished AFTER" photo, you can see where the two front batteries nest. The last picture is the cart (a buddy of mine went to pick up beer!)

erict 07-08-2012 07:28 AM

Re: DIY - 4 x 12v to 6 x 8V Conversion (Part 1)
Nice job and great write up. Also, good info on the OBC..:thumbup: I had just replaced my batteries in May and thought about doing the 8v conversion but for what and how I use my cart the 12v serve me fine......for now..:wink:

Canine_Rescue_Pilot 07-08-2012 07:40 AM

Re: DIY - 4 x 12v to 6 x 8V Conversion (Part 1)

Originally Posted by erict (Post 746787)
Nice job and great write up. Also, good info on the OBC..:thumbup: I had just replaced my batteries in May and thought about doing the 8v conversion but for what and how I use my cart the 12v serve me fine......for now..:wink:

Thank you.

You're not alone. Many people I've met use the 4 x 12V batteries just fine.
It really depends on how you use it.

Ours is Florida registered Street Legal (with a VIN#, tag and title). We use it as an actual LSV. My goal was to reduce the "depth of discharge" with each use. And since the 4x12V and the 6x8V (190AH) batteries were *approximately* the same price, the answer was right for me.

erict 07-08-2012 07:42 AM

Re: DIY - 4 x 12v to 6 x 8V Conversion (Part 1)

Originally Posted by Canine_Rescue_Pilot (Post 746791)
Thank you.

You're not alone. Many people I've met use the 4 x 12V batteries just fine.
It really depends on how you use it.

Ours is Florida registered Street Legal (with a VIN#, tag and title). We use it as an actual LSV. My goal was to reduce the "depth of discharge" with each use. And since the 4x12V and the 6x8V (190AH) batteries were *approximately* the same price, the answer was right for me.

I couldn't find the thread..:shock: WOW, it made it to the sticky quick..:thumbup:

I agree like many that the 8v conversion is a no brainier if and when new batteries are on the list and the cart gets alot of seat time.

Canine_Rescue_Pilot 07-08-2012 08:07 AM

Re: DIY - 4 x 12v to 6 x 8V Conversion (Part 1)
I've been honored with Sticky... (uuuh, wait that doesn't sound right. :lhmo:)

Canine_Rescue_Pilot 07-10-2012 06:43 AM

Re: DIY - 4 x 12v to 6 x 8V Conversion (Part 2)
1 Attachment(s)
For people's convenience, I have formatted this into a PDF document.

smallblock450sl 07-14-2012 10:10 AM

Re: DIY - 4 x 12v to 6 x 8V Conversion (Part 1)
Fantastic write up:thumbup: Only wish you could have added some detailed pictures of the cut outs before the battery install. Certinly deserves to be a sticky!

Canine_Rescue_Pilot 07-15-2012 11:50 AM

Re: DIY - 4 x 12v to 6 x 8V Conversion (Part 1)
There's a bit more detail in the PDF uploaded (above). Really the only thing missing is the picture of the cut-out for the front batteries... but no imagination is really necessary - the cut is just slightly larger than the size of the entire battery. :-P

Speedchaser 08-02-2012 11:06 PM

Re: DIY - 4 x 12v to 6 x 8V Conversion (Part 1)
Well I did a lot of reading and decided to do this as my cart is torn apart waiting for a new motor and controller. I have a pretty good roto tool and it zips through thsat plastic like melted butter. I cut smaller pieces out rather that the whole rectangle for the battery so I could really see what I was cutting into and make sure I did not hit any wires. About 45 minutes and done with one side. Looks like this is gunna work darn good. Thanks for posting this.

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