[Canine_Rescue_Pilot]

<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!)