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-   -   Project Precedent (https://www.buggiesgonewild.com/showthread.php?t=181370)

UncleJerm76 12-17-2021 10:44 AM

Project Precedent
 
This is my build thread for our new-to-us 2007 Precedent. It is the older style with all the electronics mounted in the center under the plastic cover and the 4 huge 12v batteries. I like the concept of that center console so instead of converting it to the newer style tub I decided to see what I could do with it, and if I fail miserably then I could always convert to the newer style.

This will be my permanent buggy going forward, I started moving all the DIY lithium components I had began to put on my DS over to this Precedent. Ive had that DS about 10'ish years and it now has some very nice upgrades, but the older body style eventually had us looking for a newer cart and something different. Wife also wanted a nice neighborhood card instead of the monster woods buggy we've always had. So it was time.

After searching around I'm trying out a bunch of things I haven't seen done yet on this forum, its a learning experience for me, and Ive always learned best by just doing.

Not much to look at right now other than a stock Precedent. Here it is after getting it home and riding the kiddos around.

https://uploads.tapatalk-cdn.com/202...4a31e15dff.jpg

UncleJerm76 12-17-2021 11:01 AM

Project Precedent
 
So here we go, right off the trailer I could tell the MCOR was bad. Only about 7-9mph and very jerky acceleration — most of the time it went from nothing to full throttle all at once (not good for anyone sitting on the back seat! Got in touch with one of the site sponsors; "Revolution Golf Cars", and ordered the MCOR 4 and Gen 2 Petal conversion. A short 30-min install later I was up and running with smooth petal response - but still only got 7-9 mph.

My next thought was that the speed sensor was going bad, I had no voltage at the controller from the sensor wires and others stated this was a common failure. But after replacement the speed did not improve and I still did not have voltage at the controller. Decided to carefully trace the wires and found where a squirrel had chewed through them! Replaced the wires and hit 16-17 mph, it felt like it had more left I bought a high speed magnet from Revolution Golf Cars and I now it hits 20 mph consistently. That feels about as good as it is going to get on stock components and it will be fine until a AC conversion happens in the future.

Time to start the Lithium build!
The plan is, any components I need to buy for the Lithium conversion I want to support 600A. My future plans are a large AC conversion and I don't want to have to purchase all new electronics in the future. So some components will be massive overkill for a stock buggy, but I will be re-using as many stock components as I can for the time being, such as the Contactor/Relay, Wires, Battery & Motor cables and anything else that I can make work.

First, I need to drop in the 200ah LifePo4 CALB cells to see if my measurements were correct and if any modifications were needed. Measurements were correct - but I did not account for the plastic nubs sticking out the bottom of the tub that separate the FLA batteries and hold the stock battery tie down rod. My cordless Dremel made quick work of those and they fit quite nice after that. I couldn't help but connect everything up and go for a quick drive to the road and back. The biggest thing I noticed was acceleration was vastly improved. The light weight lithium's made a huge difference and the short ride only motivated me more to get it done. I didn't want to drive it any further because I hadn't secured the batteries down yet, hooked up a BMS yet or a fuse or anything that are on my must-have list.

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UncleJerm76 12-17-2021 11:43 AM

Project Precedent
 
Time to work on the charger!

The first thing to do was an OBC bypass. Thanks to the great posts here that was a breeze and I chose to remove it all together — the gap it left behind will come in handy when finding a home to mount the BMS!

Many years ago I bought a big commercial 25A constant voltage charger to maintain large FLA packs and wondered if it would work for Lithium since that's exactly the type of charger recommended. This charger tapers off the amps as the pack gets closer to preset constant voltage so in theory it should work. Its a monster and extremely heavy making it not very practical, but it might just get me by for a while. What I really want is a charger I can choose to charge to 80% on a regular basis or charge it to 100% for those times when I know Ill be going for a long ride, but I haven't found one yet - if you know of one please let me know here! Anyway, I called the manufacturer and spoke to one of their technicians who said that with a few tweaks it would work pretty good. Its has two adjustable pots on the inside on the board, one is for the hold voltage and the other for max amps. I ponied up and bought a good quality voltage meter with an amp clamp and got to work swapping the charger cord over to it and tweaking the pots inside the charger. I was able to dial in the volts to exactly to what my battery spec was but for some reason I could not get more than about 19 or 20 amps. After carefully looking everywhere for problems I discovered that the stock plug/receiver can only handle a max of 22amps! Wires were approaching too hot to hold, so I backed the amps off to 15 and everything was working fine at that current. This 200ah pack will take a while to charge from empty so I would like to upgrade this charge connector in the future and charge at the highest rate available to me. But I would also like the plug to remain in the same location so I don't have to lift the seat to charge with an Anderson connector or something like that. Any suggestions?

I don't think its even available anymore but here's the monster charger I'm currently using and its model number if anyone cares:

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UncleJerm76 12-17-2021 12:01 PM

Project Precedent
 
BMS Challenges

I know a lot of members here aren't a fan of running the motor current through a BMS that uses mosfets but I'm going to give it a try for the sake of simplicity and room. The biggest one I could find without taking out a loan was a 500A Daly BMS w/Bluetooth. I havent seen any other members here try it but it has a large fan and heatsink that should help keep everything inside it cool. It is also waterproof rated which was important to me. I have no concerns using it in this buggies stock form, but down the road when I have a big AC conversion its 500A limit might be cutting it close. It is also much larger than I had anticipated. This thing will not fit in the center console as planned — ESPECIALLY on the side with the heatsink! ...and I had to do something about the dumb double-cable outputs on the BMS, that not going to work well in this tight space. Ill also need to work out good exhaust vent for that fan - time to go back to the drawing board! But for now, Ive got to clean up this mess of wires and remove what's not needed and organize better what is needed.

https://uploads.tapatalk-cdn.com/202...2bd7611653.jpg
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UncleJerm76 12-17-2021 12:24 PM

Project Precedent
 
After a lot of thinking I've got the BMS mounting problems solved. As you can see from the pic in my previous post the stock controller comes mounted an angle for some reason? This takes up valuable room so I repositioned it vertically. This allowed just enough space to mount the BMS next to it (if I removed the relay). This works out great because the cable on the bottom of the BMS (B-) needs to go to the main pack negative which as you know is already cut out at the bottom right of the picture below. The cable on the top of the BMS needs to go to the Controller which is a perfect straight shot to the left.

Because I was relocating the Relay to the Heatsink side, I needed to mount the BMS on standoffs so there was enough space under it to allow for any mounting hardware I might need for the components on the other side. After mounting the relay to the heatsink side I'm extremely happy with the way this all turned out and the direction its headed. There is still plenty of room leftover on the Heatsink side to also mount a fuse or relay (not sure which one I'm using just yet - anyone got an opinion on one way or the other?).

https://uploads.tapatalk-cdn.com/202...ecbc1fdbca.jpg

UncleJerm76 12-17-2021 12:38 PM

Project Precedent
 
I figured out how to eliminate the double cables on the BMS. Using thick copper flat bar, I made my own busbar, carefully drilling out mounting holes that matched the originals. Now I can mount any single cable of my choosing to the middle of this busbar. In my opinion this works out much better for my use case and it will certainly be easier to route one cable instead of two.

https://uploads.tapatalk-cdn.com/202...c4a05ab35e.jpg

Volt_Ampere 12-17-2021 12:44 PM

Re: Project Precedent
 
Where do you get the Daly BMS? It would be nice if it could be wired with a relay to interrupt current. The solid state devices get mighty warm with hundreds of amps going through them.

UncleJerm76 12-17-2021 01:19 PM

Re: Project Precedent
 
Quote:

Originally Posted by Volt_Ampere (Post 1866942)
Where do you get the Daly BMS? It would be nice if it could be wired with a relay to interrupt current. The solid state devices get mighty warm with hundreds of amps going through them.

That is on the back of my mind. My hopes are that with it being oversized for my current application combined with its fan that it wont be an issue. My fingers are crossed!

The Daly can be had from a lot of different places (google for it for a complete list) but even Amazon has this model. Once I knew I wanted to try this model the lowest price I found was from AliExpress and I didn't mind waiting the 2 weeks it took to get here.

simicrintz 12-18-2021 10:17 AM

Re: Project Precedent
 
Great write up!! I'll keep watching!

UncleJerm76 12-19-2021 03:09 PM

Project Precedent
 
Looking for suggestions for cleanly routing/mounting all the 17 small BMS balance wires??? I don’t want to slap them on looking like a bowl of spaghetti!


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