Converting CC (Ahem) to Lithium Power

[ronncat]

Originally Posted by benjylafond

Ronncat: I followed your TXT thread. That is one badass cart! I converted my TXT to lithium and initially installed the same mini-BMS you did along with a QuickCharge charger configured to cut off at 42.00 volts (I used 5 leaf modules). Had some issues with the BMS so I re-did everything and went with SportCoupe's bottom balancing method and got rid of the BMS. Haven't had any problems with the batteries and they still charge fully to 42.0 volts after approximately 100 rounds of golf (I installed digital voltmeter on dash so I can watch for low voltage issues).

What "issues" did you have with the mini-bms??? I had my share as well... I call them "me being stupid" Blew up a few of the boards on install when I accidently shorted them across the pack voltage. Also took out an EV Display board... (all in all a couple hundred $$$ lesson learned)

Now that its been installed, the whole system has worked fine. I probably don't need a bms as were not working with a whole bunch of cells that cost a bunch of $$$. But it's useful experience to me if I ever do decide to convert a real car to EV

Anyhow... it's too late...I ordered up the mini-bms and EV display this morning. Made sure to order a couple of extra boards in case I have another brain fart during the install

[benjylafond]

Originally Posted by ronncat

What "issues" did you have with the mini-bms??? I had my share as well... I call them "me being stupid" Blew up a few of the boards on install when I accidently shorted them across the pack voltage. Also took out an EV Display board... (all in all a couple hundred $$$ lesson learned)

Now that its been installed, the whole system has worked fine. I probably don't need a bms as were not working with a whole bunch of cells that cost a bunch of $$$. But it's useful experience to me if I ever do decide to convert a real car to EV

Anyhow... it's too late...I ordered up the mini-bms and EV display this morning. Made sure to order a couple of extra boards in case I have another brain fart during the install

Did the same thing by shorting out one of the boards. Also could not get the relay to cut of the charger at 40 volts to work. After reading SportCoupe's thread, just decided it would be easier to go his way!

[ronncat]

Originally Posted by benjylafond

Did the same thing by shorting out one of the boards. Also could not get the relay to cut of the charger at 40 volts to work. After reading SportCoupe's thread, just decided it would be easier to go his way!

Welcome to the club You're lucky, I shorted out a whole row of my boards (11 to be exact). Dimitri repaired them for about $5 each plus shipping. Blew out the MCU's on them as they can't handle much more than a few volts let alone 84

My bms head board connects directly into my charger as opposed to a relay that supplies power to the charger. In my understanding,it goes low which signals the charger to turn off. Remember, the way the bms is designed is that once ONE battery exceeds the max charge, the whole chain of boards opens which in turn causes the relay or charger to deactivate. By shunting charge off the more highly charged cells, the system essentially and eventually top balances the pack. Maybe you had one cell that would exceed the voltage too soon because it had way more charge than the rest of them, so when the charger was dumping lots of amps in, it overexceeded the shunting ability of the board?? Just thinking

[ronncat]

Decided to separate the 12V components from the Leaf cells, so I will be eliminating my DC converter. It was a good one... Think it supplies 30 amps and works from 40-60 volts or so. Cost me a pretty penny when I bought it.

Replacing with a 12V 35 aH AGM battery and an onboard 12V charger, same as my 84V build. Then I won't have to worry about any parasitic draw from the clock or stereo and the bms will have a dedicated source of power.

Picking up the modules this weekend. Then I just need to find the time to do the conversion. Would love to do it without removing the body, but don't have very good access as this one has the custom Mercedes fiberglass one on it

[UncleJerm76]

Originally Posted by ronncat

Replacing with a 12V 35 aH AGM battery and an onboard 12V charger, same as my 84V build. Then I won't have to worry about any parasitic draw from the clock or stereo and the bms will have a dedicated source of power.

Having done both a reducer and dedicated battery, I prefer the dedicated battery. Enjoying this thread, keep the updates coming!

[ronncat]

Okay then…

Today I took a drive to pick up the 7 Leaf modules that I purchased

Seems though I can never be satisfied. Originally I planned to use the modules to slightly increase the voltage. 7 X 7.6V nominal = 53.2V. Fully charged, they could be as high as 7 X 8.2V = 57.4V. These numbers seemed to fall well within my controller's max voltage of 60V.

On the way down I started thinking WHAT IF?

Well, I get down there and end up springing for 2 more modules… that's 9 X 7.6V = 68.4V nominal and 9 X 8.2 = 73.8V fully charged.

Now, I've just added to the complexity of my conversion. Not only will I need to buy a new controller…Can you say Alltrax? But now I'm wondering if my GE Bad Boy motor can handle the increase in voltage. Same goes for my HD solenoid as well as my F/R switch. In addition, I need to order more bms boards. Luckily, I had the foresight to have Elcon program my charger so I can modify it to fully charge the pack

So now the questions start…

Which Alltrax should I buy? will 400 amps be enough, or should I spring for 500? Right now the cart has stock CC gearing and the tires are 205/50-10 which I just measured at only 17" tall. Published specs show the tire is 18.5" tall. Guess my rims stretch em to the max. I may have to go to 205/65-10 tires if I can squeeze them under the fenders That should add a couple of inches of height.

Also have to figure out how to shoehorn 9 Leaf cells into one of the 3 battery bays in the CC frame. Want to mount the charger in the second bay and the 12V battery and its charger in the last.

Unfortunately my plate is full for the next few weeks, so I hope to start cranking this up first part of May. Should have all the pieces ready to go then

[ronncat]

Forgot one thing….

I might have to upgrade the brakes as well

[sportcoupe]

Remind me, series motor or sepex?

[ronncat]

Originally Posted by sportcoupe

Remind me, series motor or sepex?

Series motor…


GE Bad Boy rated 5.5HP @48V 5700 rpm


Also known as the GE D380 motor

[sportcoupe]

Alltrax AXE7245 has max input of 90v, so does the SPM72400. The SPM is easier to program and has a few better features. The AXE is a time proven performer.