The lithium project

[lithium.paul]

I wanted to start a thread journaling what I've done with lithium batteries in a golf cart.

My background is as follows: I've been golfing since I was 6, and I'm now 26... so 20 years. About 9 months ago I started working for a lithium battery company in Salt Lake City. This company was established to supply telecommunications companies and EV hobbyists with lithium batteries. Over my first few months here, we fielded about a dozen inquiries into supplying lithium batteries for golf carts. Nobody really knew what to tell them because nobody had any experience with golf carts. Having spent so much time on golf courses as a teenager, I at least had a basic understanding, so I volunteered to take on this project of experimenting with lithium batteries in a golf cart.

I started with an internet search, and the first thing I learned was that a company in Southern CA had done a lot of groundwork with lithium batts. They even had a couple of their packs installed into carts at La Jolla Country Club. (you can find video of that on YouTube) I e-mailed the maintenance director there and he was thrilled with the batteries, just not the pricetag! So we decided to get a cart of our own, install some batteries with a BMS, and do some testing!

At the end of February, we purchased a 2006 CC Precedent which had just been turned in from a local country club. Below are some pics up to this point. We had the cart and the nasty Lead-Acid batteries (which really aren't that bad for lead-acids...)

We banded out lithium cells into 12V packs and modified the existing system for securing the batteries. We wired in the BMS, which required a voltage reducer because the BMS itself is designed to run off a 12V aux. battery - nice for a car, not for a golf cart! There were some tricky parts in the wiring because this particular BMS will divert the throttle input through a resistor when the cells reach 70% DoD, basically providing a 'limp mode' to preserve the batteries. We had to figure out which line to tap into - it took some extra time but we got it.

We took it out for some rides and loved the power and acceleration of the lithium set-up. But the further we went, the more we felt like the BMS was more hassle than it was worth. So I pulled it out, and we've been running it for the last few months without the BMS. We've had to monitor the charging closely because working with the OBC in the precedent has been a headache. For a few cycles, the Powerdrive charge we got from the dealer wanted to charge our cells up to 67V! I was very surprised to find that. But now it typically kicks off at about 59V, which is totally fine for these batteries. I wish we knew more about the OBC, but it's so fickle...

Anyway, we like the cart a lot, but we also knew that filling carts with little 3V batteries isn't very practical in comparison to other batter options, so we decided to abandon those cells (and the BMS), and move forward with a new battery being offered by our manufacturer that comes in 12V blocks - much more consumer friendly. I'll post some pics of those soon.