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-   -   first step in DS conversion to lithium seems easy (https://www.buggiesgonewild.com/showthread.php?t=158241)

dlwilson 10-21-2019 08:00 PM

first step in DS conversion to lithium seems easy
 
1 Attachment(s)
I've wanted to convert my 2001 Club Car DS to lithium for a while, but I could never figure out exactly what parts I needed. A couple months ago I finally did a bunch of reading and bought a Chevy Volt 48v battery, a 12S 150A BMS, and a 50.4v 15A charger. The battery and BMS arrived quickly, but the charger had a long lead time, so I put them aside. Today I had some time to work with them, so I emailed the battery charger people to ask for a ship date, and figured I would try out the battery.

The meter showed 47.5V DC, so I disconnected the positive and negative from the Trojans, and hooked them to the Volt battery. When I hit the throttle I got forward and backward movement. I had the Volt battery balanced precariously, so I didn't try driving it.

Next step is to remove the Trojans, and cut a piece of plywood to act as a floor. Add some 1x2 rails to hold the battery using longer allthread.

Then wire the Volt BMS connector to my BMS, and wire in the charger once it arrives. At that point I should be ready to ride. Am I missing anything?

http://www.buggiesgonewild.com/attac...1&d=1571705844

BBBHC 10-22-2019 06:37 AM

Re: first step in DS conversion to lithium seems easy
 
Does your BMS have disconnects (relays or a contactor) for over voltage, and over discharge?

This is very important for safety concerns.

bronsonj 10-22-2019 12:07 PM

Re: first step in DS conversion to lithium seems easy
 
Good point BBBHC.

DLWilson, I'll be watching your build thread too as I'm looking to convert my neighbors cart. I was going to go 14S but the similicity of 12S is rather nice too. Remember, you don't want to go to 4.2vpc or down to 3.0vpc. Most people running lith will charge to 4.15vpc and go down to 3.15vpc. At 12S that'd be 49.8v down to 37.8v at the pack level.

When I switched to lithium I was amazed at the performance difference. It'll be interesting to see how well the DS performs with a 12S pack when you lighten the cart 400lbs (give or take).

Good luck! :thumbup:

dlwilson 10-22-2019 02:41 PM

Re: first step in DS conversion to lithium seems easy
 
1 Attachment(s)
I'm a software guy, so I'm not that familiar with hardware. Does this BMS have disconnects on it? I thought that was the whole point of a BMS. Why would it not have some way to isolate a cell?

DaveTM 10-22-2019 02:51 PM

Re: first step in DS conversion to lithium seems easy
 
I don't know what you have there, but I can only assume you have documentation that tells you "what is what"?

I am using a ZEVA BMS and the ZEVA has specific wire nodes that will cut off charging should one cell become overcharged (according to my setting) and another that will kill power draw should any given cell draw down to a low voltage number (according to my setting).

What does your documentation say?

The pic below shows my LV & HV relay setup. What this setup does is should a HV or LV occur, the relays will open an not allow any further charging, or any further discharging of the Lithium battery pack.

https://i.imgur.com/cbfUf5R.jpg

dlwilson 10-22-2019 09:29 PM

Re: first step in DS conversion to lithium seems easy
 
The directions that came with the BMS are below. They are pretty straightforward. Looking at the black components on the board, I see a part number of HY5208, and I found this datasheet: https://datasheet.lcsc.com/szlcsc/HU...8W_C330384.pdf And if I look on wikipedia for MOSFET (https://en.wikipedia.org/wiki/MOSFET) it appears to be some sort of solid-state switching device. So I'm assuming the BMS switches off the current during charging or discharging as necessary.

The Chinese charger company refunded my money once I contacted them via PayPal, so I'll have to look elsewhere. I got a 50.4V 4A charger off Amazon today just so I'll have something to work with while I wait for another Chinese charger. https://www.amazon.com/gp/product/B07T54J61Q

Next step is wiring the battery, the BMS, and the charger together.

http://www.davewilson.cc/Photos/GolfCart/bmsDiagram.png

DaveTM 10-22-2019 10:00 PM

Re: first step in DS conversion to lithium seems easy
 
The Data sheet that you have linked to is waaaayyy over my head. I'm not an engineer and whatever the stuff they list on that data sheet may mean something to an engineer......but like I said.

Perhaps someone with an EE background can tell you what you have.

BBBHC 10-23-2019 06:55 AM

Re: first step in DS conversion to lithium seems easy
 
Quote:

Originally Posted by dlwilson (Post 1663381)
I'm a software guy, so I'm not that familiar with hardware. Does this BMS have disconnects on it? I thought that was the whole point of a BMS. Why would it not have some way to isolate a cell?

Those data sheets are over my head as well... Hopefully Sergio will chime in and enlighten all of us.

The purpose of a BMS is to control the total charge from a charger. A charger just "knows" to input an amount of charge to a battery/pack. The BMS takes that charge and distributes it to the # of cells within a battery/pack evenly, so as to keep from overcharging any cells within the battery/pack. This prolongs the life of all of the cells within a battery/pack.

Most BMSs I have seen, that are in the realms of DIY, also provide the ability to cutoff in the event of over charge as well as over discharge. However, they require a means to do so, i.e., relays or contactor.

Hopefully I said that in a way that makes sense. It is a very basic way of saying it, I'm sure the gurus will be able to better explain it as well as expand on it.

dlwilson 10-23-2019 07:14 AM

Re: first step in DS conversion to lithium seems easy
 
1 Attachment(s)
That set of directions from the BMS manufacturer seems unnecessarily confusing. I've been looking at it for the past month, and I finally see how it works (I think). The BMS just goes inline between the battery and the motor/controller/charger, and acts as an on/off switch to stop current flow when necessary. Presumably those magic MOSFETs are able to control the voltage (or is it current?). I've redrawn it below the way I think it works.

http://www.buggiesgonewild.com/attac...1&d=1571832666

DaveTM 10-23-2019 07:42 AM

Re: first step in DS conversion to lithium seems easy
 
Ok....how do you know what the unit's HV and LV cutoff is? And maybe you can tell from the data sheet....how do you hook those cutoff's up?


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