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3c or 6c? what is it I really need for a golf cart?

L0veless

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Jan 25, 2021
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I'm wanting to build a 48 volt system for my golf cart, where I'm concerned is what battery do I really need?
I'm looking at 16s 105ah batteries, I see the 3c constant discharge at 100 amp with surge of 300amp My cart usually runs at around 100 to 150 amp would the 3c work or do I need to go up to 6c? I want to run a 250 amp BMS. what do you guys use for your golf carts?

TIA
 
The C rating is the rate of charge or discharge related to battery capacity. A 105AH battery discharging at 1C rate will be discharging at 105Amps and will be empty in 1 hour. A 105AH battery discharging at 3C will be 315amps and will be empty in 20 minutes (1/3 of an hour). Charging works exactly the same way.

So any battery charging at 1C will be full in 1 hour (1/1). Charging at 6C would be 1/6 of an hour. High C rates are hard on batteries.

My 48v golf cart has 150Ah batteries and I am installing a 70a motor controller (I don't need to go super fast, but I haven't been able to test it yet to know if that is fast enough). 70/150 = 0.4666C at full throttle.

Consider 1 horse power is 746w. My cart originally put out 2hp. With my new controller, 70*50v = 3500w of power. 3500/746 = 4.69hp so this is quite an increase in power for my golf cart.
 
Don't use battle born....the bigger the battery the less C you need.... Go big or go home...
 
I'm just starting the lithium upgrade to my 48 volt golf cart. Thinking of 4 100AH 12 v in series but I'm not sure that will be enough. Options? I also plan on using the cart as a power station with a 3000 watt inverter charger. Also installing 400 watts solar on the roof and more when parked. I don't need a fast hotrod cart just need it to drive and provide backup power for a couple refrigerators.
Has anybody done this with success and what was your configuration?
Thanks!
 
I have a 2013 Precedent that's 48 volts and I also run the off-grid part of my home on a large 48v lithium pack.

100 amps constant is enough if your cart isn't modified, you live on flat ground, and you don't drive hard... Beyond that, if you have larger tires, drive up hills, carry extra people, or do anything else that requires more load on the batteries, then you really need a 150 amp constant discharge at a minimum.
You will also want to install larger cables to feed the motor and controller.

I have one hill I regularly climb, its about 1/2 mile long and steep enough that my cart slows significantly. I currently run six 8 volt flooded lead acid cells because they came with the cart and are in good shape.

The batteries you see being made for golf carts are mostly the bare minimum.. probably designed for old folks in Florida who drive around their neighborhood socializing. For people who work their carts harder, they are not really enough and I see problems with them tripping out.

The lithium equivalent to the standard lead acid cells is about 3.6 to 4 kWh of capacity, which assumes a lead acid DOD of 50%.

Basically, a 100 amp hour lithium will be about the same as the stock batteries and allow you to clip the knees at the top and bottom of the discharge curves..

That said, the capacity of the battery is only part of the equation. As you have learned, that battery needs to be able to deliver a constant amount of juice without destroying itself.

If you are upgrading your controller for more torque and speed, you should rig for a 200amp discharge.

Right now is a horrible time to be buying lithium batteries.. The demand is high and the availability is low.. Most of what is on the market are Chinese cells and I won't risk my investment. I'd rather have EV cells.
 
I see the 3c constant discharge at 100 amp with surge of 300amp My cart usually runs at around 100 to 150 amp would the 3c work or do I need to go up to 6c? I want to run a 250 amp BMS.
For a 300 amp demand, won’t a 250 amp BMS shut off? I have a BMS I push the limit with, and when my 15 amp BMS hits 15.1 amps, it shuts off. I don’t think that would be good with a golf cart.

I don’t run a golf cart, but lead is much better at those surge demands. My guess is the starting amps may be more than your meter reads, and I don‘t know. If your BMS would cut that off. Would be nice to see what those who have done the build needed. I do wonder if this quick large demand would shut the BMS off going up a hill.

Here’s one video:

 
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