Suggestions for next upgrade

[Gibb]

I'm thinking of converting to 42v or 48v myself so I'll be following this as well. If you're going to 48V then do 6 8v batteries.

[JohnnieB]

Nearly everything you do to a cart is a trade off of some kind, so you have to choose what best suits your needs or desires.

8x6V vs 6x8V:
You can get more range with 8x6V, but it weighs more than a 6x8V, so you lose performance. Typically, it is akin to have an additional 120lb passenger onboard all the time. Attachment-1 is a weight chart for 48V packs using Trojan batteries. A standard 36V using T-105 batteries is the baseline for both weight and range. As you see, a 48V pack using T-875 batteries (8V-170AH) has about the same amount of stored energy (range) as the 36V pack using T-105 (6V-225AH) batteries and is only slightly heavier.

Yes, 8 six volt batteries will fit under the seat of a PDS cart, but it is a tight fit. If you relocate the controller, it is easier.

As for motor selection:
You are planing on installing tall tires, which require more torque to turn and
are part of the final drive ratio, so you the taller the tire the less torque available where rubber meets road. Attachement-2 is a chart showing speed gain and torque loss vs tire height.

The MOT-B3 mentioned is wound for higher than stock speed (IE: spins fast than stock with same voltage applied) with 10% more than stock torque due to having a longer case length. With 20" tall tires, the net torque gain would be ZERO and the cart speed will be 28.7MPH mathematically, but the motor might not have enough torque to reach 6000RPM.

In a nutshell, you should consider a motor whose torque offsets the torque loss due to tire height. Since you are planning the have a rear seat, the torque ought to more than offset the tire height torque loss.

[VanillaXtract]

Originally Posted by JohnnieB

Nearly everything you do to a cart is a trade off of some kind, so you have to choose what best suits your needs or desires.

8x6V vs 6x8V:
You can get more range with 8x6V, but it weighs more than a 6x8V, so you lose performance. Typically, it is akin to have an additional 120lb passenger onboard all the time. Attachment-1 is a weight chart for 48V packs using Trojan batteries. A standard 36V using T-105 batteries is the baseline for both weight and range. As you see, a 48V pack using T-875 batteries (8V-170AH) has about the same amount of stored energy (range) as the 36V pack using T-105 (6V-225AH) batteries and is only slightly heavier.

Yes, 8 six volt batteries will fit under the seat of a PDS cart, but it is a tight fit. If you relocate the controller, it is easier.

As for motor selection:
You are planing on installing tall tires, which require more torque to turn and
are part of the final drive ratio, so you the taller the tire the less torque available where rubber meets road. Attachement-2 is a chart showing speed gain and torque loss vs tire height.

The MOT-B3 mentioned is wound for higher than stock speed (IE: spins fast than stock with same voltage applied) with 10% more than stock torque due to having a longer case length. With 20" tall tires, the net torque gain would be ZERO and the cart speed will be 28.7MPH mathematically, but the motor might not have enough torque to reach 6000RPM.

In a nutshell, you should consider a motor whose torque offsets the torque loss due to tire height. Since you are planning the have a rear seat, the torque ought to more than offset the tire height torque loss.

What motor would you consider? I did not see which motor on Scotty’s website that had more torque.

Is lithium even better?

[JohnnieB]

Originally Posted by VanillaXtract

1. What motor would you consider? I did not see which motor on Scotty’s website that had more torque.

2. Is lithium even better?

1. Send Scotty an e-mail. he can help you pick the right motor for the way your cart is set up.

2. Yes, but $$$$$$$$$$$$$$$ and still evolving for golf carts.

[BobBoyce]

Originally Posted by JohnnieB

1. Send Scotty an e-mail. he can help you pick the right motor for the way your cart is set up.

2. Yes, but $$$$$$$$$$$$$$$ and still evolving for golf carts.

These are the GBS Lithium cells that I used.

http://www.ebay.com/itm/232523999569

He even has some used ones at a lower price.

http://www.ebay.com/itm/232503957466

I bought 32 cells and a BMS/Charger on sunday, and yesterday I bought another 16 cells. I am not affiliated with this seller. I just wanted to pass on my source of lower prices for LiFeMnPO4 cells for others to take advantage of while they are still available. He had about 50 of the 100 AH cells left as of yesterday when I bought the second batch.

Bob