What are the effects of voltage increase on cart performance? - Lithium battery pack

[Sir Nuke]

Jax.....I know you are trying to keep the cost down......but look at it like this, regardless, you are buying a new set of batteries. buy QUALITY batteries.....of the voltage you want, and get the highest AH rated batteries you can afford. its never a idea to have more than you need, but it reallys sux when you don't have enough, then your stuck. AND if you are jumping to a higher voltage.....you need to remember you will be needing a new charger.

Personally I stayed at 36v (with the 500a system) and went with the motor, and higher than normal AH batteries....and 4 years latter, I'm still happy with my 25 mph top speed and 25+ mile range.

[JaxPilot]

This thought just popped into my head. Should the cables from the battery pack to the Solenoid be 2GA, like the rest of the high current cables?

I'm corresponding with Nick at EV Batteries, and I want the Anderson connector cables to the Solenoid to be 2GA also, instead of 4GA, if required. They will also need the larger 3/8" diameter lugs.

I think I have narrowed it down to 3 options:

1: 4600Wh - 45v - GP4694-17 with the upgraded 104AH Batteries. (85 lbs, $1500 assembled)

2: 6600Wh - 54v - GP54120-17 with the upgraded 124AH Batteries. (120 lbs, $1900 kit)

3: 5400Wh - Not listed on the site, but I presume it is like option 1, only with upgraded 120 AH Batteries.

[Sir Nuke]

Jax....YES....have ALL your high current cables the same size. otherwise the flow (amperage) gets bottlenecked at that point.

[davewil@mc.net]

Did the GP54120-17 price come down to $1900?
Their website shows $2180.

[JaxPilot]

$2180 is assembled price. $1890 is the parts kit. :)


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[davewil@mc.net]

DIY54120-17 is the part number of the unassembled kit $1890.
GP54120-17 is the part number of the assembled kit $2180

[davewil@mc.net]

Has anyone looked into, or used, 4200Wh Lithium Battery Pack 12 cells, 94Ah with BMS for 48V GP4694-17 . Battery cells made in USA by LG Chem.
At $1235 including BMS, seems like a lot of bang for the buck.

[JaxPilot]

That's what Nick was saying, good value for the money. From an email exchange:
"The 4200Wh is cost effective, little higher - need 11" space, looks
little uglier, but is powerful, because the batteries are in parallel -
and can provide 500A (for short time cables limited)"
They have an option to use 104 AH batteries for an additional $280. That's where the 4600Wh and 45v @ $1500 came from.


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[JaxPilot]

Interesting email from Nick at EV battery. I asked about 2GA cables, and other options on batteries.

2GA is not a problem, the difference of the cable price is very minor. I'm not sure if will be necessary using 350A connectors. Usually we use 175A, assuming the continuous current does not go over 175A for long time. Discharge at 300-500A pulses is not a problem using SB175 Anderson.

I'm not really sure what the sustained and peak amperage pulled by the stock 36V motor running on ~50v would be. Is that information available?

Especially these batteries are also the most expensive, but compact, easy to make different configurations and excellent quality.

He is talking about Leaf and Volt cell packs.

For better price/capacity ratio - there are much more options - see for example the Tesla packs - 14S 120Ah 2x pack - 14S, 120Ah (measured 124Ah) will be about $1300 compared to $1750 for the others. But there is a catch - if fits in a size 37" long.

I actually think I could fit the TESLA cells crossways under the seat, running from left to right across the battery compartment and the two plates to either side of the battery compartment. I would need to fabricate some type of shock mount, since the battery tray and frame could flex separately from each other, it appears. I may also have to modify the floor of the battery compartment, since each of the two modules would be 7" wide, and the center divider is at the 10" inch mark. I'd have to either put one module on either side of the divider with a longer busbar spanning them, or raise the floor to have a level mounting surface to place them a little closer to each other. If I placed them both adjacent to the middle divider, then it should not require too much longer of a busbar connection..

The box in the picture is about the correct size for a mockup, except for the 2" overhang on each side. The front seat support, where the F/R lever usually goes is 37" long.

But, 120AH @ nominal 51.8v @ $1300 is an attractive option. Just what I need - more freaking choices!

[JohnnieB]

Originally Posted by JaxPilot

1. I'm not really sure what the sustained and peak amperage pulled by the stock 36V motor running on ~50v would be. Is that information available?

2. I actually think I could fit the TESLA cells crossways under the seat, running from left to right across the battery compartment and the two plates to either side of the battery compartment. I would need to fabricate some type of shock mount, since the battery tray and frame could flex separately from each other, it appears. I may also have to modify the floor of the battery compartment, since each of the two modules would be 7" wide, and the center divider is at the 10" inch mark. I'd have to either put one module on either side of the divider with a longer busbar spanning them, or raise the floor to have a level mounting surface to place them a little closer to each other. If I placed them both adjacent to the middle divider, then it should not require too much longer of a busbar connection..

The box in the picture is about the correct size for a mockup, except for the 2" overhang on each side. The front seat support, where the F/R lever usually goes is 37" long.

1. At zero RPM, a 36V DCS motor can draw all the amps the battery pack will produce, but is limited by the max the controller will pass.

As the motor RPMs increase, its ability to draw amps decreases, so the only time it will draw max amps is accelerating from a standstill or when a steep hill slows the cart down to under about 10 MPH at WOT. Cruising at speed, the motor will most likely draw less than 100A even with the 22" tall tires.

2. I don't know if it will be an issue, but be aware that the hip supports on each side of the seat hang down a couple inches under the bottom of the seat. I had to move the seventh battery in my 42V pack forward so the bracket didn't rest on the battery terminal.