10-28-2021, 08:14 AM | #1 |
Gone Wild
Join Date: Jan 2016
Location: Hickory, NC
Posts: 702
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Which Way To Go?
First of all, let me apologize in advance for the length of this post. You may want to wait until you’re bored and have nothing better to do before reading it, and it is kind of confusing and wandering so please bear with me…
GOAL - GO 35 - 40 MPH ON LEVEL STREETS AND MINIMUM 25 - 30 MPH UPHILL WITH BOTH CARTS MY CURRENT CARTS: Club Car DS Humdinger (street legal) - Navitas 600A 5kw AC system • 48v • 26" tires Eventually, I am thinking about installing a 72V lithium battery so that it will have more power pushing the 26-inch tires, as I want to be able to maintain at least 35 mph on level roads and not lose too much speed going uphill. 2014 Club Car Precedent (street legal) - Altrax XCT500 • 48v • PQ Executioner motor • 23" tires I used to have a RoyPow 48V lithium battery that I really enjoyed as it added a lot of response and mileage. However, I ended up selling it as it kept shutting down going up long hills due to exceeding the max discharge rate. I am considering waiting until January when my RoyPow dealer will have a “P” version 48V lithium battery that will have a higher max discharge rate that MIGHT allow me to go up long hills without it shutting down. I am also considering an Extreme Team lithium battery but I have serious doubts that they will be able to survive their growing pains. Or, I may sell my Alltrax and Executioner and switch to a Navitas system so that I might eventually go with a 72V lithium battery in this cart as well. However, money is always a factor so I can’t do everything at once. So now, onto my questions… DS HUMDINGER - I am pretty happy with the Navitas and can eventually reach 35 mph on level ground, but need more power to turn the 26-inch tires. Will switching to a 72V pack provide the power I’m looking for to reach my goal? PRECEDENT - Would it be better to keep my Alltrax and Executioner and install a 48V lithium with a higher max discharge rate, or switch to a Navitas AC system and run a 48V pack of FLA batteries, or possibly a 72V pack of FLA batteries? If going to 72V, I would also have to factor in the cost of a new charger and a 72V to 12V converter. I believe I read that an AC system uses less current than a DC system. Do you know if it is a big difference? Would I be able to run a lower Max Discharge Rate on a lithium battery if I were using an AC system? There are just too many options and too many ways to go. I think I am getting "paralysis by analysis", as I can't decide what to do. What do you guys think or recommend? THANK YOU for any advice or recommendations!!! |
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10-28-2021, 04:09 PM | #2 |
Gone Wild
Join Date: Jan 2013
Location: Saint Petersburg, FL
Posts: 2,089
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Re: Which Way To Go?
Going higher in voltage should help the Precedent. I am not overly familiar with the AC system of the Navitas so I can assume it'd help, on paper it looks like it should help, but I can't say for sure.
Think of the amount of work the cart needs to do. The work is Amps * Volts = Watts (Work) If you are at 48V and require 250 amps to do something then 96V will require 125 amps to do the same thing. My cart at 48V (when my lithium pack is dead) is much worse performance than my cart at 56V. Even though it's passing the same amps to the motor. Now there are limitations. DC motors can only accept so much amperage at a given speed. Once the motor is spinning past maybe 10mph (guessing) it gets to where the motor can be limiting the current. But increasing the voltage helps here too. If the motor can only take 225 amps after it's spinning 4,000 RPM then you will see more acceleration and speed holding ability at 56V vs 48V. My cart will reach about 32mph if I set the Alltrax settings as high as they go. That's on level ground with my 360 amp max controller. In fact, I've only seen a 300 amp draw once or twice on hard accel. What is the max RPM of the PQ Executioner motor? 6000 rpm on 23" tires puts your theoretical maximum at 34mph. If you want a higher top speed you'll need a motor that can spin faster safely or larger tires (or different diff gears). But larger tires and taller differential gears will make it harder to maintain speed on that hill. You may be in a situation where you need to wait for the stronger BMS options or look for another brand lithium or build your own lithium pack. |
10-28-2021, 04:16 PM | #3 |
Gone Wild
Join Date: Jan 2013
Location: Saint Petersburg, FL
Posts: 2,089
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Re: Which Way To Go?
You could try adding another 6V to make a 54V lead acid pack to see if that helps the precedent. I get that you won't want to keep it that way but that'd give you a glimpse of the performance at higher voltages. I don't know that the Alltrax will let you do a 60V lead acid pack. The max V in the Alltrax software is 62V before it shuts off and a fully charged 60v lead acid pack would be 63.65V.
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11-01-2021, 07:58 AM | #4 |
Gone Wild
Join Date: Jan 2016
Location: Hickory, NC
Posts: 702
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Re: Which Way To Go?
Thanks for the info, bronsonj!
Late Friday afternoon, I sent an email to Navitas with basically the same questions, and didn't expect a reply until some time this week. About 5 minutes after I sent my email, I got a phone call from them. THAT'S CUSTOMER SERVICE! Anyway, we talked for a long time about various options, and he confirmed the 72V vs. 48V power consumption, as well as AC vs DC power consumption, etc., etc., etc. So, I think my game plan is going to be: 1. Sell my Alltrax XCT500 and Plum Quick Executioner and switch to the Navitas 600A 5kw AC system - that way I have the same system in both carts, PLUS it leaves me the option of going to 72V on the Precedent at a later time. 2. Buy a RoyPow 72V lithium cell for the DS/Humdinger - I would have liked to have tried an Extreme Team cell but it seems there have been a few issues lately and not a lot of quick responses that I've seen. 3. Buy a 48V or 72V lithium cell for the Precedent once my wallet recovers from #1 and #2. Does anyone see a flaw in this or have any different suggestions? Thanks! |
11-02-2021, 10:23 AM | #5 |
Gone Wild
Join Date: Jan 2013
Location: Saint Petersburg, FL
Posts: 2,089
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Re: Which Way To Go?
What is the max rpm of the Navitas AC motor? You stated you want 35 to 40mph and that's over 6k rpm unless you go with taller tires or taller diff gears. The page I saw about the 5kw motor said the RPM range was 0 to 5785 for the 5KW motor and 0 to 6800 for the 4kw motor.
If you get the 4kw motor with 6,800 RPM that's a theoretical max of 39mph. If you get the 5kw motor with 5,785 RPM that's a theoretical max of 33mph. They will absolutely hold their speed better on inclines than the sepex motor currently in the cart, but if you want closer to 40 then you may be unhappy (unless the RPM limit I saw was incorrect). --- edit --- Oh, and very cool customer service! |
11-02-2021, 10:25 AM | #6 | |
Gone Wild
Join Date: Jan 2016
Location: Hickory, NC
Posts: 702
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Re: Which Way To Go?
Quote:
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11-02-2021, 10:26 AM | #7 |
Gone Wild
Join Date: Jan 2013
Location: Saint Petersburg, FL
Posts: 2,089
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Re: Which Way To Go?
Holy cow! That's over 50mph! Wow
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11-02-2021, 10:39 AM | #8 |
Gone Wild
Join Date: Jan 2016
Location: Hickory, NC
Posts: 702
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Re: Which Way To Go?
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