No idea, It removes the speed limit. Does it hold back at 25mph?
Hi @SoonerMark,
Welcome to the group.
In case you have not found the archives yet, this forum has a great collection of previous discussions that can be searched for answers to some of the most common topics. The AI even makes some suggestions at the bottom of the topic page you started. Otherwise, you can use the magnifying glass tool at the top right of this page.
The other thing you are missing from your post (today) are details about your car. It is good practice to include these in your introduction if you want us to return any helpful advice. Otherwise we are all just guessing.
But, here is a basic (non AI) response on what is involved based around what you asked today. (The problem with non AI is that there is high chance you may get additional/unexpected/snarky returns)
How fast will it go?
Speed is a formula that looks at several factors.
- What motor is in this car?
-
- When was it last serviced?
- What gears are in the gearbox
- Batteries (and their condition)
- What terrain will you be driving in (Flat/level, hills)
- Tire size (and properly inflated)
- How high is the cliff you choose to push your car off?
The biggest factor in this formula will be - What gears are in your gearbox. Iām guessing you might have 12.44. This uses math and physics.
DC motors use a lot of copper and steel in the rotating assembly. The upper speed limit can be pushed a bit beyond the basic/factory set speeds, but it is the responsibility of the nut pressing the pedal as to how far he wants to push the limit.
I personally draw the line about 6k. Assuming your car has stock height tires and 12.44 gears we can use (that math stuff) to calculate a top physical speed in the low 30ās. You can get a little more with a bigger tire or a heavier foot but it is not too good for the motor.
12.44 gears work well if in hilly terrain. If you are in the flats (Oklahoma?)
you should start sniffing out a 10.3 gearset. Given the same numbers will be closer to 40.
My apologies. I am in western Oklahoma and we have one small speed bump of a hill lol.
The 2009 GEM e4, stock motor, stock wheels and tires, I believe the gears are stock too, no idea when it was last serviced and there are no cliffs close by.
Only modification is a elefast 72v lithium I got off of amazon.
basically my situation is there is a road I drive on constantly that is 35 mph and I would like to do 35 safely.
Hi, my cart is a 2002 and it cuts out when the round cluster says 30mph, will the speed sensor help me get closer to 40 and is it still available to buy?
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The mm will raise the limit, where it cuts out, to +15mph. Actual top speed depends a lot on battery power and volts.
Soonermark: how long have you had that battery and are you getting the advertised 60 miles on a full charge?
60 miles? They sell a 12kwh battery on Amazon. 4 pcs or ship freight? I range tested a 10kwh battery in a 2016 e2, efficient ac motor, 25mph max. Got 50 miles actual.
The stupid ai bot had you silenced. No idea why. I need to do a better job.
I have only had it a week. Not sure but I charged it over night and will set the trip meter and find out.
@XxRKDOxX - Clarify - What do you mean by this?
it cuts out when the round cluster says 30mph,
- The car goes dark and loses all power?
or
- The car accelerates and when close to 30 it suddenly pulls back on the power and maintains 30. It does not go any faster, even when going downhill.
Also- Have you checked how accurate your dash display is reading compared to GPS?
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Good idea, but then limiter follows speedometer. Must have been reprogrammed at one point.
@XxRKDOxX Normal is 25mph.
I would appreciate a thorough review. Right now Iām torn between two of them in parallel through an a/b switch or ordering the cells from China and building my own.
@Cformony - [My guess] is that even tho that elefast looks like it has good amp output surge ratings, there is NO WAY a 100ah battery will give you 60 miles (unless you plan to do 10 mph everywhere).
Speed eats range. The faster you want to go, it gobbles up your range. It is fairly tough to do 25mph, double tough to do 30mph consistent. Even worse to run around above 35mph.
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Wellā¦. I thought the same thing for 105ah. My Trojans are 150ah and I donāt get anywhere near that. Iām hoping he will give us a more realistic estimate of what I could expect. Even if we could expect 20 to 25, two of them would be fine for my use. I do like that they come with a charger. Having its own dedicated charger is why Iām hesitant, otherwise Iāll order the cells (314ah) and a 200 amp jk bms and build one myself. I think that if I extend the hood of the car 14 inches, I can fit the pack over and ahead of the (āfront axleā) and still give me room for a 12v L.A. batt for accessoriesā¦. Anyway I agree with you. The 60 mile claim is somewhat dubious.
7.5kwh will do 35 miles at 25mph and 25 miles at 35mph. Use 200-300 wh per mile.
250 wh/mile is well tested real world number per myself and lithiumgods.
The only question is, can battery supply full capacity at 80 amps and 350 amp peaks. Not all cells are rated for ev use.
And you are only allowed to use 50~60% of that before you start to do harm to your WLA Trojans. Your 150s are actually 75s.
Yeahā¦.. but at least itās the good halfā¦. Lol
So I have been driving it around town normally at 25 mph (I was out of town for 3 days) I put 10.3 miles on the trip meter and I am at 78%. I will note that that my town is light on traffic and roads are flat. I will give another update later this week
I wouldnāt put any faith in that SOC until you get a few cycles on it. Depending on how it calculates battery life, it most likely needs to go through a calibration stage. There may even be rules on how it is used. It probably needs to come off a charge every day (starting from full charge)
This is one of the toughest things to absorb about E cars, especially when switching battery chemistries. Itās not at all like a fuel gauge in a car.
Iāve been fielding a lot of questions that start off āI was cruising along at 37% and my car just diedā.
Lofepo4 is very flat in its voltage curve and you wont know where you are until it falls off the cliff at the end. You should also be looking at the PackV.
A real columb counter will keep track of all the little amps that come and go out of your pack and adjust itself every time you drive.