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Electric EZGO Electric EZ GO Marathon, Medalist, TXT and RXV. |
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04-27-2016, 07:35 PM | #11 | |
Gone Wild
Join Date: Apr 2016
Location: Greenwood, SC
Posts: 1,291
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Re: Range calculation
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04-27-2016, 09:39 PM | #12 |
Gone Wild
Join Date: Sep 2015
Posts: 572
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Re: Range calculation
Is there some reason that Scottys would read high? Like hooking it up through the key switch? I will check the red one I have tomarrow. (The high one is blue) I took three readings before the run, after the run and after a rest. It was always three tenths higher than my multi.
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04-27-2016, 10:33 PM | #13 |
Gone Wild
Join Date: Apr 2016
Location: Greenwood, SC
Posts: 1,291
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Re: Range calculation
I have no idea? Do you have another multi meter to read it with?
Mabe it's a cheap meter. ..but usually they are consistent with each other. |
04-28-2016, 09:32 AM | #14 |
Gone Wild
Join Date: Sep 2015
Posts: 572
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Re: Range calculation
I'll look in to it more today.
Back to the range issue. Does anyone see a reason that I shouldn't run "full throttle" for 4 miles? I will probably feel the motor and cables at the half way point. If there really hot, I might let it cool. If I can keep my hand on it, is it safe to continue? I have driven my Marithon that far full throttle lots of times, but it's not nearly as powerful. |
04-28-2016, 11:16 AM | #15 |
Techno-Nerd
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
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Re: Range calculation
The max recommended case temperature for a motor with Class-H insulation is 239°F, so if you can keep your hand on it, it is save to continue.
The cables and connections, shouldn't be more than about 10°F, or so, above the air temperature. |
04-28-2016, 02:54 PM | #16 |
Gone Wild
Join Date: Sep 2015
Posts: 572
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Re: Range calculation
Well I did the test and almost bought a new motor. LOL.
Of course there were a few issues. I got it out on the dirt road and hit the gas. The speed went right up to 25-26. After a bit, I looked down and saw the speed was up to 28mph. So far so good. Then at the one mile mark, I had to turn. Would you know it, the county was grading the road. So instead of a nice smooth packed dirt road, it was soft graded dirt. This slowed the cart down to 23-24 mph. I wished I terminated the test right there, but I kept on. I went the second mile and stopped to check the cart before turning around. The cables between the batteries were not even warm. The two cables that go to the motor were just slightly warm. The controller was stone cold and the fan was not even running. So far so good. Next I reached in the wheel well and touched the motor next to the gearbox. Just a little warm. Then I reached in the other wheel well and touched the motor end with the cables. This was warm to hot. The place I stopped was overlooking a pretty farm with horses, so I sat there about five minutes to watch and let the motor cool a little. So after about five minutes, I figured I would check the motor one more time before heading back. Well, things changed to say the least. The end next to the gearbox was hot now and the end with the cables could be discribed as "the gates of hell". So I decided to watch the horses some more. I waited 20 minutes and it was still too hot to keep my hand on it for a count of five. I needed to go, so the test was over. I drove about 12-14 mph home and immediately squirted water on the motor. I have well water that is very cool and in a short time the motor was stone cold. I went inside to change clothes to meet my wife for lunch. I was in the house for maybe fifteen minutes. When I came back out I checked the motor. Would you believe it, the motor was hot again. The heat was radiating from the inside. I watered it down again and went to lunch. Any ways, I used three tenths of a volt to go the two miles. So I guess at that speed it uses 50% more power. So the range at that speed would only be 16 miles. Although I'm sure the motor would melt long before that. I guess you could stop every mile and let it cool. I wish I had checked the temp when I drove at the 15 mph drive. I may try that again if it still works. Lol. One thing I noticed, the GPS has a max speed feature. It said 30 mph. I never saw it while driving, but at some point today I had it up to 30. If I get home and the motor is shot, I guess I will order a D&D. LOL |
04-28-2016, 04:34 PM | #17 |
Gone Wild
Join Date: May 2012
Location: Rio Verde, Az
Posts: 7,125
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Re: Range calculation
It takes a fairly long time for the heat inside to get to the case. That is why you see a delay. The hot armature has to transfer it's heat to the case. Unfortunately, none of these motors have real good cooling and it's easy to run them too hot if you have a powerful controller. For example, 100 Amps at 48V is 8.6 HP (4.8KW) If the motor is 60% efficient, you are generating almost 2KW of heat in the motor. I know that my stock motor was only rated at under 3 HP. My controller can generate way more than 100 amps! You do the math!
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04-28-2016, 05:37 PM | #18 |
Gone Wild
Join Date: Sep 2015
Posts: 572
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Re: Range calculation
Well I got home and tested the cart. It seems to be OK.
It seemed like the main heat was from the aluminum end. I wonder why they don't put fins on it? |
04-29-2016, 07:55 AM | #19 | |
Techno-Nerd
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
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Re: Range calculation
Quote:
The formula for electrical horsepower is: (Volts x Amps x Efficiency)/746 Therefore, 100A at 48V is 6.4HP at 100% efficiency. |
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