11-18-2021, 10:43 AM | #21 | |
Gone Wild
Join Date: Oct 2019
Posts: 646
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Re: New Icon with Lithium
Quote:
I'm not that familiar with Icon and the similar clones, but it is my understanding that they have mechanical brakes (4-wheel discs, in this case, I think?). So does the Icon have a "motor brake" (like the RXVs have) in addition to the mechanical brakes? The RXVs (far as I know) don't have any traditional mechanical brakes and ONLY have a motor brake for parking and emergency stops, using motor Regen otherwise for all other braking situations. My CC Onward, in comparison, has only mechanical brakes. So while I wouldn't want my BMS to shutdown my battery while I'm driving, if it happened the cart wouldn't lock up because the Navitas motor I'm using doesn't have a "motor brake". The stock CC motor didn't have one either. If an RXV loses power though - yes, it will lock up. Apparently the Icons would do the same? I think if I were considering a lithium battery and was worried about the Full charge / downhill scenario, I might consider looking into a custom charger voltage limit (some are adjustable pretty easily) or another way (timing and automating the charges in conjunction with a shunt-based SOC meter) of limiting the max charge to ~90% of whatever level is causing BMS shutdowns. Another thing to consider could be programming the BMS to be a little more tolerant on the high end (if the BMS is one of those BT accessible ones) - or maybe a combination of this with the above. |
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11-18-2021, 11:25 AM | #22 |
Not Yet Wild
Join Date: Oct 2021
Posts: 64
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Re: New Icon with Lithium
I believe the Roypow 'P' versions of their batteries have intelligence to turn off brake regen charging once the battery reaches a certain charge capacity. There is a large resistor that has to be mounted to accommodate the regen power when the battery doesn't utilize. I believe that was done to prevent the battery completely shutting off power if it reaches an over charge state. I may be misrepresenting the finer points but that's roughly how I understand this config.
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11-18-2021, 01:10 PM | #23 | |
Gone Wild
Join Date: Oct 2019
Posts: 646
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Re: New Icon with Lithium
Quote:
I think the controller needs to decide where to "send" any excess power and the resistor is where it gets dumped if the battery can't handle it. Parameters set up in the controller determine what is "excess". If the Roypow P has special terminals on the battery (not just + and -) then it could be capable of something similar w/out the controller being involved maybe. Someone posted the wiring diagram for the "P" battery and resistor once IIRC but I can't remember the details. |
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11-18-2021, 03:03 PM | #24 | |
Gone Wild
Join Date: Oct 2012
Location: SoCal
Posts: 671
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Re: New Icon with Lithium
Quote:
The lithium concern for ICON owners is if the BMS has a shutdown event and the controller loses power, the motor brake will engage and then either break or launch people. So we're trying to brainstorm how to handle a sudden power loss. I recall my dealer telling me the e-brake was just a small piece of metal that could break if I was doing something weird with the cart. I'm guessing somebody else had broken one before. I think the motor brake is on the passenger side end of the motor where there are little hex screws because I accidentally overtightened one and the brake stopped engaging after I stopped the cart. This made me think it was magnetic or on a spring and tightening the screw holds the brake in the open position. |
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11-18-2021, 03:36 PM | #25 | |
Gone Wild
Join Date: Oct 2019
Posts: 646
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Re: New Icon with Lithium
Quote:
Just a little curious why they felt the need for a motor brake on these? Does it have an auto park brake like the RXVs do (that uses the motor brake)? Does it have a locking brake pedal like traditional carts do? Options would be to ensure the BMS didn't shutdown as mentioned above, or disable / remove the brake from the motor and rely on the mechanical brakes. Since it has them on 4 wheels, they should provide good stopping force I'd think. I know there has been considerable frustration among RXV owners over motor brake issues, but in that case you can't disable or remove it since there are no mechanical brakes on the cart. I know my local EZGO guy told me a while back that the motor brake on the RXV was only good for a few panic stops before needing replacement. He had a number of stories about power loss for one reason or another on them and the carts locking up and sometimes throwing people forward. Doesn't sound good when it could happen completely unexpectedly. |
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11-19-2021, 12:05 PM | #26 |
Not Yet Wild
Join Date: Oct 2021
Posts: 64
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Re: New Icon with Lithium
Since I don't have my cart yet I am forced to sit on the forums and contemplate.
I understand the intent behind the motor brake. If the key is turned off then the motor brake is activated and the cart won't roll away. That's nice. What I don't understand is if I'm stopped and I want to listen to music how is that achieved without the cart rolling away? As in, I arrive somewhere and the cart is on an incline, I want to listen to music but don't want to sit in the cart with my foot on the brake. Is that achievable? Is there a 'Park' setting or just forward, neutral and reverse? |
11-19-2021, 12:13 PM | #27 | ||
Gone Wild
Join Date: Oct 2012
Location: SoCal
Posts: 671
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Re: New Icon with Lithium
Quote:
I was trying to think of how to incorporate perhaps another battery and up the voltage a bit, so that if the BMS failed the other battery would at least keep the controller powered so the motor brake doesn't engage...but charging and even battery wear...it doesn't seem like it would work. Quote:
The motor brake is perfect for the most part, except this lithium issue. It engages when you turn of power or take your feet off the pedals. So when I'm parking on a hill with my foot on the brake, once the cart is at a complete stop...I just take my foot off the brake. No thinking or anything, it's natural. Even at stop lights, either my foot is on the brake holding cart position, or off the brake and motor brake holds position. It really works very well. |
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05-02-2022, 04:16 PM | #28 |
Not Yet Wild
Join Date: May 2021
Posts: 20
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Re: New Icon with Lithium
I have a lithium battery pack and experienced my first BMS power loss trip. I was driving with 4 people in the cart going up a hill around 27mph, battery was around 50%, it was a hot day and cart was baking in sun for hours. I suspect the BMS tripped due to heat, either way it tripped. Once the cart BMS tripped the entire cart lost power obviously, the electric brake instantly engaged and locked up the rear tires as I can screeching to a stop. The magnetic brake held very strong and did not break.
I wonder if there is a way to independently power the electric motor brake via another battery and only have the brake engage with a seperate toggle switch. This way if the BMS loses power then the seperate battery is still providing power to the electric motor brake. |
05-12-2022, 02:53 PM | #29 |
Not Yet Wild
Join Date: Sep 2018
Location: Puyallup WA and Eloy AZ
Posts: 4
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Re: New Icon with Lithium
I wonder if you disabled the motor brake and put something like a Line Lock on for a parking brake. They make them now that use an solenoid to activate them besides the manual lever type. Would think you could use this for the park brake. Just a thought, possibly put a electric floor switch by the brake pedal to activate.
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05-21-2022, 10:33 PM | #30 |
Not Yet Wild
Join Date: Nov 2021
Posts: 20
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Re: New Icon with Lithium
Would a capacitor or a transformer help? Could a switch somehow activate this circuit to essentially put the brake in a bypass mode to get home?
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