Stupid question about regen braking

[sgremp]

I have an AC electric golf cart (Icon i60L), and was curious about regen braking…so I physically need to put my foot on the brake and press down to engage regen braking, or is it engaged anytime I’m coasting/maxed out on speed?

For example, down a large hill, if I keep my pedal all the way down for throttle but I’m not going any faster, is regen braking working at that time or am I negating the impact because I’m still wide open on the throttle?

Same question if I let off the throttle completely and slow to a stop but don’t use brakes, is that using regen or am I not getting any benefit from it?

I have the navitas 600a controller and I can easily change regen setting, the higher I turn it the quicker I slow down not using brakes, even down large hills I’ll slow down if I have it turned up high, so wondering if by needing to ride the throttle down these hills is actually hurting my battery (or having little to no effect). Have scoured online trying to figure this out but can’t find answers to these questions, thanks!

[kernal]

Originally Posted by sgremp

I have an AC electric golf cart (Icon i60L), and was curious about regen braking…so I physically need to put my foot on the brake and press down to engage regen braking, or is it engaged anytime I’m coasting/maxed out on speed?

For example, down a large hill, if I keep my pedal all the way down for throttle but I’m not going any faster, is regen braking working at that time or am I negating the impact because I’m still wide open on the throttle?

Same question if I let off the throttle completely and slow to a stop but don’t use brakes, is that using regen or am I not getting any benefit from it?

I have the navitas 600a controller and I can easily change regen setting, the higher I turn it the quicker I slow down not using brakes, even down large hills I’ll slow down if I have it turned up high, so wondering if by needing to ride the throttle down these hills is actually hurting my battery (or having little to no effect). Have scoured online trying to figure this out but can’t find answers to these questions, thanks!

I'll try to be brief. Late model golf carts/LSVs are all speed limited from the factory to comply with Fed statutes, liability etc. They use software in the controller for this (proprietary mostly). The controller thinks it knows your speed by counting motor RPM via a speed sensor on the motor and the factory software includes an RPM limit that the controller won't go above. This is why you need to hold you foot to the floor to keep top speed even when going down hill. As you feel it bumping on the limit, that is regen kicking in. The days of golf carts that would actually coast (free wheel) are gone. You can trick the controller somewhat by putting taller tires on the cart to get higher top speed at the same RPM limit as long as the batteries/controller are strong enough to support it (torque is reduced---physics).
Electric motors turn into generators when turning by mechanical means with no current supplied by an electric power source, batteries in this case. DC sepex and AC controllers harvest this to produce "regen" sending current back to the batteries and turning the motor into a brake of sort. (Here is where you go study electric motor theory if you want.)
Sooooo, for the operator, releasing the go pedal with cart in motion generates "regen" which slows the cart while sending some charge back into the batteries with the faster you are going the more regen is generated (more resistance to motion). Forward or backward,by the way, hence walk away protection on golf carts (you can catch it if you forget to set the brake).
On some carts the regen is adjustable. The EZGO RXV for example has no wheel brakes at all--NONE--. All braking is done by the motor with regen controlled by the brake pedal and or releasing the go pedal. Parking brake is electro mechanical like on the ICON, automatic controlled by the controller.

If you were to install a digital voltmeter on your dash hooked to the battery pack you could see the battery voltage sag under acceleration and watch it sore way above nominal pack voltage when go pedal is released. I have this on my RXV and have seen regen voltage go above 60v during braking same as the finish charge on the regular battery charger. (48v cart)

I don't know if the regen is adjustable on the ICon controller. I surmise it is a compromise somewhere in the middle so it drives somewhat like a pre sepex cart like the auto manufactures are doing with their EVs. They have to ease people into the way EVs drive before they can take advantage of strong regen settings. Hope this helps.

Edit: while rambling I forgot you have a Navitas. You can play with the regen settings to adjust to your liking. I recommend experimentation as the environment will influence how it drives. The settings would probably be different in Florida than somewhere with big hills.

[sgremp]

I can control the regen with the navitas, which is why I’m curious if I max it out, I would basically be giving throttle while going downhill because the regen will be slowing me down, conversely I can set it lower and actually pick up speed going downhill, so I’m wondering is it more efficient to ride the brakes and let the cart more or less free fall or increase regen and have to keep the throttle down, or at least a mid ground where I might need to apply a little then coast and sort of get about right where I coast at my optimal driving speed without throttle at all…feel like the little power that goes back in with regen I would almost be better off without. Another example let’s take the hills out of it, if I just let off the throttle with no regen at all I could coast awhile before having significant power loss, so I’m using very little battery during this time (I think), but if I have regen and let off the throttle it slows me down within 5 seconds then I have to put more throttle to maintain speed. Curious if I do more coasting if I’d end up better off.

[kernal]

Originally Posted by sgremp

I can control the regen with the navitas, which is why I’m curious if I max it out, I would basically be giving throttle while going downhill because the regen will be slowing me down, conversely I can set it lower and actually pick up speed going downhill, so I’m wondering is it more efficient to ride the brakes and let the cart more or less free fall or increase regen and have to keep the throttle down, or at least a mid ground where I might need to apply a little then coast and sort of get about right where I coast at my optimal driving speed without throttle at all…feel like the little power that goes back in with regen I would almost be better off without. Another example let’s take the hills out of it, if I just let off the throttle with no regen at all I could coast awhile before having significant power loss, so I’m using very little battery during this time (I think), but if I have regen and let off the throttle it slows me down within 5 seconds then I have to put more throttle to maintain speed. Curious if I do more coasting if I’d end up better off.

I think its a wash. I haven't seen any data that says regen braking on golf carts adds any measurable range per charge in actual use. I believe it is advertised to be more efficient but its real use is to limit speed---hence liability.
Set it so it drives like you like it.
If you want delve into this further check out the electric (EV) auto forums. Its the same thing only fancier.

Edit: Also, Navitas removes the speed restrictions of the factory controller so how it drives will be different.

[kernal]

If you are stepping on the go pedal you are taking energy from the battery and if you release the go pedal you are not. If you have regen enabled you are putting energy back in the battery when go pedal is released.
When going down hill with the go pedal depressed you aren't taking energy out at least not much until what ever limit is in the controller is reached at which time you are putting energy back in.
If you want to know what is happening, put a digital voltmeter on your dash where you can see it while driving or hook a hand held unit to the battery pack with alligator clips and watch it while driving around. The dash unit will be a good diagnostic tool later on as your batteries age.

[sgremp]

Yeah makes sense…I’m not really worried about wearing down brakes, I think they will last a good while anyway, it seems like the regen slowing me downhill is offset by the usage when the throttle is needed to get it back to speed…maybe even more usage, so I’m going to play around with coasting and riding the brakes, at least somewhat I’ll still keep a small regen % set but not let it slow me down. With the navitas OTF I can actually dial it in just right to maintain my speed, no slower or faster, with no brake or throttle, but who wants to have to fidget with the dial every time you come to a hill and by the time you get it just right the hill is almost over anyway. I’ll do a little testing, the app for navitas does have the voltage use too so I’ll use that tel give me a read on voltage, I do have a dash one as well but not sure if it even works…the place I got it from told me not to use the battery meter on it because it’s not even hooked up it just bases the % remaining on how long I’ve been driving, so I’m under some assumption the voltage might be the same way…it does go up and down depending on how I drive but don’t know if that’s trustworthy or not.

[DM3]

Originally Posted by kernal

I think its a wash. I haven't seen any data that says regen braking on golf carts adds any measurable range per charge in actual use. I believe it is advertised to be more efficient but its real use is to limit speed---hence liability.
Set it so it drives like you like it.
If you want delve into this further check out the electric (EV) auto forums. Its the same thing only fancier.

Edit: Also, Navitas removes the speed restrictions of the factory controller so how it drives will be different.

I PM’d you Kernel but not sure you saw it yet. Hoping you’ll take a look at my question. Thanks in advance!