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Re: MAC GMAC Hot Rod Info

Posted: Jan 08 2021 7:17pm
by Bullfrog
Neppie...I did not know that, thanks. I knew I liked you for some reason :lol:.

The GMAC is a great motor and Justin has made some good improvements but it is not available in a front/100mm and I asked if Grin Tech could get me a front MAC but unfortunately they declined.

Grin Tech is a little pricey but you get what you pay for IMO...plus their customer service is great and they provide the forum we are communicating on and Justin has always been super helpful to me and the entire ebike community...he has produced some really good youtube videos lately that explain the intricacies of electric motors and IMO they should be mandatory viewing for anyone interested in ebikes. This is one good example for EVERYONE: https://www.youtube.com/watch?v=c96n0Ma2rLY&t=4858s

I don't doubt Grin sells good batteries but I still buy my batteries from Paul (you did good with the name :D )...everything else I get from Grin Tech for the most part and why I'll probably go with the Shengyi motor. With a kick bike, I don't need the torque a MAC or an eZee can produce and I am going as light as reasonably possible with the Kick Bike.

Re: MAC GMAC Hot Rod Info

Posted: Jan 08 2021 8:02pm
by neptronix
Grin can be pricey but it's a good place to go when you want quality stuff that's hand picked by a guy with a discerning eye and you don't want to spend days of research.

I like doing my own research and try to spot unknown killer products, but Justin is really competing with me on that these days and often has something in stock and ready to sell before i've even heard of it :thumb:

On a kick bike like yours, the center of gravity is really poor, so i wouldn't go with super high power anyway!

Re: MAC GMAC Hot Rod Info

Posted: Jan 09 2021 8:26am
by Jil
Thanks a lot for your answers everybody :)
I've tried the motor simulator, it appear that either with 52V or 72V battery, I can run a bit higher than 50 kph continuously without overtheating (flat land, no wind). But from my experience the 52V battery voltage goes quickly donw below 50 V, thus limiting a bit the max speed. And the amperage is also higher with the 52V, leading to a faster heating of the Phaserunner.
I am aware of the limitations of this setup for my use, I will try first a 72V bigger battery, to see the impact.

Re: MAC GMAC Hot Rod Info

Posted: Jan 12 2021 7:20am
by Bullfrog
Jil wrote:
Jan 09 2021 8:26am
Thanks a lot for your answers everybody :)
I've tried the motor simulator, it appear that either with 52V or 72V battery, I can run a bit higher than 50 kph continuously without overtheating (flat land, no wind). But from my experience the 52V battery voltage goes quickly donw below 50 V, thus limiting a bit the max speed. And the amperage is also higher with the 52V, leading to a faster heating of the Phaserunner.
I am aware of the limitations of this setup for my use, I will try first a 72V bigger battery, to see the impact.
Jil...I sent Grin Tech an email because I wasn't sure going to 72v will help your Phaserunner...below is a quote from their response.

"at the same speed, the system would need the same amount of phase current and it's independent of the battery voltages. Therefore the Phaserunner would be as hot with a 72V battery as a 52V battery."

Your battery amperage/current will be lower but the phase current will be the same. Your controller is basically a DC to DC converter and takes the input from the battery and drops the voltage and increases the amperage.

Sorry to be the bearer of bad news but hopefully I saved you some money and frustration.

Re: MAC GMAC Hot Rod Info

Posted: Jan 12 2021 12:14pm
by neptronix
The phaserunner's maximum continuous power handling is close to a 9FET controller even though it only has 6FETs, due to it's optimal design.

Not really ideal for a hot rod bike.

Re: MAC GMAC Hot Rod Info

Posted: Jan 12 2021 2:39pm
by Bullfrog
Jil...I know the Phaserunner is nice and small but if you want to go faster or accelerate quicker, Neptronix has an excellent point.

I like a 12 or 18 FET Infineon Controller for a MAC. I use a 12 FET with 3077 FETs which is more efficient than the 4110 FETs but the 3077 can't handle more than about 60v so if you think you ever might go to a 72v battery, I'd go with 4110 FETs. With the 8T MAC you may want to go with something that can provide a good bit of phase amperage like the 18 FET.

Only problem is finding one...since EM3ev stopped selling motors/controllers, I have not found a good place to buy them except directly from MAC and you can only do that once before they require you to buy a minimum of 8 pieces so use your one time "sample" buy carefully :D .

Re: MAC GMAC Hot Rod Info

Posted: Jan 12 2021 6:08pm
by pwd
Bullfrog wrote:
Jan 12 2021 2:39pm
Jil...I know the Phaserunner is nice and small but if you want to go faster or accelerate quicker, Neptronix has an excellent point.

I like a 12 or 18 FET Infineon Controller for a MAC. I use a 12 FET with 3077 FETs which is more efficient than the 4110 FETs but the 3077 can't handle more than about 60v so if you think you ever might go to a 72v battery, I'd go with 4110 FETs. With the 8T MAC you may want to go with something that can provide a good bit of phase amperage like the 18 FET.

Only problem is finding one...since EM3ev stopped selling motors/controllers, I have not found a good place to buy them except directly from MAC and you can only do that once before they require you to buy a minimum of 8 pieces so use your one time "sample" buy carefully :D .
FYI, I purchased the 6fet "500W" one from here: https://www.aliexpress.com/store/group/ ... 014174.1_0 and it is an Infineon 4 clone (KH6XX) and work very well. By the looks of them, their larger controllers appear to be Infineon 4 clones too.

Re: MAC GMAC Hot Rod Info

Posted: Jan 14 2021 11:28am
by Jil
Bullfrog wrote:
Jan 12 2021 7:20am
Jil...I sent Grin Tech an email because I wasn't sure going to 72v will help your Phaserunner...below is a quote from their response.

"at the same speed, the system would need the same amount of phase current and it's independent of the battery voltages. Therefore the Phaserunner would be as hot with a 72V battery as a 52V battery."
Bullfrog, many thanks ! I really appreciate your help, you saved me time and money :thumb:
It's bad news indeed, so I understand I should work more on the cooling of the Phaserunner... or use it more wisely :wink:

Re: MAC GMAC Hot Rod Info

Posted: Jan 14 2021 11:58am
by Bullfrog
Jil wrote:
Jan 14 2021 11:28am
Bullfrog wrote:
Jan 12 2021 7:20am
Jil...I sent Grin Tech an email because I wasn't sure going to 72v will help your Phaserunner...below is a quote from their response.

"at the same speed, the system would need the same amount of phase current and it's independent of the battery voltages. Therefore the Phaserunner would be as hot with a 72V battery as a 52V battery."
Bullfrog, many thanks ! I really appreciate your help, you saved me time and money :thumb:
It's bad news indeed, so I understand I should work more on the cooling of the Phaserunner... or use it more wisely :wink:
You are very welcome....mounting it on a finned block of copper would be best (aluminum would be almost as good and cheaper) or maybe a small fan like used to cool the inside of a computer...or both :D .

I mounted my Infineon controller on the front of my head tube to ensure it got a lot of air flow.