2017~2024 CX-5 Bypass Voltage Regulator?

[floridaplur]

2018 CX-5 2.5L Non-Turbo
Has anyone tried bypassing the voltage regulator to charge at a constant 14.4V? Some cars it is as easy as unplugging the plug from the alternator...I'd like to try this myself, but I'm hesitating because I'm currently running a headway lithium bank in the back instead of a standard AGM battery and it can not take a charge over 14.8V without possibly becoming a back seat bomb lol. Pretty sure our max charge voltage is 14.4V but not sure if it COULD be higher with the plug unplugged...

 

[HyFlyer]

@floridaplur Just curious as to why you think the system isn't doing a good job? Are you using a meter or obdii scan tool to measure alternator output? Is something undesirable happening with you're charging system currently?

I'm just trying to understand what you're looking to accomplish.

 

[floridaplur]

Doing a big audio build, and running on lithium. A locked 14.4-14.8 charging voltage is preferred with the chemistry of lithium I’m running in place of standard car battery.

 

[HyFlyer]

@floridaplur copy that.

I use FORscan and show a pretty consistent 14.5 volts output from my alternator. It fluctuates some but not much and not for long.

I'm not understanding how disabling the voltage regulator is going to be a benefit? The load required from the alternator is constantly changing isn't it? Why would you "unplug" the part that's keeping the voltage steady?

 

[floridaplur]

@floridaplur copy that.

I use FORscan and show a pretty consistent 14.5 volts output from my alternator. It fluctuates some but not much and not for long.

I'm not understanding how disabling the voltage regulator is going to be a benefit? The load required from the alternator is constantly changing isn't it? Why would you "unplug" the part that's keeping the voltage steady?

View attachment 309544

Under load, my alternator is typically only charging to 13.6V, the amplifier I’m using creates best power over 14V. I’m currently dipping to 12.9V at heavy load, and our PCM controlled voltage regulator isn’t detecting that load and telling the alternator to produce full power. Most cars I’d be able to slap on a high output alternator and call it a day; but these cars have a lin bus that’s hard coded to the ECU and can’t be bypassed making it impossible. If I can’t provide more amperage with a HO alternator, my systems would benefit from a max continuous charge voltage. I know this will decrease alternator life, if I can go a year per alternator I’ll wind up spending the same as I would buying one HO Alt over the life of owning this vehicle. Removing the lead batteries and switching over to LIFEpo4 has been a major improvement on its ability to hold and recover voltage, but I’d love to see that recovery going into the 14s instead of mid 13s.

 

[HyFlyer]

Huh, how bout that. I wonder what's different on your system. I scrolled through a recorded run and found a spot where my alternator was putting out as high as 156 amps. The voltage dropped to 13.88 as the power was ramping up but then settled back in and held at 14.62 volts.

 

[floridaplur]

What year and model? My alternator is only 100A and supposed to be max 14.4, though I’ve never personally seen it higher than 14.1

 

[floridaplur]

Huh, how bout that. I wonder what's different on your system. I scrolled through a recorded run and found a spot where my alternator was putting out as high as 156 amps. The voltage dropped to 13.88 as the power was ramping up but then settled back in and held at 14.62 volts.

View attachment 309546

I like this app over torque! What Bluetooth scanner are you using, mine wouldn’t connect to FORScan

 

[HyFlyer]

I like this app over torque! What Bluetooth scanner are you using, mine wouldn’t connect to FORScan

Just downloaded it off Google play store ...

View attachment 303017
FORScan Lite for Android
v1.5.11
Kernel v2.3.41

The Bluetooth plug-in obdii port link is one of the recommended units from ForScan website ...

https://www.amazon.com/dp/ (commissions earned)

I also purchased the vLinker USB cable to run it from a Windows based laptop in the future (but you can break stuff with that!)

 

[HyFlyer]

What year and model? My alternator is only 100A and supposed to be max 14.4, though I’ve never personally seen it higher than 14.1

Depicted is my (North American) 2019 Signature with the 2.2 diesel.

 

[floridaplur]

Diesel is why, they have much bigger alternators from factory if I recall correctly.

 

[HyFlyer]

Diesel is why, they have much bigger alternators from factory if I recall correctly.

Hmmmm, I wonder if we just accidently stumbled on a higher output alternator that would still make your pcm happy?

 

[floridaplur]

Hmmmm, I wonder if we just accidently stumbled on a higher output alternator that would still make your pcm happy?

Nope; it’s been tried. The lin bus detects for anything over 100A. Tried having a factory alternator spun up to 140 just to see if it would work, and it sent me into limp mode.

 

[cz5gt]

unfortunately my past research shows the same results. The new CX5 has a smart charging system controlled by the PCM.
On Fords where they have similar smart charging system one can disable it through the obd but I havent heard or found a way to do this in the Cx5

 

[floridaplur]

unfortunately my past research shows the same results. The new CX5 has a smart charging system controlled by the PCM.
On Fords where they have similar smart charging system one can disable it through the obd but I havent heard or found a way to do this in the Cx5

Yup. I’ve been chasing this skeleton for months in months. It’s basically a dead end as far as getting anything over stock alternator to work. But, I have hope there may be a way to fake a load that the alternator sees and runs full tilt all the time. If we were able to simulate a load somehow the PCM wouldn’t be able to tell if it was not created naturally.

 

[cz5gt]

biggest loads I have seen is when the Ac is on and also the heated mirror/rear glass + heated seats. That for Ampers from the alternator.
For higher voltage only the ambient temp seems to play a role. if its colder (i think pcm goes by the ambient temp sensor in the front of the car) voltage charge that the pcm controller gives is higher.

 

[theblooms]

Depicted is my (North American) 2019 Signature with the 2.2 diesel.

You can get a Diesel in North America? Must be a Canadian thing?

 

[cz5gt]

Mazda sold it for short period in US.

 

[theblooms]

Wow, never heard of that before. That's pretty cool. Must be SUPER rare though.

 

[floridaplur]

Wow, never heard of that before. That's pretty cool. Must be SUPER rare though.

I imagine sourcing parts wouldn’t be near as easy.