Higher-output alternators or DC power options for CX-5?

[DarkskiesIL]

Hello CX-5 hive mind,
I recently bought a 2025 CX-5, coming from a 2016 Mazda 3 hatch 6-speed manual (a magnificent car).
I'm a meteorologist and want to add ... stuff ... to my CX-5. Said stuff all requires power, more power I expect than I may be able to get off the stock alternator and battery.

Stuff includes radios (e.g. 50W ham rig), fog or specialty lights for driving in rain, cameras, mics, weather equipment, occasional battery charging for chain saw, possible electric winch -- you know ... the usual.

So, I wondered if anyone had experience with high-output 3rd-party alternators that might fit the CX-5. Looking at the engine bay, "fits the CX-5" is probably laughable, but I figured I could ask.
Another possibility or in parallel could be an additional battery and switchgear to trickle charge it and use when needed, but this seems like a hack. That or good practice, I'm not sure.

Any suggestions appreciated!

 

[Moonlighter]

CX5 has a smart alternator, so if adding an extra (LiFePo4 would be my choice) battery, you will need to connect it to the starting battery using a DC/DC charger. Just ensure that the DC/DC charger selected has a lithium charging profile (most do).

The DC/DC charger and second battery would usually be located in the trunk away from the engine as they dont like heat. This is a very standard setup for the RV crowd who want a second or auxiliary battery to run fridges and other ancilliary devices.

In fact I have this exact setup in my 4WD dual cab ute to run my fridge that lives in the back. The beauty of this is that the DC/DC charger starts charging the aux battery only when the engine is running, and a few second after the engine is turned off, it automatically isolates the aux battery from the start battery, which prevents you from flattening the start battery.

Your standard alternator should have easily sufficient power output to tun the uhf radio and fog/driving lights. You can then connect all the other ancilliary gear (and the uhf if you want to) to the aux battery. As noted earlier, when the car engine is on, the DC/DC charger will continue to charge the aux battery while you are using any of that gear.

The beauty of the lithium batteries is that they are half the weight of a normal lead acid battery and have about twice the useable power. Eg a 50ah lithium will do the same job as a 100ah lead acid.

Its then just a matter of deciding how many ah you think you might need, i would guess that 200ah would be ample and run all your gear for many, many hours.

If you need to charge devices that cannot be charged direct from a 12v source you’ll need to add an inverter with suitable capacity to your system to run those devices.

Will Prowse has done many thorough, totally professional and unbiased reviews of the lithium batteries available these days and has a recommended list. He’s on YouTube, google him and you will find his reviews.

 

[Kedis82ZE8]

You might check with this company to see if ‘25 will work. I have seen some discussion that output might get suppressed by vehicle ECU so not sure if that is still an issue.

250A High Output Alternator for 2017 - 2019 Mazda CX-5 2.5L L4 (152c.i.)

250A high output alternator for 2017 - 2019 Mazda CX-5 2.5L L4 (152c.i.). Built for car audio, upgraded electrical performance, and extreme-duty applications.

www.powerbastards.com

If you are looking for a DC-to-DC charger I highly recommend the Etaker units

F1000 Pro Smart Charger for Power Stations & Batteries | 1000W Dual-In

ETAKER

www.etakerpower.com

You can even reverse charge vehicle battery with your solar generator/power station if you have one in vehicle.

 

[DarkskiesIL]

CX5 has a smart alternator, so if adding an extra (LiFePo4 would be my choice) battery, you will need to connect it to the starting battery using a DC/DC charger. Just ensure that the DC/DC charger selected has a lithium charging profile (most do).

The DC/DC charger and second battery would usually be located in the trunk away from the engine as they dont like heat. This is a very standard setup for the RV crowd who want a second or auxiliary battery to run fridges and other ancilliary devices.

In fact I have this exact setup in my 4WD dual cab ute to run my fridge that lives in the back. The beauty of this is that the DC/DC charger starts charging the aux battery only when the engine is running, and a few second after the engine is turned off, it automatically isolates the aux battery from the start battery, which prevents you from flattening the start battery.

Your standard alternator should have easily sufficient power output to tun the uhf radio and fog/driving lights. You can then connect all the other ancilliary gear (and the uhf if you want to) to the aux battery. As noted earlier, when the car engine is on, the DC/DC charger will continue to charge the aux battery while you are using any of that gear.

The beauty of the lithium batteries is that they are half the weight of a normal lead acid battery and have about twice the useable power. Eg a 50ah lithium will do the same job as a 100ah lead acid.

Its then just a matter of deciding how many ah you think you might need, i would guess that 200ah would be ample and run all your gear for many, many hours.

If you need to charge devices that cannot be charged direct from a 12v source you’ll need to add an inverter with suitable capacity to your system to run those devices.

Will Prowse has done many thorough, totally professional and unbiased reviews of the lithium batteries available these days and has a recommended list. He’s on YouTube, google him and you will find his reviews.

Wow, this is super detailed -- thank you Moonlighter!

 

[DarkskiesIL]

CX5 has a smart alternator, so if adding an extra (LiFePo4 would be my choice) battery, you will need to connect it to the starting battery using a DC/DC charger. Just ensure that the DC/DC charger selected has a lithium charging profile (most do).

The DC/DC charger and second battery would usually be located in the trunk away from the engine as they dont like heat. This is a very standard setup for the RV crowd who want a second or auxiliary battery to run fridges and other ancilliary devices.

In fact I have this exact setup in my 4WD dual cab ute to run my fridge that lives in the back. The beauty of this is that the DC/DC charger starts charging the aux battery only when the engine is running, and a few second after the engine is turned off, it automatically isolates the aux battery from the start battery, which prevents you from flattening the start battery.

Your standard alternator should have easily sufficient power output to tun the uhf radio and fog/driving lights. You can then connect all the other ancilliary gear (and the uhf if you want to) to the aux battery. As noted earlier, when the car engine is on, the DC/DC charger will continue to charge the aux battery while you are using any of that gear.

The beauty of the lithium batteries is that they are half the weight of a normal lead acid battery and have about twice the useable power. Eg a 50ah lithium will do the same job as a 100ah lead acid.

Its then just a matter of deciding how many ah you think you might need, i would guess that 200ah would be ample and run all your gear for many, many hours.

If you need to charge devices that cannot be charged direct from a 12v source you’ll need to add an inverter with suitable capacity to your system to run those devices.

Will Prowse has done many thorough, totally professional and unbiased reviews of the lithium batteries available these days and has a recommended list. He’s on YouTube, google him and you will find his reviews.

Hey one other question ... your spare battery is in back. So, DC being DC ... do you have to run like 4 gauge wire between front and back? My "back" might be farther away than your dual cab ute, I dunno. I'm always worried about power loss even though it's not like I'm running 1000W amplifiers or anything.

 

[DarkskiesIL]

You might check with this company to see if ‘25 will work. I have seen some discussion that output might get suppressed by vehicle ECU so not sure if that is still an issue.

250A High Output Alternator for 2017 - 2019 Mazda CX-5 2.5L L4 (152c.i.)

250A high output alternator for 2017 - 2019 Mazda CX-5 2.5L L4 (152c.i.). Built for car audio, upgraded electrical performance, and extreme-duty applications.

www.powerbastards.com

If you are looking for a DC-to-DC charger I highly recommend the Etaker units

F1000 Pro Smart Charger for Power Stations & Batteries | 1000W Dual-In

ETAKER

www.etakerpower.com

You can even reverse charge vehicle battery with your solar generator/power station if you have one in vehicle.

View attachment 343574

Thanks much for the tips and suggestions! I see both positive and negative things online about that company, but we know how online reviews can be. I'll look around a bit and ask a pro car audio shop their thoughts. I may (ref: earlier post by moonlighter) not have to get the alternator - reliability being most important - but the etaker stuff looks nice and something to be aware of.

 

[Moonlighter]

Hey one other question ... your spare battery is in back. So, DC being DC ... do you have to run like 4 gauge wire between front and back? My "back" might be farther away than your dual cab ute, I dunno. I'm always worried about power loss even though it's not like I'm running 1000W amplifiers or anything.

Your CX5 trunk will be far closer than the distance between my starting battery and my aux battery and charger!

But yes, you do need to run appropriately sized wire from start battery to the DC/DC charger. Then suitable gauge to the aux battery and from the aux battery to whatever it is powering. But it will be a short run to those devices.

I would say a 20-30amp DC/DC would do the job.

Renogy have a very good reputation for their DC/Dc chargers and inverters etc. You might also consider getting a DC/DC that incorporates solar mppt inputs. You could then get a portable folding solar panel or blanket to boost the charge when stationary.

To be honest, DC/DC chargers these days are all pretty good. Mine is a “house brand” from a major sports store here in Australia called Anaconda, its worked flawlessly for about 3 years now, and incorporates the solar mppt inputs.

Keeping it simple, one of those battery boxes that include a number of different input and output plugs works well. Mine has a couple of Anderson plugs, a voltage meter, cigarette lighter sockets, usb ports etc. all came pre-wired. Just drop battery in, connect it to the charger. Done.

Photo attached of my setup. The charger is mounted to the left.

 

[Kedis82ZE8]

You can use any of the DC-to-DC chargers as well with some of the all-in-one power stations or standalone LiFePO4 batteries. I use both.. I tend to lean on LiTime for my standalone batteries among several off-grid solar installations totaling around 30,000Wh