Which Battery Used For Various Power Points?

[Glenn Freeman]

There are many power points on my 2018 C-MAX. Which ones draw on the hybrid engine battery and which ones draw on the gasoline engine battery?

Why the question? If I'm camping, which outlet(s) should be used overnight to insure the engine starter battery is not drained?

[stolenmoment]

They are all connected to the same power feeds.

 

In your situation, the best bet here is to turn the car on, but (of course) leave it in park.  The motor will come on if the big battery runs low.

[cr08]

To add on to what @stolenmoment noted, I'll elaborate a bit further:

 

For the most part, the overarching functionality isn't much differentiated from an ICE only vehicle in that the power points will pull from the 12v systems and battery. If the vehicle is shut off, the power points will drain the 12v battery which is used to start the vehicle (even if the HVB has charge. The 12v battery is needed to wake up the various modules to start the vehicle.). Once the vehicle is started, the DC-DC converter (which takes the place of a traditional alternator) takes over and draws power from the HVB to keep the 12v battery charged and power the 12v systems in the car. The ICE will start periodically as needed to keep the HVB charged. Sitting parked it'll usually just try to keep it at a minimum charge level so it may run the ICE for a couple minutes every 15-20 minutes or so depending on the electrical or AC/heat loads.

 

If you have an Energi, this period where it starts the ICE while sitting parked will be much longer depending on the charge level. Caveat being that depending on the mileage and associated battery wear, the ICE may start up periodically even if a plug-in charge is available. This is from personal experience and the educated guess is for cell balancing. Driving normally, it is able to charge individual cells during regen and the charge cycle during hybrid operation. Sitting parked, the only option to put a charge into the battery is via plugging in or intentionally starting the ICE.

 

An additional note: The two power points up front (in the center console and behind the gearshift) are switched power. They'll shut off after a certain amount of time after the car is shut off. The rear power point in the cargo area is on full time.

Edited March 21, 2022 by cr08

[nogoodbum]

Another option is to pick up a portable jump start box with USB & 12V power outlets $50-$100. Price is basically dependent on features & battery type, lead [cheapest]  NiCad, lithium [highest] & total output. Beware NiCad batteries can show signs of loss of capacity due to "battery memory". If you use one regularly until battery is down to 10% or so before recharging to 100% you will not have any problems but  if if only used to about 80%, NiCad batteries will sometimes lose capacity. In other words it's "use it or lose it". I've had one for several years now & it has come in handy many times [except when it's there & I'm here]. Thanks for the read.

 

[Glenn Freeman]

Thanks for the tips. I've come to 2 conclusions:

1. Leaving the car on seems ideal, overall, for bad weather days. BUT, is it possible to turn off the daytime running lights or instrument panel lights easily?

 

2. The cargo area 12v outlet NEVER turns off, so turning the engine off and having a portable jump start box just in case, seems the best option for good weather days. To clarify, the portable jump start box would be used to start the C-Max if the battery drains too much by using the 12v cargo area outlet?

Edited April 8, 2022 by Glenn Freeman
additional response

[Bill-N]

FYI, the cargo area hatch can not be opened if the 12v battery is dead; best to stow the jumper battery/cables under the passenger seat.

[SnowStorm]

Also, there are two posts under the hood (on driver side) where you should 'jump-start' the car. I wouldn't try using a 12v outlet.