2023+ maximum 12v battery charge rate?

[phevGoBzzzzzz]

Hi,

For the new generation PHEVs, does anyone know how quickly the 12v aux battery charges when the car is in "Ready" mode?

I've added a 7 way trailer plug with the 12v pin connected directly to the aux battery, which I will use to charge a Lifepo4 house battery in the trailer while towing.

I want to know how powerful of an LFP charger I can hook up to that on the trailer side where the car can still keep the aux battery topped up.

Thanks!

 

[PHEV07]

Hi,

For the new generation PHEVs, does anyone know how quickly the 12v aux battery charges when the car is in "Ready" mode?

I've added a 7 way trailer plug with the 12v pin connected directly to the aux battery, which I will use to charge a Lifepo4 house battery in the trailer while towing.

I want to know how powerful of an LFP charger I can hook up to that on the trailer side where the car can still keep the aux battery topped up.

Thanks!

This a photo of the Aux Battery charging in Ready Mode on my 2024 PHEV GT

 

[Johny451]

Hi,

For the new generation PHEVs, does anyone know how quickly the 12v aux battery charges when the car is in "Ready" mode?

I've added a 7 way trailer plug with the 12v pin connected directly to the aux battery, which I will use to charge a Lifepo4 house battery in the trailer while towing.

I want to know how powerful of an LFP charger I can hook up to that on the trailer side where the car can still keep the aux battery topped up.

Thanks!

I think your limitation will be the pins and wiring to the trailer socket & plug. I wouldn't exceed 10 Amps.

 

[MiPHEV]

The fusible link from the dc-dc converter is 176A, so it's roughly a 2kw converter. Usually a 30 amp self resetting circuit breaker is used on the 12v aux pin on a 7 way RV style trailer connector, that's what I used on mine. Normally I only use 80% of a circuit maximum for long duration loads like battery charging, so a 20 amp lithium charger is all I'd probably use, especially if you have anything else on the aux circuit - mine also trickle charges the little 12v gel cell for the trailer breakaway emergency brake, too, for example.

 

[Woon Chung]

The fusible link from the dc-dc converter is 176A, so it's roughly a 2kw converter. Usually a 30 amp self resetting circuit breaker is used on the 12v aux pin on a 7 way RV style trailer connector, that's what I used on mine. Normally I only use 80% of a circuit maximum for long duration loads like battery charging, so a 20 amp lithium charger is all I'd probably use, especially if you have anything else on the aux circuit - mine also trickle charges the little 12v gel cell for the trailer breakaway emergency brake, too, for example.

So, 176A max from DC-DC converter to 12V system including Aux battery. 176A x 12VDS = 2,112 W. Among 2,112 w, 30A x 12V=360 watts allowed for trailer, if we use 30A braker. Connecting 20 amp charger will consume 20Amp x 12VDC = 240 Watts.

Some guy attached 2500 watts inverter successfully. 2500 w / 120 VAC= 21 Amp. So, 20 Amp device is within the safe limit, by above example uses.

Good luck to you