Have had my 2018 Clarity for about three weeks. I just installed a L2 charger and noticed what sounds like a fan under my hood turning off/on while charging. I haven't heard this using the 110 charger. Is it normal? I'm guessing it's a cooling system but can't seem to find any information about it.
I’ve had the car since July 2018, only charge on 110. The fan seems to run when you are charging and the weather is hotter.
Completely normal. It’s keeping the battery and electronics cool. You may also hear some gurgling sounds from underneath the car toward the back. There are 3 liquid cooling loops in the car and the fans and pumps can and will come on whenever needed independently of whether the car is on or off. In a sense, the car is never completely off unless you disconnect the 12 v battery or pull a main fuse.
Since we're heading into that time of year when my garage temps start to get above 85-90F, I have 2 shop fans that are on a time schedule to start up when I charge my Clarity. I figure the extra airflow created by the shop fans will help the cooling system for the Clarity's batteries.
It's not the "L2" part that adds heat. An L2 charger at 16 amps won't produce much more heat than the OEM L1 12 amp charger. Nitpick, I know, since most people don't bother with L2 without maxing out the current.
It is the L2 that adds the heat. L2 at 16A puts 3840 watts of power into the car whereas L1 at 12A puts in only 1440. That’s about 2.7 times the power and will heat things up much faster.
Heat is not purely a function of wattage. https://physics.stackexchange.com/questions/92502/why-do-high-current-conductors-heat-up-a-lot-more-than-high-voltage-conductors
The reaction in the batteries during charge produces heat. Faster charge causes faster generation of heat that will peak higher but for a shorter time. The total amount of heat generated may not be much different. The fan speed increases as certain thresholds are reached.
I schedule my charging to start at 1:00 AM when the garague is cool. Still there is plenty of time to charge the battery with a L2 16A charger before morning. I also get lower electricity rates between 11:00 PM and 7:00 AM.
I just noticed that fan noise coming from the front of the car when plugged into L1 charger last night. It was 90 degrees at night and hotter in the garage..... Glad to see the batteries are protected by the car's smart cooling system!
