Engine fans running when charging.... normal?

[jimspandango]

Hi all,

Just got my new XC40 Plug in yesterday and took it out this morning. Drove 50 miles with a few stops. Came home, turned engine off, unloaded car and plugged in. When I plugged in the engine fans started working quite loudly. Went out 10 minutes later and still on. Is this normal?

Had a Mercedes plugin before this, and never noticed the fans running whilst charging, and had an XC60 plugin for a week and didnt notice then... Any assistance welcome.

cheers

[morganj]

Yup. Seems normal.

Fans run on mine often during charging. Tends to happen less when ambient temp is lower. And also after 1 hour to r more. Sure there is some kind of algorithm at play here.

[jimspandango]

Perfect, thanks for confirming.

[lfpcorreia]

I believe the fans are cooling the battery while it charges in order to prolong its life.

[Skyrimmer]

So the fans are cooling the battery therefore discharging it at the same time you are trying to charge it. Seems an odd set up to me.

[goi]

So the fans are cooling the battery therefore discharging it at the same time you are trying to charge it. Seems an odd set up to me.

The fans are only using a fraction of the energy that is used to charge the battery. If they wouldn‘t cool them the SOC would never reach it‘s maximum.

[Deleted User 2507]

It is a bit loud so you always think something is wrong. There must be some heat generated that is for sure, I managed a cheeky 3-pin charge at work this week and when at home it's already long since charged and cool when I remove the plug, I removed the plug as soon as it hit fully charged. Seriously hot.

My smart meter is noticing the charging still waiting on my switch to Octopus Go for the 5p kwh rate, but managed 60mpg yesterday on an 80 mile drive, so happy days. Even did a Pod-Point carpark charge yesterday and no issues.

[goi]

If you charge your car "slowly" with 4-6-10 A and only up to 80% you probably needn't to cool them down while loading.
But in case you are charging with "high" rates - 16 A 3.7 kW are not that much, even for that small HV battery - or you are charging to a SOC of >80 or your battery was already heated through extensive use immediately before charging it, you need to cool it down.

If Volvo wouldn't cool, it would affect life span of the battery instantaneously or result in "exploding" battery cells - both might be more unwanted than the noise generated by the fans.

[goi]

btw. because I could not found details about the prismatic cell used within the XC40 T4/T5, but LG CHEM and CATL are providing comparable modules for the T4/T5.

I can only calculate backwards from the specs given:

Whilst planned with a 9.7 kWh battery based on the actual technology in 2017 which was a LGX/NCM cell with 135 Wh per cell which gives us 72 cells packed in 18 cells per module and 4 modules per pack - 72 x 0.135 kWh = 9.72 kWh, the new pack has about 10.7 kWh which seems to have a 148,6 Wh cell which gives us 72 x 0.1486 kWh = 10.7 kWh.

Usually in those HV PHEV batteries you have a serial configuration (72s) which gives you a nominal voltage of 3.65 V x 72 = 262,8 V and 2.75 V x 72 = 198 V when discharged and a charging voltage of 4.2V x 72 = 302.4 V.
Based on this specs we have a theoretical capacity rating of 40,7 Ah (= 1C). Based on nominal "standard" loading curent of 0.2C for this battery using CC/CV techniques gives us with an input voltage of 230 V and 10 A an load current of 10A / (302,4 V / 230 V) = 7.6 A ~ 0.2C which is perfectly fine.

This means, when we start loading with 16 A we will produce surplus heat during charging.
And additionally we produce heat by transforming from 230V to 302.4V.

Long story short: Even if we load with 0.2C the integrated converter/inverter needs significant cooling as well. If we exceed the SOC or load faster than with 0.2C we produce additional heat in the cells which needs to be cooled.

To answer the OPs question: Yes it is fully normal that the fans are running when charging.

I hope i could clarify some constraints by the battery technology used within the PHEV.

[lfpcorreia]

btw. because I could not found details about the prismatic cell used within the XC40 T4/T5, but LG CHEM and CATL are providing comparable modules for the T4/T5.

I can only calculate backwards from the specs given:

Whilst planned with a 9.7 kWh battery based on the actual technology in 2017 which was a LGX/NCM cell with 135 Wh per cell which gives us 72 cells packed in 18 cells per module and 4 modules per pack - 72 x 0.135 kWh = 9.72 kWh, the new pack has about 10.7 kWh which seems to have a 148,6 Wh cell which gives us 72 x 0.1486 kWh = 10.7 kWh.

Usually in those HV PHEV batteries you have a serial configuration (72s) which gives you a nominal voltage of 3.65 V x 72 = 262,8 V and 2.75 V x 72 = 198 V when discharged and a charging voltage of 4.2V x 72 = 302.4 V.
Based on this specs we have a theoretical capacity rating of 40,7 Ah (= 1C). Based on nominal "standard" loading curent of 0.2C for this battery using CC/CV techniques gives us with an input voltage of 230 V and 10 A an load current of 10A / (302,4 V / 230 V) = 7.6 A ~ 0.2C which is perfectly fine.

This means, when we start loading with 16 A we will produce surplus heat during charging.
And additionally we produce heat by transforming from 230V to 302.4V.

Long story short: Even if we load with 0.2C the integrated converter/inverter needs significant cooling as well. If we exceed the SOC or load faster than with 0.2C we produce additional heat in the cells which needs to be cooled.

To answer the OPs question: Yes it is fully normal that the fans are running when charging.

I hope i could clarify some constraints by the battery technology used within the PHEV.

You seem very knowledgeable!

As such there's a question I'd like to ask: Should we charge our batteries every day? or should we let them get low/depleted before charging again?

For example, let's say I make 10km every day. Given the 40km estimated range with a full battery charge, should I charge everyday or continue to drive until the battery capacity drops below a certain percentage?

What's better for the battery on the long run?