Long term charging

[user 3859]

Unsurprisingly, I am not using my car very much, so it is plugged in to my Rolec most of the time.

Is it safe to leave it like that for days at a time, or should I disconnect it when it is charged?

 

[AlexBorro]

Unsurprisingly, I am not using my car very much, so it is plugged in to my Rolec most of the time.

Is it safe to leave it like that for days at a time, or should I disconnect it when it is charged?

The main problem is not the charger itself or any safety risk. But LI-Ion batteries usually don't like to be kept topped for a long time.
So if you do not plan to use the car for some time (I would say more than one week), it is better to let the battery about 3/4 full. This care will increase the battery lifespan.

Cheers.

Alex.

 

[user 3859]

Thanks for that, but I was wondering if the car has built-in overcharge protection. I can't believe that it doesn't.

 

[greendwarf]

As discussed elsewhere recently (in relation to an apparent high consumption once fully charged) the evidence is that in normal use current flow drops to negligble (and that seems so from my smart meter readings) - so it won't overcharge. But why would you leave it connected for days anyway if you are around?

 

[michael8554]

My PHEV has only been used for shopping trips of 2 miles each in the last 3 weeks.

The guessometer has hardly changed in that period.

So no need to keep it plugged in.

 

[AlexBorro]

Thanks for that, but I was wondering if the car has built-in overcharge protection. I can't believe that it doesn't.

For sure it has overcharge protection. But you are confusing the matters. Keeping the battery topped is not overcharging..

Overcharge would be charging more then the "top" limit (usually 4.2V/cell).

But, keeping a Li-Ion battery topped (100% charged) for a long time - and this apply for any Li-Ion, including your cell phone - decreases its lifespan.
So if you just use your car for a few km per day, just charge the battery when it get almost depleted. Your battery will, for sure, lasts longer.

Cheers.

Alex.

 

[michael8554]

Many people contemplating buying an EV wonder what the battery life will be.
That's often based on their experience of battery life in cell phones, laptops, and tablets.
The batteries on these are invariably endlessly run down to zero then charged to 100%.
Or left plugged into the charger.

As Alex says, EVs have battery management that usually signals "empty" when actually still at 5%, and won't rapid charge to more than 80% unless you force it.
That's how you can get a battery life of at least 10 years.

 

[greendwarf]

The problem is also an adjustment to life with an EV as opposed to ICE car. We are used to relying on being able to go to our cars and drive off without worrying too much about fuel - there is always a petrol station on route to top up, if necessary, irrespective of length of journey.

Now we have to try and think ahead more and try and guess when & how long our next journey will be. At least we have the back-up of the petrol engine, so if there is an urgent unexpected need then we can still drive with a flat battery. I imagine pure EV users are much more nervous about letting charge drop to low levels to maintain battery life.

 

[AlexBorro]

At least we have the back-up of the petrol engine, so if there is an urgent unexpected need then we can still drive with a flat battery.

This is the main reason I got an PHEV instead of a pure EV car. For local trips in the city you are able to make only EV.. but if you plan a travel with family, you don't need to worry about finding charging stations. Even here in Europe - which I think there is the majority of charging station in the world - you still have to well plan your journey to find charging station if you have a pure EV car.

About the Li-ion battery, the BMU keeps the voltage within 3.7V and 4.1V which is the best range for the lifespan.

Cheers.

Alex.