Ideas for keeping a healthy drive battery

[Kaboom]

Hi All,

I've been wondering about the best way to keep a healthy battery and get the longest life from it.
I found the following on the net and wondered if anyone agreed or disagreed with the following rather generalised statements about Li-ion:

Charge at a moderate temperature - instead of in the hot daytime, charge evenings, mornings or at night when it’s cooler

Keep the battery at 40% to 50% charge because a partial charge is better for the battery than keeping it at full charge all the time.
Charge to full if you need to, but try not to keep the battery at full charge for extended periods.
Switch on the charger so the battery is full shortly before you’re ready to depart.

When driving, try to avoid harsh starts and stops as heavy discharging can shorten battery life
Batteries live longer when kept cool
The Outlander PHEV will automatically prevent over-discharging by bringing on the generator
Before prolonged storage, apply some charge to bring the battery back to about 40% to 50%
Try to avoid fast chargers (especially in hot weather)

Regards,

 

[Grigou]

I agree with all theses points, and add one : do at least one full charge 2 times in a month (as said in the owner's manual).

 

[jaapv]

The charger does switch off when the battery is full. No need to get out of bed to start charging.
For the rest, that is correct.

 

[Grigou]

The charger does switch off when the battery is full. No need to get out of bed to start charging.
For the rest, that is correct.

But "Keep the battery at 40% to 50% charge because a partial charge is better for the battery than keeping it at full charge all the time.
Charge to full if you need to, but try not to keep the battery at full charge for extended periods."

is true (though personnaly I prefer 80-85% instead of 40-50% to have a decent mileage !). If you don't need full charge, it is better to stop charging at 80 %. With a timer of course...

 

[user 258]

Hi,

But yes, try to time the charge to finish as close to driving as possible. This means you charge the batteries when they have cooled down, and drive when they have been warmed upto due to charging. It is also better for the power grid to charge in the early hours.

I would agree with all the points.

Kind regards,
Mark

 

[jaapv]

Bear in mind, though that the car has a cooling system for the batteries.

 

[user 258]

Bear in mind, though that the car has a cooling system for the batteries.

Hi,
My understanding is that under normal charging scenarios the batteries don't need to be cooled. The cooling facility sounds like it is a failsafe to dangerously overheating batteries and perhaps for the rapid charge points.
Kind regards,
Mark

 

[jaapv]

I don't know the exact parameters which govern the cooling. I'm sure Boeing thought the same

 

[user 258]

I don't know the exact parameters which govern the cooling. I'm sure Boeing thought the same

I don't think Boeing had a battery cooling system as such. Just airflow, not active cooling.
kind regards,
Mark

 

[Kaboom]

Hi,

But yes, try to time the charge to finish as close to driving as possible. This means you charge the batteries when they have cooled down, and drive when they have been warmed upto due to charging. It is also better for the power grid to charge in the early hours.

I would agree with all the points.

Kind regards,
Mark

Hi Avensys,
That raises a very valid point.
If Li-ion batteries are stressed when hot - and charging and discharging both them makes them hot - I suggest an amendment to the charging advice thus:

Switch on the charger so the battery is full and has had about an hour to cool down again before you’re ready to depart.

Any good?

Regards

 

[user 258]

Hi,

But yes, try to time the charge to finish as close to driving as possible. This means you charge the batteries when they have cooled down, and drive when they have been warmed upto due to charging. It is also better for the power grid to charge in the early hours.

I would agree with all the points.

Kind regards,
Mark

Hi Avensys,
That raises a very valid point.
If Li-ion batteries are stressed when hot - and charging and discharging both them makes them hot - I suggest an amendment to the charging advice thus:

Switch on the charger so the battery is full and has had about an hour to cool down again before you’re ready to depart.

Any good?

Regards

Not good really.

When you have finished a drive allow the batteries to cool down before charging them.

Try to have the batteries finish charging before you drive so they will still be warm when you start driving. The warm batteries will work better for driving than cold batteries. The batteries should have no chance of being too warm with the normal charge cycle. Plus, it is exceedingly hard to time the finish of the charge just before you drive so your suggestion of allowing the batteries to cool again will defacto happen in practice, although slightly less than ideal.

Kind regards,
Mark

 

[maby]

If the battery is sufficiently fragile that it is necessary to take these steps, then we are all in a lot of trouble and Mitsubishi are going to sink under law suits!

 

[Grigou]

If the battery is sufficiently fragile that it is necessary to take these steps, then we are all in a lot of trouble and Mitsubishi are going to sink under law suits!

If we stay in the subject, it's absolutely not necessary, but useful for keeping a healthy drive battery for, let's say, 10% more life ...

 

[Kim]

When you have finished a drive allow the batteries to cool down before charging them.
Try to have the batteries finish charging before you drive so they will still be warm when you start driving. The warm batteries will work better for driving than cold batteries. The batteries should have no chance of being too warm with the normal charge cycle. Plus, it is exceedingly hard to time the finish of the charge just before you drive so your suggestion of allowing the batteries to cool again will defacto happen in practice, although slightly less than ideal.

Kind regards,
Mark

There's not much to add to this! I would back up every thing written in this quote!

Allow for two additional comments/suggestions:

- the harder you push the car (40-60kW or above) the warmer the batteries will get:
So, for example if you return home after a high speed chase or a tow on the motorway, let it cool down, use the charge timer function to start charging after a rest of let's say two hours
(due to the insolated battery compartment the batteries cannot loose their temp. as fast in a stationary car as in a moving one, when they can be activly cooled)

- forget about waiting after the charge is finished: charging at 3kW (13A) or 3.7kW (16A) doesn't put any stress on a 12kWh battery at all,
as long as the surrounding temperature (and therefor the cell temperature) is below 40° C

 

[gwatpe]

The battery has perceptible lack of uumpf, both in acceleration and REGEN when the ambient temp is above 40C. I just hit the save button, and use the ICE.

Having come from a computer buggy PHEV, I am now with a new one that works. I will add that from my experience with a LithiumIon battery on my home power system, long life will be attained if the battery is only cycled once per day or less. Full cycles are preferable to more mini cycles. It will always be useful to perform a driven, know full discharge and then recharge, monthly, along with the scheduled full charge, preferably from say only 50% of capacity or lower.

It is quite difficult to routinely abide by the rules, and there are enough protection systems built in to not worry too much about the battery. After 20000km now in 7 months, I just tend to drive on the battery locally, and fill it up when it gets under half, and just fully recharge after any longer trips. I am recharging on solar with the timer settings, so sometimes a recharge may be over 2 days. This is an evening and then a morning. I am retired, so any excuse for a late breakfast.

These are early days and once cars get to 3-4 years on the road, we will be much wiser.

 

[jaapv]

The battery has perceptible lack of uumpf, both in acceleration and REGEN when the ambient temp is above 40C. I just hit the save button, and use the ICE.

Having come from a computer buggy PHEV, I am now with a new one that works. I will add that from my experience with a LithiumIon battery on my home power system, long life will be attained if the battery is only cycled once per day or less. Full cycles are preferable to more mini cycles. It will always be useful to perform a driven, know full discharge and then recharge, monthly, along with the scheduled full charge, preferably from say only 50% of capacity or lower.

It is quite difficult to routinely abide by the rules, and there are enough protection systems built in to not worry too much about the battery. After 20000km now in 7 months, I just tend to drive on the battery locally, and fill it up when it gets under half, and just fully recharge after any longer trips. I am recharging on solar with the timer settings, so sometimes a recharge may be over 2 days. This is an evening and then a morning. I am retired, so any excuse for a late breakfast.

These are early days and once cars get to 3-4 years on the road, we will be much wiser.

This runs contrary to the normal advice on Li-Ion batteries. Could you please quote your source?

 

[greendwarf]

Slightly confused by the keep at 50% advice. I understood this came from experience from computer Li-on batteries where users (like me) tend to keep them plugged into the mains most of the time - something you can't do with the PHEV (and use it to travel :lol: )

By definition, the car will be cycling over the full range most of the time, surely.

 

[user 258]

Slightly confused by the keep at 50% advice. I understood this came from experience from computer Li-on batteries where users (like me) tend to keep them plugged into the mains most of the time - something you can't do with the PHEV (and use it to travel :lol: )

By definition, the car will be cycling over the full range most of the time, surely.

Mitsubishi designed it to only use about 64% of the full battery capacity under normal use (full to empty) to ensure the battery lasts the lifetime of the car.

Kind regrads,
Mark

 

[jaapv]

Indeed, so it really makes no difference what charging regime the owner uses. Except for Mitsubishi's warning against frequent ChaDeMo charging.

 

[Grigou]

Just apply the owner's manual recommandations in Chapter 3 and things will be fine.

But apply all of them !

And to be able to apply all of them, you must read all of them