Charging battery to full on regular basis or allow it to go down to 5 percent before topping up

Rolfe said:

So, if you have a Trophy, and you've finished charging to 80%, you can't start charging again from the app for just long enough to heat the cabin?

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You can, but it’s really glitchy for me with my Ohme charger and the MG iSmart app. I’ve given up doing it that way, instead head outside and unplug the charger. Then I can preheat/cool. Why is it this way? No one knows and MG, to date, don’t feel we need to know

Rolfe said:

So, if you have a Trophy, and you've finished charging to 80%, you can't start charging again from the app for just long enough to heat the cabin?

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Yes you can, works for me, although we don't need the preheat much in this neck of the woods as it is rarely cold or below 0C.

Although in the summer months you may want the pre-cool.

siteguru said:

Although in the summer months you may want the pre-cool.

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Well, all windows open is pretty good for that, but yes fair point. Fortunately because there isn't a glass roof or sunroof it doesn't seem to get too hot except for the steering wheel - could do with cooled steering wheel, not just heated!

tsedge said:

Well, all windows open is pretty good for that, but yes fair point. Fortunately because there isn't a glass roof or sunroof it doesn't seem to get too hot except for the steering wheel - could do with cooled steering wheel, not just heated!

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I’d never thought about sending cooling!!!

Just testing it now as I’m charging via solar.

Great stuff

JDMB said:

I’d never thought about sending cooling!!!

Just testing it now as I’m charging via solar.

Great stuff

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From 36 degrees to 16 !!! Awesome.

JDMB said:

From 36 degrees to 16 !!! Awesome.

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I did that yesterday lunchtime while walking the dogs at the local park. Five minutes before we got back to the car I used the app to cool it down to 19 degrees. The dogs and I really appreciated getting into the cool after our walk.

Rolfe said:

So, if you have a Trophy, and you've finished charging to 80%, you can't start charging again from the app for just long enough to heat the cabin?

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I can in our Trophy on a dumb podpoint wall box. Works a treat! However, if the car is at 100% then I can't remotely heat the cabin. It seems to need a bit of spare capacity so that it can charge.

I wonder if you can preheat if the car is equalising ?

The 10k cycles of the LFP compared to 3k cycles of the NMC is a bit of a shocker. I recently bought an SE LR with a view to keeping it till it fell apart. Looks like that was a big mistake and should have gone with the LFP. Shouldn’t long range batteries be sold with this information made known to buyers?

Plodalong said:

The 10k cycles of the LFP compared to 3k cycles of the NMC is a bit of a shocker. I recently bought an SE LR with a view to keeping it till it fell apart. Looks like that was a big mistake and should have gone with the LFP. Shouldn’t long range batteries be sold with this information made known to buyers?

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3k is probably conservative but 3000x200miles=600,000miles

Thanks JPK, panic over.

jpk said:

3k is probably conservative but 3000x200miles=600,000miles

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Or put another way. 10,000 miles per year = 60 years
That'll see me out as I only do 5000 miles per year

Plodalong said:

Thanks JPK, panic over.

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From what I've read on a few forums I believe partial charging doesn't equate to a full cycle but I'm really not sure about that. In my opinion of a worse case scenario, which I always like to work to as you're only ever in for good news if you do;

To get 200,000 miles from the car you only need 66.67 miles per charge cycle

Based on 3m/kWh you only need to use 22.22kW to get that which is 36% of the LR battery capacity so you could run your battery to a very safe 44% left and then charge to 80% to get that total mileage with 3k cycles.

Some realistic changes like charging from 40%-80% each time changes it to 24.46kW used=73.68miles per cycle=221.040 total miles from 3k cycles.

If you're a frugal driver and get high miles per kW and are happy to run to lower battery % before charging then your total mileage is gonna be astronomical!

jpk said:

From what I've read on a few forums I believe partial charging doesn't equate to a full cycle but I'm really not sure about that.

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A partial cycle doesn't degrade the cells like a full cycle no. With LFP for instance, cycling in the middle 50 % will double the lifespan, not sure if that's applicable to all chemistries but it would possibly be in that ball park.
With my SE SR, I tend to go for a middle ground and keep it between 10 ish and 90 % unless I'm setting out on a longer journey soon after, and then I'll let it hit 100. Also only gets 20 amps so never comes close to cell overheat.

We spend a chunk of money on cars, just use them, that's what they're there for. Far more important issues in life IMO.

dido said:

Hi,
I am new to the EV driving and charging.
Will be collecting my MG4 Long Range next week. I got a home charger fitted and waiting for the car.
I have a rather long commute to work about 120 mile both ways, on average 3m per kWh I expect about 40 kWh consumption each day.
Should I plug in the car on arrival to top up or should I regularly allow it to drain before topping up.
What's recommend for battery life etc.

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Hello
You're going to have to charge again again at some point cos you won't get get home in the middle of winter. I wouldn't worry about charging to 100% as some have already said. I have a 9 year old ev (van) which I use every day, I don't go far in it but I think when it was new it only had an 80 mile range? It still has about 60 mile range in the summer and about 40 to 45 in mid winter. Battery health is at 77%.
Batteries are so much better now so in 10 years time? Who knows?
I may only need fifty mile range in another 10 years for a little sunday drive when they let me out of the home!
I wonder..... when these start to come on the used market in say 5 years time, a question we should be asking is, what was your charging regime?

When a battery is said to last 3000 cycles what they really mean is 3000 Equivalent Full Cycles (EFC) with 1 EFC being 100% to 0% SOC. Partial cycles do not count as full cycles. For example; if you charge and discharge only 10% then it counts as 0.1 EFC.

It gets more complicated as the number of EFCs that a battery can perform usually depends on how it is cycled. The average state of charge and depth of discharge can all change how many cycles the battery will last for. Usually, the smaller the depth of discharge, and the closer the range is to 50% average SOC, the better:





The way to understand this is to think about what happens to the electrodes when a battery is charged and discharged. As it is being charged the lithium ions move from the cathode to the anode and intercalate (absorb) into it, this causes it to swell. When discharged they are released and move to the cathode causing the anode to contract and the cathode to swell. This repeated expansion and contraction can cause the electrode material to crack resulting in capacity loss. By keeping them half full and minimising the amount of expansion and contraction the capacity loss will be reduced.

The above is why regen has almost no damaging effects as it is charging and discharging such a small amount.

However, the above data is from 2014 and recently there has been a move from polycrystalline to single crystal electrode materials which have much greater structural stability resulting in much less of this type of degradation. CATL mention they are using “single crystal particles” on their website so hopefully it is a non-issue with our batteries.

So, when the car is in regen, is that considered as a cycle? Being a bit cheeky, but its similar to the battery getting lots of little charges. Which should mean using a zappy on solar alone on partially cloudy days shouldn't affect the battery?

Robf said:

So, when the car is in regen, is that considered as a cycle? Being a bit cheeky, but its similar to the battery getting lots of little charges. Which should mean using a zappy on solar alone on partially cloudy days shouldn't affect the battery?

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I imagine it's of no consequence as its such a small amount of recharge?

Plodalong said:

The 10k cycles of the LFP compared to 3k cycles of the NMC is a bit of a shocker. I recently bought an SE LR with a view to keeping it till it fell apart. Looks like that was a big mistake and should have gone with the LFP. Shouldn’t long range batteries be sold with this information made known to buyers?

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Stop panicking. Your battery will still last longer than the car. (It merely appears that the LFP batteries will last longer than the heat-death of the universe.)

Robf said:

So, when the car is in regen, is that considered as a cycle?

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It would be considered 0.001% of a cycle.

Robf said:

Which should mean using a zappy on solar alone on partially cloudy days shouldn't affect the battery?

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Correct. Charging say 50% to 100% is half a cycle. The battery doesn't care if this is done in one go or multiple smaller ones.

I would be concerned about the on board charger switching off and on multiple times though. That could add extra wear to any contactors/relays.