Battery sizing

[Bam Bam]

Hi Everyone,

Just thinking about battery sizing this morning and wondering if MG got this right earlier than other manufacturers.

The new BYD (Atto 2) has got the same battery size options as the MG4 and MGS5: 51kWh and 64kWh.

The Dolphin was offered with 45kWh and 61kWh and the Atto 3 with 61kWh only.

Is this because BYD know that MG are the rival and they have to match them?

Or is it because MG judged the ideal battery size options (standard and long range) correctly from the start?

What do we think?

 

[5teep]

More likely it's bulk pricing being lower, I expect MG can get a much lower price on 64kwh batteries if they fit them in everything.

 

[tsedge]

I think it is mainly just that the market is converging on common sizes. This could change if efficiencies increase significantly.

Less than 40kWh really just gives you an Urban vehicle, range becomes a problem for long journeys, either stopping more often than you need or feeling range anxiety before you stop.

More than 60kWh gives you more range than you really need, so you typically are stopping before you need to or never really getting it below 20-30% SOC, which is great for not feeling range anxiety but isn't really making the best use of the battery.

Of course, if you have a very inefficient vehicle, you'll need a bigger battery than this or if you want to make maximum range a specific virtue (and which some people need).

With improved efficiency over the next few years these sizes could shrink 20-30% and still give the same performance.

 

[Bam Bam]

More likely it's bulk pricing being lower, I expect MG can get a much lower price on 64kwh batteries if they fit them in everything.

Do you mean they just have set sizes that fit in the chassis mounting and so duplicate this?

BYD could have done this and copied the battery from the 3 into the 2, but they gave the long range more battery.

But then perhaps BYD are using the same physical pack size but they found a way to squeeze in a few more kWh. Or it is exactly the same and they have just reduced the buffer to free up a few extra kWh.

We might find out more as more info comes out about the Atto 2 battery pack.

Update
Actually I just looked at EV database and it seems that the battery sizes mentioned in a review were for the gross battery size, not the usable.

Usable is 45kWh and 58kWh respectively, so more like the Dolphin.

Anyway, it is an interesting thing to note for manufacturers and consumers what kind of battery you need.

TSedge explains pretty well.

40kWh will work for many people, particularly if it is a second car or if everyone you know is pretty local and you don't use it for driving holidays.

 

[Rolfe]

40kWh will work for many people, particularly if it is a second car or if everyone you know is pretty local and you don't use it for driving holidays.

That's what I thought about the 51 kwh MG4 when I bought it. But then I discovered I liked driving it so much that I started having driving holidays. And it still works, although sometimes I do have to stop more often and for longer than if I'd bought the LR.

 

[Everest]

Also there are diminishing returns with larger batteries (e.g. 70kWh+) due to weight, then needing more power to achieve same performance etc.

With improved efficiency over the next few years these sizes could shrink 20-30% and still give the same performance.

I'd be surprised if efficiencies will increase as much as 20-30% over the next few years (depending on your take on "few", that is).

But, I suspect that with more chargers becoming deployed and faster charging rates being achieved, probably with more vehicles going to an 800V architecture, then the range will become less of an issue because it becomes much quicker to charge them up.

 

[tsedge]

I'd be surprised if efficiencies will increase as much as 20-30% over the next few years (depending on your take on "few", that is).

With focus on the whole car, it is entirely possible. Others have made very impressive improvements (eg. Tesla, Lucid).

But, I suspect that with more chargers becoming deployed and faster charging rates being achieved, probably with more vehicles going to an 800V architecture, then the range will become less of an issue because it becomes much quicker to charge them up.

Yes. It remains to be seen where it settles though. Still a lot of people who can't charge at home who may be willing to pay for ICE-like range.

 

[Nicko]

Don't forget BYD use LFP batteries for all their sizes and MG use LFP for their standard range so not a fair comparison if you are looking at the WLTP.

 

[5teep]

Do you mean they just have set sizes that fit in the chassis mounting and so duplicate this?

BYD could have done this and copied the battery from the 3 into the 2, but they gave the long range more battery.

Well not exactly, I meant that if MG fit the same battery across the range they can buy them cheaper, they can use the same mountings, software battery management and other components etc etc. This keeps their profits high, makes it easier to deal with problems.

 

[Anon70]

If you work on an efficiency of 3 miles/kWh then every 30kW of usable battery should give 100 miles of range. For the XPower with 61.7kWh of usable battery this is about right as my GOM range varies between 180 and 220 miles at 100% charge (and the wife's Mini electric with around 30kWh capacity gives around 100 miles range).

If you work backwards from the WLTP range and usable battery you can work out what the efficiency needs to be to achieve the WLTP range.

When Hyundai/Kia first released the Ioniq 5 and EV6 the platform had more cell capacity than was used. For the 2nd generation models in these ranges they added extra cells in the same battery housing to add range (probably once they had seen some real World stats from owners).

 

[Gomev]

There are certainly efficiencies to be had and the variation between manufacturers can be quite stark. Taking the Tesla M3 LR and MG IM5 LR for example
MG IM5 LR has a 96.5kWh battery and WLTP of 441 miles and EV Database real world estimate of 355.
Tesla Model 3 LR has a 78kWH battery, WLTP 398 and EV database 340.

Ignoring all other aspects, maybe even WLTP, even thought they are similar, such as 0-62 times, the Tesla is more efficient.

 

[5teep]

Another possible sign of standardisation, I just saw a video review of the new BYD Atto 2, it comes in 2 flavours with either a 51.1kwh (214m) or a 64.8kwh (267m) battery and it's priced pretty much alongside the MGS5.