Advice on range please

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Gwynfor Hughes

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I have just completed my first journey of any distance since purchasing the car just over a year ago.
Journey 1 - Swansea to Bristol Airport. Range on departure showed 198 miles.
Actual distance 95 miles. Range remaing on arrival - 40 miles.
I travelled at a speed of 50 MPH for much of the journey and at times no more than 60.

Journey 2 Holiday Inn,Coldra, Newport to Swansea.
Range on departure 107 miles.
Total distance 59 miles.
Remaining range just 9 miles.
I drove at no more than 50 MPH but as I was worried about the range much of the journey was done at only 40 MPH.
Feedback on these figures would be much appreciated as I suspect there could be an issue with the battery as my previous thread shows.
 
Power you put into a battery has to go somewhere. If the battery is discharging internally then that's really bad. If the car is left unused have you noticed a drop in battery SOC? If the SOC isn't falling when it's left standing then I would assume that your car is using the power inefficiently a binding brake for example.
 
First thing you need to do is establish some facts. When fully charged and balanced look to see what voltage you have. Buttons on the right hand side of the steering wheel three clicks down from the speedo. Should be either 449 or 455 depending on which BMS you have installed.
Whenever setting out on a journey always reset the accumulated trip this will give you the proper starting range.
 
Glad to see you got back ok. Out of interest where did you charge after Bristol Airport?

The GOM is just a guess. Realistically you should get at least 130 miles when keeping to no more 65 on the motorway. When you fully charge to 100% what voltage does the battery reach 449 or 456v?
just seen someone else has asked this question - sorry.
 

Gomev said:
First thing you need to do is establish some facts. When fully charged and balanced look to see what voltage you have. Buttons on the right hand side of the steering wheel three clicks down from the speedo. Should be either 449 or 455 depending on which BMS you have installed.
Whenever setting out on a journey always reset the accumulated trip this will give you the proper starting range.
Click to expand...

My charge and balance voltage is 447 to 450 depending on the temperature at the time of charge
 
Battery Management System (or Software).

Basically the software and hardware that's in charge of charging and discharging your battery. The original cars had a BMS that allowed charging to around 455V. MG released a software update around a year ago that had a glitch that caused the BMS to lose full control over how balanced the individual cells in the battery pack would be. The cells are all slightly different voltages, and the BMS tries to keep those differences minimised, because a pack will only charge until its highest voltage cell reaches cut off, and will only discharge until its lowest voltage cell reaches cut off. The more out of whack these are, the less range you get. MG released a software update that fixed the issue, and lowers the max V to 449.

If your max voltage after a charge is 441V, I'd suggest getting in touch with your dealer sooner rather than later. It's fully reversible, but needs an update and many charge/balance cycles to rectify.
 
I'm just wondering. Has your car been to the dealer for any updates towards the start of this year? Since you're saying the car is just over a year old, the bad BMS didn't really come to light until around the New Year.
 
Thank you so much for your reply.
My car had been in with the dealer for nearly a month balancing the battery after being towed in. Had it back a few weeks ago.
When I charged it this time I did it on a granny charger as some threads suggested this is good practice
 
I've reread your original post on the battery issue you had.

Running the battery totally flat (or more correctly, to the cut off point. The BMS should never allow the battery to get totally flat) shouldn't be a disaster unless it was happening every day, or if it was run flat and then left for months. Doubt you've done either of those things.

From some of the posts on that thread, I'm not sure the techs in the garage were too sure of their info. In any case, they're who you've got to deal with, so I'd be heading back to tell them the fault hasn't gone away.

I'm wondering if there are any other members nearby with access to an obd reader. Then we could get the BMS data off the car and have a look at what's going on. Or have a quick search through here for "obd reader" and there should be a few threads with options from the usual internet sites. They're not hugely expensive, around the £10 mark I think. Then you can link to your phone and get some in depth (but not overly techy) data.
 
Gwynfor Hughes said:
My car had been in with the dealer for nearly a month balancing the battery after being towed in. Had it back a few weeks ago.
Click to expand...
your dealer should be able to confirm if they upgraded the BMS firmware.

i'm guesing they already updated your BMS and you need several weeks of balancing to get the voltage upto 449.
if you at 441 will be another 15, or so, balance charges.
 
40-50mph on the M4 is a worry, unless it's in rush hour of course, then you're lucky to hit those speeds. I hope you get to the bottom of your battery concerns :)
 
Thank you macd for going to that trouble and to others who have contributed to this thread.
The support you guys give is amazing.
I have contacted the dealer and waiting for them to get back to me
Thanks again
 
By balancing do you mean charging the car using a granny charger?
If that is the case maybe its best to use this method every time I charge the car to get the figure up?
Alternative of course is for the car to go back into the dealer probably for weeks again.
 
Gwynfor Hughes said:
By balancing do you mean charging the car using a granny charger?
If that is the case maybe its best to use this method every time I charge the car to get the figure up?
Alternative of course is for the car to go back into the dealer probably for weeks again.
Click to expand...
Charging using any AC ie not Rapid, charger is fine, Granny, home or destination chargers will all balance the cells. Each balance may take some hours so just leave on , and use it a bit the next day.
 
Thank you.
So my home charger is sufficient.
Normally I put the car on charge when range is down to 50.
My daily trips are normally around town 20 miles or so. Therefore I charge about once a week.
Would you recommend more frequent charging in order to undertake the balancing and hopefully rectify the problem?
 
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