DIY battery repair and maintenance

[riogrande75]

It's my first post here - please be merciful to me
I own a B250e built 01/2017 since about 5 years. As even battery warranty runs out in january '25, I wonder if someone ever did some repairings on the main battery.
Sooner or later, all of our batteries get worse and some cells might be dead and as it's a tesla manufactured battery, I guess they are almost similar to model s batteries from 1st generation.
There are forums, where model s users explained that they repaired their batteries themselfs.

I am a electronic expert and build my own (low voltage) batteries for solar energy storage since a could of years. Also microcontrollers, etc. is well know to me.
So far my Benz does great, but I want to be prepared. Also identifying error codes (in the past covered by warranty) would be fine. Right now, it's hard to do any maintenance in such cases from errors like "visit a workshop".
All I know, is to get either "star diagnose" or xentry software and a cheap 20$ connector like "Tractrix Openport 2.0".
Is anybody here experienced with this?

 

[LondonWdd14289ownwr]

It's my first post here - please be merciful to me
I own a B250e built 01/2017 since about 5 years. As even battery warranty runs out in january '25, I wonder if someone ever did some repairings on the main battery.
Sooner or later, all of our batteries get worse and some cells might be dead and as it's a tesla manufactured battery, I guess they are almost similar to model s batteries from 1st generation.
There are forums, where model s users explained that they repaired their batteries themselfs.

I am a electronic expert and build my own (low voltage) batteries for solar energy storage since a could of years. Also microcontrollers, etc. is well know to me.
So far my Benz does great, but I want to be prepared. Also identifying error codes (in the past covered by warranty) would be fine. Right now, it's hard to do any maintenance in such cases from errors like "visit a workshop".
All I know, is to get either "star diagnose" or xentry software and a cheap 20$ connector like "Tractrix Openport 2.0".
Is anybody here experienced with this?

I am based near London, UK. I am an retired electronic design engineer. I had my B250e ( manufactured September 2015) since December 23 . I am using a icarsoft CR Ultra, to clear lots of stored faults carried forward from previous owners. The most positive action I have done is to change the all the Chinese tyres ( carried forward from previous owners) to Michelin e- primacy tyres. It made a huge lot of difference in the range as well the reduced tyre noise and hugely improved ride comfort. I also had a electronic 4 wheel alignment done which greatly improved the steering. I have also added a ctek 12 volt battery bluetooth battery sensor and cigarette lighter USB port adapter with a battery voltage adapter. I also have a separate charging circuit using a ctex charger for the 12volt battery. This is because the 12 voltage battery is not charged when hv battery is on charge. So if if use your audio system while charging your hv battery you may discharge the 12volt battery and your car may not start again.

 

[OriginalGriff]

It's my first post here - please be merciful to me
I own a B250e built 01/2017 since about 5 years. As even battery warranty runs out in january '25, I wonder if someone ever did some repairings on the main battery.
Sooner or later, all of our batteries get worse and some cells might be dead and as it's a tesla manufactured battery, I guess they are almost similar to model s batteries from 1st generation.
There are forums, where model s users explained that they repaired their batteries themselfs.

I am a electronic expert and build my own (low voltage) batteries for solar energy storage since a could of years. Also microcontrollers, etc. is well know to me.
So far my Benz does great, but I want to be prepared. Also identifying error codes (in the past covered by warranty) would be fine. Right now, it's hard to do any maintenance in such cases from errors like "visit a workshop".
All I know, is to get either "star diagnose" or xentry software and a cheap 20$ connector like "Tractrix Openport 2.0".
Is anybody here experienced with this?

The B250e battery / motor was designed by Tesla (when MB owned a large stake in them which is also why Model S cars have some MB switchgear) so any company that can "recondition" Tesla Model S batteries will definitely recognise the MB battery pack (except for the desiccant system which MB insisted upon but Tesla never fitted). But if your battery was checked by MB at the last service and pronounced good then it should be OK for quite a while (assuming you don't have a coolant leak). Mine is a year older, and a full charge even in the UK in November is still (optimistically) claiming a 124 mile range.
Would I try to fix it myself? No - it's a 400V battery pack in there, and you really do need to know what you are doing before you even think of taking it out of the car let alone taking it apart! Remember the old adage: "AC hurts; DC Kills" - 400VDC is not something you want to mess with.

If you look under the dash on the drivers side near the bonnet / hood opening handle you will find a little hatch - open that and you'll find a standard OBD-II connection. You can plug pretty much any ODB-II reader into that to get the fault code numbers, and a simple google will normally get you an english explanation of those. How useful that is in diagnosing the actual fault is another question and the answer will depend on your mechanical knowledge!!

 

[LondonWdd14289ownwr]

The best mileage I got on the dashboard was 124 miles on a full charge, when outside temperature was 18°C. This is on E+ , on neutral while stationary ( traffic lights) , no fan , no AC.Also light on the accerator padel ,michelin e primacy 18in at 40psi , normal range ( extended range not selected) . Now in January with temperature about 0 to 8 °C , I am only getting 65 , with fan and heating set to 18°C . My round trip is around 40 miles . But I go charge the battery at my destination so the battery capacity status is between 20 % to 80% .but do occasionally charge it up to 100% . Even though the charge status say 100% , in reality the battery is only charged to 80% , unless you have selected the extended range. This is what the b250e specification says .

 

[LondonWdd14289ownwr]

The B250e battery / motor was designed by Tesla (when MB owned a large stake in them which is also why Model S cars have some MB switchgear) so any company that can "recondition" Tesla Model S batteries will definitely recognise the MB battery pack (except for the desiccant system which MB insisted upon but Tesla never fitted). But if your battery was checked by MB at the last service and pronounced good then it should be OK for quite a while (assuming you don't have a coolant leak). Mine is a year older, and a full charge even in the UK in November is still (optimistically) claiming a 124 mile range.
Would I try to fix it myself? No - it's a 400V battery pack in there, and you really do need to know what you are doing before you even think of taking it out of the car let alone taking it apart! Remember the old adage: "AC hurts; DC Kills" - 400VDC is not something you want to mess with.

If you look under the dash on the drivers side near the bonnet / hood opening handle you will find a little hatch - open that and you'll find a standard OBD-II connection. You can plug pretty much any ODB-II reader into that to get the fault code numbers, and a simple google will normally get you an english explanation of those. How useful that is in diagnosing the actual fault is another question and the answer will depend on your mechanical knowledge!!

 

[LondonWdd14289ownwr]

Depends on the obd2 reader . Some of them also gives an explanation on the error code while the cheaper ones don't. You can see any high voltage wire are bright orange in colour. Normally if you disconnect the negative terminal of the 12volt battery, it will isolate the high voltage from the Hv battery. You can check this with a multi meter ( multi meter should withstand a voltage of atleast 500dc . But most multimeter goes up to 1000Vdc breakdown voltage

 

[LondonWdd14289ownwr]

Depends on the obd2 reader . Some of them also gives an explanation on the error code while the cheaper ones don't. You can see any high voltage wire are bright orange in colour. Normally if you disconnect the negative terminal of the 12volt battery, it will isolate the high voltage from the Hv battery. You can check this with a multi meter ( multi meter should withstand a voltage of atleast 500dc . But most multimeter goes up o 1000Vdc breakdown voltage