Battery finally died.

[GARETH]

My 2014 V6 started coming up with “Low Battery Start Engine” messages after switching it off. I tried a recovery procedure with my smart charger, but it kept faulting.

So bought a new battery. Went for a Yuasa hsb019 from Halfords. £153.

Easy to fit. Hardest bit is getting the earth connector off as it’s a bit tight at the back.

[rjmlondon]

If the battery is replaced or disconnected, is there a reset required?

[GARETH]

Technically yes. There is the BMS (Battery Management System) that varies the rate of charge according to driving. It can be reset with a diagnostic tool. I haven’t done mine yet, but when it goes in for its new alarm sounder in a couple of weeks I’ll ask them to do it.

[CJSJAG]

So, does the BMT need resetting by a dealer each time the battery is disconnected?
What happens if both new and old batteries are jumpered together before disconnecting old battery?
Will that likely avoid the problem?

[Tel]

FWIW - I spoke with Tayna batteries regarding a replacement. Two things that I specified was the battery would be stood for a long time (as I work away) and the fact that I have had the Stop/start function disconnected since day 1.

They maintain to use the same technology, AGM and recommend Exide. https://www.tayna.co.uk/car-batteries/e ... 0/?sai=117
That said I've always held Yuasa in high esteem - they used to always be the benchmark for cold crank amps that others could never seem to meet, certainly for bike batteries.

[scm]

I've never been let down by Varta, and I like the name.

[Deleted User 1715]

If the battery is replaced or disconnected, is there a reset required?

The Battery Management Sensor only needs to be reset when a new battery is fitted, not when re-fitting the same one. It can be done by any JLR dealer with their diagnostic kit, possibly by independents too, no idea what the implications are of not resetting it.

[cj10jeeper]

As above. The reset is only so it knows it’s a different battery and adjust/learns charging pattern. Not required for disconnect and reconnect.

Changed mine in the Evoque and same system but research shows that even if you don’t do it the car does it’s own reset at max 6 month interval.
Was busy with house moves, Covid restrictions and it reset itself after 5-6 weeks, so wasn’t a job to have rushed

[GARETH]

As said, it’s not the end of the world if you don’t do it, the car will adapt eventually. The reset just sets it back to a base value and it learns from there.

If you plug a voltmeter into the accessory socket and go for a drive, you will notice that the volts will be up around 14.5 - 15.5 v depending on temperature and state of charge and load on the battery. When you lift off the throttle and coast, the volts will increase slightly, and when you a accelerate they will decrease. This is the smart charging increasing or decreasing load on the alternator to suit the needs of the engine. It’s more efficient to charge the battery on deceleration than it is to charge it when power is needed to accelerate the car. It will only do this when the battery is nearly fully charged.

[Tel]

As said, it’s not the end of the world if you don’t do it, the car will adapt eventually. The reset just sets it back to a base value and it learns from there.

If you plug a voltmeter into the accessory socket and go for a drive, you will notice that the volts will be up around 14.5 - 15.5 v depending on temperature and state of charge and load on the battery. When you lift off the throttle and coast, the volts will increase slightly, and when you a accelerate they will decrease. This is the smart charging increasing or decreasing load on the alternator to suit the needs of the engine. It’s more efficient to charge the battery on deceleration than it is to charge it when power is needed to accelerate the car. It will only do this when the battery is nearly fully charged.

Not quite...

The only 'smart' thing about the charging is that the regulator on the generator changes the field winding (thus output current), depending on the measured system DC voltage. If the voltage is low, it increases the current and vice versa. It is not speed nor acceleration/de-acceleration dependant.

Think you're confusing with regeneration on an electric or PHEV perhaps? F- types just don't do that....yet!