I meant without stop/start
Right.
The battery Varta recommended has start/stop and higher capacity.
Which is no benefit in an EV.
The exide isn't start/stop. I've been working night
The Varta is start stop and has higher capacity.
Understood! Maybe it will make more sense after some rest?
Let's see if I can explain all of this to make it clearer....
12V ICE Batteries
For decades cars have had 12V systems to power everything on the car that is separate to the engine, including the lights, air conditioning, power windows, entertainment systems, seat heating etc....
These 12V systems consist of a 12V battery and an alternator. The alternator is driven by the engine and charges the 12V battery up, so it doesn't go flat. Without the engine running, the battery will drain, which is why leaving your lights on in an ICE car can lead rapidly to a flat battery.
These 12V batteries have to be able to physically crank over the combustion engine in order to start the car. The bigger the engine, the bigger (and more expensive) the 12V battery needed. In small city cars, the batteries are small, in large executive cars they are big.
This is where the phrase Cold Cranking Amps (CCA) comes from: what kind of battery do I need in order to be able to crank over my engine from cold so that the car always starts?
Start-Stop Batteries
More recently, Start/Stop became a thing with ICE engines able to switch off at the lights. This means needing to be able to crank the engine over much more often, maybe hundreds of times a day AND being able to do so quickly, so the driver isn't held up.
To handle this, 12V batteries became heavier and bigger (and more expensive) so that you can always depend on being able to supply the huge load to turn over an ICE engine instantly.
Leisure Batteries
With camper vans and recreational vehicles, there was a different problem to solve: how do I power my lights, fridge, radio, etc... when the engine is off? These vehicles have a second 12V battery which is not used to start the engine - this is referred to as the Leisure Battery.
Leisure batteries never have to crank an engine over, instead they provide a steady, much lower level of power over a longer period (e.g. evening or overnight). What they need is to last a long time, so that they can be discharged and recharged many many times.
This is what Leisure 12V batteries are designed to do well - they cannot crank over an engine, but they can supply power and discharge a lot and keep being charged up with a good lifespan.
EVs
In an EV, there are two batteries, the High Voltage (HV) battery, which runs the motor (driving the car) and powers high-output devices like the heater. Then there's a second battery, the 12V one, to power the ancillary systems just like in an ICE car.
However, the EV never needs to crank an engine over and the HV battery can top-up the 12V battery whenever it is needed, so what's the right battery to use?
Well, any 12V battery that will fit will work, so many manufacturers (like MG) just fit a cheap small ICE car battery to save money. But that doesn't mean it is ideal.
There's no benefit to using a Start/Stop battery, but Leisure Batteries are the most suitable for long life, so these are recommended.
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