QLeo
Established Member
- Joined
- May 17, 2023
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- Location
- Scottish Highlands
- Driving
- MG4 SE LR
At the risk of adding warmth to this discussion, and largely echoing, I think, what @tsedge has mentioned, there is a difference internally in batteries that are designed to discharge shallowly, but rapidly, such as those good for turning over a cold ICE engine more or less frequently (start/stop) and those designed for longer life when discharging much more deeply, but being discharged at much lower rates, such as leisure batteries, or, more interestingly, forklift truck batteries.
The main difference, as I understand it, is the lead plates that constitute the cells in the battery. For delivering heavy amperage, and also for being able to absorb a high rate of charge, more, thinner plates are necessary, sometimes with structure such as holes to prevent buckling. For delivering power longer, and being able to discharge deeply without excessive sulfation, the most frequent killer of lead acid batteries, fewer, thicker plates of lead are necessary. So there absolutely is a key difference between an ICE starter battery and a leisure style battery.
Leisure batteries are designed to be able to discharge as low as 20% state of charge (SOC) but it's always best with lead acids not to go that far down, for longer life. The issue I am uncertain of, is that in an EV, the electronics are unlikely to require the 12V battery to be deeply discharged. The traction battery will top it up, so in that sense, a leisure battery holds no real advantage. But it is likely to last longer, because of those thicker plates, again, unless sulfation gets it.
I should perhaps add that these things are important to us as we are off grid, and use lead acid batteries as our energy storage, so I have had to make a bit of both a study and develop some experience with it. The question is the applicability to EVs' 12V requirement, and I think it's a mixture of shallow-ish discharge and longevity that we are after. I think any good quality battery will provide this; it's not a hard use case.
It is right that we do not have to be concerned about CCA rating, but on the other hand, that aspect of a battery spec can just be ignored. For absolutely sure, if a dealer started persuading you to buy a battery based on its start/stop abililty for your MG4, run, don't walk, away.
The more important question, I think, and what I haven't bothered to check, is whether the factory battery is AGM or flooded. I would absolutely replace an AGM with an AGM, or a flooded for a flooded, or I would expect the charging regime to have to take the change into account somehow.
Finally, a little car anecdote. I bought my beloved Land Rover Heritage, Mungo, new in 2000. I sold him reluctantly and sadly 17 years later. He still had his original battery under the passenger seat, working just fine. Good batteries can last. (And I hope the large 2V forklift cells now in out battery shed do last, not only because of cost, but because each 2V cell weighs 55kg, and I had to lug them to the battery shed!)
I hope that helps.
The main difference, as I understand it, is the lead plates that constitute the cells in the battery. For delivering heavy amperage, and also for being able to absorb a high rate of charge, more, thinner plates are necessary, sometimes with structure such as holes to prevent buckling. For delivering power longer, and being able to discharge deeply without excessive sulfation, the most frequent killer of lead acid batteries, fewer, thicker plates of lead are necessary. So there absolutely is a key difference between an ICE starter battery and a leisure style battery.
Leisure batteries are designed to be able to discharge as low as 20% state of charge (SOC) but it's always best with lead acids not to go that far down, for longer life. The issue I am uncertain of, is that in an EV, the electronics are unlikely to require the 12V battery to be deeply discharged. The traction battery will top it up, so in that sense, a leisure battery holds no real advantage. But it is likely to last longer, because of those thicker plates, again, unless sulfation gets it.
I should perhaps add that these things are important to us as we are off grid, and use lead acid batteries as our energy storage, so I have had to make a bit of both a study and develop some experience with it. The question is the applicability to EVs' 12V requirement, and I think it's a mixture of shallow-ish discharge and longevity that we are after. I think any good quality battery will provide this; it's not a hard use case.
It is right that we do not have to be concerned about CCA rating, but on the other hand, that aspect of a battery spec can just be ignored. For absolutely sure, if a dealer started persuading you to buy a battery based on its start/stop abililty for your MG4, run, don't walk, away.
The more important question, I think, and what I haven't bothered to check, is whether the factory battery is AGM or flooded. I would absolutely replace an AGM with an AGM, or a flooded for a flooded, or I would expect the charging regime to have to take the change into account somehow.
Finally, a little car anecdote. I bought my beloved Land Rover Heritage, Mungo, new in 2000. I sold him reluctantly and sadly 17 years later. He still had his original battery under the passenger seat, working just fine. Good batteries can last. (And I hope the large 2V forklift cells now in out battery shed do last, not only because of cost, but because each 2V cell weighs 55kg, and I had to lug them to the battery shed!)
I hope that helps.
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