Though the OEM battery has more capacity it does not have anywhere near the same start current capability so when things are not ideal the voltage will fall causing the ABS problem, its not A/H capacity you need its start current.
Ohms law's been re- wriiten!!!.
Its not ohms law that's been re written its your interpretation of it. If the voltage falls due to self discharge (gel batteries are the worst lead acid type batteries for this) Then V/R=I the starter resistance is constant so the current reduces proportionally
The internal resistance of the gel battery is much higher than an AGM battery.
So for a given current flowing V=I R (where R is the internal resistance) that means the voltage increases but this is Voltdrop and means the terminal voltage drops which means ,as explained above, the current drops.
I said the AGM battery has a higher start current capability I did not say it will deliver more than the Resistance limits, it just means that the battery voltage will not drop when drawing high current as needed by large capacity cylinders, unlike gel battery the current is not limited by the internal resistance V/R=I
with an AGM battery unlike a gel battery you are likely to supply the required full start current in situations when things are not ideal. Having more capacity A/H lust means you can supply the reduced current for longer.. no help at all!
If you need it explaining further I will but it seems doubtful with a closed mind that you would listen.
