ckris
Member
Haha, yes size matters! But the op was talking about adding 50ah lithium.That's a very small battery. You probably get away with it because you have a relatively large alternator and small battery. My lifePO4 battery is 560Ah in 12v money (24vboat) the amount of amps that battery would pull is considerably more.
LifePO4 has better charge acceptance but in reality some of your alternator output is going to heat the wire.
The point is, lowering the charge voltage does reduce the current accepted and this will be true for any size of battery (even yours if you lower the charge voltage enough). The voltage drop along battery cables may do this sufficiently to prevent alternator being overloaded in many installations.