Hi if you don't recode the battery after installing the new one you will kill the new unit in record time as the BEM still thinks its the old battery and carries on charging the new unit at the same rate as the failing unit, the BEM has no way of self rationalising the fact that the battery is new and has to be told it has a new unit and then it will modify the charge rate against the charge resistance from the new battery, plenty of explanatory blogs on the net, all this coding malarkey started back in the early noughties as they were developing multi CCM modules which don't like voltage spikes.
Steve.