My experience with 12Ah B&B is quite different. I bought locally HAZE brand of 12Ah SLA and it was mistake.
B&B has low voltage sag , never trip LVCut off on my Merida on the same hill even at 50% DOD.
nO DOUBT you have to take care of your pack - rearly if at all discharging to the end , best use only 80% at most.
I don't use my B&B at winter also and would never keep on on charger long, no need for that once is fully charged, in winter put on charger every like 30 days for say 10 minutes,