Lawn tractor battery life is also rolling the dice for battery life with me also.
When You get two summers use of a U1 series battery you are doing good. (the $35-$45 ones)
Seems anything over 1 year on a U1 series is on borrowed time.
I prefer the Battery MINDER, model 121177C as a trickle/float charger. (I buy them when on sale)
I sometimes get 4 years out of a U1 but another one of same make only 2 years or less. (and most U1's in my neck of the woods only has a 30 days freebie warranty exchange and not user friendly to get the exchange
because they want to take a DNA sample, stool sample, urine sample, blood culture (I just give them my underwear
) and do a background check and you need your
ORIGINAL receipt)
I've noticed that $75 with a 5 year warranty automotive batteries are a thing of the past.
Now days $150 and up for a 2-3 year battery.