[TC]

$89 for a mower battery! Ouch!

Bluey
Mark777 is correct. It's all about the cranking amps. I would be interested in knowing what you are putting the battery on. Please describe you mower.
Sounds like someone wants to sell you a lot more battery than you really need. Do you have a K-Mart store nearby?
WTC
1 Australian dollar = 0.9967 US dollars

 

[TC]

Bluey,
A good mower battery would have approx. 275 CCA (cold cranking amps) and 350 CA (cranking amps at 32 deg.F.). I buy from Walmart (same as K-Mart) for about $25. Be sure to take in your old battery for exchange. Good luck. WTC
PS
Walmart part number is "Everstart, U1P-7.