Lawn mower batteries are junk even when new

[CleanSump]

Last time I had a similar problem it was a bad diode in the rectifier. The lights on that rider were AC so were only on when running. The ignition, starter, and kill switches were DC. New rectifier, battery stopped discharging when off.

 

[chemman]

Check to see what the AC ripple voltage is while the engine is running (and if your mower has headlights, turn them on as well). The higher the AC ripple voltage (ideally it should be less than 0.50 V) the less the battery is going to like it and the shorter the battery life.

 

[meep]

I’ve had excellent service from ariens oem sealed batteries. About $65 each. 5-6 years

 

[Pablo]

I’ve had excellent service from ariens oem sealed batteries. About $65 each. 5-6 years

Mine is at 5+ years now. Cranks like new. I think the alternator in the Kawa twin is fairly robust

 

[Learn Ya]

No matter what brand lawn mower battery I buy they all seem to last about 3 years

I agree. Anything beyond 3 years is a bonus for any OPE battery these days. I take good care of my batteries, but they still don't last like older batteries did. Prices go up, but quality goes down. It's seems to get worse every year.

 

[zzyzzx]

Anything beyond 3 years is a bonus for any OPE battery these days.

Absolutely! I'm thinking that my winter usage to mulch leaves and occasional battery tender usage is the only reason why mine lasted 5 seasons. Also, in hindsight, it had been getting harder to start lately. The pricing today vs 5 year ago at Walmart was around $35 last week vs around $21-$25 (I forget exactly) in 2021.

 

[Touring5]

I replaced the battery in my Craftsman lawn tractor last year. The old battery was a 6+ year old FVP (cheap Korean) from Menards. The replacement was the same.

I remove the battery around Thanksgiving and store it in the basement. I put it on the Battery Minder for a week or so and let it desulphate, then do so again in early March. I believe THAT is what extends the life.

 

[meep]

Mine is at 5+ years now. Cranks like new. I think the alternator in the Kawa twin is fairly robust

I can get 2-3 years where it just cranks. Starting at year 3-4 it might hang if it doesn’t get all the way over and I have to re-key it and then it will spin and catch. Thats without keeping it on a maintainer. 2 months on the CTEK and it’s acting a year younger. By 5-6 I might have to key the starter 2-3 times but it’ll still start. This is with a one lung Briggs 14.5 hp.

 

[Not Sure]

Try to get a dry charged battery (a battery that comes dry with a bottle of electrolyte and you add the electrolyte to it yourself) next time. Dry charged batteries will not start to degrade or sulphate until you add the electrolyte to them and have a much much longer storage life then ready to use batteries.

These lawnmower and power sports batteries tend to sit around on the shelf for a long time. They aren’t on a float charger and sulphate over the course of months or even years at a low state of charge.

If you can’t find a dry charged battery take a good mulit meter with you and don’t buy any batteries that are under 12.6 volts or more then 6 months old according to the date code. Try to get your battery from a place moves a large volume of mower batteries.

Lastly don’t discount installing a recoil starter on your riding mower, that was the best thing I ever did to mine no more dead batteries to deal with, no more problems with broken compression releases and anemic starters that can’t crank the engine without a compression release. Just give it a pull, hop on and mow.