Lawn mower battery struggles

Auto Doc's said:
Battery Tender is a brand name from what I understand. It is usually a .25A slow battery maintainer (not aggressive like a conventional charger) Just powerful enough to keep the electrolyte active in a lead acid battery (FLA). They do very little good for any other battery design…
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I bought a Battery Tender some time in the ‘90’s (I think!)… it’s still working and currently in use on my RV deep cycle battery. It’s capabilities are limited and I have zero experience with the newer models.

Recently I added a NoCo Genius 1 to my arsenal.

Its advanced technology allows for use on many different battery platforms (FLA, gel, AGM, even lithium-ion), and will differentiate between 6v and 12v. All this is done automatically, place the clamps on the positive and negative terminals, plug it in and walk away.

It works and it’s idiot proof.

 
bt-99 said:
I was just wondering how many of the people on this forum dont do anything with their lawn mower battery when storing it for the season. I dont put a tender on mine. All I do is unhook the negative cable and leave battery in the mower till spring and then I just hook cable back up and start it. I can usually do this for 4 years with no problems and on the 5th year I have to jump or charge it or get a new battery. Also if I do have a dead battery come spring, what amp do most people use to charge up a rider mower battery?
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My JD 322 is used year around, mowing, log splitting, hauling brush and tree trimmings, and pushing a snow plow. It is 32 years old. Ten years ago I installed a Delco AGM battery. I have cleaned the cables/posts a few times. I have never had to jump this battery to start this tractor.
 
Smithsonite said:
Not to pee on anyone's fire, but my experience has shown the exact opposite. Warmer temperatures cause batteries of any kind to self-discharge at a higher rate. Makes sense, since when you try and start your car at zero degrees, it cranks slower - not just because of thick engine oil, but the chemical reactions in the battery slow as well.

A colder battery self-discharges MUCH slower. That's the exact reason that up here in MA I get 8-13 years out of lead acid batteries, but when I lived in Phoenix, AZ, 3 years was doing really good. So, leaving my batteries in the machines or vehicles out in the non-climate controlled garage makes most of them last over 12 years most of the time. (EDIT to clarify the small engine / Z-turn mower batteries aren't as robust as automotive batteries, so I get 5-8 years out of those.)

Caveat to that is my vehicles are all 30+ years old. You won't get that life out of any battery in a modern vehicle. There's too many modules constantly pulling power. GM products run EVAP tests while you're in the house sleeping! They've been doing that at least since the 2007 model year, maybe even prior. It's crazy these days ...



I've owned BatteryMINDer multi-stage, temperature-sensing chargers since 2016. The amount of batteries these chargers have saved me has paid for all 4 of them over and over again.

I never disconnect cables. There's no need to, unless it's computer controlled, like every modern vehicle today. Park one of those any longer than 2 weeks and you'll be out of luck trying to GET IN the damned thing with the key fob ... never mind starting it, lol. Glad my newest car is now a 1994 model. Sanity returned!!

Anyway ... having been in small engine and auto repair most of my adult life, I'll tell you that I've experimented with every new and fancy type of battery out there from AGM to lithium iron phosphate. What I've found is I always come right back to the tried and true lead acid. For one thing, none of these charging systems was designed to maintain anything other than a lead acid battery (except for modern start-stop vehicles). Even with help from my top-of-the-line battery charger, I've never had an AGM make it past 5 years. On that note, I just pulled a regular lead-acid battery from one of my 30 year old Volvos, only as a troubleshooting step. Since it was 11-1/2 years old, I left it out & kept the 8 year old one in there instead. I didn't even need to change it - was still starting the car no problem.

I've had many AGMs fail much sooner than regular lead acid ones did, both in automotive and small engine duty. The $300 Odyssey AGM I had in my Silverado barely made it 5 years with EXTENSIVE help of my charger!

The only alternative battery I use these days is a sealed lead acid (SLA) alarm system battery in my 1974 Yamaha RD350 2-stroke motorcycle that's still running dual points ignition. I've found you can abuse the heck out of those by neglecting them for months, running them way down, and I'll still get 5-6 years out of them at just $25 a pop. Can't beat that!
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Battery manufacturers recommend winter storage above freezing (40 F) and fully charging periodically. Been doing heated winter storage for the last 30 years, unheated storage for 30 years before that, and heated storage provides longer battery life. Pick your poison!
 
That's not what I've experienced servicing thousands of batteries of every size for the past 3 decades both professionally and for my own stuff. They ALWAYS self-discharge at a higher rate in warmer temps. That's just the nature of chemical reactions. There's no fudging or cheating physics. The difference from 72°F to 40°F if left to sit without a constant trickle charge can be measured in up to a month's time before getting low enough (12.4V or less) vs. just leaving it in 40° temps.

I try to remember to charge all my batteries at least once every 2 months at the most during winter. In that 2 month timeframe with temps between 45°F & 20°F average, the state of charge never drops below 12.3V on the worst (oldest, weakest) of my batteries. I've got 11 batteries in service, plus another 6 or so spares laying around. Gets to be a juggling act and some get missed!

As long as the battery has a good charge, it can be left below freezing without issue. My storage area rarely gets below 12°F. I get over 10 years out of car (pre-OBD-II stuff) batteries most of the time, and between 5-8 on small batteries (brush hog, Z-turn, etc..). The lower end of that scale was probably more battery quality than anything. Now that I think about it, that 5 year lifespan was in the house, 71° average all season as a alarm system backup.

I can see damage happening in the Arctic, but here in western central MA, I haven't seen anything below -16*F my entire life. A fully charged battery can handle that without issue. It's a LONG way to -70°F to freeze a fully charged battery. Ain't happening here.

The biggest dictators of battery life in order of importance are #1, how the battery was prepped (nuked at 50A for 3 minutes ... filled with acid and shipped ... or done the RIGHT way and left to soak a MINIMUM of a half hour after adding acid, then charged at the LOWEST possible setting OVERNIGHT at a minimum), and #2 how it is treated (constantly run down to nothing ... or keys only turned on when ready to start engine and turned off to stop engine) and maintained (left to die until spring, regular charging during storage, or left on a trickle charger).

Most places don't do it the right way because time is money. It takes TIME to prep a battery the RIGHT way. That's why there are so many varying life spans of batteries out there ... but everyone blames the temperature they're stored at or how often they were charged. The real issue is the start of a battery's life - either done right or done fast.

A battery prepped the RIGHT way will handle neglect in surprising ways. The ones nuked at 50A for several minutes are the ones that croak first, ALWAYS. Whenever possible I try to buy my batteries dry, but that's not always practical or convenient, so it's a crap shoot. At the very least, even a brand new battery I throw on my BatteryMINDer charger. I'll even bring a multimeter to the store with me and grab the battery with the highest state of charge. This has served me well for decades.
 
I was told that when charging a battery the electrolyte should not exceed 130 degrees F to prevent damage to the battery. Many years ago specific gravity testers were used to determine the charge in a battery, and they contained a thermometer inside the tester to monitor the electrolyte temperature while charging.
 
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Smithsonite said:
That's not what I've experienced servicing thousands of batteries of every size for the past 3 decades both professionally and for my own stuff. They ALWAYS self-discharge at a higher rate in warmer temps. That's just the nature of chemical reactions. There's no fudging or cheating physics. The difference from 72°F to 40°F if left to sit without a constant trickle charge can be measured in up to a month's time before getting low enough (12.4V or less) vs. just leaving it in 40° temps.

I try to remember to charge all my batteries at least once every 2 months at the most during winter. In that 2 month timeframe with temps between 45°F & 20°F average, the state of charge never drops below 12.3V on the worst (oldest, weakest) of my batteries. I've got 11 batteries in service, plus another 6 or so spares laying around. Gets to be a juggling act and some get missed!

As long as the battery has a good charge, it can be left below freezing without issue. My storage area rarely gets below 12°F. I get over 10 years out of car (pre-OBD-II stuff) batteries most of the time, and between 5-8 on small batteries (brush hog, Z-turn, etc..). The lower end of that scale was probably more battery quality than anything. Now that I think about it, that 5 year lifespan was in the house, 71° average all season as a alarm system backup.

I can see damage happening in the Arctic, but here in western central MA, I haven't seen anything below -16*F my entire life. A fully charged battery can handle that without issue. It's a LONG way to -70°F to freeze a fully charged battery. Ain't happening here.

The biggest dictators of battery life in order of importance are #1, how the battery was prepped (nuked at 50A for 3 minutes ... filled with acid and shipped ... or done the RIGHT way and left to soak a MINIMUM of a half hour after adding acid, then charged at the LOWEST possible setting OVERNIGHT at a minimum), and #2 how it is treated (constantly run down to nothing ... or keys only turned on when ready to start engine and turned off to stop engine) and maintained (left to die until spring, regular charging during storage, or left on a trickle charger).

Most places don't do it the right way because time is money. It takes TIME to prep a battery the RIGHT way. That's why there are so many varying life spans of batteries out there ... but everyone blames the temperature they're stored at or how often they were charged. The real issue is the start of a battery's life - either done right or done fast.

A battery prepped the RIGHT way will handle neglect in surprising ways. The ones nuked at 50A for several minutes are the ones that croak first, ALWAYS. Whenever possible I try to buy my batteries dry, but that's not always practical or convenient, so it's a crap shoot. At the very least, even a brand new battery I throw on my BatteryMINDer charger. I'll even bring a multimeter to the store with me and grab the battery with the highest state of charge. This has served me well for decades.
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I am glad we agree on proper prepping with acid as I mentioned in my post. I see our differences now. I live in South Dakota where winter temps can go below zero.
 
I have a Battery Tender Plus on mine, OEM battery still cranks after 4 years. The only thing I do differently is connect the positive lead to the battery and the negative to the chassis ground. It charges at 1.25a then switches to float mode to maintain the battery at a safe voltage.
 
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