Winterize and battery ??

Sam Spade wrote:

Good post but some comments are in order, I think.

Note that NONE of that really applies to a healthy AGM battery.

Those only lose 1 to 3 percent of a full charge a month and sometimes less than that. An AGM is also less prone to sulphation than a wet cell.

And with a wet cell, a 15 percent loss of charge over a month is not enough to cause any significant change to it's life spam. Usually the self-discharge loss is much less than that.

SO.....connecting a charger for 12 hours or so once a month should be plenty for a HEALTHY wet cell battery.....and once every 3 months for an AGM. That is IF they are disconnected to remove parasitic loads.

And I object to the use of the term "trickle charger" even with the "regulated" description when it comes to a charger that you leave connected all the time. Part of the reason is that particular terminology is almost NEVER used by the manufacturers of small automatic smart tender type chargers.

AGM batteries are far superior to flooded cell batteries. Yes there’s far less self discharging, however, AGM batteries still sulfate just as flooded cells do. Sulfation is an unavoidable consequence of the chemical reaction that takes place to create energy. Once sulfate ions give up their negative charge, they bond with the negative plates and start forming sulfate crystals. As discharging continues the crystals will continue to grow and become hardened. This process takes place in all lead acid batteries.

Applying a charge soon after a discharge dissolves the crystals and incorporates the sulfate ions back into the electrolyte solution. However, some crystals are not dissolved during the charging process and the cycle continues over years.

In a standby setting, AGM batteries are far superior. Due to their natural low self discharge rate the process of sulfation occurs more slowly and is more easily reversed. In a state of rest sulfation happens rather rapidly in flooded cell batteries. However, in a state of use they’re pretty much even. Batteries are discharged (frequently deeply), undercharged, and allowed to rest for long periods without a charge in trailer applications, so AGM batteries are still subjected to sulfation.

If someone wanted to upgrade to an AGM battery then that would be a good move, it’s a better battery. There’s a lot of pluses to them and they’re a little bit more dummy proof, but they’ll still have to be maintained if you want them to last for a long time. LiFePo4 and LiFeMnPo4 are even better, but those are mostly cost prohibitive now and there’s a learning curve for some.

I’ve maintained all kinds of battery technologies over the years in lots of different applications, even built quite a few packs and arrays. When it comes to motorcycle batteries, if you’ve left a flooded cell battery for a couple of months with no charge then you’ve effectively killed it. Just recycle it and get a new one because it will never recover from the damage it’s suffered. If you’ve left an AGM version for the same time period, it wouldn’t suffer the same level of damage as the flood cell, but the life has definitely been shorted. The downward spiral has already started and you’ll be lucky to get another season out if it. I’ve had this happen with practically new batteries. If you were to disassemble the battery then you can easily see the telltale crystals on the plates with a magnifying glass. Because of the physical form factor of motorcycle batteries, they’re a lot more sensitive to damage than batteries we use in RV applications.

The vast majority of batteries for trailer applications are flooded cells though. When it comes to OEM and replacement, most choose the lower cost flood cell battery. The risk of damage is far too great with these batteries which is why it’s best to keep the battery at a full charge. The damage isn’t visible, catastrophic, or immediate, but cumulative. A lot like exceeding the speed rating on a tire. If you talk to any battery manufacturer they’ll all tell you the same thing. If you want to get the longest life out of a battery then keep it charged. Keeping the battery on a trickle charger, maintainer, smart charger, or whatever you feel is semantically correct, is the way to go.