Topic: AGM battery only 75% is it still good

[chewbacca5000]

I bought a sealed battery for my 750 and it has sat for a year or so now is only charging to 75%.  Should I just buy a new battery?

[MauiK3]

Yes
It will only get worse.

You could give it more time to charge but I doubt it will get better. Maybe put a load on it for a bit and then resume charging. Worth a try.

[Stev-o]

How many volts is it reading, Chewie?

[TwoTired]

Have you done a load test to see what amperage the battery can deliver?  Reading voltage only tells you if the plates are still intact.  A load test tells you what those plates are able to deliver on demand.

Cheers,

[Flyin900]

The new AGM I just bought was supposed to be charged and ready to use, yet was in the 70% range out of the box new and manufactured 03/21 this year.
These manufacturers only charge them into the 70% range is my understanding before they leave the factory supposedly charged and ready to use.
This technology is still lead acid with plates so it is in your best interest to fully charge the AGM battery before any use or memory effect is still possible on a AGM style battery.
This new AGM battery I bought  still took an additional 8+ hours at 1.5 amps charge rate to reach a full charge of 12.80 volts. So beware of buying and just installing a fresh supposedly charged battery right off the hop, without checking it’s state of charge first.

[chewbacca5000]

How many volts is it reading, Chewie?

I got it to 100%. Will check volts in the morning.

[Pappy]

Chewbacca - There are some newer pulse style chargers out on the market that will do a bit of good in removing sulfation in standard lead/acid and AGM batteries.
There are some YouTube videos on the subject that do a better job of explaining how they work and their benefits.
I have one of the chargers and have been keeping a 6 year old Optima battery going as well as a 6 year old standard Lead/acid. The Optima came to me after a customer replaced it with a new battery in his boat. It was down in the 70% range. I put it on the charger and after several days on the charger the battery had come up to the 100% mark. Same with my other battery. No instant gratification here but they do work over time. Once up to charge these batteries have performed flawlessly and without issue.

[PeWe]

A bad battery can be "fully" loaded very quick.
Thats how my batteries acts when bad. All leds on my CTEK charger indicate OK after a few hours despite weak when charging was started. That was GEL and std batteries.

[stocky]

A bad battery can be "fully" loaded very quick.
Thats how my batteries acts when bad. All leds on my CTEK charger indicate OK after a few hours despite weak when charging was started. That was GEL and std batteries.

Had pretty much the same exact symptoms. Just got worse and worse till the battery failed to start the bike even though voltage read fine but couldn’t take much of a load. Hooked up an external battery pack and the bike started right away. Currently waiting for a new lithium battery to arrive today, where’s that Amazon truck at?

[TwoTired]

Beware the marketing hype of those chargers that "pulse" to "de-sulphate".  Battery cells have very very large capacitance.  The pulse may actually do something to the end cells.  But, there will be little to no pulse reaching the inner cells.  Now if the pulse could somehow reach a sulphated cell, it just might be of benefit.  But, the common lead acid/AGM batteries don't have access taps to those inner cells.

All the data I've seen for de-sulphating is experiments with single cells.  Pity we don't use single cell batteries in our bike.

The pulsing doesn't hurt anything.  The battery just sees voltage potential to stimulate ion movement.  Just don't be paying extra because it pulses and expect it to work any different than chargers that don't pulse.

Think about it, the starting motor draws huge switching amps from the commutator and a good battery hardly sags in voltage.  What could you expect from a charger that produces 2-3 amps for any kind of voltage dip (pulse) at the battery plates?

And yes, I have some chargers that tout pulsing.  They were on sale.  Haven't experienced any difference between those a other chargers that don't pulse.  My inventory is; three chargers that pulse and four to six that don't.

Cheers,

P.S. Why do you suppose manufacturers don't have pulsing chargers incorporated into vehicles?  The "tech" has been available for over ten years.  I haven't heard or found any.  Have you?

[dave500]

a "pulse charge"alternator,just something else to go wrong?

[TwoTired]

a "pulse charge"alternator,just something else to go wrong?

True, extra parts usually means a reduction in Mean Time Between Failures  (MTBF).  But, you *could* make a pulse circuit that fails "safe", like reverting to no pulse charge.  And you can use parts that have high reliability and low fail rates, like mil spec parts usually do.  But, that often means higher parts cost.  The prudent engineer will do a cost/benefit analysis to prove worth.  (Not the domain of Marketeers and salesmen.)  The military and government don't mind using your money to pay extra for this sort of stuff, or NASA.  But, they usually will have some sort of study to justify the cost, even if only on paper or provided by some relative or political ally.

Might be interesting to inspect military motor pools to see if they employ pulse chargers to extend their fleet battery life.  But, I have no access to such.

Cheers,