AGM battery on a non AGM car?

[SC Maintenance]

I read where a lot of guys are only getting 3 yrs. Out of them in vehicles that are set up for them.

Any battery is based on build quality. So they last longer via their design, all things being equal. I seldom get even 3 years on lead acid in our heat, and I float charge all mine monthly.

They do not like being overcharged.

No battery does.

In fact Ford targets 80% charged, Honda targets 85%.

Based on what? To save the battery, to save the alternator, or for CAFE (smart charge). Few vehicles fully charge a battery in the car, even lead acid. It takes a very long time at to get that last little bit of charge. Most every OEM has been turning charging off long before that in order to get 0.001 better MPG for Cafe reasons.

I wouldn't read anything into this. The battery manufacturers themselves make no such claims. Its unlikely any alternator based charge system would get to full charge on its own - it would need an ECU controlled modulator to match the proper final charge profile, and no Auto OEM is going to pay to implement that.

Lots of misinformation floating around.

Yep.

 

[PWMDMD]

how does a fuse "...allows 0.5v more to be produced..." ?

It's a diode, not a fuse. You replace the existing diode in the ALT-S fuse spot in the fuse box with the new diode.

 

[SC Maintenance]

It's a diode, not a fuse. You replace the existing diode in the ALT-S fuse spot in the fuse box with the new diode.

Have you tracked your max voltage out now? I am guessing its something approaching 14.7 Volts, maybe even higher?

 

[PWMDMD]

and my car comes with a factory Varta AGM, yet i haven't seen it produce more than 14.5V. In fact it usually sits at a steady 13.8V

Yup, 14.5V was the usual max/saturation voltage with the new diode and it is also usually steady state at around 13.8V. Before the new diode, it was less, I can't remember how much now, it's been 5 years.

 

[PWMDMD]

Have you tracked your max voltage out now? I am guessing its something approaching 14.7 Volts, maybe even higher?

14.5 was typically. Maybe I saw a 14.6 or 14.7 here or there. I tracked it for a while but it's 5 years old now so I don't worry about it at all now - I just drive the truck.

 

[joekingcorvette]

I have an AGM battery in my Corvette and F-150 and have not had any problems.

 

[Kalle.J]

80Ah AGM in Volvo instead of stock 70Ah EFB. No coding, works like a charm.

Check voltage from alternator with load if you are unsure.

From Varta:

 

[Mechanician]

14.5 was typically. Maybe I saw a 14.6 or 14.7 here or there. I tracked it for a while but it's 5 years old now so I don't worry about it at all now - I just drive the truck.

Standard spec on FLA charging systems was always 13.5 - 14.5 volts.
Automobiles are not actually a 12v system, they are a 14 volt system, with a 12 volt battery.
If the voltage at the battery slips below 13.5, a car will not fully charge the battery.
As noted earlier, newer cars with managed systems will cut the voltage slightly under 13.5, but only after the battery is determined to be fully charged.

 

[HowAboutThis]

I'd never heard of this before. I know they have different charge settings on chargers, but I've run them in cars in the past and they seem to last fine. When I search on website it comes up with AGM's for an option on my car so that wouldn't make sense if you couldn't use them.

Another Internet folklore discussion or real? I emailed a manufacturer to see. I'll keep you posted.

 

[LenZee]

how does a fuse "...allows 0.5v more to be produced..." ?

That's a diode, You need to install a fuse inline with the diode or you may have problems if that circuit shorts to ground.

 

[Speedbird001]

Think you have to dig into your exact model to be certain. Tacomaworld says 3rd gen alternator/computer does not support. But, can be done by occasional trickle charging or CPU Flash or similar sorcery…

I’m not in the hard core battery use and decided 2-3x the cost was not worth it.

 

[Kalle.J]

I’m not in the hard core battery use and decided 2-3x the cost was not worth it.

Since when is AGM 2-3x the cost?

If you have BMS you probably need to keep the same size capacity, otherwise no need to do anything.

 

[Donald]

Can an AGM battery be used in an old car that just has a standard lead acid battery?
Would there be issues for the alternator or battery?

I had that question for my 2015 F-250 PSD. I emailed East Penn. They have a chart and looked it up and said yes. So both batteries in my pickup are AGM from Walmart.

 

[f355spider]

AGM batteries have been around for 40 years or so. It's all I have ever used in any of my cars, including my 1980 Rabbit. I don't know when smart charging became common. My 2013 BMW had IBS.

Same. I have used AGM batteries in many cars over the years that did not come with them from the factory. Absolutely no issues at all. I have been using them for over 25 years. 1978 Ferrari 308 GTS, 2001 BMW 540 M-Sport, 2001 Toyota Highlander, 1997 Ferrari F355 Spider. I like not having to check the electrolyte level and generally longer life.

 

[E150GT]

I only use AGM these days. None of my vehicles came with them from the factory

 

[f355spider]

I have an AGM in my Tundra (it does not come with an AGM) but also replaced a fuse that controls voltage. This new fuse allows 0.5v more to be produced to allow the AGM to charge fully.

https://voltageboosterpro.com/product/spark/

 

[Speedbird001]

Since when is AGM 2-3x the cost?

If you have BMS you probably need to keep the same size capacity, otherwise no need to do anything.

View attachment 247307

sorry, I meant top of the line AGM battery, "Tune" to increase the voltage my '17 Tacoma puts out and a new battery tray.

 

[KJSmith]

If anything, the agm would be undercharged vs flooded,

Would there be issues for the alternator or battery?

Damaging the AGM battery would be the risk.

People seem to have misread this.
A simple answer to a simple question.

I would tend to agree with you that the AGM may run a little under charged.... but who knows.
Maybe some of the folks who are running AGM batteries in older cars could tell us what the standing voltage of thier battery is without the engine running.

As far as longevity goes.
My wife's '14 Ford Edge went through 3 AGM batteries in 9 yrs.
We bought the car new. The dealer installed the second and third.
IIRC the original made it through the warranty period, the second did not.

On my '17 F150 I made it 6.5 years on the AGM

I see several guys on FTE that only get 3 yrs on an AGM....

Two things that kill an AGM, overcharging and letting them drop below 50% charged (usually around 12v dc).

 

[KJSmith]

Any battery is based on build quality. So they last longer via their design, all things being equal. I seldom get even 3 years on lead acid in our heat, and I float charge all mine monthly.

My wife's '14 Edge went through 3 AGM batteries in 9 yrs.
Motorcraft brand....don't know who made it.

My '17 F150 went 6.5 yrs on its original AGM...again, Motorcraft....don't know who made it.
Two things that kill an AGM, overcharging and letting the charge fall below 50%

No battery does.

An AGM is a sealed battery.
Overcharge it and you may blow its relief port.
For most folks that means its trash.

 

[KJSmith]

Based on what?

The reason they are going to AGM batteries.... especially in cars with start/stop function is because an AGM battery has the ability to be recharged rapidly.....up to 80% charge.... after that they have to be charged/topped off at a much slower rate.

Both Ford and Honda manipulate charging strategies for better MPG.
The charging strategies they use actually save more fuel than the start/stop function.

If you are using an AGM battery and you need to charge it, you need to use a charger meant for an AGM battery.
You should not use a regular battery charger.