I have a 2005 Honda Civic. I think the battery is starting to die and want to take care of it before winter sets in and I get stuck with a dead battery. The Civic takes a 51R battery size. Can I upgrade to an AGM in that size or will my alternator not fully charge it. The car is stock with no add-ons
Lead Acid Battery to AGM
- Thread starter cb450sc
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I put one in my 2011 Frontier. It doesn't seem to get fully charged, the charge profile is for lead acid. It seems to stop charging too early. But it has lots of CCA so starting is never an issue. I throw it on a charger every month or two to get the full charge.
Only had it a year, so I don't know if this "not fully charged" thing will affect it long term. Is from Walmart with a 4 year warranty, so we shall see.
Based on this, I put new lead acid batteries in my other two vehicles instead. Not sure there is one right answer here.
Only had it a year, so I don't know if this "not fully charged" thing will affect it long term. Is from Walmart with a 4 year warranty, so we shall see.
Based on this, I put new lead acid batteries in my other two vehicles instead. Not sure there is one right answer here.
I saw around 14.5 volts with the engine running in the next generation civic. Plain old flooded battery with about 12.5 volts before starting. 51R Battery.
My Sienna's almost made 8 years, Still passed testing but changed it anyhow.
If it passes CCA testing it's fine.
This past weekend our son was home with his 2004 Volvo. Battery was over 10 years old, an AGM battery I installed. I replaced with another AGM. He is in western Pennsylvania with cold winters. I don't want him to be stuck somewhere, so a new battery.
Doesn't the "lots of CCA" come from the battery being charged (well) ?
JHZR2
Staff member
I put AGM in my 91 BMW and 2004 Saab 9-3, and ran then for a long time no issues. The BMW, like older euro cars do, kept a lower max alternator voltage, and I upgraded the car to a group 49 size. Even if it abused the battery, it was never an issue.
I do tend to top up my batteries manually from time to time.
I do tend to top up my batteries manually from time to time.
No.
Battery is rated at 900CCA. Its not only AGM but larger than the OEM, so it likely has double what is needed. The alternator typically keeps it at 85-90% charge (according to my tester). Still lots of amps to crank, but not fully charged.
I also monitor charge voltage constantly, and its typically floating around 13.3 - 13.5V after initial start - when its up around 14 - 14.2. So the voltage regulator believes it to be fully charged, but its not.
What I do not know is how this will affect long term life of the battery. If 85% charge keeps it happy, then it doesn't matter. If not, then I guess I will test the walmart warranty.
My Hyundai came with a AGM, and I am on my second one, and my battery meter already says I need a new one and it is one year old. So I started charging it every other day and it goes back and forth from from good to replace. I am a short tripper and with me going daily to my daughters house to renovating it 25 mins away, so I can't blame short tripping.
I had a 11 lbs AGM racing battery and it doesn't like to "take a charge " well, same with my OE style AGM. They are slow excepting of "the charge". I read somewhere that is the bad side of the AGM MO.(modus operandi).
My Hyundai alternator puts out 14.1 to 14.6. My newer AGM when kept up and manually charger as an internal resistance of between 3.75 to 5.30 NOW. It was only at a 45% health and 55% charge. LIke I said, the AGMs in my car just don't quick charge like a regular flooded lead acid. The battery will last 3+ years like this, but it is beating itself up with no solid charge by the alternator. I have a Big Three cable system installed with large and multi cables of very high end copper and all connections are anti-oxed. I do know this battery likes my 40 amp garage style 15.9 volt charger. I have 3 different AGM chargers and both those have been tested on this battery. I am using those for my every other day charging routine. Two are PulseTech chargers, the other is a high end Minkota AGM charger.
I think my next battery for winter will be a quality flooded lead acid conventional battery. I myself am not impressed with AGMs, or at least the plate style. I have to research if the spirial ones except a charge faster and better. I am still in research mode with my battery.
I question if Hyundai even has a AGM algorithm, it would not surprise me if they DID NOTHING to get a proper charging program for a AMG battery.
I had a 11 lbs AGM racing battery and it doesn't like to "take a charge " well, same with my OE style AGM. They are slow excepting of "the charge". I read somewhere that is the bad side of the AGM MO.(modus operandi).
My Hyundai alternator puts out 14.1 to 14.6. My newer AGM when kept up and manually charger as an internal resistance of between 3.75 to 5.30 NOW. It was only at a 45% health and 55% charge. LIke I said, the AGMs in my car just don't quick charge like a regular flooded lead acid. The battery will last 3+ years like this, but it is beating itself up with no solid charge by the alternator. I have a Big Three cable system installed with large and multi cables of very high end copper and all connections are anti-oxed. I do know this battery likes my 40 amp garage style 15.9 volt charger. I have 3 different AGM chargers and both those have been tested on this battery. I am using those for my every other day charging routine. Two are PulseTech chargers, the other is a high end Minkota AGM charger.
I think my next battery for winter will be a quality flooded lead acid conventional battery. I myself am not impressed with AGMs, or at least the plate style. I have to research if the spirial ones except a charge faster and better. I am still in research mode with my battery.
I question if Hyundai even has a AGM algorithm, it would not surprise me if they DID NOTHING to get a proper charging program for a AMG battery.
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edyvw
$50 site donor 2025
That would be negligence.
BMW for 20yrs has different profiles for different batteries. For example, my E90 has two battery profiles, flooded and AGM, and then 10 different amp profiles for each type of battery.
So, I had a flooded 80ah battery but installed a 95ah AGM. In BMW software, you code from flooded to AGM and then choose closest or exact Ah profile, which in my case is 90ah.
So, is there Hyundai software? A better OBD scanner might have the option to change it.
Not all of it, the cca is basically the maximum current the battery can deliver, for a very short time. Even a nearly depleted battery can deliver a lot. From fully charged to near depleted, on a healthy battery is maybe 30% difference in cranking amps.
Of course depleted batteries don't stay healthy.
That’s a Nissan “smart charging issue” more than the battery. My wife’s 6 month old EFB went bad and the dealer replaced it with an agm. Less than 2 weeks and no real short trips and the battery was down to 70% of its charge. Precisely why I’m following the advice of a 30 yr Nissan tech and just replaced my 21 battery with a deka gold. I’ve watched all of my Nissans put out 14.2 volts at startup then throttle down to 12.9 for an hour. Sometimes lower.
I disabled the “smart charge” long ago. It runs off the alternators internal voltage regulator. Like I said - it now floats between 13.2-13.5 after it senses the battery is full according to it. Never below.
You might want to measure your battery tray & do a little research, IIRC some Hondas can handle a bigger battery than the tiny 51R.
^^The 51R is a smaller battery. Might you want to go larger, if one fit.?
A member here provided the group # for the larger battery originally fit. Honda retrofit a 51R into Accords.
The one I was caring for was a 2010. Drastically reduced driving during 2020-2021 hastened the death of the 51R.
I recall the 'full sized one' being a 24. However, I didn't take notes.
A member here provided the group # for the larger battery originally fit. Honda retrofit a 51R into Accords.
The one I was caring for was a 2010. Drastically reduced driving during 2020-2021 hastened the death of the 51R.
I recall the 'full sized one' being a 24. However, I didn't take notes.
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