Lets talk batteries

[JEFFYBOI]

So today i got into a conversation with a guy i recently met regarding the resting voltage of his AGMs. He had a pic of his CT VM reading 13.8V with car off and system on with vol. on low end ( this is what he said). It really seems high to me and thats why im here to get some input. He wont list the brand but he claims they are 2.25-2.3V per cell 6 cell AGMs. I found a chart on AGMs and now im kinda concerned if my AGMs are low or maybe a weak cell? My batteries are only sitting at about 13V. If this chart is correct, i feel my batteries are resting fairly low....

[hdorre]

Looks like safe floating voltages for the batts

Here's XS, for reference..

[Tarball]

Remember, Rest, Float and Charge are each different.

[martydmb]

Wanna know what he did. He had them charged by his alt. Turned car off. Then turned radio on. Guess what. Mine will "Float" at that also for a lil bit. But guess what. Let it sit with car off after a period of time and check and I bet you its around 12.8 give or take. Resting voltage and floating voltage are 2 different things. He was at floating volatage.

[JEFFYBOI]

Wanna know what he did. He had them charged by his alt. Turned car off. Then turned radio on. Guess what. Mine will "Float" at that also for a lil bit. But guess what. Let it sit with car off after a period of time and check and I bet you its around 12.8 give or take. Resting voltage and floating voltage are 2 different things. He was at floating volatage.

Remember, Rest, Float and Charge are each different.

Looks like safe floating voltages for the batts

Here's XS, for reference..

Ok so charging and resting voltage is pretty clear to me. I guess im not exactly familiar with floating voltage. So would you say my batteries resting around 12.9-13V is normal? Your right because he was driving through a drive through and parked to eat his food and thats when he shot the pic of his voltage. Floating voltage specs tell you weather your batteries are being over charged or under charged? Just trying to understand the purpose of floating voltage. First thing i thought was his volt meter was off or he was overcharging his batteries.

[TaylorFade]

Let me guess...

He's using magic NSB batteries?

12v batteries are 2vpc nominal (duh). 2.12, maybe 2.14vpc fully charged (resting voltage).

2.25-2.3vpc is float voltage. Like....a trickle charge.

Batts can hold a surface charge higher than resting voltage for a while (depends on age), but if they don't settle out to < 13v then they aren't friggin 12v batts.

I have this "conversation" all the time with the physicists on FB. It goes like this...

"ZOMG! My magic NSB batts are holding 14v with my stereo playing!"

"ORLY? Try it with the car off and see how long they hold 14v"

"Dooood...I'm telling you,these batts are AMAZING!"

"They are good batts, but they aren't magic"

"Bruh, I had Brand X batts before and I would drop to 9v."

"Then your old batts were bad"

"You're just a hater. I'm holding 14v"

"What kind of amperage draw are you clamping?"

"Wut? I dunno. I have a Brand X 300A alternator."

"Well... go thank Brand X for your voltage."

You get the idea.

[JEFFYBOI]

Let me guess...

He's using magic NSB batteries?

12v batteries are 2vpc nominal (duh). 2.12, maybe 2.14vpc fully charged (resting voltage).

2.25-2.3vpc is float voltage. Like....a trickle charge.

Batts can hold a surface charge higher than resting voltage for a while (depends on age), but if they don't settle out to < 13v then they aren't friggin 12v batts.

I have this "conversation" all the time with the physicists on FB. It goes like this...

"ZOMG! My magic NSB batts are holding 14v with my stereo playing!"

"ORLY? Try it with the car off and see how long they hold 14v"

"Dooood...I'm telling you,these batts are AMAZING!"

"They are good batts, but they aren't magic"

"Bruh, I had Brand X batts before and I would drop to 9v."

"Then your old batts were bad"

"You're just a hater. I'm holding 14v"

"What kind of amperage draw are you clamping?"

"Wut? I dunno. I have a Brand X 300A alternator."

"Well... go thank Brand X for your voltage."

You get the idea.

Actually they are some off brand AGMs. I guess when I asked him resting voltage he didn't understand the batteries have to sit for a little while. He was just bragging--- " I got my car off and system on low and my batteries are putting in work saying they are resting at 13.8V. O well sometimes its not worth the argument. Hardheaded and stubborn people drive me nuts! I still wanna looking into floating voltage a little bit. Something im not really familiar with.

[Bump4life]

floating voltage is essentially a charge. a battery charger goes into float mode. pretty much this is a trickle charge. if you continued to charge your batteries at charging voltage once full they would gas and degrade the battery. the float charge just keeps them topped off without ruining. pretty much charges them up, then lets them fall back down to resting, then charges a little and lets them fall back down.

a float point on a battery can only be obtained after charge from an outside power source. this higher float voltage creates a surface charge which will only last at most 24 hours maybe 48 hours before the battery falls to its true resting voltage.which should be 13.1 ish or under for agm

[CleanSierra]

Side note, by big data batteries are floating currently at 13.2 @ ~85-90°. Is that good?

[JEFFYBOI]

floating voltage is essentially a charge. a battery charger goes into float mode. pretty much this is a trickle charge. if you continued to charge your batteries at charging voltage once full they would gas and degrade the battery. the float charge just keeps them topped off without ruining. pretty much charges them up, then lets them fall back down to resting, then charges a little and lets them fall back down.

a float point on a battery can only be obtained after charge from an outside power source. this higher float voltage creates a surface charge which will only last at most 24 hours maybe 48 hours before the battery falls to its true resting voltage.which should be 13.1 ish or under for agm

Good info! I think that actually answered all my questions. Lol, Thanks!