charging deep cycle batteries?

[bgowdy 5,000+ posts]

How high of voltage can you safely charge deep cycle batteries at with a 2 amp charge?

Just curious. My smart charger reaches 15.5v during charge while on 2 amp deep cycle setting. It shuts it self off of course when full charged but I didn't know they could be charged at that high of voltage.

Thanks

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[shizzzon 10+ year member]

Well, this is tricky to answer so i'll tell you this-

If i worked for the company who built the batteries, i would say NO!, that's too high.

However, if i were a competitor, i would say you are attempting to train your battery but i believe you are also doing it dangerously.

To train, you would need a high voltage of around 16v but i believe 2A maybe too high. I believed it was less than that, but anyway-

Training a battery under high voltage, low current will force it to rest at much higher voltage.

Only BIG problem with this is if you are using it for daily driver, this technique is completely a waste of time.

So if you are, stop doing that immediately and get a proper AGM charger.

The DieHard Platinum chargers from Sears work fine on all car audio AGM batteries.

 

[bgowdy 5,000+ posts]

Well, this is tricky to answer so i'll tell you this-
If i worked for the company who built the batteries, i would say NO!, that's too high.

However, if i were a competitor, i would say you are attempting to train your battery but i believe you are also doing it dangerously.

To train, you would need a high voltage of around 16v but i believe 2A maybe too high. I believed it was less than that, but anyway-

Training a battery under high voltage, low current will force it to rest at much higher voltage.

Only BIG problem with this is if you are using it for daily driver, this technique is completely a waste of time.

So if you are, stop doing that immediately and get a proper AGM charger.

The DieHard Platinum chargers from Sears work fine on all car audio AGM batteries.

I mean its a smart charger with that feature. It only goes to 15.3. I thought it went higher. Once they are charged it goes down to 13.3v and sits there only charging when they drop below a certain point. But it only charges at 15.3 when you first hook them up

 

[bgowdy 5,000+ posts]

Well, this is tricky to answer so i'll tell you this-
If i worked for the company who built the batteries, i would say NO!, that's too high.

However, if i were a competitor, i would say you are attempting to train your battery but i believe you are also doing it dangerously.

To train, you would need a high voltage of around 16v but i believe 2A maybe too high. I believed it was less than that, but anyway-

Training a battery under high voltage, low current will force it to rest at much higher voltage.

Only BIG problem with this is if you are using it for daily driver, this technique is completely a waste of time.

So if you are, stop doing that immediately and get a proper AGM charger.

The DieHard Platinum chargers from Sears work fine on all car audio AGM batteries.

Seeing its a deep cycle setting on the charger I don't see why it would not be safe though, seeing its programmed that way

 

[Jeffdachef 5,000+ posts]

Seeing its a deep cycle setting on the charger I don't see why it would not be safe though, seeing its programmed that way

most deep cycles and agms dont like charging above 15. From what I see, it shortens the lifespan and lowers the total amount of amperage it can hold.

 

[bgowdy 5,000+ posts]

most deep cycles and agms dont like charging above 15. From what I see, it shortens the lifespan and lowers the total amount of amperage it can hold.

Understood. Now that its charged them all the way up, its resting them at 13.3v so in guessing its ok. Like I said its the built in setting for the smart charger. You think if it was to dangerous they wouldn't have programed the charger that way right? Again its the deep cycle setting on the charger.

 

[shizzzon 10+ year member]

If everything was built right, then there would be no competition.

they should not be charged above 14.4v for long life or above 14.7v for decently long life... however its worded.

In a vehicle, its fine as voltage fluctuations occur.

however if they do not, its a result of batteries warping under the hood from overcharging.

That area is hot and heat requires less voltage.

In certain conditions in the summer, charging above 14.2v is dangerous.

Thats why pcm controlled alts in newer cars is a big plus! They change voltage automatically so overcharging is not possible.

 

[NASTY08IMPALA 5,000+ posts]

Both my schumacher agm chargers charge up to 15.6..and have been charging my 3 batts for 3+years no problems ..and i run my mechman externally regulated at 15.1 and have had no issues ..so i dont see the big deal

 

[NASTY08IMPALA 5,000+ posts]

And pcm controlled alts are crap thats exactly why i externally regulated ..when my impala kicks into 3cyl mode it drops voltage to 12.9 and doesnt come back up until u restart the car

 

[shizzzon 10+ year member]

It typically isnt because the resistance goes up closer to full charge which pulls less current from alternator.

High voltage and high current will kill a low esr battery.

there is no way around that.

Notice how the wording is long life suggestion.

If proper care is taken for most agms, they will not reach 60% SoC rest for 10-15yrs.

 

[shizzzon 10+ year member]

12.9v is shutting your alt off. Thats different.

im referring to regulating the actual charging voltage while its on.

And they are not crap.

if i were to bypass my regulator in my alt and go external regulation, id lose temp sensing protection on my rectifier.

That would be a stupid thing for me to do.

This protection system allows me to abuse my alternator without possible failure to the rectifier.

 

[NASTY08IMPALA 5,000+ posts]

12.9v is shutting your alt off. Thats different.im referring to regulating the actual charging voltage while its on.

And they are not crap.

if i were to bypass my regulator in my alt and go external regulation, id lose temp sensing protection on my rectifier.

That would be a stupid thing for me to do.

This protection system allows me to abuse my alternator without possible failure to the rectifier.

Well in my case anytime u get into a cruising speed and car kicks down to 12.9 thats just a really shittty starting voltage for my amps..hence the ext regulation

 

[shizzzon 10+ year member]

Those regulators do that to conserve fuel economy.

once a large enough load is present, they do kick back on.

There is always a purpose.

 

[NASTY08IMPALA 5,000+ posts]

Those regulators do that to conserve fuel economy.once a large enough load is present, they do kick back on.

There is always a purpose.

Yes i know its called afm (active fuel management) but once it kicks in 3cyl mode even when it kicks back into 6cyl mode it wont go above 13v..and car gets shittt for gas mileage so idk what chevy has goin on with this "fuel saving mode"

 

[bgowdy 5,000+ posts]

Both my schumacher agm chargers charge up to 15.6..and have been charging my 3 batts for 3+years no problems ..and i run my mechman externally regulated at 15.1 and have had no issues ..so i dont see the big deal

That's how my smart charger does. It charges up to 15.3 but onces it hits a certain point it shuts down and rests /maintains them at 13.3