Optima Batteries not charging fully

[jimmbo]

Sometimes you have to connect a wet cell battery in parallel with the AGM to fool the charger to put out enough voltage/current to charge the AGM. Goofy things

 

[bruceb58]

Sometimes you have to connect a wet cell battery in parallel with the AGM to fool the charger to put out enough voltage/current to charge the AGM. Goofy things

That's only when they are severely discharged.

 

[dannyual767]

just wanted to update my thread. With the several automatic chargers I could not get them to stay past 12.5. - i now have both batteries at 12.8 now.

What i did was get an old 10 Amp manual charger - i put a separate 2 hour charge in each one (used a timer on my phone) - Both batteries got warm when I did this (but not hot) - this raised them to 12.7 resting

I waited 2 days - then I put a 3 hour charge in both of them (this time they only got slightly warm) - this got them both to around 12.8 resting. And it's holding nicely I owe the credit to this video - https://www.youtube.com/watch?v=6x-JfckAt20

i realize the batteries should be at 13 but I think 12.8 is a nice compromise vs buying new ones for now.

Ding, ding, ding, ding!!!! We have a winner. I read through your entire battery thread and I was wanting to post what you wrote because that has been my experience with these new, smart chargers. I've got this NOCO Genius smart charger:

 

[dannyual767]

This NOCO Genius charger is too "smart" for it's own good. It quits charging a 50% discharged AGM battery within minutes and says it's completely charged .

My dad recently passed away and I got his two old school battery chargers and they just blow this stupid smart charger away. They'll actually charge a battery!

It's almost like the smart battery charger manufacturers are in bed with the battery companies and they purposely make the new chargers unable to charge our batteries so we'll go out and buy more overpriced batteries :mad-new: . I'm being a little sarcastic here..........but maybe not!

BTW, one of his battery chargers was so old it says, "Made in USA" on it! It's now my primary battery charger.

 

[bruceb58]

Should never have bought a 3.5A charger in the first place. AGM batteries need to be charged at a much higher current than that. For example, Odyssey in their approved list of chargers has the chargers at least 15A output.

 

[dannyual767]

Should never have bought a 3.5A charger in the first place. AGM batteries need to be charged at a much higher current than that. For example, Odyssey in their approved list of chargers has the chargers at least 15A output.

I'm sorry. I should have been more specific and said that my main battery charging is for smaller, personal watercraft batteries.

 

[Fed]

My next battery charger will be big, dumb & have a Voltmeter & Ammeter on it.

 

[dannyual767]

No Title

Dang! I posted the wrong link in post #23. Here is a pic of the NOCO Genius 7.2 amp charger that I own. I wouldn't recommend it.

 

[bruceb58]

Dang! I posted the wrong link in post #23. Here is a pic of the NOCO Genius 7.2 amp charger that I own. I wouldn't recommend it.

Out of curiosity, do you keep your battery fully charged 100% of the time? Don't let it discharge over long periods of time?

I have a lot of 3 stage smart chargers on different boats and RVs. I would never buy anything other than a smart charger. If an RV has an old convertor that is not 3 stage, it immediately gets pulled and a 3 or 4 stage version gets put in its place.

 

[SkiDad]

I'm the thread starter. In my case, I bought this boat this spring from a private owner - the batteries were only 1 season old (installed spring of 2016) but the stickers showed 7/2015. Well anyhow I think the owner left them in a low charge state over the winter. At one point I measured 10.5v. My smart charger was able to get both of them to 12.4-12.5 or so after charging each battery for 24 hours. But that is all they could do because they kept thinking they were fully charged.

I think if the batteries were maintained i think a smart charger is the way to go. My batteries were sulfated pretty good and the smart chargers don't have a good way to deal with that. Overcharging helps break up the sulfation. I'm not sure i could get away with what I've done on some AGM batteries, but these have such low resistance that the are not getting hot - maybe 100 degrees

 

[Maclin]

The latest charger I bought has the AGM setting, along with a percent charged display and voltmeter. It also has a Marine and Power Sports setting, power sports is for the smaller PWC type batteries and uses the smaller amp range. If I inadvertently have it on the AGM setting and hook to my regular battery the readings are way lower, does not think the battery is charged but to 70% even if I know it is at 90% or more and I am just "topping it off". Changing the setting from AGM back to normal then shows 89-90% and charges for 2 hours or so then goes into maintenance mode.

 

[SkiDad]

just a further update - over the last 2 days I put an additional 4 hour 10 amp charge in each battery and I now have them to 13V each ! I'm really happy with the outcome b/c I didn't want to buy batteries this year. I think part of the secret is waiting a few days and letting the sulfation dissipate (totally guessing)

So to sum up
2 hours @ 10 Amps - went from 12.5 to 12.7 (waited 2 days)
3 hours @ 10 Amps - went from 12.7 to 12.8 (waited a week)
4 hours @ 10 Amps - went from 12.8 to 13.0

I'm not sure I would recommend what I did (i monitored the batteries every hour when I did this) So if you try this be very careful

 

[bruceb58]

You have to take the battery off the charger and let them sit for 30 minutes before taking the voltage reading. What you are measuring is a "surface" charge which dissipates.

According to Optima, you battery(Blue 34M) has a fully charged voltage of between 12.6V and 12.8V

One huge advantage of AGM batteries over flooded lead acid are that theu are less prone to sulfation.

 

[SkiDad]

You have to take the battery off the charger and let them sit for 30 minutes before taking the voltage reading. What you are measuring is a "surface" charge which dissipates.

According to Optima, you battery(Blue 34M) has a fully charged voltage of between 12.6V and 12.8V

One huge advantage of AGM batteries over flooded lead acid are that theu are less prone to sulfation.

Hi Bruce, I'm measuring the batteries after sitting for 12 hours. You are right the 34m (a starting battery) is 12.6-12.8 but I have the D34M with are deep cycle and are supposed to be 13.0-13.2.

 

[bruceb58]

Hi Bruce, I'm measuring the batteries after sitting for 12 hours. You are right the 34m (a starting battery) is 12.6-12.8 but I have the D34M with are deep cycle and are supposed to be 13.0-13.2.

Sounds good. Your batteries are fine.

 

[dannyual767]

Out of curiosity, do you keep your battery fully charged 100% of the time? Don't let it discharge over long periods of time?

I have a lot of 3 stage smart chargers on different boats and RVs. I would never buy anything other than a smart charger. If an RV has an old convertor that is not 3 stage, it immediately gets pulled and a 3 or 4 stage version gets put in its place.

I had 3 older PWC AGM batteries that were in varying stages of "distress." Two of the three really couldn't sit for more than 3-4 weeks without being charged. After I bought the NOCO Genius, I thought my charging would get easier. Wrong. The Genius couldn't and wouldn't charge the batteries. Once I put an old school charger on them, they charged right up and I was able to start my jetskis.

As of today, two of the three are gone (sold the skis) and the third gets charged with my dad's old school charger. My other two PWC batteries are much newer with no problems. Perhaps the Genius can keep good batteries good. I needed to charge older, not so good batteries and the NOCO Genius was 100% unable to do that.

 

[bruceb58]

I have an Odyssey battery in my Harley. I use an Odyssey smart charger. Works perfectly. The Harley uses the same sized battery as your PWC does.

I have a bunch of smart chargers for my vehicles. One RV, 2 boats, one portable, one motorcycle. All work fine.

 

[dannyual767]

I have an Odyssey battery in my Harley. I use an Odyssey smart charger. Works perfectly. The Harley uses the same sized battery as your PWC does.

I have a bunch of smart chargers for my vehicles. One RV, 2 boats, one portable, one motorcycle. All work fine.

Bruce I get it. A smart charger has no problem dealing with a good battery. Maybe I'm not thinking about this properly but quite frankly, I need a battery charger for when my battery is NOT "good." In this case, the NOCO was a no-go for me.

In addition, I've got a smart, maintainer charger that I got from my brother when I got the GP1200 ski from him. This was my first experience with smart chargers and I learned that they're not so good with batteries that aren't perfect. I need a charger that can recharge batteries that need charging. My two smart chargers are very challenged in that regard!

The NOCO Genius that I purchased is sold as a battery charger as well as a maintainer. I was not able to get it to charge my batteries when they needed to be charged. My dad's 30+ year old, old school charger had no problem getting the job done.

 

[bruceb58]

I have a smart charger on a NOT so good battery in a camper and it works fine. I do try to not let my batteries get into that state since I keep them 100% charged all the time. Usually with batteries, it's human error that lets them get into that NOT too good state.

I threw all of my 30 year old chargers away since they can ruin a battery so easily. Not cost effective using an old tech charger on new expensive batteries especially AGMs that run over $200 each. I spend my money on a good smart charger for my Odyssey AGMs.

If you ever look at newer RVs and also look at what older RVs get updated to, they all get 3 or 4 stage chargers now. Golf cart battery chargers are also the same....all are smart chargers. Expensive deep discharge batteries ALL use smart chargers.

Because you had a bad experience with a poorly maintained battery doesn't mean that smart chargers are bad.

 

[Maclin]

I had a lead acis boat battery go down all the way when I had left the key on for several months. Dead, no horn, nuttin. Hooked up a smart 10/6/2 amp smart charger, it showed an error as if it was hooked up backwards or something and would not start charging. I waited a bit, tried a couple of unplug/plug cycles, same thing. The charger had a 50amp "start" setting also, so I tried that for about 10 seconds or so, then reset the charger to see what it would do. It showed a good hookup then started charging right away. I used that battery until the boat sold 2 years later.