yellowtop optima not holding charge?

[vanhack]

It is now 16 months since I installed a dual battery system in my camping 4x4 (nissan patrol). I have a 50 quart (47l) ARB fridge fed by a D34/78 55Ah Optima yellowtop, charging the main battery (normal cranking SLA) battery and Optima is an Australian made piranha dual battery management system, DBE180sx. This dual battery management system is a voltage sensing isolator, i choose it due to availability here in Dubai UAE and others reporting good results from it.

The optima powers my arb fridge, rear LED fog lights that are also extra brake lights, and a rear led work lamp, which also switches on when car is in reverse gear. I also power a USB port that i use for an extra LED strip light and recharging mobile phones when engine is off. All other electrics are powered from the main starter battery, uhf/VHF radio, stereo amp, headunit and GPS and 3 front LED spot lights.

Since last 3 weeks i have noted that my fridge shuts of before 12 hours, perhaps around 9-10 hours, so i started recharging the optima with a AGM charger to revive it, as it may have been powering the fridge without a charge for more than 14 hours and my driving time would not have charged it fully. I believe the optima should reach 13.1-13.2V when fully charged. After charging it with my AGM 3 stage charger, the optima would settle at 12.6V. I have since bought a CTEK 7 stage charger that has ability to desulphate and float charge the battery. I have not seen the charger detect sulphation, so does not go into desulphation, i believe that it would only if beloe 10.5v, if i am correct in my reading. i use the CTEKs 'snowflake' mode as this is recommended for optima batteries and boosts the voltage output needed for deepcycle AGM batteries.

i have just removed it from a 24 hour charge cycle, with it on float charge for more than 12 hours, and it has trickled down to 12.7V in 30 minutes or so.

I am not sure what to do now, this Optima is only 16 months old, just 4 months outside the 12 month warranty that we get here in Dubai, as Optima distributor does not give 3 years as in the US.

Note the ARB is set to medium shut off, therefore shuts off when optima reaches 11.4v and will only restart if 12.2v detected, which would be engine start.
piranha allows alternator to charge auxilliary optima battery if 13.4v detected and cuts off if main battery reaches 12.8V when engine is on.

Alternator output is regulated to 14.1 to 14.7V 70Amps maximum

 

[Cult Hero]

Hate to say it but that has been my experience with optima. I had one that died in less than a few weeks. I returned it and switched.

I have since switched to interstate and odyssey agms

 

[Ducky's Dad]

Before you give up on it, try multiple desulfation cycles with the battery completely disconnected from load, resting overnight between cycles. Test the open circuit voltage after the overnight rest off the charger and see if the OCV begins to creep up over the course of a few cycles. If you can get it to stabilize at 12.9 or better you might consider swapping it with the starting battery until it is no longer useful. I have had a pair of Optima Yellow 34/78s in one of my trucks for several years (5?) with no issues, on a standard GM 105amp alternator. I don't think I have ever run a conditioning cycle on those batteries, but that truck is my daily driver.

 

[dstock]

Having gone through similar issues with a dual battery system and Diehard Platinums (re-badged Odyssey), the process you are going to have to work through before deciding the Optima battery is an issue, is if your whole system is charging properly to begin with or has the Optima been getting deeply discharged and not properly recovered in the first place. Deep discharges over time without proper recovery will shorten a battery's life regardless of the brand. So while it's easy to say the Optima now has a resting rate issue based on their spec, the real question is how did it get that way.

If it were me, (and it was) go through your entire system looking to make sure everything is functioning as it should. I had a very reputable and expensive dual battery system that turned out not to be doing it's job and since I swapped the system out I have not had any issues. Granted, I went through my whole system checking for drains etc before that conclusion was reached. It's a huge pain but worth the effort in the long run.

I also recommend solar if you aren't going to be driving much as a way to keep batteries topped off especially in high ambient temps.

 

[vanhack]

Hi ducky, my starting battery is normal starter battery, not a deep cycle.
DSTOCK my optima is used for fridge and extra brake and reverse light duty. I do have my fridge on always, and it has a 11.4V minimum setting, so fridge will turn off when 11.4v is detected from the optima. In theory the optima only reached 11.4V. As the car that is installed with the optima is a daily driver it is only possible to reach that levels, on the, weekend.

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[dwh]

Daily driver doesn't mean much. A vehicle charging system spends most of its time trickle charging. Unless you are daily driving for hours every day, it's likely that your battery is suffering the effects of long term chronic undercharging.

 

[dstock]

There are much smarter folks on here than I where this stuff is concerned...but 11.4 is a deeply discharged battery. I'm not clear on how many times you have reached 11.4?

 

[dstock]

Daily driver doesn't mean much. A vehicle charging system spends most of its time trickle charging. Unless you are daily driving for hours every day, it's likely that your battery is suffering the effects of long term chronic undercharging.

That's what I was thinking as well...

 

[DiploStrat]

Daily driver doesn't mean much. A vehicle charging system spends most of its time trickle charging. Unless you are daily driving for hours every day, it's likely that your battery is suffering the effects of long term chronic undercharging.

Agreed. The vehicle's alternator/regulator combo is going to read the voltage of the starter battery. If that voltage is high, then the battery is "fully" charged and the alternator will shut down.

In order for the alternator to "see" the second battery, you have to do one of two things:

-- Connect the second battery with a cable of sufficient size to allow the demand of the second battery to register, or,

-- Use a B2B (battery to battery or DC to DC) charger which will artificially drop the voltage of the starter battery to (typically) 13v, thus causing the alternator to start producing current. (Gross oversimplification (forgive me Charles Sterling, Sr.) but close enough for our purposes.

Connect your second battery with a small wire and drive only three hours a day and you will eventually have a sulphated and dead second battery.

 

[vanhack]

As mentioned I have a dual battery management system installed. I also have a voltage monitor on both batteries. From the battery monitor I do notice that the alternator starts supplying charge to the optima within a couple of minutes of engine starting.

I was not aware that 11.4V is deeply discharged, as optima say 10.5v is deeply discharged. It seems I should not be having my fridge on always, as this is draining the battery and my 40 minutes commutes both ways to work are not enough to recharge the battery.

I only switch my fridge off when on vacation. Otherwise it has been on since may 2015, everyday.

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[DiploStrat]

Do the math.

Most refrigerators draw between one and five amps per hour, depending on size, load, ambient temperature. So call it two amps per hour, or 2Ah. Sooooo, 12 hours of refrigerator use on a 55Ah battery is 50% discharge. That is a lot.

What is your recharge rate? With 2x125A alternators and 2x 1/0 AWG wire, I start off at about 100A, but that only lasts about thirty minutes. Thereafter the charge rate drops to below 50A because the internal voltage of the battery rises. I would bet you don't have as much alternator/wire. You need to clamp an ammeter on your cable to see what kind of amp flows you are getting and for how long. I would be surprised if you get 50A for more than 15 minutes and even lower rates thereafter.

And finally, most AGM batteries (e.g. Lifeline) call for two hours of absorb charging AFTER you reach 100% charge.

Bottom line, two 40 minute drives per day probably aren't even beginning to do the needful.

You may want to start looking for at least 5A (10A would be better) of solar or a good shore charger. (100w of solar generally gives you 5A of charge.)

These are just guesses, and YMMV.

 

[vanhack]

Diplosat I should not be using my fridge always. Because my daily drive will not charge it enough. Only when I am camping or on weekend trips. I also do believe our 3 months of summer here does not allow alternator and battery to charge properly. My alternator is factory, and only outputs 70amps, again not enough to recharge the battery. Solar would have been an option, but I am about to move into a new office with underground parking, so no go there. I should stop using the fridge always.

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[DiploStrat]

... I should stop using the fridge always.

No, but you do need to know how much it draws, the capacity of your battery, and your ability to recharge that battery.

I run a small Nova Kool refrigerator full time, but I also have a 600Ah battery bank. (Run a lot of other loads as well.) And 500w of solar.

My only point is that one should not demand the impossible. A refrigerator is a bigger draw than most folks realize and even more so in the Gulf.

In your case, you may need another camper battery and a good shore charger in that new basement.

Good luck!

 

[rayra]

Sounds like the OP needs to move up to a higher output alternator. There's apparently a 110A variant available -
https://www.google.com/search?q=nissan+patrol+alternator+options&ie=utf-8&oe=utf-8

 

[dwh]

In the world of "12v nominal" batteries, 10.5v is considered a dead battery. So yes, that would certainly be "deeply discharged".

A larger alternator won't really help. Oh, it might you a few more amps in the first few minutes of driving, but once the battery voltage (and resistance) rises, there won't be many amps flowing, and again, from that point on you are looking at hours of trickle charging to get the battery topped off.

You might be able to recover that battery by putting it on a shore power charger that does desulfation. After a few weeks of that you might see some improvement.

I wouldn't hold my breath though...