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Old 06-11-2020, 20:27   #1
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Do I need a Different Batter Charger?

Hi Folks,
I have a bank of 4 T05 deep cycle batteries for a total of 450 Amps. I have the boat on the hard for a refit which will last the winter. I would like to keep the batteries healthy and in tip top condition. In season they are kept charged with 270W of solar and the alternator when under power. I never plug in.
The charger is an old Freedom 10 charger/inverter properly wired.
When researching a charging regimen, I referred to the Trojan literature-it stipulates the following charge rates :

Bulk 14.82 Float 13.50 and Equalize 16.2.

The freedom is not programmable but offers two selectable charge rates-one for a cool bank and another for a warm bank. The cool setting charges at:

Bulk 14.3, Float 13.4 and Equalize 16.3.

My question is do these charge rate differences affect the long term health of my bank if I leave it plugged in for the winter? Is it ok to leave it plugged in for the winter or should I charge/equalize and then unplug? I should mention that the batteries are kept charged in the summer with a 240W array and never plugged in during the sailing season. I'd like to keep these batteries in the best possible charge state over the winter as they get cycled deeply on a daily basis in the summer.
Appreciate any thoughts.
Jim
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Old 07-11-2020, 04:26   #2
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Re: Do I need a Different Batter Charger?

If youíre cycling ďdeeplyĒ all summer and then only charging with 270 watts, anything the charger does will be better for the batteries than that.
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Old 07-11-2020, 04:48   #3
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Re: Do I need a Different Batter Charger?

Sailmonkey
You are right,"discharging deeply" was too vague-they never get below 12.2V in the summer-so 50% discharge is what I am calling a deep discharge.
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Old 07-11-2020, 05:20   #4
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Re: Do I need a Different Batter Charger?

Still though, doing that discharge daily, Iíd bet youíre never fully charged all summer. I still maintain that the charger will be far better for the batteries than your summer treatment.
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Old 07-11-2020, 05:45   #5
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Do I need a Different Batter Charger?

You have multiple issues here. Yes, You have likely killed your batteries by charging them at different voltages than recommended.
240w of solar is also probably way to little to appropriately keep a 450amp hr battery bank charged.
There is just absolutely no way that 240w of solar can put in 225amps at 12v daily. If you are reaching 50% DOD like you say.
The math isnít there plain and simple and never will be. Even under Ideal laboratory conditions you wonít be able to cycle 2.7KW though. My 660watts of high efficiency Panasonic panels (in sunny S Florida) put an average of 1.5 KW daily with a most Iíve seen of ~ 2.8.

Undercharging is also a classic way to kill your batteries.

My initial thought is that you have a lot of issues and likely would benefit from hiring someone a little more knowledgeable who can design a proper battery and charge system for you.
Why did you spend thousands of dollars on batteries and get a cheap charge controller?
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Old 07-11-2020, 07:38   #6
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Re: Do I need a Different Batter Charger?

Quote:
Originally Posted by Sailing Ohm View Post
You have multiple issues here. Yes, You have likely killed your batteries by charging them at different voltages than recommended.
240w of solar is also probably way to little to appropriately keep a 450amp hr battery bank charged.
There is just absolutely no way that 240w of solar can put in 225amps at 12v daily. If you are reaching 50% DOD like you say.
The math isnít there plain and simple and never will be. Even under Ideal laboratory conditions you wonít be able to cycle 2.7KW though. My 660watts of high efficiency Panasonic panels (in sunny S Florida) put an average of 1.5 KW daily with a most Iíve seen of ~ 2.8.

Undercharging is also a classic way to kill your batteries.

My initial thought is that you have a lot of issues and likely would benefit from hiring someone a little more knowledgeable who can design a proper battery and charge system for you.
Why did you spend thousands of dollars on batteries and get a cheap charge controller?


Iím thinking you need to re-read the original post.

There is no mention of the charge controller, Trojan t-105ís are not thousands of dollars.

Per the original question, the charger (assuming it switches to float properly) will do no harm left on all winter. It will in fact treat the batteries far better than the daily cycle that cannot ever fully recharge during the summer.
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Old 07-11-2020, 08:59   #7
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Do I need a Different Batter Charger?

Quote:
Originally Posted by Sailmonkey View Post
Iím thinking you need to re-read the original post.

There is no mention of the charge controller, Trojan t-105ís are not thousands of dollars.

Per the original question, the charger (assuming it switches to float properly) will do no harm left on all winter. It will in fact treat the batteries far better than the daily cycle that cannot ever fully recharge during the summer.


If it does not reach the appropriate voltages per the battery manufacturer then yes it will do harm to the batteries, I donít see how that can be challenged...
If a charger is either constantly under or over charging a battery system then you will experience battery damage and reduced lifespan.

And yes while there is no official mention of a solar charge controller the OP says that solar charges the batteries during the summer so one must assume a solar charge controller is used. Therefore potentially up to half (at least a considerable portion) of the batteries life is spent on a solar charger so it should be considered. Especially when it sounds like the batteries could rarely be getting fully what they need whether on solar or shore power.

Once you add all batteries, and necessary wiring Iím sure the Installation came close to if not over $1k. He has at least 4 batteries if running a 12VDC system @450amp. Thatís also probably before chargers, controllers and assuming a DIY situation. And thereís always some additional unfactored in costs.
Things add up so I maintain the thousands of dollars as the investment ballpark. Im basis this on personally doing a few battery bank design and installs for boats.

A battery charger can raise a battery to its absorb and then float charge while running no issue even if the batteries are damaged and you might even see that voltage stay for a few hours. But if the battery cells are damaged (due to under or overcharging) once you apply load or give enough rest time after charge youíll notice a quick drop in voltage and performance.
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Old 07-11-2020, 09:34   #8
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Re: Do I need a Different Batter Charger?

Quote:
Originally Posted by Sailing Ohm View Post
If it does not reach the appropriate voltages per the battery manufacturer then yes it will do harm to the batteries, I donít see how that can be challenged...
If a charger is either constantly under or over charging a battery system then you will experience battery damage and reduced lifespan.

And yes while there is no official mention of a solar charge controller the OP says that solar charges the batteries during the summer so one must assume a solar charge controller is used. Therefore potentially up to half (at least a considerable portion) of the batteries life is spent on a solar charger so it should be considered. Especially when it sounds like the batteries could rarely be getting fully what they need whether on solar or shore power.

Once you add all batteries, and necessary wiring Iím sure the Installation came close to if not over $1k. He has at least 4 batteries if running a 12VDC system @450amp. Thatís also probably before chargers, controllers and assuming a DIY situation. And thereís always some additional unfactored in costs.
Things add up so I maintain the thousands of dollars as the investment ballpark. Im basis this on personally doing a few battery bank design and installs for boats.

A battery charger can raise a battery to its absorb and then float charge while running no issue even if the batteries are damaged and you might even see that voltage stay for a few hours. But if the battery cells are damaged (due to under or overcharging) once you apply load or give enough rest time after charge youíll notice a quick drop in voltage and performance.


Youíre inserting information into the conversation that was not provided by the OP and seriously clouding the original question.

Itís obvious the batteries are most likely already damaged by the deep discharge and more likely than not undercharging by the solar. That said, a winter on a charge that only misses the target voltage by a few hundredths will do no harm.
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Old 07-11-2020, 11:45   #9
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Re: Do I need a Different Batter Charger?

The monkey is correct. To the OP: you can try to rejuvenate the bank by first cycling it down to 30% SOC, then fully charge with the shore power charger and when it reaches float, (and only then) top it off with water. Then let it stay in float charge for a couple days, then do the equalize.

After the equalize, you can improve by taking it down to 30% SOC again followed by a full charge and a couple of days of float charge.

They will then be as good as they can be. You can expand battery lifespan by fully charging them once every two weeks, using the engine, generator etc. and do an equalize procedure like described above every year.
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Old 07-11-2020, 12:06   #10
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Re: Do I need a Different Batter Charger?

Batter charger? What can't hit to first let alone a home run. Yeah, I'd change him.
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Old 08-11-2020, 18:39   #11
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Re: Do I need a Different Batter Charger?

Hi All,
I've been offline for a bit-sorry for the delay in responding. As you have all pointed out, I neglected to mention the Morningstar TriStar 30 MPPT controller-sorry about that ommission.

Rethinking my post, the batteries likely do not get discharged to 50% more like 25%. I don't have a gauge yet, but the the biggest draw is the fridge Well insulated-draws around 8 Amps -80-100 amps from sunset to sunrise. Everything else is low draw LED fixtures. Peak solar input is around 15 Amps so I estimate I'm adding about what I draw out-say 7 amps/hr over a 12 hours. Usually arount 10:00 PM the bank was at 12.4-12.6 so I don't think there getting crushed, Nor do I think they were ever in float except when the engine was spinning the 125Amp alternator.

So its a mixed bag, but I know T105's can take a lot of abuse. They are 6V wired in series and paralleled to yield a 450A bank. I just don't want to ruin them with an inadequate winter charging regimen. The battery charger/inverter is just a device for winter charging and equalizing.
My question was less about are my batteries trashed by undercharging -I don't believe they are-my question is about the worthiness of my charger as a winter charging mechanism given its generic non-adjustable charging profile.

The Trojans want Bulk 14.82 /the charger produces 14.3 Bulk
The Trojans want to Float at 13.5/the charge produces 13.4
The Trojans want to Equalize at 16.2/the charger equalizes at 16.3

The difference in the Bulk rate is 0.52V That seems like a lot to this non-marine electrician. Is this true?

The Float and Equalization differences are only off by 0.10. In my limited understanding 0.10 Volts is perhaps significant.

Are these differences in charge rates problematic? Do they justify shopping around for a new charger/inverter? The batteries are two years old the Heart Interface Freedom 10 charger came with the boat.
All advice and thoughts appreciated.
Jim
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Old 08-11-2020, 20:18   #12
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Re: Do I need a Different Batter Charger?

If your use is 80 - 100 amps from sunset to sunrise you are definitely not returning that to the batteries with solar. We figure 5 hours at full solar output in non-tropical latitudes, an hour or so more if in the tropics. This assumes good sun and no shading. In perfect conditions your max solar return is maybe 80 amps. Perfect is rare.

Your batteries have been suffering from PSOC throughout the seasons.

Any AC charger is a large improvement.

Get a good battery monitor - Victron BMV-700, 702, or 712.

Without this you don't have a clue where you stand.
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Old 09-11-2020, 03:38   #13
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Re: Do I need a Different Batter Charger?

The solar panels will easily keep the batteries topped off during the winter. You don't need the shore charger. You should be able to check the condition of the batteries with a hydrometer.
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Old 09-11-2020, 05:34   #14
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Re: Do I need a Different Batter Charger?

If you have easy access to the boat then do yourself and your batteries a favor. Follow the Jedi's advice. Once complete, and assuming your fridge is shut down for the winter and there is essentially no load, then if you want you can unplug and allow the solar to keep the batteries at float voltage.
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Old 09-11-2020, 05:40   #15
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Re: Do I need a Different Batter Charger?

I appreciate everyones input, thank you. This winter the panels are off the boat due to another project, so it has to be the charger or another charger. I like the idea of a couple of deep discharges and complete charge to float then equalize. Makes sense to me.
Anybody want to recommend a charger/inverter in place of the Freedom 10?
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