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Old 05-02-2016, 10:46   #46
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Re: Can my batteries be saved?

I think you should get a 12 to 25 watt solar panel with a voltage regulator to keep the batteries charged up. You could keep a monocrystalline 25 watt panel behind a port or hatch, one example is 21'" X 11 ". Monocrystalline is about two thirds the size of a polycrystalline. A 15 watt polycrystalline example is 14.4" X 14.1". If you do not run the refrigerator while moored, these solar panels should keep the batteries charged. Make sure no partial shadows fall on the solar panels because it can stop the charging. The cost is about $70.
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Old 05-02-2016, 15:05   #47
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Re: Can my batteries be saved?

Have you considered taking your Rolls batteries to the local dealer and having them test and equalize them? If they don't recover, then shouldn't they replace them under warranty?

I'm a big fan of golf cart batteries. Rugged, pretty forgiving, they stand up to the abuse of drunken golfers day in and out and they're really cheap at Costco ($83) and Sam's Club. They're 225AH and 60 lbs ea., 4 would get you 450AH (240 lbs), 6 would be 675AH (360 lbs), 8 would be 900AH (480 lbs.) and 10 would get you 1125AH (600lbs.)
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Old 05-02-2016, 15:39   #48
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Re: Can my batteries be saved?

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Originally Posted by socaldmax View Post
Have you considered taking your Rolls batteries to the local dealer and having them test and equalize them? If they don't recover, then shouldn't they replace them under warranty?

I'm a big fan of golf cart batteries. Rugged, pretty forgiving, they stand up to the abuse of drunken golfers day in and out and they're really cheap at Costco ($83) and Sam's Club. They're 225AH and 60 lbs ea., 4 would get you 450AH (240 lbs), 6 would be 675AH (360 lbs), 8 would be 900AH (480 lbs.) and 10 would get you 1125AH (600lbs.)
thought of it. but i figure they have a vested interest in selling new batteries. The rolls dealer is pretty far away, plus i want to learn about this process and DIY it.

been a member of costco for 25+ years. never seen an actual GC battery there. at least at the Avon MA store. Biggest they have are some group 24 'deep cycle' batteries

If the batteries are under warranty, they would be at the tail end of it, and maybe get 5-10% back. few batteries warrant 100% for the life of the warranty.

I think the defect is between my ears, not the batteries. Can't blame them for my bad behavior!
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Old 08-02-2016, 17:56   #49
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Re: Can my batteries be saved?

ookkkkkk hope im not going to sound like a retard.. but got the power supply Robot Check

but I think it is DOA

hooked it up. It sees the battery is 6.1v. but there is no output from the unit. I put a multimeter on the leads and saw no voltage coming out. turned the knobs.. did nothing..

put the leads together and played with the knobs.. all say 0

The manual was next to useless. Unless I need to do something I think the unit is DOA
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Old 18-02-2016, 08:08   #50
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Re: Can my batteries be saved?

Got a replacement power supply. seems to work. Havent had the time to try it on the batteries. hope to do so soon.

However, I was at the boat show, asked the Rolls rep about the situation. he recommended hitting the batteries with more amps (40) til the batteries got real warm and doing a discharge/recharge cycle.

More confused than ever!

should I hit it with more volts as suggested earlier, or with more amps? pros/cons of either method?
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Old 18-02-2016, 14:44   #51
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Re: Can my batteries be saved?

The batteries themselves will determine the amps they will accept at any given voltage and SOC.

Just be sure the voltage is right, and don't sweat the amps :-)

Bill
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Old 18-02-2016, 14:59   #52
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Re: Can my batteries be saved?

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Originally Posted by btrayfors View Post
The batteries themselves will determine the amps they will accept at any given voltage and SOC.

Just be sure the voltage is right, and don't sweat the amps :-)

Bill
Wot 'e sed.

The way you control the Amps going into a battery is by changing the voltage of the source. Adjust the voltage to give you the Amps you want.
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Old 18-02-2016, 15:40   #53
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Re: Can my batteries be saved?

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Originally Posted by phantomracer View Post
Got a replacement power supply. seems to work. Havent had the time to try it on the batteries. hope to do so soon.

However, I was at the boat show, asked the Rolls rep about the situation. he recommended hitting the batteries with more amps (40) til the batteries got real warm and doing a discharge/recharge cycle.

More confused than ever!

should I hit it with more volts as suggested earlier, or with more amps? pros/cons of either method?
Was he telling you to hit the batteries with 40A constant current with no voltage limit or just a bulk charge rate of 40A then let it transition to constant voltage....?

Cycling your batteries to 10.5V at the 20 hour discharge rate then recharging to 100% SOC, then equalizing should show some improvement. After I deep discharge thick plate batteries I usually recharge slowly, at the 20 hour rate or less. This tends to penetrate the plates and reform pathways that are no longer being used or have not been used in a while. Sometimes multiple deep discharges with full 100% recharges is what it may take. Once the battery comes to absorption voltage I then hold absorption for at least 8 hours or until current has dropped to below .5% of Ah capacity at absorption voltage...
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Old 18-02-2016, 16:49   #54
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Re: Can my batteries be saved?

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...... Once the battery comes to absorption voltage I then hold absorption for at least 8 hours or until current has dropped to below .5% of Ah capacity at absorption voltage...
Yes, I agree. However, even this isn't truly 100% charge. What is, then?

I believe it's when the current falls to about 0.0004 % of AH capacity @ 13.8VDC and ambient temp of about 67F.

This is based on my six Crown CR-235 6-volt golf cart batteries on 24/7 charge @ 13.8VDC in my basement for the past several weeks. Ambient temp is 67F.

The bank consists of 3 pairs of Crowns in series/parallel, equal to 3 x 235AH or 705AH total capacity. With a stable voltage of 13.8VDC for several weeks these batteries are receiving a total charge of 4.1 watts or 0.29 amps. Thus each 12V pair is receiving 0.097A or about 0.0004% of AH capacity.

These numbers have remained constant over the past several weeks on my Watts Up in-line monitor (verified periodically with my Fluke 335 clamp ammeter and Fluke 189 voltmeter).

Anyone who's watched carefully the amperage acceptance as a battery nears 95-100% full charge knows how very long it takes to reach a truly full charge.

Bottom line: for practical reasons, most boats don't come near a truly full charge on their batteries unless they are plugged into the dock for extended periods or else have solar panels or do an awful lot of motoring.

Bill
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Old 18-02-2016, 18:45   #55
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Re: Can my batteries be saved?

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Originally Posted by btrayfors View Post
Yes, I agree. However, even this isn't truly 100% charge. What is, then?

I believe it's when the current falls to about 0.0004 % of AH capacity @ 13.8VDC and ambient temp of about 67F.
That is just the point to end absorption and either go to float or to equalize. If you turn your batteries back up to absorption voltage you will still find them accepting a very minimal amount but more than float.

In capacity testing, literally hundreds and hundreds of capacity tests, I have not really noted any additional capacity once beyond absorption voltage and 0.3% to 0.15% of Ah capacity. Yes accepted current still goes down from there but the usable energy is not really there in usable stored energy..


Quote:
Originally Posted by btrayfors View Post
Anyone who's watched carefully the amperage acceptance as a battery nears 95-100% full charge knows how very long it takes to reach a truly full charge.
And why guys like you and I can get a good chuckle out of "My solar system is awesome and my batteries are at 100% by noon." statements...

Quote:
Originally Posted by btrayfors View Post
Bottom line: for practical reasons, most boats don't come near a truly full charge on their batteries unless they are plugged into the dock for extended periods or else have solar panels or do an awful lot of motoring.
Quote:
Originally Posted by btrayfors View Post
Bill
Absolutely and the "premature floatulation" on so called smart charging systems only leads to the demise of many batteries rather than helps them...
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Old 18-02-2016, 18:51   #56
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Re: Can my batteries be saved?

Quote:
Originally Posted by Maine Sail View Post
Was he telling you to hit the batteries with 40A constant current with no voltage limit or just a bulk charge rate of 40A then let it transition to constant voltage....?

Cycling your batteries to 10.5V at the 20 hour discharge rate then recharging to 100% SOC, then equalizing should show some improvement. After I deep discharge thick plate batteries I usually recharge slowly, at the 20 hour rate or less. This tends to penetrate the plates and reform pathways that are no longer being used or have not been used in a while. Sometimes multiple deep discharges with full 100% recharges is what it may take. Once the battery comes to absorption voltage I then hold absorption for at least 8 hours or until current has dropped to below .5% of Ah capacity at absorption voltage...
He said to get a dumb 40 amp 12v charger and 'hit it hard' with 40 amps til the batteries got warm..

i'll try your suggestions.. im sure the power supply will be able to breathe some life back to these batteries..
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Old 19-02-2016, 15:24   #57
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Re: Can my batteries be saved?

ok some progress.. well i hooked up the power supply to the worse of the 2 batteries.

turned it on. volts all the way up got 7.2v at 9.2a after a minute or 2, the amps went to about 5.x , had to turn the volts down to keep it at 7.2.. after about 10 minutes amps went to 2.9a at 7.2

Just bumped it up to 7.7v went to about 5.4a

I assume i should run it til its below 2.5a (262 ah battery at 6v)

keeping a log with the readouts. first time doing this.. good learning experience for sure!
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Old 19-02-2016, 19:28   #58
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Re: Can my batteries be saved?

doing more studying while the battery bakes downstairs..

found this Rolls battery sulfation help

Quote:
Originally Posted by From Rolls Website
... the battery "won't take a charge" is a result of improper charging procedures which allowed the sulfate to harden. In most instances, it is possible to salvage a battery with hardened sulfate. The battery should be charged from an outside source at 2.6 to 2.7 - volts per cell and a low current rate (approximately 5 Amps for small batteries and 10-Amps for larger ones) until the specific gravity of the electrolyte starts to rise. (This indicates that the sulfate is breaking down.) Be careful not to let the internal temperature of the battery rise above 125° F. If it does, turn the charger off and let the battery cool. Then, continue charging until each cell in the battery is brought up to full charge (nominal 1.265 specific gravity or higher).This time needed to complete this recharge depends on how long the battery has been discharged and how hard the sulfate has become...
I'm charging the 6v battery at about 7.7v, should I charge at 8.1 (2.7*3) instead?

just trying to get a procedure down... battery is bubbling away, not hot or even warm after a couple hours.. amp drop seems to have slowed..
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Old 19-02-2016, 21:08   #59
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Re: Can my batteries be saved?

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Originally Posted by phantomracer View Post
doing more studying while the battery bakes downstairs..

found this Rolls battery sulfation help



I'm charging the 6v battery at about 7.7v, should I charge at 8.1 (2.7*3) instead?

just trying to get a procedure down... battery is bubbling away, not hot or even warm after a couple hours.. amp drop seems to have slowed..
Generally you'll want the equivalent of about 15.5V at 12V so for 6V you'd want about 7.75V... 8.1V is the equivalent of 16.2V and is the Rolls max but unless your batts are cold 7.75V is a suitable EQ voltage. I've not found pushing to 16V + to yield better results than 15.5V but you can if you want to..
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Old 19-02-2016, 22:42   #60
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Re: Can my batteries be saved?

Quote:
Originally Posted by Maine Sail View Post
Generally you'll want the equivalent of about 15.5V at 12V so for 6V you'd want about 7.75V... 8.1V is the equivalent of 16.2V and is the Rolls max but unless your batts are cold 7.75V is a suitable EQ voltage. I've not found pushing to 16V + to yield better results than 15.5V but you can if you want to..
ok.. sounds good. at least it sounds like im on the right track.

been on the charger for about 5 hours, the battery has been hovering around 7.7 at 4.1a for the past couple hours.

plates look better (well, changed from whitish to greyish).

SG has not budged since starting to charge (ez red needle between 1225 1250)

unsure what is considered cold. basement is about 65F or so. battery is not hot or even warm. water is bubbling, but still well above the plates

looks like it still needs some time, either way
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