Sulfation

OldBawley

OldBawley

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9 Aug 2010
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Cruising Med
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Some months ago I noticed our batteries ware gone. Full time liveaboard, our batteries ( 4 x 130 AH open lead ) must have got 1800 partial discharges. I decided to wait till autumn to buy new, our solar and wind easily coping with demand in summer.
In the last weeks I noticed that the AH counter was always indicating negative.
The batteries are so dead that at 9 am the solar panels have cranked the tension up to 14,3 V so the MPPT regulator turns down the charge from 8 A to 2 A.
The night consumption been around 30 AH, this means it takes more or less 15 hours of charging to reach a theoretical zero on the AH counter again.
Keeping in mind that about 10% more charge is needed to eliminate chemical to electrical losses, this means the battery’s cant be charged up to full.
Each night, a bit more is discharged. Now the fridge refuses to start after midnight while the voltage drops so fast with sulphated batts. Frozen food gets defrosted each night, frozen in the morning. Will have to order new now.
Can´t complain, five years is good for 365 days / year use.
 
Will do, and buy new battery’s as soon as I get back to Poros.
Something must be wrong with the charging system, in 14 years of Med cruising I never had to top up the water.
I intend to build a bypass, even knowing it could be disastrous for the regulator. I once grilled a perfectly good Uhlmann regulator by putting 26 V on the exit. An almost unbelievable accumulation of Murphy´s successive events and my super efficient but stupid alternator regulator took care of that.
Attached a pic of the grilled regulator thingy.

http://i1155.photobucket.com/albums/p543/OldBawley/DSCF3159_zpse196fad7.jpg
 
I read that MPPT regulators are good for extra input to batteries but PWM will give longer battery life. I went for PWM with wind and solar charging as my domestic bank is 960 amp/hour and I don't fancy having to replace the batteries prematurely.
 
I am coming out on the 7th July I have a very good contact in Aegina kipseli that sells batteries at a good price. I myself want a 120 ah and a 200ah if you are looking for batteries we may her get a better price together .
cheers bobt
 
1bobt said:
I am coming out on the 7th July I have a very good contact in Aegina kipseli that sells batteries at a good price. I myself want a 120 ah and a 200ah if you are looking for batteries we may her get a better price together .
cheers bobt
Click to expand...

I have been looking at and repairing a number of systems lately, best value for money if you are a liveaboard are T105's (they are 6v 225ah units) they are more than semi deep cycle as real ones are forklift batteries which weight a tonne. The T105's are available around the world and will give about 1400 cycles at a 50% discharge if you are carefull they will do 2000+

They are a comprimise as OLA but I have tested in various situations , on land , marine etc and they give a very good life/value return. Am currently testing 2v forklift 800ah batts which are great but heavy (should last 15 yrs) 48kg per (288kg for a battery bank Ah.............)verses 28kg per T105.
 
Last night, 22h, laptop charger stopped charging. Tension to low. Fridge was already in starting cycle. ( every 60 sec a start, seconds later the fridge controller switches the compressor off but leaves the fan on. )
So those batts are as dead as my anchor.
This morning I rigged a bypass around the solar MPPT regulator, now I´m really gone make a mess. Monitoring batt tension and regulating by hand. ( Switching off one of the panels and later partly covering the other one. )
I have been using a “ Megapulse “ since we went cruising. It does something to medium old battery´s, for old heavily used chunks of lead its useless. Those pulsers are meant for small starting battery´s, not for a big domestic bank.
The MPPT regulator claims to have a pulser incorporated. I doubt it.
 
OldBawley said:
Last night, 22h, laptop charger stopped charging. Tension to low. Fridge was already in starting cycle. ( every 60 sec a start, seconds later the fridge controller switches the compressor off but leaves the fan on. )
So those batts are as dead as my anchor.
This morning I rigged a bypass around the solar MPPT regulator, now I´m really gone make a mess. Monitoring batt tension and regulating by hand. ( Switching off one of the panels and later partly covering the other one. )
I have been using a “ Megapulse “ since we went cruising. It does something to medium old battery´s, for old heavily used chunks of lead its useless. Those pulsers are meant for small starting battery´s, not for a big domestic bank.
The MPPT regulator claims to have a pulser incorporated. I doubt it.
Click to expand...

Those are all the signs of knackered batteries. I had the same. I have since changed my shore charger and found that the engine charger controller was set to the wrong type. Once the batteries were fully charged (i.e. not taking in any more charge at the normal absorption voltage, I put the shore charger into the desulphanation mode (despite all the dire warnings in the documentation about it, and the complex procedure to do it).

This has significantly improved the batteries. The fridge will now run all night. Also the engine now pumps considerably more amps into the batteries for longer - i.e. really does charge them up. Also with the battery fully charged, the voltage is over 13V with the fridge on. Before the fridge would pull the voltage down to 12.2V when they were "fully charged".

Don't give up yet until you have tried desulphanising them - it worked a small miracle for me.
In my case the shore charger puts 15.6V out in desulphanation mode for four hours (best to disconnect everything else first).
 
Back in “Home “ waters I had some days before Swmbo arrives, so went to work on the dead battery problem.
First, it turned out that the Aerogen 4 was not charging any more. Fixed that and at the same time gave the small windgen some maintenance and made some design improvements. Last winter I build a big windgen so now I am a DIY specialist who knows everything about out of scrap made scary contraptions.
So the small windgen works again, at least equalising the consumption of the fridge at night.
I also disconnected the ( Just a few months old ) MPPT regulator for the solar panels. Simple bypass.
It took my solar panels ( 170 W ) three days of full charge to bring the battery’s back to 14,3V.
The battery’s still accept load so are not completely dead.
Now the curious part. During loading, the fuse panel ( Main connection panel ) tension went up to 15,5 V whilst the batt tension was 14,3V. In the middle of the charging, fuse panel 14,6 V with 12,3 on the battery’s.
I now suspect that de solar panel tension is on the fuse panel and so fooling the MPPT.
There must be some back-door between solar panel- fuse panel and battery’s, raising the tension on the out going terminals of the MPPT.
Sounds strange, but if you saw the electrical system on board our old classic, you would not be surprised.
I bought the boat, restored it and made a brand new electrical system. The longest wire in the old system was a foot long. Some ware tied together to form a longer wire. Now, 26 years and many alternations later we are almost back at a foot. So pure theoretical it is possible I messed up.
Back to work.
 
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