Cooked Batteries

[jrudge]

I have a Fairline Targa 40 - 2004 - and would appreciate views from the forum regarding a pair of cooked batteries.

The boat has 3 x 170ah wet cell batteries. Only 2 of them are charged by the charger, the other is only for (Stb?) engine start and does not charge from the charger, only the engine.

The 2 x charged batteries have cooked. They were replaced by Fairline when I bought it abourt 20 months ago .

I noticed a loss of charge at the end of last season. On checking the batteries they were dry. Added water not really expecting a miracle cure but the boat lives in France and I could not get new ones fast enough. France does not really do next day!

Just visited for a few days and with the charger on the 1 x battery was steaming and the other was warm but not actually bubbling. It has a Jennlec charger so I called the number on the box and spoke to an increadibly helpul man. Asked if the bsatteres had failed so cooked or if the charger had failed and cooked them, Could swing either way, but he said was a constant voltage charger and if it measured 13.8v it was probably OK. I measured 13.78v so i though that was close enough!

The batteries were not so old so if ( and it is an if) the charger is OK (but it seems that it is on basic evidence) what caused them to fail? The boat is in La Rochelle and we do trips to N Spain (6.5 hours in one hit) so I am not sure what stops the alternators cooking the batteries over such a long trip? Could this be the fault?

Equally the battery that is only charged by the engine is in fine fettle.

I suspect that some of this is "how long is a piece of string" but I just wondered if anyone in the know had any pearls of wisdom

New batteries are on the way for Euro 450 and I would rather not cook those as well! Not least at 50kg each they are a bugger to get out single handed ( tip - use the Stanless Steel Flag Pole braced between the fuel tank and the generator and alot of rope).

Thanks in advance

 

[vas]

maybe your port engine alternator rectifier has failed and cooks the batteries?
could be talking blx, but if the charger is providing 13.8 it could only be the alternator itself producing foul current, no?
I guess it's fairly easy to check (if you can jump start the port engine that is...)

For sure there's some action to be taken unless you want to through away two batteries per season!

V.

 

[halcyon]

I have a Fairline Targa 40 - 2004 - and would appreciate views from the forum regarding a pair of cooked batteries.

You need to check the voltages from both alternators and mains battery charger, when you fit the new batteries. The old faulty ones could be giving a false reading.

The alternators should be 14.2 / 14.4 volt, and should do no damage on a 6.5 hour trip.

Has the battery charger been running all season ? 13.8 volt is a lttle high to run 24 / 7, have had batteries boiling at that voltage, depends on battery.

It could be faulty batteries, so do not condem the system.
Once got blamed for one of our chargers boiling batteries. Turned out to be a intermittant short on a cell, resulting in a 10 volt battery.

But you cannot do a lot without fitting the new batteries, then checking voltages.

Brian

 

[boatmike]

Not wishing to state the obvious or be rude but how often do you check the electrolyte level? If you are constantly deep discharging the batteries and recharging either with a step charge battery charger or a smart charger on an engine alternator the rate of charge goes up to 14.something on boost and only settles to 13.8 or so on float. This can mean you need to top up the electrolyte quite often. You only need to boil dry once to bend plates and short out... Then I agree with halcyon that you will get a rather different reading. All previous advice is good but I would tend to check levels weekly for a while and certainly check before any long trip....