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tuffyluffy

Reviving dead lead acid batteries

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We're finally getting around to a weekend or few away on the boat and I've discovered an electrical issue that i cant solve with my limited knowledge.

 

Due to what I suspect is a faulty auto bilge pump, my house bank is completely flat, and i mean completely flat ie it wont even power a light bulb. Its 4 6v lead acid battery's wired to 12v and charged via a separate alternator and next step controller

 

When i start the engine to recharge (starter battery is separate and has its own alternator) the house bank doesn't receive any current via its separate alternator and next step controller. The next step controller is flashing green on 'state indicator' and flashing red on the 'error indicator'. Hence something is wrong and probably the reason the house bank isnt getting any charge. 

 

Question for those that know about this stuff.

If the house bank is completely flat, could it be that the controller doesn't 'see' it stops feeding juice to it, and hence the error message?

 

The plan is to put a big meaty battery charger on the house bank and hopefully revive it a bit, which in turn will hopefully correct the flashing red error light.

 

I've given every thing a visual check and tightened all terminals and nothing has changed nor was their anything obviously wrong.

 

I appreciate that I'm probably up for a new house bank sooner rather than later, but if i can get another summer out of this bank I'll be happy.

 

If any of you who are in the know can offer any advice it'd be much appreciated.

 

Cheers

 

 

 

 

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as above

 

check electrolyte is just above plates

 

then try something like this

  1. Recond Reconditioning of deeply discharged batteries. This step is used to restore deeply discharged open vented batteries. With increased charging voltage over a limited time, the voltage is allowed to rise so that the battery starts to emit gas. As a result you get a mix in the battery that is good both for its capacity and service life. Note that the battery may emit explosive gases during this step...................The charger reconditions the battery between 30 min and 4 hours depending on the need of the battery. 

http://www.cteknz.co.nz/tabid/319/ProductID/2069/Default.aspx

 

yes, completely flat batteries can be hard for smart-chargers to see

 

yes, a "manual" charge can give them enough charge so the smart charger can see them and start charging them

 

if that's enough - good

 

if not, and they are open top types where you can check the electrolyse, you could try bringing them home and trying to charge them (4 x 6v batteries) individually with around 8 volts, with caps off, until they are popping and spitting for 10? min

 

then rest them for 10 min, then charge for 10min, rest for 10 etc.

 

when the electrolyte is up around 1.275 sg you should be done

 

really need a digital volt meter, a range of small appliance transformers to get 8v and an electrolyte tester for this kind of mucking around...

 

old laptop transformers that put out 16-17v at round 2amp are good for this kind of stuff for 12volt batteries - or two 6 volt in series...

http://support.rollsbattery.com/support/solutions/articles/4347-measuring-specific-gravity

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Ouch. Sorry to hear that tuffyluffy.

Do you have any idea how long the bank may have been totally flat for?
Do you have a charge splitter to divide and send charge to House and Start Bank, or a VSR? If a splitter, then the charge current will be going to the Start Bank only. The House Bank is not "seen" by the splitter, because there is no resistance. If the Start bank is close to the House bank, grab some Jumper cables and link them across and start the engine and run it for say 5minutes and then disconnect and check the voltage on the House bank. That should have brought the Voltage up enough for the battery to accept a charge.

How big is the Alternator? It is really good to give them a good belt of a charge. At least you have a Next Step, because that will ensure exactly that happens.

Don't worry about equalization charger or the Ctek version called Recon, which is rubbish. You cannot recon a battery sadly. Equalisation charge is purely about gassing a battery. The gas stirs up the electrolyte and mixes it up. It does nothing else to the battery. If you are hard charging a battery, it does pretty much the same thing. It is when a Battery sits in Float mode for too long that Stratification takes place. Thats where the Acid separates from the water and the gassing stirs it all back up again.

 

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Thanks for the feedback guys.

 

Of course! I hadn't thought to through the emergency parallel switch to liven up the house bank, that should do it, i hope.

 

Funny how often there's a simple solution looking you straight in the face that's overlooked, or is it just me.

 

Will give it a go and if that doesn't work, I'lll try the charger idea. Here's hoping the dead bank is the problem and not something a bit more complicated.

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The issue with charging is that there needs to be sufficient volts available to excite the alternator. The emergency parallel should do that, but it will be hard on the start battery,as it will try to charge the house bank. The alt with the next step regulator will charge WAY faster than almost any charger.

If you want to use a charger, then check the specs and ensure it can charge a flat battery - many can't as they too need a min starting voltage.

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The issue with charging is that there needs to be sufficient volts available to excite the alternator. The emergency parallel should do that, but it will be hard on the start battery,as it will try to charge the house bank. The alt with the next step regulator will charge WAY faster than almost any charger.

If you want to use a charger, then check the specs and ensure it can charge a flat battery - many can't as they too need a min starting voltage.

 

The house bank alternator is a monster 120amp unit, so if i can get it to recognize the bank, it wont take long before large dollops of current hit it and hopefully bring it back to life - fingers crossed.

 

I appreciate that the banks capacity will be well down, but if i can get it to last the rest of the year, the Lithium batteries I'd like to replace it with will get even cheaper - They're about half the price they were 5 years ago and falling rapidly

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