bu@@erd battery?

Georgio

Georgio

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georgeisted.blogspot.com
Having fitted my new battery monitor the voltage was a little on the low side so put the bank on charge for 24 hours using a "proper" multistage charger.

Having been off charge for a week the bank voltage was at 12.7 but when a small load was applied (4 to 6A) over a period of 30 mins the voltage dropped off to 12.3. Removed the load and this slowly recovered to 12.4.

I put the batteries on charge and after an initial high charge for a couple of minutes the battery bank would take very little.

I would expect with such a small load the voltage would remain at 12.6 to 12.7?? All this makes me think that my batteries have died over the winter but I would appreciate another opinion.
 
certainly sounds like it! in your place I'd be inclined to seperate the batteries and try them individually using a known load such as a car headlight bulb. It could be that one in part shorted and discharging the other (s).
depends how old they are, how flush you are. the book says replace all at once, but I'm from Yorkshire ...
 
Just a silly point, are you checking with your newly fitted battery monitor ?, and have you checked the monitor ? Also check the voltage on the actual battery terminal post not the connector, just to be safe, hate to buy new batteries and find a bad connector.

Brian
 
Add EDTA+ to the battery, this will clean off the sulfate during charge and will release the sulfate back into the sulfuric acid during discharge.
It continues to recycle the battery for the whole life of the battery.

Batteries will last 7-8 years instead of 2-3.
Can be added any time, brand new or one 2 years old off the battery dump !


http://www.courtiestown.co.uk/batteries/shop.htm
 
[ QUOTE ]
I would expect with such a small load the voltage would remain at 12.6 to 12.7??

[/ QUOTE ] You dont tell us the size of your battery bank but unless it is several hundred Ah I would not call 4 to 6 amps a small load. Not a big load I would agree .. significant perhaps.

Did you check what the volts recovered to after a few hours. If they did not recover to 12.6 or better then it does not sound too hopeful. Although 12.7 after resting for a week after charging is good.

Did your "proper" multistage charger include an equalising charge That might help if you can do it.

I'd charge them for longer and consider having them tested by a battery supplier, a Lucas depot or an automobile electrician.

You could try Leadersail's suggestion and give them the EDTA treatment. I am quite anxious for someone to give the stuff a good fair trial and report back so that we can dismiss it once and for all to the "snake oil" category. /forums/images/graemlins/laugh.gif Seriously there is a scientific basis for it and I wish I had tried it in the days when I had a good supply on the laboratory shelf.

I am hoping to get hold of an old battery or two during the fitting out season and to give it a try.
 
[ QUOTE ]
You could try Leadersail's suggestion and give them the EDTA treatment. I am quite anxious for someone to give the stuff a good fair trial and report back so that we can dismiss it once and for all to the "snake oil" category. /forums/images/graemlins/laugh.gif Seriously there is a scientific basis for it and I wish I had tried it in the days when I had a good supply on the laboratory shelf.

I am hoping to get hold of an old battery or two during the fitting out season and to give it a try.

[/ QUOTE ]

I have already dosed up my bank so I will be years before I can try it again.

Please don't use an old battery, what you need is a battery 2-3 years old that has sulfated plates (one that has had little use and been left for months with 30% dropping to 15% charge.

By looking in a Marina battery dump there will be loads of matching banks looking as new.

If you just use an old car battery then chances are the plates will be damaged and edta+ will not renovate that.

It doesn't repair plates only cleans them.............................................. ................................................................................... ....................................................................................... ............................... I think
 
[ QUOTE ]
Please don't use an old battery, what you need is a battery 2-3 years old that has sulfated

[/ QUOTE ] I was thinking of keeping an eye open around the boat yard for people fitting new batteries this spring and grabbing the old ones. do you think that's not going to be any good.

I was planning to try charging any I get and assessing, as best I can, their performance. With luck I might be able to hire or borrow a battery tester. Then give them the EDTA treatment and see if they are improved. At £3 a go I'm not going to try many so it will always be dismissed as on too small a sample but I thought it would be an interesting excercise.
 
iT'S A GREAT PLAN.

The ideal ones are where they are complaining they are only 18 months old.

Need to dose
charge
discharge
charge
etc a few times although I noticed an immediate effect, edta+ really needs time.

I hope it works or I am going to look silly.
 
Back to Georgio a battery (yes seperate the batteries in the bank) are dead when they won't do the job you need done.
So any one battery should start the engine with enthusiasm and should give you reasonable lights and other services for a period representing perhaps 50% of rated Amp hour capacity before dropping below about 11volts. If the batteries individually pass this test then hang on to them until clearly they do'nt in which case they are no good to you. olewil
 
First I would check the voltages with a digital multimeter, you may have a bad connection or the batt monitor may need 'tweeking'. Next, do you have an inverter, if so use it to give a load that should discharge the batteries in 10 hours. When the trip on the inverter goes (usually at 10,5v) you know the batteries are flat and the amp hour counter on the batt monitor will tell you exactly what capacity is left. I believe it is usual to say batt are shot when they are down to 80% of origional capacity but this may be a bit conservative, depends really on what you are doing. The other test you can do with an inverter if its big enough is the heavy discharge test. When the garage puts that big thing accross the car battery to test it they are chaecking if it will maintain volts with a heavy discharge. You need a current of around 1/2 the batt capacity, ie 50 for a 100a/h bank. If the battery is duff the volts will drop of very fast, is its good it should maintain around 12v for a few min's. Also look for gassing on an individual cell - means that one is shorted. Could be worth checking the hydgrometer readings from each cell, again a big variationg suggest a duff cell but just becase the hydrometers says the batt is charged does not indicate its capacity only that what plate material is left is fully charged!
 
Other than dosing with EDTA, you could also consider using a pulser. I'm not sure whether it will recover a completely dead battery but it sounds as though yours have not yet reached that stage. My pulser, bought from Courtiestown, has made a remarkable difference to my domestic batteries. They charge to a higher voltage and retain it to a noticeably better extent than previously.
 
Thanks everyone, I have put both batteries on charge again for 24 hours and will now leave them for a week to settle. Will check them individually with a digital meter both before and after a load has been applied.

The total bank should (when new) offer approx 200AH so running a load of 5 amps for an hour shouldn't (I believe) drop the voltage as much as it has.

If knackerd I think I'll go for some new leisure batts rather than risk being caught short.

Thanks again for all your comments, what a usefull forum /forums/images/graemlins/grin.gif
 
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