Batteries not charging

Have a pair of Optima Yellow Top batteries, model D27F.

These are apparently the Ducks Nuts of marine batteries.

Heres my problem:  they are 3 years old, haver an inbuilt charger onboard which I always connect when boat parked up.  Anyway the extension got accidentally unplugged form power point, the battery isolator was in the "on" position.  This was for a period of no more than 3 weeks, maybe shorter.  Thay have enough power to illuminate the nav lights, but cant tilt motor, let alone start it!  After discovering the cable issue, I promptly plugged it back in, left it for 12 hours but nothing.  My charger saying that below 8 volts so cannot charge them.

Am I up for 2 new batteries or can they be rescued?  At $320 a pop it hurts!


Taffy's picture

Posts: 183

Date Joined: 04/11/10

Are you using

Thu, 2015-09-24 13:08

 Are you using the Correct Charger ,

Optima batterys are AGM and require a specific Charger with a higher voltage, my optimas are 5 years old and still like new

Posts: 10

Date Joined: 21/05/12

I guess so, previous owner

Thu, 2015-09-24 13:18

I guess so, previous owner had it installed.

Its a Minn Kota onboard charger.

You think its worth while getting another charger to bring the voltage back above 8 volts then the onboard charger will kick in, or new batteries?

Posts: 563

Date Joined: 27/08/09

OK the hard facts are you

Thu, 2015-09-24 13:39

OK the hard facts are you have damaged your batteries. How much and if they are recoverable will depend on what contrition they were in and how long they have been in a discharged state. Be aware that they may no longer be reliable enough to trust in a marine environment.

first. try and charge them individually. This is the best way and may get you charger to talk to them.

Beg steal or borrow a modern multi stage charger. These often have "soft start" algorithms designed to bring up deeply discharged batteries.

Don't delay. the longer you keep them discharged the less chance of recovery.

Posts: 10

Date Joined: 21/05/12

Will try that straight away! 

Thu, 2015-09-24 13:52

Will try that straight away!  Thanks

Swompa's picture

Posts: 3757

Date Joined: 14/10/12

I have a multi stage charger

Thu, 2015-09-24 13:56

I have a multi stage charger which you can borrow if you are near thornlie?

It saved my battery after my lovely kiddo flicked on all of my switches, and i didnt notice for 4 weeks.

Posts: 10

Date Joined: 21/05/12

Is it suitable for AGM

Thu, 2015-09-24 14:01

Is it suitable for AGM batteries Swompa?

Taffy's picture

Posts: 183

Date Joined: 04/11/10

where are you located

Thu, 2015-09-24 14:09

 Where are you located mate, i have a battery Analyzer/ tester if your not to far away,im in Byford, and you cant go past a Ctek Charger in my opinion

Swompa's picture

Posts: 3757

Date Joined: 14/10/12

 It is a Ctek smart charger,

Thu, 2015-09-24 21:20

 It is a Ctek smart charger, very good one I am lead to believe. I just charged up the two AGM's in my camper this week so it goes Ok.

PM me is you want to borrow it. I work in west Perth and can take it there...

 

it it has a repair mode for flat batteries, as well as a supply for just maintaining.

 

Posts: 10

Date Joined: 21/05/12

Im in Waikiki mate but work

Thu, 2015-09-24 14:10

Im in Waikiki mate but work as a plumber from Freo through to Mundaring.

Posts: 10

Date Joined: 21/05/12

Which model Ctek would you

Thu, 2015-09-24 14:15

Which model Ctek would you recommend?

 

Taffy's picture

Posts: 183

Date Joined: 04/11/10

Pm sent with

Thu, 2015-09-24 14:18

 Pm sent with my number

Posts: 563

Date Joined: 27/08/09

I use a ctek mxs 7.0 in my

Thu, 2015-09-24 14:20

I use a ctek mxs 7.0 in my camper.

z00m's picture

Posts: 1086

Date Joined: 10/05/14

Even though they are under 8v

Thu, 2015-09-24 14:28

Even though they are under 8v for the charger to kick in it doesn't mean your batteries are dead. You can charge them briefly with a regular charger to get the voltage up a bit and then get the proper charger back on the job.

Posts: 10

Date Joined: 21/05/12

Thanks guys, most helpful!My

Thu, 2015-09-24 14:42

Thanks guys, most helpful!

My mind is eased somewhat.

ChardWon's picture

Posts: 5

Date Joined: 30/10/14

Could try getting a fully

Thu, 2015-09-24 14:42

Could try getting a fully charged battery and join up with jumper leads. The battery might equalize voltage across the two batteries to get above 8volts. Then you will be able to put your charger on. Do it one battery at a time.
Worth a try if you a spare.

Posts: 94

Date Joined: 27/01/10

As z00m said above. Smart

Thu, 2015-09-24 17:49

As z00m said above. Smart chargers overthink things in situations like yours. Connect up a very basic old dumb charger for an hour or 2, then connect up the smart charger and try again. Repeat until the you succeed. I keep a 30yr old 8A charger just for those situations when Smart is dumb.

Posts: 274

Date Joined: 08/10/13

parrallel

Thu, 2015-09-24 21:02

 disconnect one battery and one at a time hook up a good battery in parrallel with the dead one with jumper leads. Turn the charger on and it should see the voltage on the good battery and start charging.   I would supervise this and keep an eye on the battery temp. It should get warm but not overly hot.  If it gets red hot battery is probably dead. After 2 hours the voltage should come up enough for the charger to recognise the battery and charge it by itself. Once one is charged connect the other battery back up and it should charge.  I got this technique of their website and has worked for me.

Posts: 48

Date Joined: 19/02/09

As the others have said, try

Thu, 2015-09-24 22:30

As the others have said, try hooking up a working battery in parallel with at least 12v and put the ctek on them both. The charger cant deal with the Battery under 8v and wont start putting power back in. Its designed as a safety for the charger. The charger sees the combined voltage and its happy to start doing what it was designed for.

Hopefully the battery isn't buggered and once happy to accept charge you run the ctek desulphation and it should be ok.

The reason you need to keep an eye on it is if the plates inside are damaged then you end up with a short and it will get hot and possibly swell. Warm to touch is ok but if its hot then disconnect and bin it.

Your Batteries and charger are top shelf so should be ok.
Once charged you should be able to get a battery shop to put a carbon Pile load tester on it and confirm it can deal with supplying power and recovering. If it passes this then its good to rely on
I have done this to big 300amp units and its pretty common hence it being on the website as Cruzy put up.

Posts: 5738

Date Joined: 18/01/12

 Zoom and the last couple of

Fri, 2015-09-25 06:37

 Zoom and the last couple of posts are onto it.

Connect another battery briefly to get the charger to sense a higher voltage.

After that they should charge ok. 

I doubt there is noticeable damage but there may be a reduced capacity

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