Sealed Batteries

[Mrs Ronnie H]

Hi Guys

We have two sealed batteries in our boat and was wondering if they were any different to Charge than a normal battery. (Nameless didn't turn batteries off and both are flat):idea:

What are your opinions on Sealed batteries???.

Ronnie

[TheRealAndy]

Yes, Sealed lead acid batteries do require slightly different charging. Firstly, they dont like fast charging. Secondly, they prefer a good voltage regulated charger. Your $15 supercheap charger wont cut it.

Are SLA batteries better? This depends on how you use them. IF charged correctly, they dont vent gasses. The can also be mounted anyway you want, as they dont use a liquid electrolyte. However they are dear as poison. I uses standard wet cell batteries. I figure if i get 2 years out of a $100 battery compared to 4 years from a $300 equivelant then I am getting better value for money.

[Mrs Ronnie H]

Hi
Thanks for the reply. Where do I get a charger suitable for these batteries???
Brand etc would be useful!!!
Can i take them somewhere and have them charged.

Thanks
Ronnie

[TheRealAndy]

There is another thread running at the moment about the same topic. Some of the guys say CTEK is pretty good, albeit dear. I have not used them but they do look good on paper. Any three stage charger is good, try your local battery shack and see what they can do. Camping and caravan stores also tend to carry good chargers.

[Rod Fishing]

You can still use your cheap charger from supercheap if t has a trickle charge feature on it. When it comes time to charge your batteries take then out of the boat and when cahrgeing ensure that you put then on some rubber amtting. This is to ensure that that if there is a surge it wont earth through the concrete floor of your garage/shed.

Rod....

[TheRealAndy]

You can still use your cheap charger from supercheap if t has a trickle charge feature on it. When it comes time to charge your batteries take then out of the boat and when cahrgeing ensure that you put then on some rubber amtting. This is to ensure that that if there is a surge it wont earth through the concrete floor of your garage/shed.

Rod....

Mate its not going to surge/earth through the concrete floor.

The main reason you want to be careful when charging is because too much voltage on a Sealed battery causes it to gas. Gassing means grid corrosion and also causes the battery to vent through its saftey valve. Its a great way to shorten the lifetime of an expensive battery.

[FrankFWM]

If they are AGM's then they do like FAST CHARGING - they do not like over charging - ie. voltages such as 14.8.

Fast charging in terms of high AMPS are what AGM's love and a key benefit to AGM's.

[PWCDad]

Fast charging in terms of high AMPS are what AGM's love and a key benefit to AGM's.

AGMs have a lower internal resistance so charge much faster than flooded ... charge current is only limited by temperature. 50 Deg C case temperature is about as high as you'd want to go.

The better chargers have temperature probes (thermocouples) attached to the battery and reduce charge current as temp rises.

Anthony

[Mrs Ronnie H]

Hi All

Called in to Battery World Morayfield yesterday and looked at buying a charger.
At the salesmans suggestion he said why go to the expense and suggested I drop the batteries off, they will test them and charge them for me and very little cost. I thought this was very gracious-- instead of trying to sell me something to make a few bucks for himself he offerred another solution. Made me feel pretty good as the usual thing I find being of the female kind is " quick sale coming as she hasn't a clue"' and this time they would of been right.??? Nice to know there are still some helpful sales staff around.

Thanks guys for all your help and suggestions even though some of your tech talk was a little beyond me!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Ronnie

[TheRealAndy]

AGMs have a lower internal resistance so charge much faster than flooded ... charge current is only limited by temperature. 50 Deg C case temperature is about as high as you'd want to go.

The better chargers have temperature probes (thermocouples) attached to the battery and reduce charge current as temp rises.

Anthony

Perhaps some clarification is required on this topic. Firstly, an AGM battery will tend to charge FASTER than a standard wet cell battery. This does not mean they can be fast charged. IF you have ever pulled apart a battery pack from a mobile phone (old style) or a battery drill you will often find a little silver box attached to one or more of the cells. This is a temperature sensor and is used to terminate a fast charger. Fast charging is typically reserved for NiCad and NiMh chemistries.

With commercial chargers, temperature probes are used for things.
Firstly, and most typically they are used to measure ambient temperature. Probes are usually placed near the batteries so that the readings are more accurate. Ambient temperature compensation is used to modify the chare voltage.
Secondly, probes are used to check for overcharge and fault conditions. They are used to eiher measure absolute temperature, or sometimes in the fancy chargers will measure the rate of change of temperature as an early indicator of problems.

[oldboot]

firstly you need to establish exactly what you have.


its most likely you have some sort of absorbed mat/ starved electroloite battery.


As far as beeing fussy about chargers....... well you problay should be anyway. that way you might get more than 2 years out of your batteries.

Any decent multistage charger should do the trick.
there are lots of them arround

jaycar have em, some of the marine shops have identical items or similar or you can spend lots of money on a realy nice one.

The realy BIG issue is not leaving any battery on a crude automotive battery charger for any more than necessary....... left on for an extended period it will stew the battery.

there was a " full and frank" discussion about al most all of these issues a couple of weeks ago...... seach it up and most of your questions will be answered from a number of points of view.

The other point is dont believe all that is calimed about sealed batteries.
sure they will run on their sides or upside down .... but it is not smart to install them that way.
Thats right they don't vent if charged properly....... but if they are charged incorrectly they most certainly can vent.... if upsidedown or on their side they will vent acid
As for the cost effectiveness...... HMMM ther was some vigourous discussion about that too.......

Do yourself a big favour....... buy yourself at least a half decent multi stage charger with a float function and learn how to use it properly.
Regardless of battery type that will extend the life of your batteries and save you money... guatanteed.

cheers

[Mrs Ronnie H]

Hi All
Thanks for a little more info. I have discovered a few things from this thread and the info has been helpul.
I took the batteries in to Battery World yesterday and they are actually going to charge them for nothing. Great service if you ask me and some very helpful info gained as well.
Found out today that number one Feral (Son) has charger so will use his in future if so needed.

Anyway guys thanks for all the help and clarification on these.

Ronnie