Help needed with replacement of batteries & se

[Hookem_Herby]

Ok lads, need some help, ideas and input with replacing the old batteries in my boat.
Just trying to assertain what batteries would be best for my rig and it's set-up.
I currently have a twin battery set-up. Last week my 3 year old marine batteries died (without warning) and now need replacing. So I'm currently wondering what I should replace them with? I'm after info on brands and types but was also thinking about installing 1 x heavy duty marine battery and 1 x deep cycle battery as I am somewhat prone to spending overnighters on my boat and have a few accessories (tv, toilet, fridge, etc) that source a fair bit of power from the batteries whilst anchored overnight.
I've been told that marine batteries are a 'crank' battery and don't generally like being totally flattened and then recharged again, hence my suggestion to perhaps opt for a deep cycle as my 2nd battery which I'd use to run the appliances on the boat on o/n trips. That way if I drained the battery I could still start the outboard with the marine battery and recharge the other once the motor is running.
What do you guys think? Or should I just stick to the standard 2 x H/D marines?

I'm a novice at this stuff so all help is very much appreciated. Many thanks in advance to all those that reply. [smiley=2thumbsup.gif]

Cheers,
Herby

[Payneful]

If you can afford/justify it, 2 x Lifeline AGM 105aH, fast charging, long life, truly maintainence free and are SUITABLE (ie no compromise) for BOTH starting and deepcycle use . Also low self discharge rate, handy if you don't use your boat often.

Sam.

[Hookem_Herby]

Thanks Sam. Any idea how much they cost? Are they readily available in Oz?

Cheers,
Herby

[mini696]

I use twin batteries on my tinnie. One runs almost everything (radio, elect start, bilge, two-way, lights etc. Its only a Marine heavy duty. The other is a deep cycle I use for my electric motor (and jumpstarting if I forget to charge the other overnight).

I like this setup. But I am always open to suggested new ways.

Most batteries wont give you any hint they are about to die. They just quit on you in a snap.

[Volvo]

Okay whilst on the subject of batteries n save starting another post if yez dont mind that is :)..
Two battery Rig...what do most do?? Run out on both batteries allowing both to charge at the same time as well..
Not forgetting if one has a fault it may drain the othery down at the same time...
run out on one and back on both allowing for a full charge one both , ready for the next trip??..
Run out on one and run back on the othery, thus sharing the workload between the two??..
I tend to use number one , say this trip leaving the othery(No.2) ("Just incase" )..And next trip use the othery..
Thoughts please??
Herby hope ya dont mind my jumpin in on your post mate :-[..
Will make up for it though after i get home n check out the brand of batteries i dropped in my rig after four years of good running:):)...
Battery World offcourse:)..
Cheers

[Custaro]

G'day Herby

I highly recommend reading the relevant chapters in "Boat Owners Mechanical & Electrical Manual, Nigel Calder". It will give you valuable knowledge on how batteries work, what type you need, how to install, how to charge etc etc. Borrow from it from your local library. Its about $80-$90 to buy.

Clay

[Hookem_Herby]

No worries Volvo, would'nt mind finding out the answers to the questions you posted myself! ;) :P
Clay, thanks for the tip. Will do that. Can't hurt to learn a bit more boating wisdom.

Cheers,
Herby

[Payneful]

Herby

The lifeline AGM's i was talking about sell for around the 270-300 mark.

Volvo

The best solution I have found for dual batteries is to use a voltage sensitive relay between the batteries. When the main battery (starting) is charged (>13.8 V) it connects the batteries together in order to charge the aux battery (which you run your bait tank, lights etc off). When the motor is switched off the voltage falls and it disconnects the batteries. This means that your starting battery is not being used and should be full of beans when your ready to start the motor.

No switches to remember to turn off/on and your sure to have a fully charged starting battery.

Sam.

[ozz]

there is a schematic for a two battery set up in the fisherman & boat owner mag #102. They also use a voltage sensitve relay in this set up with a deep cycle battery for acc and crank for engine.
cherrs Ozz

[Hookem_Herby]

Thanks heaps guys for the replies. #[smiley=2thumbsup.gif]
Have decided to go with a voltage sensitive relay set up of 1 crancking and 1 deep cycle.
just one question - what's the biggest/best deep cycle battery avail on the market? I'm looking at a Surpercharge 130 amp deep cycle (US made). Open to advice and suggestions though.
Cheers,
Herby

p.s. Was told by 2 guys at Specialist Battery outlets that AGM batteries are really suitable for QLD (tropical/hot weather) conditions because you can't perform basic maintanence on them (ie topping them up with more acid).
THOUGHTS?#??? :-/

[Payneful]

Sorry mate would really have to disagree with them. What happens when you charge agm batteries is that the water splits up into hydrogen and oxygen (2 hydrogen molecules to 1 oxygen .. hence H2O) since the battery is sealed the pressure builds up and forces the gaseous hydrogen and oxygen back together into water (liquid). Where you will go wrong is if you _severly_ overcharge them the pressure builds up too much and you get "venting" ie lost water. No venting ... no lost water ... no problem.

The agm battery was originally designed for the concorde, so the technology is not new ... but relativley new to the consumer market, so your going to get consumer resistance and die hard flooded battery blokes.

The agm battery will kick your motor over as well if your starting battery fails (deep cycle will too ... but not good for them).

Have a look around on the net ... lots of info on batteries.

We used century marine pro 600's in everything (cars, boats) but we are now changing over to the lifeline AGM's, much better battery in our opinion.

Sam.

[Glug]

Sam,Talking about venting wouldn't that also take place if the battery gets too hot? Like if it is sitting exposed to the sun.

I know some of the first ones on the market cracked the cases because they did not vent and got too hot in the summer.