Duel battery set up

[Brian D]

My battery is about 4 yrs old, which is pretty good but I am waiting for the day that it craps itself. What I thought I would do is to replace it with a double battery set up and pu on a switch that allows me to choose battery 1 or 2 or both. This is for duel purpose of making sure I don't crap oout in the middle of the shipping lane and to allow me to run more electronics like live bait tank, extra llong lasting ights without fear of failure. Does anyone know anything that would help me?

[fishenmick]

Hi Kazabri,

Mate I posted a reply to this last night but for some reason it did not post:unsure: So here I go again with a much briefer version, I hope.

I am also going to go for a duel battery set up when I return. I am going to go with a VSR elay Module from BEP Marine. They had an advert in April Boating and Fishing (I think it was).

Follow this link:

/>http://www.bepmarine.com/showproduct.cfm?productid=1114

There is also a wiring diagram link on that page to allow you to do the job yourself.

This is a great little unit and allows the crank battery to be charged first. Once the crank battery voltage rises above 13.7 VDC, it switches to charge both batteries. A great unit.

From memory the unit was a couple hundred $. But what is the cost of safety and satisfaction of knowing you will never be caught short in a tricky situation.

I think there are two main points mate:

First, if you are going to use a dual battery system, both batteries need to be the same.

Second, if you go for a manual switch, you will have to do the switching by hand and I do not think you can switch whilst the motor is running (a pain in the arse).

Hope this helps mate. remember though this is just my opinion and anything you choose to do you need to research yourself and make sure it is right for you. That doesn't sound like arse covering does it?

Cheers,

Mick

PS... I know I said it was going to be short, sorry:whistle:

[Brian D]

Hey Mick

I read your first reply but not sure where it is now. At this stage I am having a re-think. I have had a look at your suggestions and know about the wireing and switch. I realy like the idea of the auto re-charge system but I have taken the cheap option for the time being.

What I ended up doing was going for a over-size cranking battery and will run a seperate auxiliary battery for extras. The aux battery is re-charged at home on a 240 / 12v recharge unit. I am looking at 100 amp hrs which should run the live tank and extra lighting.

One thing is I couldn't find anywhere to put the battery switch, except for on the dash which would mean an extra 8 mtres of full size battery wire and I am starting to worry about weight.

Also I read in F&B boat owner to keep it as simple as possiable. When they said keep it simple stupid, they were talking about me!

[Brian D]

Mick, Hope you can help again.

I was going to install the live bait tank on the back seat, above the battery housing, but when I think further that might not be a good idea. If I sprung a leak it might short out the wiring. So now I am thinking to moving the live tank to the other side but this would mean that it would be above the auto oil housing storage. Can I store a battery next to a oil housing or does it run a risk of blowing up in a fire ball? I'll post a photo to explain it better next time I get near the boat.

[Brian D]

Does anyone know anthing about batteries? Can my battery be too big? The voltage guage has gone off the rectro scale, it is showing way pass the normal green secton on the meter!

Is it simply saying I got heaps of charge or it is trouble waiting to happen? Help someone please

Post edited by: kazabri, at: 2006/06/18 19:00

[Feral]

YOur gauge is crook, it is not possible for a battery to go over its normal voltage range. They will read 3 or 4 volts higher while on rapid charge, but go straight back to 12 when the charger is removed

[Brian D]

Hey Farel, Sorry but I'm confussed.

I was referring to the inboard battery which is charged direct from the alternator within the motor so I don't have to put it on the charger, On the boats dash board instruments it did read more then the old one straight after I installed the new one but after the trolling today it went up further on the meter.

On the meter there is a blk, then red area then geen arae the another blk area. The old battery used to sit mid green area now the neddle sits above the green in the blk!.

I don't think it says any numbers.

I will take your comments on board for the aux battery when chargeing cause I realy have no idae when it is charged.

[Feral]

Generally a battery on charge will read somewhere between 14 and 16 volts, but as soon as the charging source (be it auxilary charger or part of the boat system) is removed it will drop back to around 12.

Depending on the battery, it will not deliver useable power once the voltage drops below about 10, so those \"colour\" type guages are over a very restricted range (a couple of volts). I'd be checking the actual voltage with a voltmeter (or multimeter).

Post edited by: Feral, at: 2006/06/19 04:30

[Brian D]

Feral, I think I am geting it. No matter how big the battery, if it's 12 volts that's all the vaultage you get, but the size dictaites how long you get 12 volts for. Is that about it?

Is that what they mean by amp hours?

[Feral]

Yes roughly, there are two type of battery, standard car type, which you can get away with in a pinch if you have a motor with a good charging system you use often. (But the shaking will tend to kill them eventually), and Deep cycle batteries.

Deep cycle marine grade batteries is what you should run in boats, they can go near flat time after time with no damage, and they are able to take a fair pounding without dropping their guts.

Batteries have 2 ratings, Amp Hours, and CCA (Cold Cranking Amps)

Amp hours is the rate it can deliver power at over time, ( an hour I think, memory is a bit rusty) CCA is the power it can deliver over a short time, generally to start a motor. Unless you are running a huge boat motor, it is generally the first that is important for a boat.

[blue_mako]

my mate tom bought a marine battery from the tinnie and tackle show for $75 i think it was for his little tinnie... i think he should have bought it at the end of the show so he didnt have to carry it around all day!

troy