dual batteries

[Seahorse]

i was just thinking about having a second battery put in the boat. Can anyone tell me if this is a good idea and why. If so i will ring dealer in the morning and oganise it. Also what is the cost of extra battery and is there ones better than others.

cheers
greg

[madmix]

Hi greg

depends on how much electrics your running, and how big your
motor is. If you can easily pull start in emergency then 2nd battery
is not a priority.
Spare battery does not have to be wired with isolator switch etc.
I just put a spare fully charged battery on board and if main fails
just change over batteries.

Yes some batteries are better than others and cost accordingly

cheers Mick

[Seahorse]

its a 75hp. i will have navlight, anchor light, interior lights, radio, sounder, just the normal stuff.

cheers
greg

[Chimo]

Hi Seahorse

if you want to fit a 2nd battery because you motor battery is not reliable maybe better to get a better battery. # if its to give you a range of other benefits then yes and making your second, preferably, deep cycle battery, a house battery will certainly protect your expensive nav and fish finding gear and more. #(Deep cycle are totally different to starting batteries in the way they release their power, are built and whats in them)

You can also ensure that you can always start you engine after operating at night or running bait pumps etc if you fit an automatic battery coupler between the two. #

That way you don't have to worry about manual switching to charge your 2nd battery as the auto battery coupler also reconnects the two batteries after the motor has started and electrical spikes are no longer an issue as well as disconecting to protect the electrics from spikes when you start you motor..

In my case soon after I bought my Seafarer I noticed I was losing pixcels in my Lowrance Global Map and while the Lowrance guarantee covered a replacement, Lowrance urged me to not run nav and other electric from the motor battery any more or at least to have the electrics off when starting motors. #

To make a long story shorter, I got a marine electrician to rewire the boat and add a house battery (deep cycle). #He also introduced me to the Auto battery Coupler, a cheap bit of gear made on the Gold Coast that takes all the worry out of batteries and instrument management.

It was such a pain to have to turn the GPS and depth finder off every time I started motors.

There a couple of the wire diags in the electronics sectn under battery switches and you can re read this there too plus some other info on the auto battery coupler that I still have to source and price for you too

Hope this helps

Chimo

[Seahorse]

thanks chimo. I think i will go the second battery. I havnt had new boat delivered yet, so think i will give the dealer a ring in the morning and have it all fitted up, prior to me picking it up.

cheers
greg

[Cheech]

Go the second battery.

We had to pull start my 100 merc once. Was not fun. And had to worry about how to get the engine cowling back on in a bit of a sea with the engine spinning.

I was running 2 batteries as well, and flattened both of them. What happened was that I had one good and one bad, but because I had the switch on BOTH, the bad sucked the power out of the good. Now I make sure I switch to a single battery when at rest. I use to do this but then got slack. Actually I usually do this when running as well and charge one or the other just in case.

600 Centuary marine are the batteries I have.

Cheech

[timddo]

hmm, i have a 2 battery setup witha bep isolator, switch.
the first is a marine battery for the boat and the other is just a car battery, got it free. I use one battery per trip. and the other battery the next trip, so they both are in use. if one dies there is always the other.

2 batters are good, but i'm sure your can pull start your 75 anyway.

tim

[troy]

Seahorse,
I put in dual batteries with a isolating switch about 8 weeks ago.
I took everyones advise to do this and it was one of the best things i have done.
All up cost was $415.00.
Troy

[Seahorse]

thanks troy.

[Seahorse]

i plan on doing few overnighter so thought this would be way to go.

[eimeo]

i have a 75hp and decided that for safety sake to put in dual batteries.At rest i run all the nav off 2nd battery and start with 1st battery .When running i switch to both to charge.A flat battery is not something you want out at sea and with 2 batteries,provided you remember to switch them over,you certainly minimise that problem.Small price for peice of mind

my thoughts anyway
dave :)

[troy]

Eimeo,
Some members told me not to run the motor on both batteries as if one is not as good as the other it will have a affect on the good battery.
Could be wrong but might pay you to check it out.
Troy

[marlinqld]

Troy,

I have dual batteries with switch.
At rest i run everything on No 1 battery. When steaming along i switch to both so it charges both batteries. occasionally i change and run everything on No 2 so both get even wear and tear.

never had a problem, as long as you give both batteries a go at running lights etc so wear and tear is even.

Mike

[Seahorse]

i ordered second battery today. total cost is $200 includes battery, switch and fitting. not bad i thought

[troy]

Seahorse,
Half the price i paid good on you.
They must have seen me coming.
Troy :'( :'(

[Seahorse]

maybe i got it cheaper because boat is still coming from factory and dealer is going to fit prior to delivery

[BaysideMarine]

Fitting a VSR (Voltage Sensitive Relay) is the best way to go. No battery switches to fiddle with as the system works automatically, disconnects the second battery from the circuit when you pull up and reconnects the second battery when th eprimary battery reaches 13.7 volts.

Battery switches are in some ways agricultural and well behind.... VSR's are intelligent power management.

Cheers

[Seahorse]

thanks bayside. any extra in costs

cheers

[mirage]

Seahorse, good to see you ordered a 2nd battery. If you are ever intending to go offshore they are a must have!

[HarryO]

G'day Seahorse.

Two is much better than one.

The VSR set up only handles the charging circuits.

If you run two batteries without the ISO switch,
you either cannot run them independantly, and you cant use the
second battery to start the engine if the primary battery fails,
other than by swapping them.

The VSR determines where the charge flows automatically,
but you will still need the ISO switch if you want the ability
to choose which battery you want to start the engine with.

Harry.

[Seahorse]

thanks harry

[BaysideMarine]

Why would you want to choose which battery to start with? In a dedicated system there is a start battery and a house battery and they remain that way.

[HarryO]

Bayside,

No offence intended,

but for whatever reason you install a second battery(ies),
it makes sense to be able to have that power available
quickly to start the engine/s if needed, should the primary
start battery fail.

It is also wise, whether single,dual, or dedicated start / house
battery systems are fitted, that ISO switches are fitted to
each system.

I think that you would be hard pressed to find a qualified marine
sparky that would recommend otherwise, but, these days,
you never know whats around the corner as far as new
electronic tech is concerned. :) :)