NaClH2OK9

Car Batteries on Boats

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G'day Raiders.

I currently run a dual battery set up on my boat, with an isolator for Bat A or Bat B.

I alternate these and try to use only one for the day out (leaving the other for emergencies).

I've found the last few outings that my battery is getting flat by the end of a day on the water (even when trolling , so the motor running in just over tickover for much of the day).

I run VHF, a big simrad, and usualy have some tunes playing, poss a live bait pump too.

I know I should do the maths and size a couple of big batteries and even switch to a start and gizmos on separate setup, but funds are limited at the mo with the car gearbox having gone pop and buying a Pajero.

Both batteries test at 12.75 V and hold their charge well when parked up for a week or 2 (and I always trickle them for a couple of days before a trip) I've also unplugged the battery when the motor is running to confirm i'm getting alternator output (but don't know how much output i'm getting)

So, to my question.

Currently

Battery 1 is a Century Marine Pro 650 , CCA 650, RC 140

Battery 2 is a NRMA HEAVY DUTY, CCA 520, RC 95

My car with the buggered transmission is probably going to be scrapped but has a 6 month old battery on it

Battery 3 is a Lion 357 (looks like a standard car battery ABS standard issue) CCA 550, RC110

Is it worth switching battery 2 and 3 for the extra capacity OR am I asking for trouble putting a car battery on a boat ? part of me says a battery is a battery but the 2 existing both have lables indicating the plates are braced for vibration.

Thanks

Steve

Steve

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i have been using normal car/truck batteries in the boat for last few years and had no problems

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Marine batteries are designed to cope with the rough ride - constant bashing into waves when underway etc. Car batteries aren't so you are more likely to have cell failure.

If you do use a car battery in a boat it would be best positioned in the stern to minimise the vibration and impacts.

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Marine batteries are designed to cope with the rough ride - constant bashing into waves when underway etc. Car batteries aren't so you are more likely to have cell failure.

If you do use a car battery in a boat it would be best positioned in the stern to minimise the vibration and impacts.

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Mmm is that a fact or what you get told to justify the "marine " pricing.

Genuine question- Do country cars on corrugated roads churn through batteries? Much tougher conditions than on the floor at the transom

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Thanks guys. With heading out tomorrow. I jumped on chickenmans advice and switched them.

I'm interested in people's experience though. ( and they are at the stern)

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Hi mate,

There is a vast range of battery's available on the market to suit many different applications.As your aware they come in all shapes and sizes.Its obvious as soon as you go shopping at the range available to suit all these different applications.It can be quite confusing to determine what capacity and ratings would suit the application the battery is needed for the novice user.

The first thing that a battery does is store energy/power,it does not produce energy/power.

For it to store this energy it needs some form of device to produce amperage/voltage to it which is the job of your charging system or when you have it on the battery charger at home.

Automotive and marine battery's have differences in the way they discharge.Automotive Battery's can not be discharged to as low a voltage as a marine battery without risking damage.(Deep cycle batteries are designed for this purpose)Automotive battery's provide a large current for starting the engine then the engine and all electrical loads are feed by the alternator which also tops the battery back up after the initial engine starting.

Basically once the car engine starts the battery has very little to do with the running of the motor vehicle.

Turn that engine off though and have the radio,lights etc on and you will start to delete the energy/power stored in the battery.This is primarily why they are called cranking battery's as they provide large amounts if current/amperage but can not sustain it for long periods.

If you try cranking an automotive engine which won't start it will very quickly drain the battery as the starter motor draws a heap of amps.

Marine battery's are more designed as a cranking/house battery that will both get an engine started and run ancillaries to a degree such as lighting,bilge pumps,radios etc.Marine battery's will happily start your engine and run the ancillaries again within limitations.

How automotive and marine battery's are made are different.

They both are called lead acid battery,s but where they differ is the energy storing plates are thicker in a marine battery which raises the cost significantly and will provide better shock proof.When you have dissected a Automotive and Marine battery like I have you'll soon realise where that extra cost for the Marine battery went.

The short answer to your question is Yes a automotive battery will work for a while,but is a Marine Battery better long term?yes again.

Hope this clears things up a little.

My advice is if your budget allows go a marine battery.

Cheers

Fabian.

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Thanks Fabian. That makes lots of sense.

Starting at the end and going backwards. I don't have any budget for this. It was just the 'free' availability of battery "c" in my scenario.

Battery "b" is marked heavy duty but not marine.

So. Would you go

B 078a0e8790ffbc457e65626f59e872b3.jpg843c59d73ea2ca6359bd2e3bf2f53a4f.jpg

Or C

ad81513de11b9b5eb90067979de2430a.jpgd3f9e5ef98f3e129ff17ab923d4a7852.jpg

( I can see myself putting them back as was)

Cheers. Steve.

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Thanks Fabian. That makes lots of sense.

Starting at the end and going backwards. I don't have any budget for this. It was just the 'free' availability of battery "c" in my scenario.

Battery "b" is marked heavy duty but not marine.

So. Would you go

B 078a0e8790ffbc457e65626f59e872b3.jpg843c59d73ea2ca6359bd2e3bf2f53a4f.jpg

Or Cad81513de11b9b5eb90067979de2430a.jpgd3f9e5ef98f3e129ff17ab923d4a7852.jpg

( I can see myself putting them back as was)

Cheers. Steve.

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Neither,I would buy a quality marine battery but if worse came to worse I'd do a load test on all if them and pick the one with the best results in the meantime.

You mention you run a dual battery set up combined with being able to pull start you should be ok in the meantime.

If you haven't done so already I would also seriously consider going through all the wiring to ensure its in good condition and making sure all connections/grounds are clean and secure as this is a very common reason for both cars and boats having trouble starting.

Cheers.

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G'day Raiders.

I currently run a dual battery set up on my boat, with an isolator for Bat A or Bat B.

I alternate these and try to use only one for the day out (leaving the other for emergencies).

I've found the last few outings that my battery is getting flat by the end of a day on the water (even when trolling , so the motor running in just over tickover for much of the day).

I run VHF, a big simrad, and usualy have some tunes playing, poss a live bait pump too.

I know I should do the maths and size a couple of big batteries and even switch to a start and gizmos on separate setup, but funds are limited at the mo with the car gearbox having gone pop and buying a Pajero.

Both batteries test at 12.75 V and hold their charge well when parked up for a week or 2 (and I always trickle them for a couple of days before a trip) I've also unplugged the battery when the motor is running to confirm i'm getting alternator output (but don't know how much output i'm getting)

So, to my question.

Currently

Battery 1 is a Century Marine Pro 650 , CCA 650, RC 140

Battery 2 is a NRMA HEAVY DUTY, CCA 520, RC 95

My car with the buggered transmission is probably going to be scrapped but has a 6 month old battery on it

Battery 3 is a Lion 357 (looks like a standard car battery ABS standard issue) CCA 550, RC110

Is it worth switching battery 2 and 3 for the extra capacity OR am I asking for trouble putting a car battery on a boat ? part of me says a battery is a battery but the 2 existing both have lables indicating the plates are braced for vibration.

Thanks

Steve

Steve

For your question, I think you should use the battery that is in the best condition. Whichever is newer and been used or abused the least.

Your battery getting flat at the end of the day doesn't sound right to me. I think you should check to see how well the engine is charging it.

I can run 2 sounders, lights and bait pump continuous all night and day for a 12 hour trip and the battery will still be full when I get home and put it on charge to check it. My trips are usually a mix of anchoring, drifting and slow (idle) trolling. Engine is 60HP.

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I have a 4WD battery for my starting battery in the N70 size and a deep cycle battery for the toys.

4WD batteries are supposed to be designed for going off road so i fugure that is a bit like bumps

on the ocean.

You battery that runs the toys, does it have amp/hours written on it anywhere?

Mine says 120A/H so in theory, that means I can run a 1 amp fishfinder for 120 hours

with out recharging, or 1 2amp radio for 60 hours or 1 120amp toaster for 1 hour ;-)

I'd consider putting in your newest battery as your starting battery then what ever is best for the

toy's battery and save some $$$$ to get yourself a deep cycle. Also consider taking a little

jumpstart battery so that if there is a disaster, you can get the engine going and get home.

Reread Fab1's post above, he makes a lot of sense ;-) and doing the trickle charge when

you get home is important, and I like to do it again before I head out. Do't leave your

batteries flat, they don't like it

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Fab. With the exception of noting, I'm looking for a zero spend atm . It's about utilizing what I have available ( when I stop shelling on sh1t like whole cars I'll happily invest on a thought out new set up)

Fantastic advice.

Also from Anthony and Roylo.

Cheers all.

How do I do a load test?

Yesterday and today my main battery ( the original batt a) has been perfect. So I'm thinking it may have been the batt b ( which I was using alternative outings) that was not up to a days disco.

But. My motor is due a service and I'll make sure I get the alt output checked. Apart from reading the specs. How do you check how many amps are being drawn by my gadgets? I've got a basic multimeter that tbh I only use for continuity.

Is this likely to be able to give me my amps drawn if I put it inline and switch stuff on?

Thanks again for the great advice.

Steve

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Fab. With the exception of noting, I'm looking for a zero spend atm . It's about utilizing what I have available ( when I stop shelling on sh1t like whole cars I'll happily invest on a thought out new set up)

Fantastic advice.

Also from Anthony and Roylo.

Cheers all.

How do I do a load test?

Yesterday and today my main battery ( the original batt a) has been perfect. So I'm thinking it may have been the batt b ( which I was using alternative outings) that was not up to a days disco.

But. My motor is due a service and I'll make sure I get the alt output checked. Apart from reading the specs. How do you check how many amps are being drawn by my gadgets? I've got a basic multimeter that tbh I only use for continuity.

Is this likely to be able to give me my amps drawn if I put it inline and switch stuff on?

Thanks again for the great advice.

Steve

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have a look at my battery and charging issue post in the workshop to do a load test.

Cheers.

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Thanks Fabian.

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