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Engine and battery charger on at same time?

DeanS

By DeanS
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DeanS Veteran II

DeanS

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This ones been niggling me for a bit. If I am on elec hookup in a marina, and the battery charger is on (first question..what happens if I leave the charger on permanently), and then I run the engine as well....for some reason like I like to know it will start........is it a problem for the alternator and the battery charger both to be charging the battery at the same time? 3 things connected...battery, battery charger, alternator. Can one damage any of the other two and vice versa.

 

Thank you for your shared knowledge in advance.

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canaldrifter Experienced

canaldrifter

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Why try it? What's the advantage? Just disconnect the power hook up when you start the engine. You won't harm the charger if it's connected but isn't charging. I leave mine connected but unplugged when the engine is running and the inverter is working, all the time.

 

Tone

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DeanS Veteran II

DeanS

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Why try it? What's the advantage? Just disconnect the power hook up when you start the engine. You won't harm the charger if it's connected but isn't charging. I leave mine connected but unplugged when the engine is running and the inverter is working, all the time.

 

Tone

 

I forget to unplug. I only remember when I've started the boat..that the battery charger is still connected and on? So you're saying nothing should get damaged?

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Naughty Cal Veteran II

Naughty Cal

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It very much depends on your charger.

 

Our Newmar battery charger is safe to leave turned on whilst the engine is running but it can damage some battery chargers. You really need to read the manual for your specific battery charger to find out if yours is safe to leave on whilst the engine is running.

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mrsmelly Veteran II

mrsmellyDonate to Canal World

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This ones been niggling me for a bit. If I am on elec hookup in a marina, and the battery charger is on (first question..what happens if I leave the charger on permanently), and then I run the engine as well....for some reason like I like to know it will start........is it a problem for the alternator and the battery charger both to be charging the battery at the same time? 3 things connected...battery, battery charger, alternator. Can one damage any of the other two and vice versa.

 

Thank you for your shared knowledge in advance.

 

Hi

 

Dont know if this helps but if my boat is plugged in to shore mains the engine cannot be started this is a safety device to ensure you know whats happening with electric bits and stops you inadvertantly setting off whilst still connected to a shoreline. It is probably a simple bit of kit that does this and I am suprised when I hear of even new boats not having this as standard, cant be much of a job to fit ? and is in my opinion a bloody good ides.

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Ray T Veteran II

Ray TDonate to Canal World

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Never really paid attention to the make of battery charger I have but it has a sticker on it saying do not run the engine whilst the charger is hooked up to the mains and on.

 

When the batteries are charged the charger goes into standby mode.

 

Decided it may be too expensive if I tempt fate and experiment.

 

I think you need to find your charger instructions.

Edited by Ray T
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blackrose Veteran II

blackrose

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A decent marine 3 stage charger should be ignition protected so no damage would occur. Having said that I always turn mine off before starting the engine - just a habit, but I have forgotten a few times and there's never been any problem.

 

Yes, a proper 3 stage charger can be left on permanently.

Edited by blackrose
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NB Lola Rising Star

NB LolaDonate to Canal World

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I was recently advised not to have the shoreline connected with the engine running. Now most are aware I have little practical knowledge on any subject but i was told it is because it can mess with the alternator settings/battery charger.

 

Happy to be corrected/laughed at for being gullible

 

:cheers:

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Gibbo Veteran II

Gibbo

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In my time in this game I reckon I must have repaired, worked on or been involved in the design of, at least 500 different makes and models of battery charger.

 

In all that time I have not come across a single charger that would be damaged by running at the same time as another charger or the engine alternator.

 

Not a single one.

 

It would be an utterly crap design that would be damaged by such a situation. In fact, I think it would actually be more difficult to design one that would be damaged than to design one that wouldn't.

 

Yes, manoeuvring whilst disconnecting shoreline.

 

:lol: There's always one!

Edited by Gibbo
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ditchcrawler Veteran II

ditchcrawlerDonate to Canal World

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Yes, manoeuvring whilst disconnecting shoreline.

We use to have a diesel Landrover Fire Engine fitted with an electric engine heater and the supply plug was chained to the back of the garage, so if you drove off it just pulled the plug out. (for plug read socket)

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nb Innisfree Veteran II

nb InnisfreeDonate to Canal World

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We use to have a diesel Landrover Fire Engine fitted with an electric engine heater and the supply plug was chained to the back of the garage, so if you drove off it just pulled the plug out. (for plug read socket)

 

A certain fire station many moons ago experimented with appliance engines which could be fired up remotely by fire control. That was ok until someone left it in 1st gear and it went through the appliance room doors :lol:

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gypsy Gongoozler

gypsy

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This ones been niggling me for a bit. If I am on elec hookup in a marina, and the battery charger is on (first question..what happens if I leave the charger on permanently), and then I run the engine as well....for some reason like I like to know it will start........is it a problem for the alternator and the battery charger both to be charging the battery at the same time? 3 things connected...battery, battery charger, alternator. Can one damage any of the other two and vice versa.

 

Thank you for your shared knowledge in advance.

 

I'm thinking on my feet here having asked the same question of myself and my conclusion is that it has to be similar to jump starting a car - your'e battery being charged by another cars' til you start up, run the engine for a few minutes then take the jump leads off. The alternator will take up the chrging role once the engine is running so there just isn't any need to stay hooked up as well and the battery isn't gonna know or care where its charge comes from and then pick a favourite so there isn't much point unless you are sure your battery is flat - like mine 'cos its got sooo cold out there. As for leaving it on constantly - I was told that batteries are better charged then used then charged than just kept topped up but I fear that a battery expert somewhere will be shaking his head and give a good tecchie explanation about that. In summary I dont think it does any harm but there isn't really any point.

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nb Innisfree Veteran II

nb InnisfreeDonate to Canal World

Posted
Posted (edited)

I'm thinking on my feet here having asked the same question of myself and my conclusion is that it has to be similar to jump starting a car - your'e battery being charged by another cars' til you start up, run the engine for a few minutes then take the jump leads off. The alternator will take up the chrging role once the engine is running so there just isn't any need to stay hooked up as well and the battery isn't gonna know or care where its charge comes from and then pick a favourite so there isn't much point unless you are sure your battery is flat - like mine 'cos its got sooo cold out there. As for leaving it on constantly - I was told that batteries are better charged then used then charged than just kept topped up but I fear that a battery expert somewhere will be shaking his head and give a good tecchie explanation about that. In summary I dont think it does any harm but there isn't really any point.

 

It's a myth, cycling a lead acid battery reduces it's service life, better to keep it at 100% SoC (with a reduced float voltage)

 

It's an ugly truth but using it will lose it.

Edited by nb Innisfree
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Naughty Cal Veteran II

Naughty Cal

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It's a myth, cycling a lead acid battery reduces it's service life, better to keep it at 100% SoC (with a reduced float voltage)

 

It's an ugly truth but using it will lose it.

 

Forgive me if im way off the mark here, but is the point of a domestic battery bank to provide power, hence they will get used.

 

Batteries are a consumable item, they will get tired and need replacing, surely it is better to budget for replacing them every 2 or 3 years than to have a constant battle trying to keep them in top condition. Life is a just a little bit too short to spend it worrying about replaceable batteries.

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nb Innisfree Veteran II

nb InnisfreeDonate to Canal World

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Forgive me if im way off the mark here, but is the point of a domestic battery bank to provide power, hence they will get used.

 

Batteries are a consumable item, they will get tired and need replacing, surely it is better to budget for replacing them every 2 or 3 years than to have a constant battle trying to keep them in top condition. Life is a just a little bit too short to spend it worrying about replaceable batteries.

 

Exactly, that's my point, you have two choices, don't use them and rot in one place or use them and live a little.

 

Life's scary :unsure:

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canaldrifter Experienced

canaldrifter

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In my time in this game I reckon I must have repaired, worked on or been involved in the design of, at least 500 different makes and models of battery charger.

 

In all that time I have not come across a single charger that would be damaged by running at the same time as another charger or the engine alternator.

 

Not a single one.

 

It would be an utterly crap design that would be damaged by such a situation. In fact, I think it would actually be more difficult to design one that would be damaged than to design one that wouldn't.

 

 

 

:lol: There's always one!

 

Thanks Gibbo. A +1 for really useful info.

 

( I wish the same rule applied to running an inverter and a power line at the same time. It cost me nearly £300 to find out THAT didn't work!)

 

Tone

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