Two twelve volt systems

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I want to have a single battery powering my Wallas oven and hob with a seperate battery and its own solar panel and wiring with the exhaust for the oven hob exiting through the steel of the boat,can any one see a problem with two 12 volt systems on a boat? Reason I would like to do this is my boat has no gas and I would like to know that the Wallas will run even if the main battery's are low as the hob will also work as a heater if my main heater fails so it's also a back up system

Thanks for all the healpfull replies to my other questions and hope this is not a daft question

[Lampyrichard]

Lots of folk do it, many have eg one set of batteries for an invertor & another for the rest of the 12V system.

 

You don't have to have completely isolated systems, there are lots of ways of charging multiple banks from one or more sources (solar / engine / landline...)

 

However, there id a school of thought that suggests you'd be better off having one large battery bank for everything...

 

Have a read of this page for an in depth look at what you're proposing & why it might not be such a good idea.

 

I'm sure others will be along shortly to explain where Gibbo got it wrong:-)

[Arthur Brown]

Do you also have a starter battery? Can you design the wiring so that there is no possibility of confusion and user errors. You could well end up needing three alternators with extra pulleys and belts, only you can justify the extra complexity for a limited benefit.

[lockedout]

Prior to my recent re-wiring, our boat had two different 12v systems. I have no idea why and it is one of the reasons I did a full re-wire. I had three 110s running the domestics and two 110s completely separate running the 240v through the inverter. The only point of contact between the two systems was the feed from the charger and the feed from the alternator.

 

It could be argued that I actually had 4 different systems, if you count a single 110 running the bowthruster and a single 110 for the engine.

[NMEA]

I am a Wallas partner and fit the things regularly, personally I can see no benefit in your adding extra complexity to the supply if your main domestic bank and charging regime is properly specified, Wallas are pretty good on power consumption. You will find the hob blower a boon by the way, when set on a low burn they maintain the cabin temperature and circulate the air quite nicely.

Edited August 16, 2016 by NMEA

[WotEver]

I see only disadvantages in splitting the bank with no advantages.

[bottle]

I would explain the reasoning behind keeping one bank and not two.

 

Take a bucket of water and you need to use half that bucket

 

Now take two buckets of water and use the same amount of water, that means each bucket is three quarters full, instead of one being half full.

 

Batteries like to be full and if you empty them less and refill them fully they will last longer (life)

 

The above, that know, could described it better and more technically but I understand it this way.

[Robbo]

I want to have a single battery powering my Wallas oven and hob with a seperate battery and its own solar panel and wiring with the exhaust for the oven hob exiting through the steel of the boat,can any one see a problem with two 12 volt systems on a boat? Reason I would like to do this is my boat has no gas and I would like to know that the Wallas will run even if the main battery's are low as the hob will also work as a heater if my main heater fails so it's also a back up system

Thanks for all the healpfull replies to my other questions and hope this is not a daft question

Do you have issues at the moment? I can see your reason why wanting two banks looks beneficial, but having one bank and a good charging schedule is much better.

 

If you do go for two banks then using a Voltage sensitive relay between them both is key, then when charging any bank all batteries get charged using whatever charging method your using whether solar, engine or shore.