charging and fridge use advice please

[Falcoron]

Hi,
I have an Ocean 30 and the fridge is a 12v only unit that will run perfectly when engine running but not when stationary. I have 2 off 110amh leisure batteries and the engine starter battery that all charge from the alternator. I have a 40w solar panel connected to the starter battery but its a bit MEH! no real charging power from it. I keep the leisure batteries topped up with an optimate trickle charger.
what I really want to do is have a single charger off the 240 shore power and be able the charge all batteries ( 2 linked leisure and the starter) and to run the fridge all the time, even when we are not on the boat. I have had 2 companies recommend different set ups one recommended a mastervolt 30 amp 3 way charger with wired feed directly to fridge via a fuse and an on off switch, the other recommended a single point 30amp victron charger with a 240v relay to have the default charge to batteries and fridge when engine running as she does now but to trip over to the charger when the alt is not running. Then I got a recommendation to run the victron ip22 30 but a single output'
Quote.
As your leisure batts are links this is counted as one battery so you need to add the Cyrix-ct battery combiner which isolates starter battery from leisure one however allows safely sharing the IP22 charger to charge both batteries ( starter and leisure). Also the Cyrix-ct allows you to start your engine on leisure battery in case the start battery is dead.
A fused line to an on off switch to the fridge is fine.

I am not a spark but can wire up to a diagram, anyone doing this already and could help me with this please so confussing.
Ron

 

[jrudge]

If you are charging the leisure batteries then the fridge would just connect to them in the normal way - the charger will then both charge and deal with the load of the fridge as required.

Some boat fridges have a 240v supply and a 12/24v supply and sense when 240v is not available and flip to 12v.

If yours does not have this feature then just run it off 12v and leave the charger to do its job.

 

[kashurst]

I am a bit confused, the fridge should run off the battery all the time regardless of the engine running or not. The alternator will recharge the batteries whilst engine running and as jrudge said the battery charger should maintain the batteries when you are on shore power. It maybe who ever fitted the solar panel has messed something up. Check if you have 12v all the time at the fridge connections and go from there. Its quite easy with boats to get sucked into spending lots of money when the solution is often quite simple.

 

[jimmy_the_builder]

Guessing here, but if it's a 12v fridge that works ok w engine running but not when engine off then could it be that the charging voltage when engine running (c.13.8v or whatever) is enough for the fridge, but the not-on-charge voltage (c.12v) is not? My 12/240 Isotherm fridge will switch off the fridge compressor when running on dc if the voltage falls below a certain threshold; could it be that you have a bad dc connection to your fridge which is dropping the voltage enough for this cut-out to happen when the engine is not running? Have you tested the dc voltage actually in the fridge (ie after your loom connections) with engine running and stopped, to see what actual voltage you're getting? You might find that simply remaking the connections, or (better) upgrading the cable to the distribution bus might solve the problem.

 

[Falcoron]

I am a bit confused, the fridge should run off the battery all the time regardless of the engine running or not. The alternator will recharge the batteries whilst engine running and as jrudge said the battery charger should maintain the batteries when you are on shore power. It maybe who ever fitted the solar panel has messed something up. Check if you have 12v all the time at the fridge connections and go from there. Its quite easy with boats to get sucked into spending lots of money when the solution is often quite simple.

OK, I may not have given all the details, this is an old 1978 boat and from what im told it only runs the fridge with engine running it will shut off then engine is off. Im thinking there si a relay that only operates the fridge from the alternator and flicks off when that stops. I have not bought a charger yet ( bar the optimate im using for trickle charge)
the solar panel is wired correctly and has the correct distribution hub to prevent the battery draining when no sun is about
( diode ) its not charging enough so im going to sell that on.
the charger I want is expensive but is touted as safe and for marine use ( probably why its expensive) but it has good safety features.
this is the single output one
http://www.12voltplanet.co.uk/victron-blue-power-ip22-7-stage-adaptive-battery-charger-12v-30a.html

this is the 3 way
http://www.12voltplanet.co.uk/victr...battery-charger-12v-30a-3-output-uk-plug.html

all I want to do is charge all batteries and run the fridge safely, and not do any damage to the charger when I start the engine and it reverts to alternator charging.
not sure if im over complicating this and have had several confusing options to look at which include buying special battery protection devices and the likes.
cheers

 

[prv]

Guessing here, but if it's a 12v fridge that works ok w engine running but not when engine off then could it be that the charging voltage when engine running (c.13.8v or whatever) is enough for the fridge, but the not-on-charge voltage (c.12v) is not? My 12/240 Isotherm fridge will switch off the fridge compressor when running on dc if the voltage falls below a certain threshold; could it be that you have a bad dc connection to your fridge which is dropping the voltage enough for this cut-out to happen when the engine is not running?

That's my bet too. I wasted a lot of time and a certain amount of money trying to "fix" a fridge that was actually perfectly fine but hadn't been connected properly. The supply appeared to have a healthy voltage on it, but in fact it was dropping way down whenever the fridge tried to start, because of the loose connection hidden under a bunk.

EDIT: Now see the OP thinks he has a relay controlling the fridge...

Pete

 

[duncan99210]

The situation described by the op in his second post is common place for charter yachts here in the Med. The fridge only runs when the engine is running: there's a relay that operates when the engine is on but isolates the fridge again when the engine stops. Helps prevent flat batteries due to overuse. All the OP has to do is to re-wire the fridge to the domestic battery(ies) and it will continue to run from them when the engine is off. However, he will need to remember to switch it off before leaving the boat as the solar panel mentioned will not keep pace with the fridge.

As for a charger, a two outlet one will do fine: any of the modern ones will cope quite easily with charging the battery banks and running the fridge whilst they're doing so. No need for an additional third output just for the fridge. My charger is hard wired to the batteries. The engine can be run whilst plugged into shore power with no damage to either the alternator or charger.

 

[Trundlebug]

Look up Sterling chargers, they are probably more reasonably priced than Mastervolt and they do a good range which will charge both house and start batteries with one charger (up to 3 outputs IIRC).

Should be easy to fit, their instructions are good and telephone help also reasonable if you do have questions.
http://sterling-power.com/

 

[vas]

The situation described by the op in his second post is common place for charter yachts here in the Med. The fridge only runs when the engine is running: there's a relay that operates when the engine is on but isolates the fridge again when the engine stops. Helps prevent flat batteries due to overuse. All the OP has to do is to re-wire the fridge to the domestic battery(ies) and it will continue to run from them when the engine is off. However, he will need to remember to switch it off before leaving the boat as the solar panel mentioned will not keep pace with the fridge.

As for a charger, a two outlet one will do fine: any of the modern ones will cope quite easily with charging the battery banks and running the fridge whilst they're doing so. No need for an additional third output just for the fridge. My charger is hard wired to the batteries. The engine can be run whilst plugged into shore power with no damage to either the alternator or charger.

agree with Duncan, re-wire the fridge!
however I'd question the reason of having a 40W solar panel charging the starter battery! This is the battery that gets the least load, just cranking the engine then the alternator keeps it nicely topped up.
Just swap the solar panel to charge the service batteries. I doubt the 40W will be enough to keep the fridge running 24/7, but worth a try...

I'm installing 2X250W panels to charge 2X2X180Ah 12V service bank batteries to be able to run nav. gear and one fridge 24/7 but that's in Greece with a lot of sunshine (but also a lot of heat for the summer)

cheers

V.

 

[KevB]

The situation described by the op in his second post is common place for charter yachts here in the Med. The fridge only runs when the engine is running: there's a relay that operates when the engine is on but isolates the fridge again when the engine stops. Helps prevent flat batteries due to overuse. All the OP has to do is to re-wire the fridge to the domestic battery(ies) and it will continue to run from them when the engine is off. However, he will need to remember to switch it off before leaving the boat as the solar panel mentioned will not keep pace with the fridge.

As for a charger, a two outlet one will do fine: any of the modern ones will cope quite easily with charging the battery banks and running the fridge whilst they're doing so. No need for an additional third output just for the fridge. My charger is hard wired to the batteries. The engine can be run whilst plugged into shore power with no damage to either the alternator or charger.

+1

What he said

My fridge is connected to the domestics via the switch panel/distribution board along with everything else of 12v on board.. I have a 3 way charger, one for the domestics x 2, one for the starter and one for the bow thruster.

 

[Falcoron]

agree with Duncan, re-wire the fridge!
however I'd question the reason of having a 40W solar panel charging the starter battery! This is the battery that gets the least load, just cranking the engine then the alternator keeps it nicely topped up.
Just swap the solar panel to charge the service batteries. I doubt the 40W will be enough to keep the fridge running 24/7, but worth a try...

I'm installing 2X250W panels to charge 2X2X180Ah 12V service bank batteries to be able to run nav. gear and one fridge 24/7 but that's in Greece with a lot of sunshine (but also a lot of heat for the summer)

cheers

V.

Lucky you! i'm in Ireland ( north) and when we see the sun there is a flurry of UFO reports LOL!
dont think the solar panel i have is up to much.
Thanks for all your imput i think i can get somethin sorted from this.
If i link the fridge to the Leisure batteries what rating of fuse should i put on the live wire?
Cheers

 

[jimmy_the_builder]

If i link the fridge to the Leisure batteries what rating of fuse should i put on the live wire?

Surely it's already connected to the leisure batteries?

 

[vas]

Surely it's already connected to the leisure batteries?

+1000!!!

engine battery should only have the engine starter and their whatever control panel and possibly the bilge pump (but it shouldn't really...)

cannot help with the fuse, depends on fridge I guess, should have it's rating on a sticker somewhere, or check the model on the web

V.

 

[Falcoron]

The situation described by the op in his second post is common place for charter yachts here in the Med. The fridge only runs when the engine is running: there's a relay that operates when the engine is on but isolates the fridge again when the engine stops. Helps prevent flat batteries due to overuse. All the OP has to do is to re-wire the fridge to the domestic battery(ies) and it will continue to run from them when the engine is off. However, he will need to remember to switch it off before leaving the boat as the solar panel mentioned will not keep pace with the fridge.

As for a charger, a two outlet one will do fine: any of the modern ones will cope quite easily with charging the battery banks and running the fridge whilst they're doing so. No need for an additional third output just for the fridge. My charger is hard wired to the batteries. The engine can be run whilst plugged into shore power with no damage to either the alternator or charger.

What charger do you use?

 

[Falcoron]

Surely it's already connected to the leisure batteries?

I'm not sure it is as it only ever works from the alternator, don't think it was designed to run on the batteries.
Even after a long run on the engine and the fridge is working 100% it stops working once engine stops so I don't think it's connected to any dattery only a relay and the alt.

 

[vas]

I'm not sure it is as it only ever works from the alternator, don't think it was designed to run on the batteries.
Even after a long run on the engine and the fridge is working 100% it stops working once engine stops so I don't think it's connected to any dattery only a relay and the alt.

should really be relay and battery, making it easy to change. I cannot understand how a load is directly connected to the alternator, haven't seen it ever but I'm not an electrician. Typically the alternator "feeds" the battery or batteries through spliters and/or other fancier (and more expensive) devices.
Loads are sucking juice off the batteries.

V.

 

[duncan99210]

I have an ancient Sterling 40 amp one (vintage 2000) with two outlets: one to the domestic bank (490 ahr) and one to the engine start battery.

The fridge will (should) already be connected to the domestic battery bank but it will have a relay in the circuit that will only supply power to the fridge when the alternator is supplying power to the battery. Bypassing the relay is the only change required for the fridge wiring.

 

[SteveSarabande]

should really be relay and battery, making it easy to change. I cannot understand how a load is directly connected to the alternator, haven't seen it ever but I'm not an electrician. Typically the alternator "feeds" the battery or batteries through spliters and/or other fancier (and more expensive) devices.
Loads are sucking juice off the batteries.
Maybe it is wired via the engine ignition switch

V.

 

[vas]

Maybe it is wired via the engine ignition switch

yep, maybe
However, in that case, the engine ignition switch will be triggering the relay that powers the fridge from the battery. Doubt ignition switch will be strong enough for such a constant load.
Anyway, a two minute job to bypass the relay and have the fridge running all the time (and emptying your batteries rather quickly...)
You may also be lucky to have a rotary switch thing in the fridge to tune the temp which often has an off position, which means you wont even need to wire the fridge back to the main el.panel as you'll be able to switch the fridge off like that (although if I were the OP, I'd definitely do it!)

cheers

V.

 

[ARE]

Is it a compressor or absorption fridge?

Anthony