While in my slip, my C36 mk1.5 12VDC fridge is connected directly to the batteries. When the battery drops, the charger kicks in to bring the batteries back up to 12V. I want to do away with this process while in my slip, and simply use a AC to DC converter. Any suggestions?
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Bob Gray
Corbeta #1117
Lake Erie, Great Lakes
1991 C-36 mk1.5 TR/SK M35B
Hi there and welcome to the C36IA!
Depending on your boat and what equipment it has, you already may have this in place. Most modern chargers, if they are working correctly, maintain the batteries in float once they are charged and then pick up any loads on the DC circuits. The batteries effectively don't see it at all. What make and model of charger do you have now?
If you could fill in some more details on your boat and yourself, such as the hull number, year, engine, keel type, sail plan, where you sail from, it will help the members here help you. Using the auto signature tool under the User CP is an easy way to do this.
You may also want to check the manual for the Fridge. Often they require the battery to be present as it guaranties a true DC flow of current. AC to DC converters are not always pure. Same goes in the other direction, not all Inverters are true sine wave.
Ross & Joanne
Wavelength
Saint John NB
RKYC
C36 #658 TR 1987
RXG31,
With all due respect, I can't think of any good reason to do what you want to do. Having an appropriate battery charger supply the DC current to both your batteries and any DC loads is the proper way to do it.
If the battery charger is working properly, it isn't like the batteries discharge and then the charger chargers them up. The battery charger should keep the batteries fully charged at the proper float level at all times and then also supply any additional current as needed for the fridge or other loads.
Perhaps if you explain why you think you want this other approach, it will help.
Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/
[QUOTE=rxg31;12407]While in my slip, my C36 mk1.5 12VDC fridge is connected directly to the batteries. When the battery drops, the charger kicks in to bring the batteries back up to 12V. I want to do away with this process while in my slip, and simply use a AC to DC converter. Any suggestions?[/QUOTE]
If your charger is behaving in that manner then you you really just need a new charger. This is how many older ferro chargers behaved..
The newer "power supply" based chargers, like those from Mastervolt, Sterling, Victron & ProMariner, among others, act as a power pack and will keep the batteries full unless the DC loads exceed the charger output capability..
I am a big fan of the new Sterling Pro-Charge Ultra chargers (the ProMariner Pronautic P is the same charger) and find it to be one of the best designed and nicest chargers I've worked with or installed in a very long time. They are also "world voltage" chargers and can run on any voltage from 90V to 240V and put out full rated current. Great for docks with big power drops and other power issues that would kill other chargers....
[B][URL="http://www.pbase.com/mainecruising/installing_a_marine_battery_charger"]
Installing A Marine Battery Charger (LINK)[/URL][/B]
[IMG]http://www.pbase.com/mainecruising/image/140421733.jpg[/IMG]
-Maine Sail
https://www.marinehowto.com/
The boat is 1991, and I'm pretty sure my charger is the Flyback 20 made by Professional Mariner. The charger is mounted on the backside wall in the aft cabin. I have two interstate batteries to do everything.
What's most important to me is to have battery power available when I want the engine to start.
For several years, I live on board during the summer months. I spend most of my time in a slip or port...somewhere. When I travel, I normally am at my destination in less than 9 hrs and I use 2 blocks of ice while I travel 9 hrs. The fridge cooling is ok, not great. Probably should have this serviced if stillo possible. Once I get to my destimation, I have shore power almost always.
What I noticed is, while in a slip during the summer months with only the fridge on and no other electrical devices on, the charger seems always to charge the batteries. I can tell from the hum I hear through the aft wall, and the wall is warm to touch. I did some investigation and crawled down into the starboard aft "hole" to take a closer look at the charger. Yes, it was on, and very hot to touch. I could touch it only for a second or so.
I didn't use any tech measurement equipment to better understand fridge power needs and actual charger cycling, and haven't been able to find a theory of operation manual for my charger, but my gut feeling is things get hot so that must be a fair amount of power drawn - when the voltage drops on the battery, the charger senses this and begins to re-charge the battery; at the same time the fridge is trying to draw the battery down. There's a cycle of some sort. It's a tug and war game. Not sure who wins, but I think they both lose over time. It's called wear-out.
I'm not saying I want to do without using my batteries to power the fridge. I'll use the batteries to power the fridge while motoring if I want. I'm looking at powering the fridge in a stand alone way while on shore power.
Another thing I think would be nice in doing this, would be that if shore power would ever be lost, my batteries won't die, just the food in the fridge will need replaced.
Bob Gray
Corbeta #1117
Lake Erie, Great Lakes
1991 C-36 mk1.5 TR/SK M35B
PLEASE get rid of that charger ASAP. They were affectionately referred to as the FRYBack.... Yes many of those actually started fires. Battery charger technology has come a long way since the days of the Fryback...
Also in order to do an AC to DC converter right, for a DC fridge gets very expensive. Manufacturers like Norcold specifically advise against a DC converter or using a battery charger as a power supply as some modern chargers can be used as a power supply without batteries connected..
[B][I]
"Can I connect my DC refrigerator to a battery charger or converter?
Do not use a converter or battery charger to supply the DC power directly to the unit because these two devices do not supply filtered DC power."[/I][/B]
[B][I]"How should I connect my DC refrigerator?
Connect the refrigerator directly to the battery. No other switches, lead wires, or electrical equipment should share the wiring between the refrigerator and battery. "[/I][/B]
-Maine Sail
https://www.marinehowto.com/
Ok, will definitely replace the charger.
Is there a better place to mount the charger than the aft wall?
Will get new batteries too. Just double-checked - I have two Deka Marine 24M7, MCA@32 deg 1000, 875CCA.
Appreciate all the feedback and info.
Bob Gray
Corbeta #1117
Lake Erie, Great Lakes
1991 C-36 mk1.5 TR/SK M35B
Bob,
That's a horrible spot to mount the charger! The PO should be shot at sunrise. Long wire runs for everything. The chargers (and inverters) for most MkI's are mounted under the nav table (very close to electrical panel and batteries, plenty of air circulation for cooling). Most MkII's are mounted under the settee just forward of the sink.
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
I checked Deka's website and they show those batteries as being starting batteries. You really need some good deep cycle batteries for the house bank. Ideally you would have a dedicated house bank (like 4 X 6 volts of good quality in series/parallel) and a separate starting battery. There's many ways to do this and some good articles on this site.
Might I also suggest you check out the IOTA chargers with the IQ4 module. They are very good chargers and sell for prices mere mortals can afford. Some people diss them because they are not "marine" chargers, but I've used one for 6 years and it is like new in appearance and does an outstanding job of keeping sulfation off the batteries. As Tom pointed out, under the nav table is a good spot, short cable runs and lots of air flow.
[QUOTE]"How should I connect my DC refrigerator? Connect the refrigerator directly to the battery. No other switches, lead wires, or electrical equipment should share the wiring between the refrigerator and battery. "
[/QUOTE]
Of course, when the word "directly" is used, it does mean to use a properly sized circuit breaker. A reminder: wire gauge is sized for the appliance load and run length, and the circuit breaker is sized for the wire gauge that it protects.
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
[QUOTE=LCBrandt;12438]Of course, when the word "directly" is used, it does mean to use a properly sized circuit breaker. A reminder: wire gauge is sized for the appliance load and run length, and the circuit breaker is sized for the wire gauge that it protects.[/QUOTE]
Yes and the fuse or breaker should be as close to the battery bank as possible.
The fridge manufacturers don't generally want DC converters or power supply type chargers used because they don't deal with start up loads an in-rush nearly as well as a battery bank does. DC converters can be fine for loads like lighting and non-motor loads but to do a DC converter than can effectively handle the in-rush and have clean output they get quite costly. The battery can supply massive amounts of current for the start up load then once running a good charger will balance the acceptance with the load and the batteries will remain full..
-Maine Sail
https://www.marinehowto.com/
Thank you very much for all the advice.
Placed an order for the Sterling battery 12V, 30A charger. The charger has 3-separate outputs to charge 3 battery banks. Will use two banks, one bank will be for starting only, the other will be for the house bank. Not sure which batteries to use, but my guess is the banks will be different battery types. The charger can be programmed to each battery bank uniquely.
Also purchased a Victron BVM 602S battery monitor so I may understand better the charging process and battery state. This monitor will allow me to view two separate battery banks.
All this talk about batteries has now made question the state of my overall charging system. For example, I wonder if my alternator diodes are ok. My guess is they're not ok. Will have to check out how best to look at the AC ripple output from the alternator (AC on the multimeter?, low DC output? use an O'scope?, take the alternator off and take to a repair shop for check?), but need more information for the stock alternator on the M35 engine. To avoid diode problems in the future, I plan to connect the output of the alternator directly to one of the battery banks. Also need to better understand the stock regulator circuitry. If someone can tell me where to find the stock alternator and regulator circuitry, would appreciate the information.
Also will check the fridge compressor, fan, etc. to make sure it's working ok. My guess is the refrigerant needs charging. Being that it's R12, not sure what options people are using to service the Danfross compressor?
Again, appreciate your inputs.
Bob Gray
Corbeta #1117
Lake Erie, Great Lakes
1991 C-36 mk1.5 TR/SK M35B
Yes, purchased the Sterling ProCharge Ultra charger that Maine Sail recommended.
Bob Gray
Corbeta #1117
Lake Erie, Great Lakes
1991 C-36 mk1.5 TR/SK M35B