Another question regarding dual batteries

R

rock knocker

New member
So another question as i get more into this boat. Is running the wallas heater stove, 110 plugs, radar etc all going to be able to run off the 2 small batteries that are in the starboard side while the motors are running? If motors not running can they still be used? Im sure these are ridiculous questions but ive never had a boat of this caliber. Again... thanks again for any help.
 
rock knocker

We will need to know more (I think), like what size are your 2 small batteries?

I know there are folks who run their Wallas stoves all night. I just spent a weekend at Mystery Bay State park dock and the overnight temps were down into the mid thirty's. My buddy there ran his over night. I have 2 Group 27 batteries, and run a CPAP device on those every night, 6 - 8 hours. We both start our outboards and have them running when we initially start the Wallas until it is producing heat, then shut down the OB's and run the stove off the battery. I do not have a dedicated "house" vs "start" battery, not sure what Andy has.

I am very careful about what I run and for how long it runs, on the battery.

I use a small cigarette lighter plugin volt meter to keep track of my battery voltage. It is easy and simple and has worked for me for 14 years, with never a battery running dead, or failing. I also keep both batteries plugged in to (brand specific here) BatteryMinder trickle chargers. They have kept my batteries in perfect shape for 7 years now.

Others use different systems and have different results that work for them. I'm just not very techy.

Harvey
SleepyC:moon

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I will have to look to make sure but i had a group 29 on my last non cdory boat and it was big. So youre running a trickle charger while on the water or when charging on land. Sorry i guess im not used to running so much off a couple small batteries.... but im also new to all this.
 
The "BatteryMionders" are plugged in when the boat is off the water and stored in the barn. My group 27's are as big as will fit into the lazurettes. When you say "small" hard to tell what. I have seen motorcycle batteries used for start batteries and have see group 24's as both house and start. ????

Harvey
SleepyC :moon

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Rock Knocker, I have 2 group 24 batteries set up in the starboard lazaret. They have a simple switch set up to run either one or both as house or start batteries. I normally use one at a time for the house, but switch back & forth depending on their charge status. They should run what you mentioned except for the 110 outlets. Normally the power from 110 outlets will be from a dock power cord or an on board generator with the exception of a 12V to 110 inverter wired to the batteries. I have twin Honda’s with only 10 amp apiece charging, so if running only one engine during the day, I must give the batteries a boost with my portable generator or dock power cord to keep them topped off. If both are running during the day they remain charged & then only need to charge more if I’m staying put for a couple days or more. I use, like Harvey a simple plug in digital read out for monitoring the charge condition of the batteries. There are better more costly systems for monitoring the batteries, but this has worked well for me. Simple or complex, either way you do need to know the charge condition of the batteries & a way to combine or switch between them.

Jay
 
Harvey, you posted; " I have 2 Group 27 batteries, and run a CPAP device on those every night, 6 - 8 hours. " Do you use an inverter for AC or do you have a DC connection for the CPAP? I would love to find a DC connection for my CPAP.
 
Most of the C Dory come from the factory with group 24 (this number indicates case size--nothing more). Group 24 batteries can have amp hours from 50 to 80. I use larger batteries; group 31, which are 110 amp hours. But I have high 12 volt loads, such as refrigeration and freezer.

You do not want to discharge batteries to lower than 12.2 volts (steady state--that is no draw or charging for an hour). 12.2 volts is 50% discharge. The battery should be charged up to full capacity after you use the boat. It is rare that outboard engine alternators bring batteries back to full capacity. Thus a 110V AC mains charger should be used. This is a whole other subject--some battery chargers can be left on "indefinitely"--many others should be used, and then turned off.

Only you know what you usage will be with the engines off--but I don't run radar with engines off--unless for a brief period to check out an anchorage--but the GPS often gives more information--at night. There are also "anchor drag alerts"--but these require the GPS to be running. Smart phones can also monitor position in an anchorage.

If you run a high power stereo that can draw the batteries down. The Wallas as a significant draw on startup, but once running is fairly low.
 
DW, I also use a Cpap on my boat. It does not have a DC adapter and requires AC only. I do have a small 150 watt inverter I run it on that is plugged into my accessory plug in the cabin. My Cpap is the Resmed S9. On the boat, I use it without the humidity chamber attached, as that would draw to much current. I'm not sure what total amperage it draws, but it must not be very much. Along with the CPap I also run a Webasto heater, a small fan and an LED anchor light. After 8-10 hours, I still have 12.0-12.2 vts on my Group 27 house battery. Colby
 
DW":2cl4516h said:
Harvey, you posted; " I have 2 Group 27 batteries, and run a CPAP device on those every night, 6 - 8 hours. " Do you use an inverter for AC or do you have a DC connection for the CPAP? I would love to find a DC connection for my CPAP.
Click to expand...

DW, Hope I can help. First, I said "Group 27" but they are really Group 29. No, I do not use an inverter. My first thought is that uses extra electricity, because I use an old CPAP, a Respironics RemStar series, with about 17000 hours. I think I am the 3rd user, and it stays on the boat, so not a lot of continous hours now, 30 to 50 nights a years average...The older Respironics machines run on 12 VDC so converting to 110 is superfluous. They have a 12VDC input on the side, and I have a cig lighter plug at the helm that it gets plugged into directly. Yes, the machine is old, bigger and heavier than the S-9 of Colby's, and like him, I do not run the heated humidifier due to the power load of the heater.

A typical CPAP electrical load is about 5 amps. Running on my twin batteries my typical voltage drop over a 7.5 hour night is from 12.8 down to about 12.5. I also run a small Garmin GPS for anchor watch and breadcrumb track.

Harvey
SleepyC :moon
 
Harvey, Colby, I owe you guys. Thanks for the details. You made me look closer at my CPAP. I see that it is rated at 12VDC/5.0 Amps. I'm guessing that is 5 amps continuous which is quite a bit. But at least knowing the amperage I should be able to make up a connection. I think I'll make contact with Respironics to see if they can assist. Drives me crazy to go from a DC machine to an AC converter to an AC inverter to DC batteries.
 
Havey, Colby, just ordered the adapter for DC lighter outlet on Amazon. They also have a DC battery pack available in the $300 range. Wow, that is going to help big time. Happy New Year!
 
Glad we could help. I wish my Resmed machine ran on 12 vts. I wouldn't be surprised if it does and the big box in the cord is just stepping down from 110 vac. But there are no other connectors on the CPap other than where the AC cord plugs into. I spend a lot of the summer on the boat, so it's nice being able to use my spare Cpap machine on the boat. I really like the Resmed S9. I had to get a new machine a little over a year ago. I think it's a Resperonics Dream Machine. And I don't care much for it. The Resmed was so much nicer. But insurance pays for most of it, so I get what they provide. I already had an accessory plug in the cabin at the switch panel, and ended up adding another one over on the port side. So I can plug my inverter in on either side. Of course when I'm on shore power, I can plug the cord directly into one of my ac outlets. Although many times I'll just keep my cpap on the inverter in case the shore power goes out over night.
 
Colby, I believe your S-9 actually runs on 18 volts, converted via the "brick" on the power cord. Respironics runs on 12VDC.

There are several new "travel size" CPAP units available now. I know Resmed just came out with one. Shortly before I retired, the first travel unit came on the market, Transcend. It is about the size of a 12 oz pop can, and it runs on 12 volts and has 2 different sized batteries available. I have that one and carry it as a backup, in case my old machine dies. I also use it when traveling and can charge the battery off the car or bike cig plug outlets.

I always told my patients, "You are not tied to the wall plug by the bed. There are options. Life is not over because you are starting on CPAP. "

Harvey
SleepyC :moon
 
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