Battery Switches while at anchor...

Chris Benwell

New Member
Dec 9, 2017
23
Austin, TX
Boat Info
2012 Sea Ray Sundancer 370
Engines
twin Merc Cruiser 375
Question for the Sea Ray fam,

I'm fairly new to this boat and have never stayed overnight on the hook with my 370, primarily because I'm scared to death of waking up far away from the marina with dead batteries. Here are 2 common scenarios that I could use some advice:

1. If the generator is off and you pull up to a restaurant on the lake for a few hours and shutdown everything on the boat...do you also turn off the 3 battery switches on the main panel? Or will that "de-energize" the batteries? Should I just leave them on?

2. If you are overnighting, and at anchor and shut off the generator for the night to go to bed, do you leave the batter switches on but shutoff the non-essential breakers on the panel to preserve the refrigerator? Or do you just shut off the 3 battery switches, even though it will shut down all DC accessories?

I'm determined to overnight once I get the smarts and courage.
 
1)We leave batteries on so we have cabin lighting, accessories, toilet, etc. Batteries are only turned off when “storing” the boat. No reason to turn them off once you arrive at the beginning of your usage.

2)Leave batteries on. Leave fridge on.

You may sleep better if you use a gps anchor / movement alarm (app store), and check your CO detectors regardless if you’re running your gen. We tied up once and ended up on the receiving end of someone elses exhaust.
 
I leave batteries on in both cases. Have been on trips for 10 plus days and just run the generator in the morning and evening for an hour or two to charge the banks and to turn the hot water heater on. No need to energise the gen starting circuit, so leave that switch off.
 
Don’t want to offend you but make sure you check the water levels on your batteries on a regular basis. Learned that lesson the hard way over 25 years ago.
 
If you are a belt and suspenders type person, you could also keep a charged jump pack with you as a standard boat item. It may not start your mains but will give you enough juice to start the gen. I have seen this done and they connect using the 12 volt outlet to "jump" the generator.
 
All great advice! I'm feeling better about it now. I'm told you have to disconnect the batteries (mine are in parallel) to get a true measure with a digital meter. I recently had the boat hauled out for new bottom paint and stern drive maintenance and even with switches off, the port side battery was dead after 5 days. The mechanic said there is always some draw on the batteries from certain DC devices like stereo memory etc. We got both engines started with the emergency start. The mechanic suggested checking the batteries. Is it true you have to disconnect them to check voltage?
 
Yes you have to disconnect the parallel battery to do a test.

How many batteries do you have, how old are they and how are they situated on your boat?
 
Not sure about disconnecting required but I would to check fluid levels. I had one battery that “worked” last year but took 3/4 gallon water this year. Not sure how bad it was last year. I replaced it.

5 days with batteries “off” isnt good. You may have some things wired “hot” like the bilge, aftermarket amplifier, led lights, but most things should be completely off.
 
Yes you have to disconnect the parallel battery to do a test.

How many batteries do you have, how old are they and how are they situated on your boat?
I have 2 pairs.
Notes from survey in December of 2017:
TWO banks of two “DEKA™” group #1231PMF 931
– 1000 CCA - marine grade, sealed cranking 12-volt lead acid batteries connected in parallel. The age of the 932 batteries is unknown, as tabs were still attached
 
If you dedicate the starting batteries (2) and dedicate the genny starting battery and isolate the house batteries you should have no worries about dead batteries for the engines or genny.
House system can afford to go dead
 
tiara in the snow 01.JPG
Agree with much of what was said earlier. We do a lot of overnighting and really don't ever worry about batteries. Having said that, our boat is energy efficient with a holding plate that stores "cold" any time an engine is running. So the fridge does not run very often when the boat is turned off. Also, our genny has its own starting battery and if we should run down our main batteries, there is a reliable back up system. We have never needed to use that. Before we had all of the redundancy, we used to switch our battery switch from "Both" to "1"or "2" using the battery that ran the fridge for overnights. We also turned the fridge down to the lowest setting to preserve that battery and conserved on lights. We did not have gennys on those boats and never got stranded because one of our house batteries was always held in reserve. You could do the same with your boat, but probably would not need to. However, it does provide peace of mind if you remain concerned.
 
Load test your batteries and if they fail, replace them. Especially since you don't know the age. I usually get 4 seasons on mine. We run on them all day and into the evening regularly. Using the 12v systems and an inverter for the TV and sometimes a fan or other small appliance. Your gps should have a battery alarm on it to tell you if your voltage gets down to a set level. I have mine at 11.5 volts, but it has only gotten that low once. We had been out all day with a ton of stuff being used - air pumps, stereo with 4 amps, kids playing tv games and watching movies, 2 fridges, blender, etc.
Relax and enjoy. :)
 
Load test your batteries and if they fail, replace them. Especially since you don't know the age. I usually get 4 seasons on mine. We run on them all day and into the evening regularly. Using the 12v systems and an inverter for the TV and sometimes a fan or other small appliance. Your gps should have a battery alarm on it to tell you if your voltage gets down to a set level. I have mine at 11.5 volts, but it has only gotten that low once. We had been out all day with a ton of stuff being used - air pumps, stereo with 4 amps, kids playing tv games and watching movies, 2 fridges, blender, etc.
Relax and enjoy. :)
Thanks Korkie, probably a good idea to check them; especially before the summer madness begins.
 
Not to hijack this thread but I have a similar question. What about when docked, should the battery switch be turned to “OFF”? And what about when starting the boat, “1”, “2” or “BOTH”? Why even have the option to switch between each battery?

Thanks
 
If docked, hooked up to shore power, leave the switches on, turn on the battery charger if you think you need a charge. Battery charger is named ac converter on my 07 320. Replace batteries with AGM next time you need new ones, seems like that took all my worry about batteries away.
 
It sounds like you have a similar setup as my boat. Half the house + one engine served by a pair of deep cycle batteries in parallel, the other Half of the house + the other engine served by a second pair of deep cycle batteries in parallel. There is a separate starter battery as well - solely dedicated for starting the generator.

I've been on the hook with both pairs of batteries on the "way out" but nursing them through the last of the season only to find the head struggling to build pressure at 3AM and the lights flickering on and off with the pulsing of the vacuum generator - uh oh! (is this what you're afraid of?). Getting up in the morning, I confirm that both sets of batteries don't have enough umph to start either engine. I fire up the genny but not wanting to wait for the batteries to recharge, I use a set of JUMPER CABLES kept near the batteries using the genny's starter battery to jump one of the pairs of batteries and start one engine. After that, I use the "emergency" button to start the second engine and remove the jumper cables.

A key part of my ability to do this is the day hatch which allows me to access the engine room and all the necessary batteries. Without that hatch, there wouldn't be enough power to electrically raise the ER hatch for quite a while after starting the generator to recharge the batteries. Not sure what your setup is like.
 
Hmm, I didn't even think about hatch access with dead batteries. I do have 2 small circular hatches that allow me to get my arm into the engine room and release the hydraulic lift. I imagine lifting the hatch manually would be a chore. I did check all of my batteries and confirmed that one was dead (which I replaced) but the other 3 are good to go. I think I'll store some jumper cables per your suggestion. I also think I'm going to unplug this weekend and stay overnight on the boat, in the "safety" of the marina, and see how things go while running certain appliances. I know, not very courageous.
 
Hmm, I didn't even think about hatch access with dead batteries. I do have 2 small circular hatches that allow me to get my arm into the engine room and release the hydraulic lift. I imagine lifting the hatch manually would be a chore. I did check all of my batteries and confirmed that one was dead (which I replaced) but the other 3 are good to go. I think I'll store some jumper cables per your suggestion. I also think I'm going to unplug this weekend and stay overnight on the boat, in the "safety" of the marina, and see how things go while running certain appliances. I know, not very courageous.

Better safe than sorry. By asking here you have learned a lot. The magic of CSR is real.

MM
 

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