R25 SC battery issue

R

Rcireland

Active member
Joined
Jul 7, 2019
Messages
29
Fluid Motion Model
C-26
Hull Identification Number
FMLR2505G314
Vessel Name
Sea Salt II
We have been on Block Island for a two night stay. Our battery bank 3, which I was under the impression was for the windlass and thrusters, will not hold a charge. What is curious, to say the least, is that the overhead lights, 12 volt receptacles, and even the autopilot were affected - things that I thought were controlled by house batteries which seem to be fine. Fortunately our portable generator came to the rescue, but battery bank 3 loses its charge within 6-8 hours. I am reasonably certain that I need a new battery but trying to understand why other things which I didn’t think were controlled by battery bank 3 were also affected.
 
The first thought that comes to mind is a modification that many owners have done, I saw Martin (Submariner) had a video on it, to change the on/off battery switch for the thrusters to an on/off/parallel switch so that the thruster battery can be paralleled with the house battery when desired to increase the size of the house bank. Essentially a three battery house bank instead of two. Worth checking if that's been done with yours.
 
Do you have a parallel switch? What position is this switch in? Lead Acid Batteries? What is the age of the battery? Do you have a battery monitor?

I cannot find a schematic for your electrical wiring, but I found three battery switches a House, an Engine and an Emergency Parallel switch. Battery 1, is the engine, 2 is the house and 3 is the thrusters.

Do you have a DC Current Clamp? Very helpful when troubleshooting electrical on a boat.
 
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I suggest before you replace any batteries, that you get a handheld digital voltmeter and check directly the batteries in question and positively identify which one(s) has/have low voltage. Also, check the ACRs connected to the batteries with low voltage. The ACR servicing the low voltage battery(ies) may not be functioning properly and may not be providing charge current.
 
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Brian John said:
Do you have a parallel switch? What position is this switch in? Lead Acid Batteries? What is the age of the battery? Do you have a battery monitor?

I cannot find a schematic for your electrical wiring, but I found three battery switches a House, an Engine and an Emergency Parallel switch. Battery 1, is the engine, 2 is the house and 3 is the thrusters.

Do you have a DC Current Clamp? Very helpful when troubleshooting electrical on a boat.
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Brian John said:
Do you have a parallel switch? What position is this switch in? Lead Acid Batteries? What is the age of the battery? Do you have a battery monitor?

I cannot find a schematic for your electrical wiring, but I found three battery switches a House, an Engine and an Emergency Parallel switch. Battery 1, is the engine, 2 is the house and 3 is the thrusters.

Do you have a DC Current Clamp? Very helpful when troubleshooting electrical on a boat.
Click to expand...
Brian, Thanks fir your reply. I have a West Marine Lead-Calcium group 27 battery which was purchased in 3/21. Parallel switch is off. I have four switches - 1 engine, 2 House (w/ 2 bats), 3 thrusters/windlass and 4 Parallel. There is a switch below the meter on the power panel that allows one to check voltage of batteries on 1,2 and 3 switches. No I do not have a DC clamp. My knowledge of electronics is limited.
 
CaspersCruiser said:
I suggest before you replace any batteries, that you get a handheld digital voltmeter and check directly the batteries in question and positively identify which one(s) has/have low voltage. Also, check the ACRs connected to the batteries with low voltage. The ACR servicing the low voltage battery(ies) may not be functioning properly and may not be providing charge current.
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Thanks for your reply - I will check them directly with hand-held meter. Incidently, I checked them all beford launch in April with liad tester and they were all the same. However, all four are now three years old.
 
Rode Trip said:
The first thought that comes to mind is a modification that many owners have done, I saw Martin (Submariner) had a video on it, to change the on/off battery switch for the thrusters to an on/off/parallel switch so that the thruster battery can be paralleled with the house battery when desired to increase the size of the house bank. Essentially a three battery house bank instead of two. Worth checking if that's been done with yours.
Click to expand...
Thanks for your reply. Pretty sure this has not been done yo my boat.
 
Brian,
So today I did an experiment (my science background coming through) where I unplugged the boat from shore power so there would be no power input and the monitored each battery with a volt meter and via the DC panel meter. Over 7 hours there was very little difference between the four batteries.
This led me to another thought. Last year we purchased a portable Honda generator after having problems with keeping batteries charged on a five day trip to Block Island. The first time I used it I got a Reverse Polarity light on the AC panel. My Query regarding this to TugNuts lead to the suggestion that I purchase a crossover plug to plug into one socket on the generator and the shore power cord into the other. When I did this on our latest trip of only two nights, there was no Reverse Polarity light as expected but the we ran into the problems described in my initial post. Should I have not used the crossover plug? Is Reverse Polarity from the generator a problem or not?
 
The plug is not your problem, and yes you should be using it with the Honda as it is a 'floating ground' generator. AC power sources should always connect the ground to the neutral at the source and no where else, and that's what the plug is doing.
About your science experiment, did you have any DC loads running, like the refrigerator, etc.? You should be able to see your house batteries drop voltage while the start battery and thruster/windlass battery remain at a stable voltage. (Around 12.8 V)
 
Rode Trip said:
The plug is not your problem, and yes you should be using it with the Honda as it is a 'floating ground' generator. AC power sources should always connect the ground to the neutral at the source and no where else, and that's what the plug is doing.
About your science experiment, did you have any DC loads running, like the refrigerator, etc.? You should be able to see your house batteries drop voltage while the start battery and thruster/windlass battery remain at a stable voltage. (Around 12.8 V)
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The only load would have been the refrigerator. Using the volt meter each battery started at 13.6 before I disconnected from shore power and over the course of 7 hours the house batteries were at 12.8 and the start and thruster/windlass batteries were at 13.0. The DC panel meter had house at 12.8, start at 12.8 and thruster/windlass at 12.2.
 
Rcireland said:
The only load would have been the refrigerator. Using the volt meter each battery started at 13.6 before I disconnected from shore power and over the course of 7 hours the house batteries were at 12.8 and the start and thruster/windlass batteries were at 13.0. The DC panel meter had house at 12.8, start at 12.8 and thruster/windlass at 12.2.
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From the details you posted in this thread, it appears to me your thruster battery is carrying a load. What that is telling me is that at some point your batteries may have been wired incorrectly and that your thruster battery may be carrying part or all the house load.

Study how the batteries are wired on your boat now and compare it to the schematic in your owner’s manual. However, if the electrical schematic in your boat’s owner’s manual is like the one in the manual for my 2012 R27, there may be errors and omissions. For instance, in the schematic for my boat, the house batteries are not shown wired in parallel. That is an error. On my boat, the windlass is powered through the thruster battery. On the electrical schematic for my boat, the windlass doesn’t exist. It simply is omitted from the schematic. Good luck!
 
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CaspersCruiser said:
From the details you posted in this thread, it appears to me your thruster battery is carrying a load. What that is telling me is that at some point your batteries may have been wired incorrectly and that your thruster battery may be carrying part or all the house load.

Study how the batteries are wired on your boat now and compare it to the schematic in your owner’s manual. However, if the electrical schematic in your boat’s owner’s manual is like the one in the manual for my 2012 R27, there may be errors and omissions. For instance, in the schematic for my boat, the house batteries are not shown wired in parallel. That is an error. On my boat, the windlass is powered through the thruster battery. On the electrical schematic for my boat, the windlass doesn’t exist. It simply is omitted from the schematic. Good luck!
Click to expand...
Thanks- I’ll take a cliser look.
 
You can access a battery wiring diagram by using the R27 manual available from the factory technical publications
 
snydzy said:
You can access a battery wiring diagram by using the R27 manual available from the factory technical publications
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If your post was directed to me about my R27, I have that manual. The electrical schematics in it contain errors and omissions.

The Tugnut who made the original post has an R25SC. I was cautioning him that his manual’s electrical schematic may contain similar errors and omissions.
 
I have a 2013 25sc….. there is no manual…..The 25sc schematics are the same as the R27… not everything is perfect, but its better than nothing…..
 
What year is your boat? The older boats were wired 1=engine, 2=thrusters, 3=house. At least that's how my 2009 25 classic was wired and what is shown on the wiring schematic. Also sounds consistent with what you described in the OP. Assuming you have four batteries the house bank will be the two that are wired in parallel.

As to how long the battery should last it all depends on what electrical components you're using. If you have an inverter and use any type of AC electrical equipment without the engine running it will kill a battery pretty quickly.
 
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