2020 R31s House Battery Replacement

FishOff

FishOff

New member
Joined
Jul 30, 2025
Messages
4
Fluid Motion Model
R-31 S
Hello everyone. It is time to change the house batteries on our R31S. Any tips or advice to make the job easier? Also, any suggestions for an upgrade while I'm at it?

Thanks in advance 🙂
 
Proper and safe procedures while working on the batteries. Insulated tools have dropped in price and are way safer and better than taped-up wrenches.
 
Best advice I can give you is hire a strong 25 year old to pull them out.

Ralph
 
Josh:

I just completed a total battery change on our R29 Sedan. The following advice may be applicable to you:

  • The job was very doable and I am glad I did it as I learned a lot.
  • I thoroughly planned out the job; lots of info on Tugnuts.
  • Battery selection was challenging as there are so many opinions. In the end, I stayed with the UPG Universals for the house and Optima Bluetops for the starter and thrusters. I got a great price for the UPGs from Home Depot with a military discount and the Optimas from Amazon, all with free delivery to my house.
  • I wrote down every major step and documented with pictures. I labeled EYERY wire.
  • The battery trays slide was not screwed down and would not slide until 4 of the 5 batteries were removed.
  • Once all the batteries were removed, I thoroughly cleaned the locker and completed the following projects: Painted the deck; caulked any openings where deck and fiberglass met; upgraded the solar controller; organized all the wiring; replaced the hatch gasket.
  • Save all your old batteries nuts and bolts. I found a number of the new hardware short so I reused the old ones.
  • Sliding the new batteries in-place was fairly easy as they slide.

In the end, I estimate it took me about 40 hours to complete the batteries swap and my add-on projects. I took my time as the weax was hot and working in a tight space was a challenge. I just kept reminding myself there was no rush!!!!!!!!!!!!!!!!!!!

Hope this helps. If you need some more in-depth info, give me a shout.

Mike
 
Bosn Mate said:
Josh:

I just completed a total battery change on our R29 Sedan. The following advice may be applicable to you:

  • The job was very doable and I am glad I did it as I learned a lot.
  • I thoroughly planned out the job; lots of info on Tugnuts.
  • Battery selection was challenging as there are so many opinions. In the end, I stayed with the UPG Universals for the house and Optima Bluetops for the starter and thrusters. I got a great price for the UPGs from Home Depot with a military discount and the Optimas from Amazon, all with free delivery to my house.
  • I wrote down every major step and documented with pictures. I labeled EYERY wire.
  • The battery trays slide was not screwed down and would not slide until 4 of the 5 batteries were removed.
  • Once all the batteries were removed, I thoroughly cleaned the locker and completed the following projects: Painted the deck; caulked any openings where deck and fiberglass met; upgraded the solar controller; organized all the wiring; replaced the hatch gasket.
  • Save all your old batteries nuts and bolts. I found a number of the new hardware short so I reused the old ones.
  • Sliding the new batteries in-place was fairly easy as they slide.

In the end, I estimate it took me about 40 hours to complete the batteries swap and my add-on projects. I took my time as the weax was hot and working in a tight space was a challenge. I just kept reminding myself there was no rush!!!!!!!!!!!!!!!!!!!

Hope this helps. If you need some more in-depth info, give me a shout.

Mike
Click to expand...
Thank you Mike! That is exactly the type of advice/info I was looking for. I appreciate it!
 
Bosn Mate said:
Josh:

I just completed a total battery change on our R29 Sedan. The following advice may be applicable to you:

  • The job was very doable and I am glad I did it as I learned a lot.
  • I thoroughly planned out the job; lots of info on Tugnuts.
  • Battery selection was challenging as there are so many opinions. In the end, I stayed with the UPG Universals for the house and Optima Bluetops for the starter and thrusters. I got a great price for the UPGs from Home Depot with a military discount and the Optimas from Amazon, all with free delivery to my house.
  • I wrote down every major step and documented with pictures. I labeled EYERY wire.
  • The battery trays slide was not screwed down and would not slide until 4 of the 5 batteries were removed.
  • Once all the batteries were removed, I thoroughly cleaned the locker and completed the following projects: Painted the deck; caulked any openings where deck and fiberglass met; upgraded the solar controller; organized all the wiring; replaced the hatch gasket.
  • Save all your old batteries nuts and bolts. I found a number of the new hardware short so I reused the old ones.
  • Sliding the new batteries in-place was fairly easy as they slide.

In the end, I estimate it took me about 40 hours to complete the batteries swap and my add-on projects. I took my time as the weax was hot and working in a tight space was a challenge. I just kept reminding myself there was no rush!!!!!!!!!!!!!!!!!!!

Hope this helps. If you need some more in-depth info, give me a shout.

Mike
Click to expand...

Where did you purchase the hatch gasket?
 
Brian:

I ordered the following from Amazon: "Adhesive Rubber Strips Neoprene Rubber Sheets, Rolls & Strips with Adhesive Backing Rubber Pads Self Stick Seal Rubber Gasket Adhesive Back for Matting Padding - 1" Wide x 1/5" Thick x 20' Long".

Mike
 
How did you attach this to the hatch? I was looking at some round foam and slicing it to fit the hatch.
 
Brian:

The gasket material has adhesive that is very strong! I took some time to ensure that the surface was clean before applying.

Mike
 
Take lots of pictures, before you start. Twice I have changed batteries and both times I ended up with engine codes. Both times I had good photos of before to troubleshoot my problem.
Wires fall down behind and get missed.
 
done it twice on a cutwater.

best tip I have for you.
Get a piece of rope and loop it through the battery handles. use your legs to lift the batteries and not your back. This gives you the ability to lift the batteries from standing position and not on your knees.

take photos of all the connections.
be methodical
Note the state of tide when tackling the marina ramps with a cart full of batteries
a 60lb battery swinging will easily chip the fiberglass around the hatch. be careful how they swing.
 
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