R29 CB Battery Replacement

[Scuba Too]

Final notes on replacing the battery:

- The battery sled does move! However I wasn't convinced of that and didn't check again until I had all the batteries off of it (I had meant to check when the aft batteries were out). Getting to the engine battery will forward under the icemaker reminded me of my caving days! It did really help though in being able to install new batteries and troubleshoot after that. The handles on the factory batteries are great for pulling while having your feet on the forward lip of the lazarette.

- The thruster battery sled moved - but there wasn't enough slack on one of the grounds (there's 3 attached) that went forward behind the bulkhead. I was just able to reach to remove the battery leads. I then ran down to West Marine and made up a 6 ft extension for the short ground cable - so all is good now.

- I bought the batteries from Northern Arizona Wind & Sun, Inc. They had a great price of $170 with free shipping. Everywhere else I looked was in the 200+ range. I went with the factory battery for the house and thruster and bought an OPTIMA BLUE D31M for the engine. I went with the Blue rather than Yellow as the Blue had a marine style stud so no adapter was needed (someone else suggested that here 🙂 )

And now its time for the annual maintenance - so I'll probably be posting again sooner than later lol

 

[Alpina]

I suggest that you load test each battery. That way you know for sure if you have a lemon among them. You can have 12.5 volts on a battery but under load you have squat. Here is a cheap and easy to use load tester:

https://www.amazon.com/Schumacher-BT-10 ... ive&sr=1-2

I second Bobby’s recommendation. I purchased something similar and found a battery that charged OK but didn’t work well under load. Not with my boat but nonetheless.


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[Submariner]

I upgraded my two house batteries to Firefly Oasis G31’s. They are about as close to lithium as one could get, while staying AGM.

They are 110Ah batteries. It’s recommended that you not take them below 80pct DOD. That right there is 20pct more capacity for the same AGM footprint. The manufacture state that you can run them to 80pct DOD up to 1300 cycles, which is twice what a normal AGM battery can do.

And they state that you can run them to 100pct DOD and not only will it not kill the battery, you could do this for 600 cycles.

Twice the cost, 20pct more capacity, at least twice the lifetime, probably more.


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