I know your are happy with your Duracell 34AGM.
How long would you say your Duracell lasts without a charge assuming you don’t charge on the water somehow.
My friend has a 27 AGM he wants to sell me but it’s like 65 lbs!
I’m using my thruster for docking but also fighting tuna (if the fish goes under the boat, to spin the bow).
I just want to prevent me spending the money on a 34 then wishing I went with a larger one.
Thanks for all the help and suggestions! The protest coming along good so far!
My boat is 27'. The Group 34 AGM does a great job. In Florida I have to turn the boat 180 degrees in a 35' wide canal. The bow thruster makes it a breeze. I also do a fair amount of sailfishing. See out post in the fishing forum. Often we have to turn the boat and chase the fish down. Once we have line back we rotate around the fish with the bow thruster and bumping the engines. Usually fishing with one other person onboard so it takes a while. Never noticed it running down.
I'm assuming you are two battery single engine? Adding a third battery? I'm not sure how you can charge the third battery while on the water without twins. I have charging shunts on boat engines. Each engine can charge a starting battery and another battery. There may be devices that can overcome this - members can help with that.
This chart show MCA. No hand-me-down battery - you need a good fresh one. In my opinion the 34 is the right choice. Higher MCA than a 27, lighter, smaller, inexpensive. Less AH but that hasn't been an issue. If thruster and he new battery is in the back I would be less concerned about weight and a using a 27. Mine in forward next to the thruster and weight up there can make a big difference.
I'm using all Duracell AGM's purchased at Sam's Club. Latest pricing.
Group 34 43.10 lbs. 955 MCA 55 AH. $134.86
Group 24 52.40 lbs. 800 MCA 78 AH. Did not see availability at my store.
Group 27 61.55 lbs. 900 MCA 92 AH. $199.28
Group 31 67.35 lbs. 1,000 MCA 105 AH. $214.32
I used a Group 34M Duracell Marine AGM for my Yamaha F150's. About 9 lbs lighter than a Group 24 and 17 lbs lighter than a Group 27 with higher MCA rating but less capacity. Also used for my 4th battery for bow thruster, windlass and bait tank pumps.
For the house battery I use a single Group 27M AGM.