Sea Ray

Also own (long term owner) of a 2000 380DA) that has converted from flooded cell to AGM. I went from five to six Lifeline GPL-31XT batteries, because this has 25% more capacity than other brands / models at 125Ah capacity for more on-hook run time.

https://lifelinebatteries.com/products/marine-batteries/gpl-31xt/

No way I would ever return to flooded cell. As an example, adding distilled water was a royal butt pain.

The charger is important, as shown in this Technical Manual. Mine was upgraded long ago to a nice 50A device.

https://321166-984045-raikfcquaxqncofqfm.stackpathdns.com/wp-content/uploads/2015/12/6-0101G_Lifeline_Technical_Manual.pdf

The charger doesn't spend much time in the high current Bulk stage before toggling to the Absorption stage.

I bought my 2000 380da in spring of 2019 also. The batteries were shot when we went to survey it, so the PO put new ones in. I never looked at them , they went with starting batteries which I abused thinking they were deep cell or dual purpose type.

Switched to AGM’s last Memorial Day weekend. Love them, never have to worry about checking /adding distilled water. My boat had the upgraded charger already, I would start there. Those AGM’s should be good for 7 years or longer

When I got my boat 4 years ago. A 400DB 2001. All 7 batteries were bad (not AGM). It has 2 batteries for each engine, 2 for the bow thruster and 1 for the gen. The previous owner had replaced the main charger with some large custom charger but kept the original 24v bow thruster charger. The boat was often unplugged for many days and batteries were dead for extended periods. So I had planned to change all the batteries from the start. I first replaced the custom charger with a promariner prosport 20 plus. The 2 bow thruster batteries were completely dead and shorted! So I bought 2 new batteries, put them for one of the engines and used the 2 old batteries for the bow thruster. I was surprised that this worked well and batteries were revived! 1 season later, I had to change only 2 batteries, the second engine batteries. Another season later, the old bow thruster batteries became bad. Bow thruster would last only a few seconds... So I replaced the 24V stock charger with another promariner prosport 20+. The next season, I was surprised the same batteries were going very well. They're still on today. So before changing any batteries, I suggest you look at the newer prosportHD 20+, amazon: ProMariner 44029.

AGMs for sure. Wet cells you can take down to 50% before you NEED to recharge. AGMs can go to 30%. Deeper discharge, more usage. A good battery shunt style battery monitor made a big difference for me. I am now able to monitor everything that goes in and out of batteries and adjust / charge accordingly. We have to banks. One dedicated to port engine and bow thruster and the other dedicated to stbd engine and house. Battery monitor is on house side.

@Kerry Klear
What battery monitor do you have, I need to get one, just haven’t decided in one

I have the Victron 702. Will monitor the main house bank and give you the voltage (only) of a secondary bank

I was a confirmed AGM user. Then, I discovered they were't cost effective. At twice the price they didn't last twice as long.

If your batteries discharge even to 50%, you aren't using the boat enough or aren't maintaining the properly. Unless you need to replace all 5 batteries, just replace the 2 with AGMS and then buy a smart charger. Check monthly and recharge as necessary.

I have all 5 AGM Group 31 Odyssey batteries on board with the Pro Mariner 52036 12v 36 Amp ProTournament 360 Elite Triple Bank Charger... Added a remote charge indicator up at the helm. All works Great!

Hi! I saw that you had a post a while back about repowering your 2000 380DA. Am about to do the same thing and was wondering what motors you went with and of any lessons learned or recommendations that you might have from your experience. Thanks!