So … I have changed my mind. Yes old dogs can learn new tricks . Whether you want to watch is another matter !
So.. I was chatting with my eastern sailing buddy Mike who is a retired electrician and my go to guy when it comes to anything with electrons on my boat. He just moved from a Hunter 31 to a CS 33 and we were c hatting about the new to him boat. And has a Li set up. He explained in detail how it all worked and suggested I check “Maine Sail How To” the site run by Rob Collins. Which I did leaving a tip in the jar.
Long story short I have decided to switch to Li. I need to do a few not so complicated things.
- Move my Trojan Deep cells to the start battery position. Maine Sail How To BTW is a big fan of using them for start batteries. And we were doing it for years …
- Keep all charging sources on the Trojans as is the case now.
- Install a DC to DC charger to charge the Li from the Trojans. This protects the alternator, acts as a buffer plus allows the existing charging to remain configured for lead acid. Li is is not temp depended for charging , at least not in the temp ranges we see.
I’ll use Victron equipment and install a Victron monitor as there are advantages staying in the same product line. My 125 amp alternator is capped at 80 amps and for now I will leave it there and see how it goes. The guidance is 50% of alternator capacity, but I have a continuous duty alternator and are already around those numbers. I can factor a delay in the start of the charging to allow for windlass use if need be.
The 314 ah battery is from Wattcycle (who is recommended by MSHT and a couple of mainstream articles). Comes with Bluetooth and a good BMS. Weighs 57 lbs and fits easily in the compartment under the aft berth.
The cost of the carbon batteries and weight was part of it. The Li and all the changes comes to less B $ , I get more AH and 1/3 the weight … so I will be faster than a 30 LOL
This is a basic diagram , missing the alternator, solar and a few fuses but the concept is the same.
And a final word on Battery Bank Manager. I look long and hard at it but decided against it not wanting to base my design on a more complex design from a small supplier . I am sure it works but I’m not sure of the how and why of it.
And in closing I’ll put in a plug for Rod Collins, his web site has saved me more than a few boat buck over the years, advice of quality and freely given. He’s ABYC certified and been working on boats for a long time. Check it out and maybe consider leaving a tip.
Thor