Care and feeding of battery banks

[Kit_L]

Nigel Calder's Boatowner’s Mechanical and Electrical Manual

Anyone else second this books as the best way forward for me? I am working my way through Marine Electrical Basics on YT (Pacific Yacht Systems) in the meantime; are there other resources recommended? TIA, KL

[rbk]

Yes. One of the best books to have on board. Also his diesel book is a great learning tool. I think someone also mentioned the 12 volt bible. All should be available on Amazon

[Kit_L]

The 12V bible I have read twice, so far.

Basically, I want to get up to speed ASAP; if there were an intensive marine electrical course I could do, that is possible in my present circumstances, and I can travel to do it—but I have searched here in Australia and have not found one, yet. All suggestions gratefully received.

[rbk]

Maine Sails page is also invaluable

https://marinehowto.com

His info is very up to date with the latest and greatest tech that he’s tested.

[Kit_L]

https://marinehowto.com

I have read almost everything there; and donated $50, too. Once I understand more about what I am looking at, he also offers an on-line diagnostic service too, charged by the hour.

My dream scenario is for a local marine electrician to contact me with a day rate, and I would contract with him/her to go over Sea Biscuit in detail, taking whatever time we need: trace wiring, replace/repair as necessary; and I label every wire in the process. I want someone who can see the details in the context of the big picture, and make the kind of changes and recommendations that result in a safe and efficient system I can maintain myself.

By "big picture", here's an example. SB is fitted with a Sea Wasp 9KVa generator, but I do not need this. I want to remove the generator and use the space in that hold to add water and fuel capacity, in time. The boat already has quite generous (400W) solar capacity—as indicated in the first post, that is the system I want to optimise.

I want to end up with a bullet-proof starting (or reserve) system, and a solar charging system that provides sufficient voltage to the two kinds of batteries I have (the start ones are new, and the gel ones are 2017).

And thanks to everyone who has replied so far, too.

[john61ct]

Using a make before break 1-2 switch ( no Both, no Off) ideally with AFD is to me the only way to do charge source redirection, but really the whole concept is outmoded.

DCDCs like Sterling are great, but if you can avoid added cost, complexity, and limiting your current to House, that's all good.

Put all significant charge sources to House where the amps are needed, with proper setpoints for that bank.

Starter really does not need much to stay topped up, or something else needs fixing.

If V spec is a bit off, so what, it's just a Starter, when you replace it match the House chemistry.

[Stu Jackson]

Originally Posted by Kit_L

I have read almost everything there; and donated $50, too. Once I understand more about what I am looking at, he also offers an on-line diagnostic service too, charged by the hour.

My dream scenario is for a local marine electrician to contact me with a day rate, and I would contract with him/her to go over Sea Biscuit in detail, taking whatever time we need: trace wiring, replace/repair as necessary; and I label every wire in the process. I want someone who can see the details in the context of the big picture, and make the kind of changes and recommendations that result in a safe and efficient system I can maintain myself.>>>>>>>>>>>>>>>>>>>>>>>>>>

And thanks to everyone who has replied so far, too.

Kit, you may be getting ahead of yourself. while I'd been boating since I was a kid at summer camp, I didn't own a boat until I moved to SF in 1978, and we bought a C22 with an outboard in 1983, a C25 in 1987 also with an outboard. I knew nothing about diesel engines and boat electrical systems until be bought this boat in 1998.


While I'm an engineer and know how to draw piping diagrams, electrical was always something I never understood, even though part of my business was just that (building systems: HVAC - me - electrical and plumbing/fire protection).



So we bought the boat. And the first thing I bought was Calder's Boatowners Manual. I read it until I understood some of it and then went tracing wires. You do NOT have to be an engineer to trace wires. Every wire has two ends and starts and stops somewhere. If you look at diagrams in books, they will give you enough information and ideas so you can draw your own. Forget about software, use a pencil and paper.


Do the BIG stuff first: batteries to switch(es), electrical panel inside the boat and to the engine: starter and alternator. Figure out how the power goes: batteries store power, the panel uses it and the starter uses it; once the engine starts the alternator makes power and sends it back to the batteries.


Essentially, you're in the same place as I was 21 years ago. And none of us was born an electrician, we all had to learn.


You might find some material here helpful in addition to Maine Sail's website (which is more for advanced than beginners).


Electrical Systems 101 Electrical Systems 101


Good luck.


PS Just realized I'd sent you that link before. Try it yet?

[Kit_L]

PS Just realized I'd sent you that link before. Try it yet?

Yes, Stu; most assuredly, and working my way through everything there. I am a researcher by trade, so am used to working things out (eventually!).

You wrote:

Do the BIG stuff first: batteries to switch(es), electrical panel inside the boat and to the engine: starter and alternator. Figure out how the power goes: batteries store power, the panel uses it and the starter uses it; once the engine starts the alternator makes power and sends it back to the batteries.

And that's exactly where I am starting. My multimeter is getting a workout, too, and the snarl of wires behind the helm position is looking less threatening every time I look at it, but only slightly.

The main problem I see is that the technician that installed $9,000+ worth of the nav. gear we needed to make our recent offshore trip doable did not fuse any of it—simply poked the ends of the wires straight into an already overloaded bus... So that (making a new distribution point, and fusing it for the individual instrument's power wires) is a job for the near future.

For the present concern (insufficient bulk charge going to start batteries), I am thinking that a new MPPT controller to feed the gel batteries (after checking the float and absorption parameters) is the way to go, and resetting the existing Manson to the recommended levels to charge the sealed lead-acid start batteries will do the job. I will check the alternator's output the next time I am going somewhere, too.

A real newbie question: is it acceptable practise to parallel the output leads from the two solar panels, make a distribution point, and attach the input wires from the two solar controllers to that point?

[john61ct]

Output from charge sources should go directly or close as possible to the bank posts.

Unless four-wire chargers, where the voltage sense pair is separate from those carrying the charge current.

Heat sensors wires usually direct to batt case

[Kit_L]

In case the question was lost in the details:

A real newbie question: is it acceptable practise to parallel the output leads from the two solar panels, make a distribution point, and attach the input wires from the two solar controllers to that point?

[john61ct]

Already clearly answered, by me, immediately above.

Acceptable to some, and yes even to me **if** the SC's voltage and temp sensing functions are not compromised.

If a cheap SC without decent functionality in those areas, then of course little difference, many people don't care about maximising performance.

[Kit_L]

john61ct,

Thanks for your follow-up replies; they answer the question perfectly.

I am considering a Victron Smartsolar MPPT 100/50, as suggested by sailorchic on the "Do I need a new solar controller" thread. More to come.

[john61ct]

great choice

[Kit_L]

A quick question: on a number of threads, small-case alternators, for the most part, seem to be repurposed car or truck alternators, and IIRC, their internally regulated output is between 14-14.4V.

I have seen this output criticised as being insufficient for full charging of lead-acid batteries, with a higher upper output limit (14.7) recommended.

Why do car and truck batteries last as long as they do? Or is the recommendation for external regulation made for ultimate control of bulk and float charging voltages, and to take a temp. sensor's output into consideration, and designed to attain that last 10–15% of efficiency? I have seen that standard alternator outputs can vary 0.3V from manufacturer's specs, too. Or is there something else I am missing?

[john61ct]

Deep cycling batteries need much more precise care, orders of magnitude better, compared to Starters.

Cranking an engine draws down maybe .001% of its SoC, in effect Starters remain at Full 99.99999% of their lifespan. In effect calendar aging gets them, no cycling wear & tear.

Thus they do not need to be of as good quality