Question about battery chargers. How many? Best configuration?

[rja7]

First off... my apologies if this seems somewhat elementary! I'll be the first to admit my electrical knowledge is limited... so any response in layman's terms is welcomed and appreciated.

The 30 ft trawler I am looking at has 2 batteries: hooked up in parallel I believe- used to start a single engine Ford Lehman and run the house system - minimal interior lights, navigation, instruments (minimal) and a small fridge. (Ac/Dc)

Lets assume no battery charger as it is likely to be replaced.

What I am wanting to install and have set up. A windlass; a bow thruster. My thoughts are to have a dedicated battery for the bow thruster (located very close to the thruster to minimize cable length); to have one dedicated battery for the engine and windlass (as the engine will be running to operate the windlass) and retain the 2 existing batteries for the house (which I am looking at adding solar (200w) to keep these charged. We prefer to gunk hole as much as possible thus the solar arrangement for the house system.

I am uncertain as to what/how best to set up a charging system (and what goes where). i.e. do I need a charger for the starter/windlass battery or as I assume, like my vehicles they will self charge while the engine is running.

Do I have 2 chargers? one for the thruster in the bow and one for the house bank located in the aft engine room... or one charger with battery 1,2 or even 3 switch option to all 3 banks (thruster, starter and house bank)

As I will also need to add 2 batteries (present thinking for engine/windlass and the bow thruster; suggestions on type and size are welcomed as well)

While I am at it; is it worthwhile to add gauge(s) to monitor battery status; charge etc. The boat at present is minimally set up with instruments and I do like the KISS method.

BTW; our boating is done in the Great Lakes - freshwater for us for the time being.

I know there is a lot of wisdom on this forum hence my reaching out to those with much more knowledge than I in this area. Thanks in advance to your replies.

 

[Comodave]

There are so many variables that could be taken into account. Do you have shore power where you dock the boat? Does the boat have a generator? With just a 30’ boat the battery cables would not have to be really long so with larger cables you could run the windlass and bow thruster with the same battery bank you have now. If you go that route I would add a start battery with an ACR to charge it. You could add a second alternator to the engine to charge the house bank because the stock alternator isn’t too big. I think that I would pay a certified marine electrician to come and look at the boat and design a system that will meet your needs. There are just so many different ways that you could go it is hard to design a complete electrical system over the internet. Good luck and welcome aboard.

 

[rja7]

Thanks for your reply. Yes shore power (30A) is available - no generator aboard. (considering taking along portable Honda 2000 for just in case situation) Good suggestion to have marine electrician to come aboard and walk through things not to mention perhaps shortening my learning curve.

 

[Baker]

I will try to keep it as simple as possible....and you said you like KISS. What I am about to say will go against just about everyone on here. My general philosophy is everything on one bank. WHY??? Well batteries are damaged by cycles...the deeper the cycle, the more the damage/wear. If you allow them to share the load, they do not cycle as deeply and they last longer. Allow me to explain....my current boat has simply one bank of 5 GRP31 AGM batteries and 1 generator start battery...that is it. The thinking is that if I pull a boner and drain the batteries I can start the generator and run the battery charger. This philosophy has served me well and my current 6.5 year old batteries have not so much as flinched and I don't expect them to any time soon. I do have TWO batter chargers simply because I wanted an inverter. So my OEM charger is a Charles 80 amp. Then my inverter/charger is 100 amp. The OEM charger can charge all batteries. The (Magnum) inverter/charger can only charge the house. All batteries are monitored by a Magnum Battery Monitoring Kit(BMK). You can see everything that is going on with your batteries on this unit.

NOW....to the present....I just Bought a Meridian 411....and they have the ONE BATTERY FOR EVERYTHING mentality...as you are alluding to. There is a battery for each engine to start. There is a battery for the generator to start. There are batteries for a bow thruster AND a stern thruster. And then there is the house bank. Meridians are known for their electrical issues due to this complexity and the heavy loads each battery must carry. Thrusters and windlasses are extremely heavy load appliances. I think what I might do is combine house and start banks(like on my current boat) with their own charger and then maybe have seperate banks for each thruster....with one charger charging both banks. That is just my thoughts. Hell I have even thought the thrusters and windlass can go on the house/start bank and just have a seperate generator start battery. I challenge you to ask how long people's batteries last and then ask them how they are wired....

Thanks for asking the question....I am now following and opening myself up for ridicule as people think this way of doig things is not redundant enough....and I am a professional risk manager...

 

[ranger58sb]

What I am wanting to install and have set up. A windlass; a bow thruster. My thoughts are to have a dedicated battery for the bow thruster (located very close to the thruster to minimize cable length); to have one dedicated battery for the engine and windlass (as the engine will be running to operate the windlass) and retain the 2 existing batteries for the house (which I am looking at adding solar (200w) to keep these charged. We prefer to gunk hole as much as possible thus the solar arrangement for the house system.

I am uncertain as to what/how best to set up a charging system (and what goes where). i.e. do I need a charger for the starter/windlass battery or as I assume, like my vehicles they will self charge while the engine is running.

Do I have 2 chargers? one for the thruster in the bow and one for the house bank located in the aft engine room... or one charger with battery 1,2 or even 3 switch option to all 3 banks (thruster, starter and house bank)

As I will also need to add 2 batteries (present thinking for engine/windlass and the bow thruster; suggestions on type and size are welcomed as well)

Hard to pin down, without some specifics already decided... so the marine electrician idea get's my vote too.

That said, I think you could consider charging the windlass and thruster batteries only with the engine alternator... along with the engine start battery... assuming you'd usually have the engine running when using any of those... and assuming they'd also be recharged every time you're running. (And a parallel switch to the house bank, or a set of jumper cables, could be the easiest set-up.)

Or... there are battery-to-battery chargers, or auto charge relays...

Or... you could run thruster and windlass from the house bank, not an uncommon solution... especially if your bow isn't located all that far from your house bank.

You could add capacity to the house bank (especially if you power thruster and windlass from that bank). You could also maybe use an inverter/charger on that bank to run small-ish stuff that might otherwise need a bit of shorepower or generator power...

3-bank chargers are said to do slightly better if all banks are generally similar in size. (We had a bit of a boil event on our small genset battery once, possibly since it was so much smaller than each of the other two banks. Not sure about that, though, since I think batteries generally only accept what they can accept.)

For the thruster: two Odyssey 31M-PC2150s. Very high cranking amps, very good allowable depth of discharge, very good longevity.

Allow me to explain....my current boat has simply one bank of 5 GRP31 AGM batteries and 1 generator start battery...that is it.

Just a "FWIW"... I've read it's not great to parallel more than 4x batteries. No clue why.

-Chris

 

[rja7]

Thanks guys. You have given me some options and directions to think about.

Moving over from a 30 ft sailboat with 18 hp Volvo: 2 batteries to handle house, start and fridge. Fridge was a big draw and we had to watch it closely. Much better after adding solar panels.

I do like the simplicity of what Baker has done... maybe just add 2 more batteries to the existing 2 and call it a day... review after a season of use.

Will engage a marine electrician though as a couple of you have suggested.

I knew there was a reason I joined this forum. Thanks again. Rob

 

[OldDan1943]

My recommendation is to sit down with a marine electrician and discuss your needs, wants and desires.
Then let him/her do the install.

My own experience, bow thruster on start battery, electronic Cummins.
Engine would shut down, on low voltage, caused by the bow thruster usage.
Results, replaced 4 batteries (3 house, one engine battery)
Moved bow thruster to the house batteries.
Problem is apparently solved.

 

[ranger58sb]

A little more thought...

I could definitely see a single big house/start/windlass bank -- with a separate thruster bank -- being a pretty decent solution. Maybe max capacity that will fit into the available space.

The thruster bank could be a decent backup (Battery switch, jumper cables, whatever) if for some boo-boo reason the house bank is over-depleted.

Especially in a 30' boat... and with solar augmentation...

And that inverter/charger idea would still work.

See what the electrician says...

FWIW, our setup is actually similar, combined start/house banks. Just happen to have two of those, and the house loads are split, but the affect if pretty much the same.

-Chris

 

[boatpoker]

As Comodave said in the first response there are too many varibales to give a comprehensive answer here and a qualified marine electricain should be consulted.

Be careful. I know most of the ABYC Certified"marine electricians" in Ontario and some are very good but there are many more without training or qualifications who call themselves "marine electricians". Some of these fly-by-nighters can cost you big time.

 

[C lectric]

I have a 32' boat and a few years ago I added a larger windlass. I did not even consider a dedicated battery. ROOM. I simply ran 0000 wire to the solenoid control H.D. relays which are close to the windlass to minimize Vdrop. THe final feeds to the windlass were much smaller, limited by the windlass case which was too tight to run 0000 wire directly into it. The total cct. was about 64 ft. return. The Vdrop was entirely OK and the unit runs very well hauling the anchor without a slowdown.

Your likely stock alternator will not help much with the anchor windlass. ALternators do not produce much power at idle or just off idle, often as little as 10% or their rated output. It would take you running the engine at likely close to half of full revs to get much at all. If you don't believe then get a hold of the output curve for your alt. or for any similar unit. THere are ways around this but require a new alternator AND an external regulator. I would wait to do this for at least a season to see how this all works out. THis can be done as an add on later. Still some work and expense but find out if you need it first.


Like me, you will be limited by space and the extra battery would be better used by making it part of the house set which is where I wired mine to. I think you will find power useage by house loads will become a major consideration solar or not.

I attach absolutely nothing to my engine start batteries except the engine. That engine must start and I have had a bad experience with using the eng. start batteries for other uses. I was close to being stranded. I do of course have a means of providing a jump from the house set just in case. A parallel switch and a good quality pair of jumper cables.
Protect it, monitor it like your life depends upon it as that may be the case.

A lot of this dedicated battery thinking comes from necessity in much larger vessels where the cable runs become excessively long even with 0000 increasing Vdrop unless the wiring is made even heavier or twinned. Many times an even larger windlass is involved needing more current creating more Vdrop problems. Then it becomes a reality for dedicated batteries with ACR or a separate charger or whatever.

Make your house bank 3 batteries, get a 2 or even a 3 output charger of about 40-60A and that will look after your batteries properly unless of course you get some of the very new types like LiFePo4 or the Fireflys.

For operating, alternator charging, get an ACR to charge the engine start battery from the house set.
Of course this is what I have done but may not be exactly what you want.

I strongly agree with the suggestion to get a marine electrician to review what you have and design your changes.

I will also suggest you get a hold of:
Nigel Calder's book Boatowners Mechanical and ELectrical Manual as it does a good job of explaining the options. He is now on the fourth edition but a used older version would be suitable for the basics which is roughly where you are at. That way you will start learning and understanding a lot faster.

 

[JDCAVE]

Chuckle! I read C-lectric’s post and I have to laugh because he came to my rescue during my first trip on our brand-new-to-us boat. Some good advice from many on this forum. Get Nigel Calder’s book (which “C” also recommended to me) and find a good electrician to spend an hour with you reviewing your system. As Boat Poker says, there are some who don’t really know what they are doing,

CMS occasionally posts on this forum and is very helpful when he does. His website is here:

https://marinehowto.com

Steve D’Antonio occasionally chimes in with useful advice as well.

Good luck!

Jim

 

[C lectric]

Yes, definitely look up CMS site. Lots of excellent advice for free.

Steve D'Antonio also runs a site which has good info available for the looking.

 

[siestakey]

Some great advice on here already and even though I am engineer by education I do not know the right answer. With my 46' boat I have a dedicated for the windless but not sure if that is the right way to go but I have to say I have been happy with it

 

[syjos]

On Sandpiper with one FL 120, I have two battery banks and one 110 VAC battery charger to minimize the number of batteries and to keep thing simple:

Two Group 31s in parallel for engine and generator starting. A large battery cable from the starting batteries goes to the bow to power the windlass and bow thruster. Using the thruster and windlass with the engine running provides more power to them. The starting batteries get charged from the alternator on the engine or generator. There is no 110 VAC battery charger on the starting battery.

For house and inverter, there are 6 Golf Cart batteries. They are charged by a second 150 amp alternator on the engine when it's running or the 125 amp charger/inverter.

There is a switch to parallel the house batteries with starting batteries in case assistance is required.

I configured this system 20 years ago and have not had any issues.

I do carry a spare back up battery charger in case, but have not had to use it.

 

[FF]

If you are cruising constantly with a small diesel what ever you choose that is common should work.


The hassles come when 4 or more batts are combined and left on shore power to charge.
Does a great job , till one batt dies , then all will be overcharged and boil and are scrap.


Only long term solution for me is a tiny charger for each isolated batt in the string .


PIA to uncouple the batts for a few weeks or months of non use , but way better than buying a ton of lead, again.

 

[rgano]

Because I have a 30-foot boat which came battery-equipped much like yours, I feel I might have something to add here. While it is NOT a trawler, I wanted it to have some of the redundancies I had installed in my 1972 Grand Banks 42 which ALSO came equipped much like your 30-footer. Being in Florida, where air conditioning is often required to support intelligent life afloat, both my boats had/have a generator, but you can simply include your proposed Honda or exclude it as you feel right. I never felt solar was suitable for my needs, and in Canada, well, are you sure?

I found no need to try to install the added bow weight of a dedicated windlass battery. I mean for 1/4-chain on a small windlass???

Anyway, here is what I ended up with on this cramped boat without having to disassemble it to get what I wanted. All batteries are AGM, no battery monitor -yet. Battery charger is Promariner 50-Amp.

 

[clyde]

i have a 40 ft single engine trawler, my single MD-70 volvo has 10,850 hrs. have 6, 260 amp flooded 6v`s in series, [ie, 3 12v`s ] and 2 group 31`s in paralell for starting. all the 6v`s last 10 yrs, almost to the day!! I went thru the sooper charging regulators, changed the whole system abt 5 yrs ago, bought a leece/nevele 165 amp aternator/double belt small pully, their newer alternators don`t go over 14.1 volts! 1+ volt over 14.1 will atempt to use some water! the pully is just over 3", so it will charge when trolling for salmon in british columbia/alaska...i bought a 6o amp house charger from CHARLES INDUSTRIES.COM, and it works GREAT!!...CLYDE

 

[rolomart3]

Hard to pin down, without some specifics already decided... so the marine electrician idea get's my vote too.

That said, I think you could consider charging the windlass and thruster batteries only with the engine alternator... along with the engine start battery... assuming you'd usually have the engine running when using any of those... and assuming they'd also be recharged every time you're running. (And a parallel switch to the house bank, or a set of jumper cables, could be the easiest set-up.)

Or... there are battery-to-battery chargers, or auto charge relays...

Or... you could run thruster and windlass from the house bank, not an uncommon solution... especially if your bow isn't located all that far from your house bank.

You could add capacity to the house bank (especially if you power thruster and windlass from that bank). You could also maybe use an inverter/charger on that bank to run small-ish stuff that might otherwise need a bit of shorepower or generator power...

3-bank chargers are said to do slightly better if all banks are generally similar in size. (We had a bit of a boil event on our small genset battery once, possibly since it was so much smaller than each of the other two banks. Not sure about that, though, since I think batteries generally only accept what they can accept.)

For the thruster: two Odyssey 31M-PC2150s. Very high cranking amps, very good allowable depth of discharge, very good longevity.




Just a "FWIW"... I've read it's not great to parallel more than 4x batteries. No clue why.

-Chris

For what is worth folks,


1) There is no limit to the number of batteries one can parallel (the Tesla cars parallel over 100).
2) A bow-thruster typically consumes about 5 times more power (and that much current) than a windlass.
3) Multi-banks were preferred in the past because just one shortened cell in one battery of a single battery-bank would be enough to prevent starting a diesel engine. But today with portable li-ion power boosters like the Viking available from Harbor-Freights-Tool for about $70 a piece, one can start a diesel by paralleling two of them. Then, there is no point in having the complexity of a second bank
So, parallel the largest number of batteries space allows into a single bank, get an alternator capable of handing the budgeted DC load to include underway AC load if using an inverter, and run the proper wire gauge to handle the bow-thruster. Yes, it makes sense to tap from the bow thruster wire to power the windlass provided that additionally the typical 50-70 amp windlass fuse/circuit-breaker is placed between the tap and the rest of the thinner-gauge windlass wire. This additional fuse or circuit breaker is required. Lastly, buy the two Viking li-ion car starting bricks.


Rolo

 

[clyde]

as far as battery configuring/charging systems, i try to live by the KISS principle when desiging mine, or any charging system. the high amp charger from charles industries, compinsates for cold weather by automaticly increasing the charge voltage when the outside ambiant temp goes down, and it senses the batteries are getting colder!...clyde