wiring multiple batteries

[kevinr]

i found the attache diagram on a previous post. Questions:

1.  if i want to run more than one house or start battery, how would i add a battery to each bank?
2.  i'd like the motor to charge all batteries when it is running? what - if anything - would i need to change to make that work.
3.  I'd also like to do a dual bank charger on shore. anything additional needed?

Thanks for the help!

[Capt. Bob]

1. To add capacity while keeping voltage constant (12v) you need to wire the battery(s) in parallel (not series).

Based on your prior posts, your charging system isn't state of the art. you can however add devices that sense the need to charge that would be in your best interest.

https://www.westmarine.com/buy/blue-sea-systems---add-a-battery-dual-circuit-system--8646275?cm_mmc=PS-_-MSN-_-BSC%3ENonB%3EProduct%2520Type-_-8646275&creative=73736013195909&device=c&matchtype=e&msclkid=c134dfd2dd1e12e9512c81721141d2c4

Whether your charging system is up to the task is out of my swim lane.

Good luck.

[kevinr]

Capt - the good news (or the bad depending on your perspective) is that my current system is non-existent. I'm rewiring the boat to suit my own needs, so the canvas is blank. i'd like to start with two banks - house and start. I'd like to be able to add batteries as needed to either bank. i have a trolling motor...have to check to see if its 24 and saw in another post i can use a combiner for that. i want to run lots of led lights, bait tank, radio etc but i also want to be very sure i have start power that in not drained by all that (but backed up by any available power from other batteries.

i'm out of my sandbox too as a car guy, but I love learning new stuff. maybe i'll do a couple of battery banks on my 64 impala ss. bet i'll be the only guy on the block with a bait tank in the trunk.

[Capt. Bob]

Many of us run two batteries.

Most use a dedicated start battery and a dedicated deep cycle type for the house battery.

A few (or at least one, me) run two large deep cycle/combination type batteries. That is, I use one to both start and run my accessories. I only switch between outings. That is I start/run all day on battery 1 and then the next time out I start/run on battery 2.

Larger craft with many accessories will run one start and two house batteries. In any case, the device I posted the link to will allow you to start/run/charge your batteries without the need for multiple switches and a solid memory of which switch position you need to be in at any given time.

As for the trolling motor, some run a separate bank dedicated to the motor. With that, you're looking at a minimum total of 4 batteries. 1 start, 1 house and 2 trolling (to achieve 24 volts). You also can combine one battery with your house and eliminate one but need switching to go between 12v and 24v. Too much work for me but doable.

Read through the link I posted and since you are starting from scratch, that unit makes for a good foundation.

More light reading.
https://classicaquasport.com/smf/index.php?topic=14600.msg143832#msg143832

https://classicaquasport.com/smf/index.php?topic=14296.msg141593#msg141593

https://www.abebooks.com/12-Volt-Bible-Boats-Brotherton-Miner-Sherman/30535984387/bd?cm_mmc=ggl-_-US_Shopp_Trade-_-used-_-naa&gclid=CjwKCAjw-YT1BRAFEiwAd2WRtjjHnWPyDpxhiqgGphNgEn-TesIQguusf1MN6nJFnSw9KOdclbvsQxoCkE4QAvD_BwE

https://www.google.com/search?q=wiring+perko+dual+battery+switch&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwi0roDwrZ3MAhXEKCYKHVMhDeMQsAQIKQ&biw=1366&bih=659#imgrc=pWSMDMk-E3byIM

Good luck.

[mshugg]

The ACR Add a Battery kit is great for keeping house and starting batteries charged.  The diagram you started with shows one.  Plus, there are video resources on the ACR website that can help.  https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A

As for trolling motors, I’ve always made that a completely separate system with its own battery switch.  This will work weather you’re going with a twelve, twenty four or thirty six volt motor.  It’s just one battery or two or three batteries wired in series depending on voltage.  Though it would be possible to charge trolling motors off of the alternator, if you’re putting enough hours on your TM to drain them, you either need to go up in voltage, or you’re likely not running enough to charge them on the go.

The New Wire Marine website has a great tutorial on boat wiring.  https://newwiremarine.com/how-to/wiring-a-boat/

[Capt. Bob]

 

[boatnamesue]

Cranking battery should always be isolated from any other load and charge, that is if you’re expecting the cranking battery to be fully charged with every key turn.  If you were to splice the starter cables at the battery side for the purpose of using the engine stator to charge house batteries, electrons will flow to the path of least resistance.  If your house batteries happen to have less charge than your cranking battery, guess which batteries will receive the stator charge.  Never a good idea to include a cranking battery into parallel series with house batteries.  No bueno. 

[Fish Head]

]



Found this on the web and considering to save the weight of a extra battery. Might entail wearing out  battery switches from lots of use?lol  Also battery “A” does not get charged by motor? Curious if anybody sees anything really wrong with diagram? Bonus get to keep my 3 bank charger and not have to buy a 4 bank one.
Maybe some version of this can work for you?
Cheers T

[kevinr]

i'm thinking this may be the way I wire up. the only things I dont like are that BATT A can only be used for the trolling motor (not as backup for the 12v stuff) and BATT A doesnt charge off the motor. I can add a solar power charge for BATT A, but I'd still like to use it for 12v stuff and/or the 24v trolling motor.

anyone suggest a way to accomplish that? or a better way to wire it?

[Fish Head]

I had a version of this setup before I started my rebuild and never had any issues with trolling motor batteries draining. I have to admit I am not an “all dayer” so my fishing trips would last about 5 hours max using my 80lbs thrust 24v on a 19’6. Like Mike suggested you might want a separate battery bank for trolling motor and than you could hook up the solar charger to them like you mentioned if your still concerned.Also need a four bank charger when back to your slip unless your going to charge separately at home? Not recommended to charge 2 batteries off one bank from the charger.
 
Key to this setup is
1. Startup - cranking switch set to batt C- accessory switch set to off
2. Motor on/ cruising- cranking & accessory switches set to B & C in parallel. Both batteries getting charged.
3. Motor off/fishing - cranking switch set to off - accessory switch set to batt B
Cranking batt C is protected and not in use

Starting motor back to step 1.
Never ever turn cranking battery switch to off while motor is on!

Agree not optimal but works. Still looking for a schematic using ACR switch with 3 batteries. Let you know if I find one.
Cheers T