Battery isolator info

I thought getting a battery isolator would be simple but after reading this im not sure?

I just want to wire my boat up so that i have one starting battery and one deep cycle to run house stuff.

How would you set this up? Last thing i want to do is manually switch to the house battery after i turn the engine off and then manually switch back to start the motor. From what i gather i need to aim for a dual set up with hybrid starter/deep cycle batteries and alternate use between the the two. Im not sure if this hull truth thread is old news but it confused the issue for me and im thinking i might just wire up the starter battery to the motor and run the house totally separate on the deep cycle. But saying that, I would love to charge the deep cycle while underway. Any help out there?

www.thehulltruth.com/boating-forum/8971-proper-way-use-dual-battery-switch-3.html

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scubafish's picture

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Date Joined: 15/08/12

VSR

Mon, 2021-06-14 19:12

https://www.youtube.com/watch?v=kTQp5d5mMio

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 You need to fit a VSR

Wed, 2021-06-16 06:35

 You need to fit a VSR (voltage sensitive relay) and an isolator (if not already fitted).

Depends on your own experience whether you can do it yourself, need some electrical understanding.

Depending on whether you want to be able to use the house battery to start in an emergency 

 https://chsmith.com.au/Products/BEP-Dual-Charge-Battery-Switch.html 

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dmck's picture

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Date Joined: 07/03/19

You have to be very clear

Wed, 2021-06-16 13:48

 about what you want to achieve.

Your initial statement indicated a motor (start) battery and a separate house battery, and a desire to charge the house battery whilst travelling`

Pretty simple, 2 batteries - 2 isolator switches and a VSR to charge the hose battery.

 

BUT.... if either battery fails .. do you want to run the entire boat off the remaining battery?   I'm guessing that as a safety precaution... you do.

also simple, add another isolator to connect the 2 circuits together... BUT..... (BIG BUT !)  your house battery needs to be capable of starting the motor.

 

--simplest solution... have the same battery type for house and start.

 

Next question:  WHY do you want/need a separate 'house' battery?   Are your power needs so high that you may flatten the start battery?

 

Simplest solution- the one I use on my 575 BarCrusher... is 2 identical batteries, 1 main and 1spare.

 I can run the boat off either battery- (and I take it in turns.)- or both batteries commoned together (never needed to).  Very simple wiring - 2 isolator switches or 1 compound expensive switch (1-both-2- off)

If you want to charge the spare battery you can still fit a VSR- but it will only charge the spare when you are operating on the main battery--- and IT WILL NOT charge the main, when you are operating on the 'spare'.

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I had all this done by my mechanic before summer

Wed, 2021-06-16 15:27

Dual Battery isolator switches at whitworths marine (the OFF, 1, 1+2, 2) type switches start at $32 for the TMC brand up to about $80 for the blue sea brand. They have 2 types of VSR modules ranging from $50 - $60. I went and bought the starter battery, deep cycle battery, isolator switch and VSR and mechanic wired it all up for $100 plus cost of cables - all runs perfect

 

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Date Joined: 05/05/06

 Cheers fellas, I have read

Wed, 2021-06-16 20:01

 Cheers fellas, I have read about the vsr's but have heard of them failing, leaving me in the situation I wanted to avoid!  But anything on my motor could fail so if its the done thing ill bite the bullet and get a quality one.

I can do the wiring and a vsr would fix my needs somehow.

Ideally i want two hybrid starter/deep cycle batteries but my budgets blown.  So have to try and keep my house charged on a smaller deep cycle. The loads  arent huge but 2 sounder/plotters 1kw transducer and all the other usual bits and bobs but the battery i have is small. I do have an extra a fully charged spare battery under the deck i can use if my boat wont start but was trying get away with using a small deep cycle battery for the house. I just needed to charge it.  I wanted to keep the deep cyc battery near the helm and run the short cables direct to accesories but not sure how that would go hooking up to the engine to charge.  This deep cycle would not start the motor by a long shot. im not sure of the amps of it as im away right now but im sure it would do.

Hope that mkaes sense!

 

 

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dmck's picture

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Date Joined: 07/03/19

check and see....

Thu, 2021-06-17 07:05

 

if you motor can run a dual charging system.  I believe they are an option on some new motoes.

They are a seceond charging coil and regulator and provide you with a second, totally isolated from the first, battery system.

 

I even went to the extent of buying a very small alternator that I was going to fit to my 86 Yam and run off a belt around the pull-start pulley... but I ended up selling the boat.

Jackalchub's picture

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Date Joined: 10/03/12

  Victron DC to DC system

Thu, 2021-06-17 10:16
  •   Victron DC to DC system instead of VSR be a far superior charge and the only option for a lithium house battery 
dmck's picture

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Date Joined: 07/03/19

excellent.....

Thu, 2021-06-17 11:43

 

... advice

Jackalchub's picture

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Date Joined: 10/03/12

HAS to be an "isolated"

Thu, 2021-06-17 15:48

HAS to be an "isolated" victron, as their is no chassis neutral. You'll hold constant 14V.. electronics will run like they're on the gas. You can check the voltage via bluetooth too 

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Date Joined: 05/05/06

 Cheers fellas, looks like

Fri, 2021-06-18 18:59

 Cheers fellas, looks like the vitron will do the trick nicely. saves getting a 12v to 240v inverter with an extension cord!

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