Batteries

[KennyPowers]

I think I’m going to run two batteries in parallel on the new boat to accommodate the use of deck lights and fm radio when engine won’t be running, will the engine charge both of these together perfectly fine or will I need to add/change something?

[JonC]

You need to fit a split charge system, Blue sea I think is a popular brand I think. 
Most people have two batteries now I think. 
@suzook12?

[GPSguru]

 

Generally you would have an 'Engine' battery and a 'House' battery, where the house battery runs all the ancillaries.

There are lots of ways to do this, but the most common methods are ...............

1. Use a '1, 2, Both, Off' isolation switch ............ then it is up to you to manage the batteries by switching between them. The switch is designed as a make before break so there is never a battery disconnect until it is in the off position. I use this type of management on my boat as I prefer it's simplicity.

2. Use something like a 'Bluesea' add a battery kit, which adds some automation to the process often using a VSR (voltage Sensitive Relay) or a split charge diode .........

 

One thing you don't want to do it to connect the batteries in parallel ............... if one fails then the other will discharge into it and also fail.

Edited December 5, 2020 by GPSguru

[suzook12]

27 minutes ago, GPSguru said:

 

Generally you would have an 'Engine' battery and a 'House' battery, where the house battery runs all the ancillaries.

There are lots of ways to do this, but the most common methods are ...............

1. Use a '1, 2, Both, Off' isolation switch ............ then it is up to you to manage the batteries by switching between them. The switch is designed as a make before break so there is never a battery disconnect until it is in the off position. I use this type of management on my boat as I prefer it's simplicity.

2. Use something like a 'Bluesea' add a battery kit, which adds some automation to the process often using a VSR (voltage Sensitive Relay) or a split charge diode .........

 

One thing you don't want to do it to connect the batteries in parallel ............... if one fails then the other will discharge into it and also fail.

Following on from GPS's comment, as far as the engine charging both batteries, yes, either with a vsr/scr or some engines have dual outputs. Take into account what the charging rate is of your engine and useage, a small engine may not recharge the engine battery fully on short trips so you may need an aux charging device.

The charge systems generally prioritize the engine start battery, so if that doesn't get recharged fully, then your house battery won't get charged at all. Obviously this only really applies to old 2 smokes and small outboards..... Newer 4 strokes will generally be able to manage a 20A+ charge current

[MegaByte]

I fitted a this 6 years ago, it's been brilliant, Fit and Forget.

 

Edited December 5, 2020 by MegaByte

[Andy135]

I fitted a Blue Sea Add a Battery kit to my Predator. Quite simple to do DIY and makes charge management a fit and forget affair. Strongly recommended.

[Saintly Fish]

On top of the above suggestions I would if I were you carry one of these..

 

it’s a jump start power pack. Relatively cheap on Amazon and a life saver should you ever need juice when you have none. 

[GPSguru]

1 hour ago, suzook12 said:

Newer 4 strokes will generally be able to manage a 20A+ charge current

Indeed, IIRC my merc 150 charges at 45A @ 1000 rpm, with a max charge rate of  60A, merc specifically designed the alternator to do this in response to ‘testing the market’ to see what users wanted from an engine.

Edited December 5, 2020 by GPSguru

[KennyPowers]

Awesome info guys, I’ve already looked a these bits here. It’s something I’ll endeavour to do down the line, the split system sounds perfect because in theory the master battery will always be fully charged.

[MegaByte]

The problem with a "1-2-Both" switch is that you have to remember to switch it. 

Edited December 5, 2020 by MegaByte

[Andy135]

Just now, MegaByte said:

The problem with a "1-2-Both" switch is that you have to remember to switch it. 

Agreed. That was one of the reasons I went with the Blue Sea kit - eliminates the need for manual battery switching. Just switch the master switch to ON when launching the boat and the VCR box takes care of charge management. Then switch OFF when ready to leave the boat.

[suzook12]

4 hours ago, GPSguru said:

Indeed, IIRC my merc 150 charges at 45A @ 1000 rpm, with a max charge rate of  60A, merc specifically designed the alternator to do this in response to ‘testing the market’ to see what users wanted from an engine.

Although a merc 40 is only 18A

Its worth knowing what the alternator capabilities are

[KennyPowers]

£180 for the blue sea add a battery vs a generic switch for £20 🤔you will get away with that in Alabama but that’s classed as rape in the UK🤣🤣🤣🤣

Edited December 5, 2020 by KennyPowers

[JonC]

1 minute ago, KennyPowers said:

£180 for the blue sea add a battery vs a generic switch for £20 🤔you will get away with that Alabama but that’s rape in the UK🤣🤣🤣🤣

Thats boats for you Micky, quality is money. 
My boat has a conventional 4 way switch, but like you I mainly fish at anchor with tech shut down except the vhf. 
A lot of these guys spend a lot of time drifting ( not cars) so they are stop starting engines and plotters etc running all day. This gives their batteries a good kicking so it makes sense to fit the best. 

[Andy135]

19 minutes ago, KennyPowers said:

£180 for the blue sea add a battery vs a generic switch for £20 🤔you will get away with that in Alabama but that’s classed as rape in the UK🤣🤣🤣🤣

I think you're missing the point of the Add A Battery kit. The money is in the VCR module that manages the charge distribution. The switch is just the Blue Sea version of any other ON/OFF/COMBINE switch.

If you buy a generic switch you won't be installing any charge management hardware unless you also buy a VCR or other charge controlling diode.

[Geoff]

I have just fitted a VSR (£20 ish) and an isolator (about £8) which I think (hope) should do the job OK. Geoff.

[Andy135]

4 minutes ago, Geoff said:

I have just fitted a VSR (£20 ish) and an isolator (about £8) which I think (hope) should do the job OK. Geoff.

And it'll be how long til it gets used in anger?? 🤣

[Geoff]

Just now, Andy135 said:

And it'll be how long til it gets used in anger?? 🤣

I figure that so long as the boat remains on the trailer I shall have no battery problems. but I may install a small solar panel charging unit just to be on the safe side. Geoff.☺️

[GPSguru]

1 hour ago, KennyPowers said:

£180 for the blue sea add a battery vs a generic switch for £20 🤔you will get away with that in Alabama but that’s classed as rape in the UK🤣🤣🤣🤣

A decent 1, 2, Both, Off switch is £60 ish ............ mine is a BEP rated at 600A continuos, 800A peak ............. be very wary of cheap Chinese switches as their load contact rating is not that high .........

 

 

Edited December 5, 2020 by GPSguru

[Geoff]

I find that much of the electronic stuff sold in this country originates in China, Vietnam etc., whatever whatever the brand. Geoff.

[KennyPowers]

1 hour ago, Andy135 said:

I think you're missing the point of the Add A Battery kit. The money is in the VCR module that manages the charge distribution. The switch is just the Blue Sea version of any other ON/OFF/COMBINE switch.

If you buy a generic switch you won't be installing any charge management hardware unless you also buy a VCR or other charge controlling diode.

It will automatically switch from primary battery over to secondary when the primary reaches full capacity in charge, as opposed to me be using the primary to start engine and motor out, then switch over to secondary 

[GPSguru]

13 minutes ago, Geoff said:

I find that much of the electronic stuff sold in this country originates in China, Vietnam etc., whatever whatever the brand. Geoff.

 

Whilst that is true, there is a huge difference between a 'managed factory' product and a 'knock off' product ! , unless of course it comes from the same factory as the 'managed' product , and a good example of this is Spectra Braid and Shimano Power Pro braid ..... Spectra is a fraction of the price but equally as good, mainly because it is produced in the same factory, but without the fancy branding

Edited December 5, 2020 by GPSguru

[GPSguru]

1 minute ago, KennyPowers said:

It will automatically switch from primary battery over to secondary when the primary reaches full capacity in charge, as opposed to me be using the primary to start engine and motor out, then switch over to secondary 

I generally leave mine on both, unless I am at anchor for a long period (over  5 hours), then I switch to battery 2 as the house battery ...........

[KennyPowers]

1 minute ago, GPSguru said:

I generally leave mine on both, unless I am at anchor for a long period (over  5 hours), then I switch to battery 2 as the house battery ...........

Is it generally considered a modern 60hp 4 stroke outputs enough amps to recharge two battery’s at once? 

[suzook12]

2 hours ago, KennyPowers said:

£180 for the blue sea add a battery vs a generic switch for £20 🤔you will get away with that in Alabama but that’s classed as rape in the UK🤣🤣🤣🤣

£104 from pacer marine gor the 65A version