twin battery

[majorbow]

please can some one tell me how to fit a extra battery so that i can change over from 1 battery to back up and what i would need to do this i have a 2010 785 s rib eye and will 70a battery be ok many thanks.

[ChrisMW]

Hi

I did this fairly recently.

I used a battery switch like this one: Marine Battery Isolator & Changeover Switch Marine Battery Isolator & changeover switch. Rated 175 amps at 12 volts, 300 amps for 5 seconds. Selects between batteries 1, 2, both or Off. Auto & Marine Electrical > Battery Switches

Also a Voltage Sensitive Relay (VSR) like this: Voltage Sensitive Relay for Dual Battery Charging 140 amp *SPECIAL OFFER!* 1 x Voltage Sensitive Relay for Dual Battery Charging.<br> Load: 140 amp<br> Voltage: 12 volt<br> Cut In;: 13.3 Volts<br> Drop Out: 12.8 Volts<br> This Voltage Sensitive Relay

The VSR will connect the batteries in parallel only when the alternator (or battery charger) is switched on. This means that both batteries will remain topped up and ready for use rather than just the battery that is currently selected via the switch.

If batteries are connected in parallel without a VSR and one of them is has less charge than the other I've been informed that it will charge itself from the stronger battery which is very bad for them.

I can send you the wiring diagram I used if it would help?

Regarding the size of the battery, try and find out the Cold Cranking Amps (CCA) rating as this can be a bit more relevant than the ah. For instance our 115hp optimax requires a huge 800CCA. Also try to go for a sealed marine version as I've found these to be better than unsealed car batteries.

I've just gone for a lovely Numax ?CXV27? battery with 900CCA and 113ah which really seems to be making a difference.

Hope this helps

Chris

[majorbow]

Cris many thanks

[Miller]

Could I get hold of that wiring diagram? I m just about to undertake a twin battery installation and any help would be appreciated.

[Jamesg514]

I would like a copy of this as well if possible.

James

[Oscarguitar]

Try this link

716-V-100AVSR - Single Engine, Two Battery Banks

I installed this a couple of years ago with 2 x AMG batteries (Odessey) and faultless so far.

Links to fitting instructions and wiring on the page

[Crusher]

Having just killed my twin batteries (operator error DOH) I was very surprised when I removed them to find they were leisure batteries!!
Just what batteries is everyone using for their boats?..........

[martini]

Everyone's got their own view but a lot on here inc me use cheap leisure batts as we find that you're lucky to get more than 3 or 4 seasons out of any battery. You might get a bit more on average with an expensive marine battery but not enough to justify the extra cost.

Sent from my portable speaking device using Rib.net

[Oscarguitar]

These take some beating, but pricey. Depends on the set up. As Martini says you could buy a couple (3!) of cheapies for the cost of one of these, but I haven't found a way to bump start my boat and don't want to hear that click, click, click of the solenoid when I have had the cooler, music, lights, plotter, VHF fired up all day!!

Power Store

[hobbit555]

Maintenance free batteries = 2 to 3 years of service

Batteries with openable cells + regular maintenance = many years service

Just looked at receipt for the last boat batteries I purchased and it's 7 years so far

[ashbypower]

Originally Posted by hobbit555

Maintenance free batteries = 2 to 3 years of service

Mmm intresting Statement, just changed one this week, 11 Years Old !!!

[A1an]

If you treat a battery CORRECTLY it should do you a damn sight more than a couple of years.

The biggest mistake people make is thinking that because a battery is left fully charged at the end of the season itl STILL be fully charged come the next.

Even "maintenance free" batteries need some sort of maintenance charge during the winter months

[ChrisMW]

Originally Posted by Miller

Could I get hold of that wiring diagram? I m just about to undertake a twin battery installation and any help would be appreciated.

Originally Posted by Jamesg514

I would like a copy of this as well if possible.

James

I've had a look and I've got it saved as a pdf. If you PM me an email address i'm happy to send it over if you think it might help.

Chris

[guernseylee]

Originally Posted by Oscarguitar

Try this link

716-V-100AVSR - Single Engine, Two Battery Banks

I installed this a couple of years ago with 2 x AMG batteries (Odessey) and faultless so far.

Links to fitting instructions and wiring on the page

ec smith are uk agents

Electrical Products, Battery Switches from E C Smith & Sons UK Marine Supplier