Dual battery project - Land Rovers Only

rover1st · 11-06-2006, 12:44 AM

Hi,
I found this Dual battery for defender nice project, do you know where I can get the switch?

Disco · 11-06-2006, 02:57 AM

This post will probably get me flamed, but I don't care cause I'm wearing my flame proof underwear. Personally I have found dual battery installations are a pain in the arse. I used to have such a system a few years ago and found that when one of your batteries dies, it dragged down and eventually kills your other battery. With great confidence you get into your truck, turn the key (usually out in the boon docks) and guess what. Click, click! Both batteries dead!

TerryS · 11-06-2006, 03:50 AM

That battery switch is available from any marine hardware supplier, like West Marine. I also see them at the local battery shop.
I agree with Disco, One bigassed battery is alot less trouble but in situations where extended slow drain is the norm, such as camping, fridge, inverter, it's nice to know you're not going to be looking for a jump come sunday afternoon.
Split charge circuits, Isolaters, etc will each work in some situations but can be fried in others. Batteries are sold based on size, both physical and amp hour capacity, and life expectancy. If you're going to run two batteries, get two new ones to start off with. If you go with the 1-2-BOTH type switch, only run in the both position when your in need of max current, such as winching. Charge them individually. alternate weekly or some such interval.

rover1st · 11-07-2006, 04:46 AM

thanks!

Den · 11-26-2006, 01:06 PM

I installed this type of dual battery system about 10 years ago as a backup when running an AC inverter and/or the winch. I haven't had an ounce of trouble from it. Actually, I've never been stranded with a failed battery - ever! Some pointers:

1. The Off-1-2-Both switch is installed on the Earth/Negative side of the batteries, so there are fewer "hot" contacts around to short-circuit (when you drop a spanner in the battery bay!). The Live/Positive battery poles are simply bridged instead.

2. When switching between batteries, do so through the 'both' position. Going through the "off" position will interrupt the power to/from the alternator and may cause some serious electrical problems.

3. Alternate between batteries about once every week. Try to switch over just after you've started the car for the first time in the morning. A slightly discharged battery will hold its charge longer, and is less likely to go bad, than one that is fully charged.

4. If possible, use only one battery at a time for inverters, winches and other accessories. I you "MUST" use both simultaneously, ensure that the motor is running so that you're not left stranded.

rover1st · 11-28-2006, 08:03 AM

I am not sure about the negative switch.
it means that your vehicle ground will be switched?
Also, in this picture:

you can see that the contacts are safe.

11-06-2006, 12:44 AM	#1 (permalink)
rover1st Member Join Date: Nov 2006 Posts: 4 Gallery: 0	Dual battery project Hi, I found this Dual battery for defender nice project, do you know where I can get the switch?

11-06-2006, 02:57 AM	#2 (permalink)
Disco Super Moderator Join Date: Dec 2004 Posts: 1,819 Gallery: 0	This post will probably get me flamed, but I don't care cause I'm wearing my flame proof underwear. Personally I have found dual battery installations are a pain in the arse. I used to have such a system a few years ago and found that when one of your batteries dies, it dragged down and eventually kills your other battery. With great confidence you get into your truck, turn the key (usually out in the boon docks) and guess what. Click, click! Both batteries dead! __________________ No hand signals, driver playing with his transfer Knob.

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11-06-2006, 03:50 AM	#3 (permalink)
TerryS Moderator Join Date: Aug 2004 Location: Bloomfield, CT If I died today, I lived there all my life. Posts: 2,182 Gallery: 0	That battery switch is available from any marine hardware supplier, like West Marine. I also see them at the local battery shop. I agree with Disco, One bigassed battery is alot less trouble but in situations where extended slow drain is the norm, such as camping, fridge, inverter, it's nice to know you're not going to be looking for a jump come sunday afternoon. Split charge circuits, Isolaters, etc will each work in some situations but can be fried in others. Batteries are sold based on size, both physical and amp hour capacity, and life expectancy. If you're going to run two batteries, get two new ones to start off with. If you go with the 1-2-BOTH type switch, only run in the both position when your in need of max current, such as winching. Charge them individually. alternate weekly or some such interval.

11-07-2006, 04:46 AM	#4 (permalink)
rover1st Member Join Date: Nov 2006 Posts: 4 Gallery: 0	thanks!

11-26-2006, 01:06 PM	#5 (permalink)
Den Member Join Date: Aug 2005 Location: Johannesburg, South Africa Posts: 41 Gallery: 0	I installed this type of dual battery system about 10 years ago as a backup when running an AC inverter and/or the winch. I haven't had an ounce of trouble from it. Actually, I've never been stranded with a failed battery - ever! Some pointers: 1. The Off-1-2-Both switch is installed on the Earth/Negative side of the batteries, so there are fewer "hot" contacts around to short-circuit (when you drop a spanner in the battery bay!). The Live/Positive battery poles are simply bridged instead. 2. When switching between batteries, do so through the 'both' position. Going through the "off" position will interrupt the power to/from the alternator and may cause some serious electrical problems. 3. Alternate between batteries about once every week. Try to switch over just after you've started the car for the first time in the morning. A slightly discharged battery will hold its charge longer, and is less likely to go bad, than one that is fully charged. 4. If possible, use only one battery at a time for inverters, winches and other accessories. I you "MUST" use both simultaneously, ensure that the motor is running so that you're not left stranded.

11-28-2006, 08:03 AM	#6 (permalink)
rover1st Member Join Date: Nov 2006 Posts: 4 Gallery: 0	I am not sure about the negative switch. it means that your vehicle ground will be switched? Also, in this picture: you can see that the contacts are safe.

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