Running electronic's off my van's stock 12 volt hookup's.

[FreeBird]

I apologize if this is a dumb question but my van already has plenty of 12 volt hookup's, if I install a house battery(s) and a switch to go between my starter battery and my house set-up, will using the stock 12 volt hookup's still run off my starter battery even if it's switched to use the house battery set-up?

Much Appreciated.

Chris

 

[PastTense]

You need the right kind of electrical setup.

Here are explanations:
http://www.rv-batteries.com/construction.php
http://www.fridge-and-solar.net/dual_bat.htm

 

[highdesertranger]

basically no. you have to physically rewire the outlets to the house battery. highdesertranger

 

[FreeBird]

If you use a switch such as one used on boats this should work for switching the whole electrical power for the van. There are several types but they allow the use of battery 1, battery 2, both batteries in parallel or both batteries off. This setup will not allow you to split the load between the batteries unless you hard wire (and fuse) them to the house battery as highdesertranger said.
http://www.wholesalemarine.com/perk...systems.html?gclid=COby6rCvj8ACFZTm7Aod8kYAxw
http://www.boatingmag.com/how-to/how-to-install-marine-dual-battery-system

Guy

Great info gsfish, I'll check with an auto electrician first but if what your saying is right, that would be quite awesome, thanks given.

 

[akrvbob]

I'm a big fan of A-B switches (commonly called that because you can switch between battery bank A or B or off). It's cheap and easy and works well.

But it has two disadvantages:

1) It depends on you to remember and some of us don't do that well. If you have it between the house and starting battery, forgetting can mean a dead starting battery.
2) You should not ever turn the switch with the engine running. It can send a spike through the van that does some severe damage to your electrical system.

If you can avoid those two drawbacks, it's a very good idea.
Bob

 

[Zil]

Switching while the engine is running could cause damage to the alternator as well.

 

[highdesertranger]

some of the switches have an extra terminal to connect to the alternator that allows you to switch while the engine is running. highdesertranger

 

[Zil]

".....could..."

 

[SternWake]

Turning an A/B switch with the engine running is OK

IF.... the switch is a make before break. Most are.

AND, as long as the switch is not turned to OFF with the engine running.

Most switches are make before break, meaning when switching from battery 1 to both or from Both to battery 2 it makes contact with the next battery during the change before losing contact with the previous setting.

Turning the switch to OFF with the engine running can indeed fry the alternator, and perhaps some vehicle electronics too as removing the battery means removing a portion of the load from the alternator and voltage spikes during this event can be extreme, and more so if the battery was depleted and sucking a lot of juice from the alternator when the load (depleted battery) was removed.

As mentioned some manual AB/Both switches come with an alternator field disconnect. This feature can only work on alternators that are externally regulated, as many makes of vehicles have the voltage regulator inside the alternator.

One of the two field disconnect wires coming from the voltage regulator must run to the smaller contacts within the switch. When this is done and the switch turned to off the alternator will also be told to make No juice. But this is no guarantee that the engine will stay running nor that something else will not release the magic blue smoke.

I've been using AB/Both switches since 2001, and turn the switch every day with the engine running. I just make sure to not switch it to OFF with the engine running.

Also switching it to OFF with the engine not running erases the engine computer memory, and it runs crusty for a few miles while the computer relearns the engine.

Any secondary battery system is going to require that the loads, lighting, ciggy plugs, ect, be required to take power from the second battery to be effective. Some conversion vans will just have a fuse block for most of the rear lighting, and sofa bed, TV/VCR, and one can just move this fuse block wire to the house battery, fused again at the house battery, but the stereo and dome lights will still draw from the main engine battery, so their use can still deplete the engine battery. I left my dome lights(LED) on the engine battery, but the stereo is wired directly to the house battery.

A?B switches do require the operator to remember to combine with the engine running to charge, and separate after engine shut down, and this might not be a wise Idea in this day and age where people expect everything to read their minds intent. No, there is No App for that.

A/B/Both switches are just one of many methods to allow battery isolation while stopped and the alternator to feed both batteries when driving.

 

[Zil]

awful amount to go wrong for an inexperienced operator.

 

[SternWake]

If remembering to NOT turn the switch to OFF with the engine running is too much to ask, then perhaps such a person should not have a driver's license in the first place.

NOW, inadvertently turning the switch the wrong direction is another matter. I've done this after changing to a different brand of Switch that had "Both" in the 6 oclock position where as my previous model had it in the 12 o'clock position.

But this was on my manual switches for my loads or solar, not my Ignition. I am more careful when moving my Ignition Switch.

For the price of a good manual switch, one can get a CD solenoid, and wire it to be automatic, or have it wired to be automatic as the case may be. The important part is using thick cabling between alternator, solenoid and 2nd battery so that shorter drives stand a better chance of getting the battery back upto ~80%, or higher as soon as possible.

Far too many people kill their batteries by thinking their alternator can do in short drivers what it cannot do in long drives. That 15 or 30$ saved on cabling can cost hundreds of dollars in failed batteries that were never recharged properly.

 

[Zil]

yes i agree. modern automobiles are much too easy to drive.