Battery isolator...

[RoyP]

I'm pretty new to this, so please pardon my naivete...
I want to install a second battery in my wagon, to run electrical stuff, on some touring trips of unknown duration, I will need to run a laptop for a few hours a day, charge up a lot of photo gear each night, use a photo printer on occasion, run a fan in a propane heater some times, a regular fan sometimes, battery chargers for camp lanterns and misc. Gennerally, nothing enormous but lot's of litte things all the time. Then again, maybe a bed warmer (6 amp) on some nights. I think the simplest route to fill my needs is to get a deep cycle battery and connect it to my alternator and existing battery, using an isolator. My existing alternator is rated at 160 amps. Can anyone give me advice, and perhaps tell what you make of these products, or perhaps some others, and reccommend a battery, too...

http://www.e-marine-inc.com/products/alternators/isolators.html

http://www.powerstream.com/battery-isolator.htm

Thanks

 

[FishPOET]

This is what I use and recommend.

http://www.hellroaring.com/4wheel.php

 

[RoyP]

Thanks FishPoet. If I understand, based on this....:

"Hellroaring BIC FAQ - Our BIC-95150B and BIC-95300B units are the most current version. The BIC-95150B is suitable for the Auxiliary battery setup or the Start side isolation method. The BIC-95300B is most suitable for the Backup battery setup. "​

...it looks like I would want the BIC-951950B, to isolate my 2nd battery for non-engine starting loads. Is that what you use? If that's right so far, I have some follow up questions.
1) Is this plan overkill for me, or do I need a second battery? Whats a reasonable size (charging a laptop 4 hrs/day, charging several camera batteries, phone, and misc. each night, running a 6 amp bedwarmer at 50% some nights, possibly a 1.4 amp fan in a Heatsource some nights, or a regular fan some other nights, and I don't know what else... using a color photo printer sometimes.)
2) Is it appropriate to mount the 2nd battery and thisolator gizmo in a ventilated metal box on a rear cargo carrier? Can I combine functions and add a propane cylinder in the same box, and do I need to partition the inside into two compartments?
3) My vehichle alternator spec is for 160 amps, but the amp spec for the Hellroaring unit says max current 95 amps continuous, 150 amps for 20 sec, and 250 amps for 50 ms. I'm just copying numbers, I don't know what to make of any of that. Is it ok?
4) It seems there is to be a manual switch. What is that for?

Appologies again for being a complete novice. Any help will be appreciated.

 

[FishPOET]

it looks like I would want the BIC-951950B, to isolate my 2nd battery for non-engine starting loads. Is that what you use? If that's right so far, I have some follow up questions.

I have the 75150. It is my understanding that the updated versions have better resistors, but to be real honest electronics is a foreign language to me.

3) My vehichle alternator spec is for 160 amps, but the amp spec for the Hellroaring unit says max current 95 amps continuous, 150 amps for 20 sec, and 250 amps for 50 ms. I'm just copying numbers, I don't know what to make of any of that. Is it ok?

Probably the best connection method is to connect your starting battery only to your starter circuit. Then isolate this circuit from all other loads and your deep cycle battery using the BIC-75150A. A starting battery rarely accepts more than 60 amps from an alternator. The BIC-75150A can handle this very well. And since all your accessory loads and deep cycle batteries are connected directly to your alternator, you can use any size alternator! A 300+ Amp alternator will not affect the BIC-75150A battery isolator / combiner when connected in this way!

2) Is it appropriate to mount the 2nd battery and thisolator gizmo in a ventilated metal box on a rear cargo carrier? Can I combine functions and add a propane cylinder in the same box, and do I need to partition the inside into two compartments?

Do you realize the size wire you would have to run from the front of your vehicle to the rear to mount a 2nd battery on a rear cargo carrier? IMO If this is your only mounting option you should just carry a self contained battery booster.

4) It seems there is to be a manual switch. What is that for?

To hook both batteries together directly bypassing the isolator. (starting boost)

1) Is this plan overkill for me, or do I need a second battery? Whats a reasonable size (charging a laptop 4 hrs/day, charging several camera batteries, phone, and misc. each night, running a 6 amp bedwarmer at 50% some nights, possibly a 1.4 amp fan in a Heatsource some nights, or a regular fan some other nights, and I don't know what else... using a color photo printer sometimes.)

That is a decision only you can make. For me a 2nd battery brings peace of mind. I volunteer for the USFS and I can use my winch all day without fear of the Jeep not starting.

 

[ntsqd]

I use a simpler system.

One of these:
Marine Battery Switch

Combined with one of these:
Voltage Sensing Relay

I mount them right next to each other and attach the relay's two wires to the large studs on the switch. I can still self-jump start and should the VSR fail I can still charge the aux battery. More important to me is that aside from the battery cables it is only a two wire connection, and those wires are both short and do not need a hole into the cab. I like simple and compact. And the ~$125 total investment doesn't hurt either.

 

[socaljeeper]

With this system, would there be a problem of both batteries drawing off each other when it is switched to 1 & 2? The way it was explained to me is that once it is switched to dual mode, both batteries will equalize. Is this correct? With the hell roaring system, this will not happen.

I use a simpler system.
I mount them right next to each other and attach the relay's two wires to the large studs on the switch. I can still self-jump start and should the VSR fail I can still charge the aux battery. More important to me is that aside from the battery cables it is only a two wire connection, and those wires are both short and do not need a hole into the cab. I like simple and compact. And the ~$125 total investment doesn't hurt either.

 

[RoyP]

I have the 75150. It is my understanding that the updated versions have better resistors, but to be real honest electronics is a foreign language to me.

Updated transistors, ok. Foreign language, me too.

Do you realize the size wire you would have to run from the front of your vehicle to the rear to mount a 2nd battery on a rear cargo carrier? IMO If this is your only mounting option you should just carry a self contained battery booster.

I am driving a Volvo AWD cross country wagon. The battery is in the rear, right below the rear door, and adjacent to the cargo carrier.

To hook both batteries together directly bypassing the isolator. (starting boost)

I see

That is a decision only you can make. For me a 2nd battery brings peace of mind. I volunteer for the USFS and I can use my winch all day without fear of the Jeep not starting.

Ok.

Thanks for your help

 

[ntsqd]

With this system, would there be a problem of both batteries drawing off each other when it is switched to 1 & 2? The way it was explained to me is that once it is switched to dual mode, both batteries will equalize. Is this correct? With the hell roaring system, this will not happen.

Long term if there is any resistance in the hot and ground side cabling and they are connected directly together then the batteries can spiral into a self-discharge mode. It does not happen at a very fast rate, even connected together for a couple of days shouldn't be a problem unless there are other problems in the system.

In normal operation it is not a problem as the switch is set on either "1" or "2", not "both" and neither battery can 'see' the other. Then the only method of connecting both batteries directly together is through the VSR, which disconnects when the charging system stops charging and does not re-connect until the primary battery (i.e. the battery that it is not connected to directly) has reached a full charge state.

The only instances that I can see where you would set the switch to "both" is winching or being need of a jump-start. In those cases you'll likely already have the hood open.

RoyP,
Does the Volvo have the disconnector in one of battery cables like the BMW wagons (with the battery in nearly the same place) do? If so that may present a problem that needs some thinking. The goal of that lump on the cable is to disconnect the battery when the airbag system sees a blow to that region of the car. What ever you do will probably want to maintain that functionality.

 

[RoyP]

Long term if there is any resistance in the hot and ground side cabling and they are connected directly together then the batteries can spiral into a self-discharge mode. It does not happen at a very fast rate, even connected together for a couple of days shouldn't be a problem unless there are other problems in the system.

In normal operation it is not a problem as the switch is set on either "1" or "2", not "both" and neither battery can 'see' the other. Then the only method of connecting both batteries directly together is through the VSR, which disconnects when the charging system stops charging and does not re-connect until the primary battery (i.e. the battery that it is not connected to directly) has reached a full charge state.

The only instances that I can see where you would set the switch to "both" is winching or being need of a jump-start. In those cases you'll likely already have the hood open.

RoyP,
Does the Volvo have the disconnector in one of battery cables like the BMW wagons (with the battery in nearly the same place) do? If so that may present a problem that needs some thinking. The goal of that lump on the cable is to disconnect the battery when the airbag system sees a blow to that region of the car. What ever you do will probably want to maintain that functionality.

Attached below are pics of my existing battery compartment; the wire from each terminal goes to that white raceway and exits the pic to the upper right, presumable to the engine compartment. A second wire from the left terminal goes towards the rear bumper... I don't see any thing like a disconnect re: the air bags, but who knows, it could be anywhere along the way. Maybe I have to ask a Volvo mechanic.

Here is my mechanical pod concept sketch:

Also, some pics showing the rig and the "lunar module" folding minibike ,that will also go on the cargo carrier:

New pics attached below