Back-up Battery

[Mek-a-nik]

As some may know, I use a step van in my mobile small engine business. I have some work lights and a winch which are 12 volt. I have to be careful how much current I use when sitting somewhere with the engine off so that I can get started.
A couple years back, I saw somewhere, a set-up that entails two batteries. One is used for lights, etc., with engine off, the other is used for starting. Then while driving, both batteries are recharged, thus ensuring the engine states.
I can't remember what it was called, or where I saw it. Anyone know what I''m looking for?

[okie]

A lot of RVs are built this way. Maybe if you have a RV supply nearby, they could help.
I fell sure that that KE4AVB could tell you how to build one but you may want a store bought unit. (Not having time to build it yourself)

Travis

[grunt]

Mek-a nik, they are called battery isolators. I used this twin battery setup for many years on a truck I snow plowed with. As okie stated, an Rv supply or Amazon for a unit.

http://www.amazon.com/s/?ie=UTF8&keywor ... oc6znbvo_e

[bobodu]

Or boat dealers.

[Mek-a-nik]

That's it! I knew that you knew that I knew what you knew!
I wish I would've thought of this in the slow season. It ain't gonna happen till I slow down some now.
Thanks, Gents.

[Arkie]

Napa auto supply sells isolators. (several on ebay/

They start at around $40 at Napa. The rating needs to be at LEAST the size of your alternator output and the higher the isolator amp rating the higher the cost normally. Their are also types for 3. 4 Auxillary batterys.

Here is one on ebay that is for 2 batteries, 171755509135 Your engine battery and one aux battery. This is the solid state type and it wires into your alternator output. Keep all wiring safely installed because if a wire get shorted their are no fuses involved and you will have a major melt down.
It allow the aux battery to be completely discharged and the main starting battery will still be isolated from the Aux and the vec can be started and the aux battery will charge when the main battery is charging.

Here is the ebay link. http://www.ebay.com/itm/COLE-HERSEE-BAT ... 8f&vxp=mtr

Their are relay types, but this solid state diode type has not moving parts and is more user friendly and will last forever if no short circuits.

[Mek-a-nik]

Thanks Arkie. I was just looking into the amperage rating and the diode versus solenoid designs when you posted. I plan on installing a larger alternator to go with the electric cooling fan I plan on adding. It's only about 60 amps now. It's a 40 year old Chevy step van. So, I guess all of this will have to wait til next winter. I use the truck a lot during "the season".

[bobodu]

60 amps should be plenty if you use the truck a lot....Here's what ya need !!
That will burn 1/8 inch rod ALL DAY at 140 amps.

[Arkie]

Agree that your 60 amp alternator should be great. The larger alternators (Delco Remy for example) usually have a larger case and mounting arrangement and won't just bolt on, could be a real challenge getting one one bolted onto a van engine with limited access anyway.
Just make sure the diode type isolator is rated at least 60 amps (size of your alternator), 100 amps isolator or more will be even better and run cooler. Mount the aluminum fin isolator under the hood, firewall area so as the fan air will blow across the aluminum heat sink. Very high heat and short circuits is what will ruin one. I've never had any of the solid state type go bad

Several vec's (Ford F100s) for instance had 35 amp alternators even with A/C, etc and I used 40 amp isolators on them 70's fords with aux battery and no problems with the alternators or isolator.

That's a neat welder/bat charger in the pic. I've rigged those few years ago and also used them as back woods battery chargers when camping/fishing and needing to charge the trolling motor battery as fast as possible and no utility power available. The on board battery is the exciter bat to get er started genning. I have some of that eq with no belt guards that I'm the only one that operates, It gives me an excuse to not loan the eq. (my existing dogs, cats and chickens get a heads up and stay away when my redneck eq starts running. One of my good mouser cats only has 1/2 a tail.

I've gradually started using Solar cell trickle chargers (watch for them on closeout sales) on some of my old riding mowers/tractors and vec's that I don't start up very often (especially on mowers and tractors in the winter) and the solar cell keeps them ready to crank, instead of looking at a dead battery.

[Mek-a-nik]

I haven't looked into it yet, but I thought that cooling fans draw a lot and need more amperage. Maybe something like this: http://www.summitracing.com/parts/sum-810340

How many amps is that alternator, Bo?