I'm looking for some input on choosing a dual battery (auxiliary battery) control system for my '02 6.8.

As it stands for me now I have (sitting on the shelf on standby) a Painless part#40102 - 250 Amp Dual Battery Current Control System. When I purchased it I was convinced that it was the way for me to go trusting it was one of the better options for my needs.

Now I'm second guessing myself (what else is new).
It seems that Painless recommends using the MAIN battery for accessories (winch, audio equipment, etc,,,). I have always thought that using the auxiliary battery for accessories was the prefered method to draw power from.

Can any of you old pros shed some experienced light on this for me. Am I going to be ok with the Painless 40102 and trust using the main battery for accessories,,, or should I be looking for a different product that supports drawing power for accessories from the auxiliary battery?

Accessories I'll be needing it for:
Winch-12000lbs or 15000lbs / Power hungry audio&video system / fridge / off road lights.

I already have 2 Optima Yellow Tops ready to go and will be ordering a Wrangler auxiliary battery tray soon.

Rick...

 

Painless def makes some quality electronic products for aftermarket projects!
My buddy ran this kit in his Suzuki Samurai to keep his winch happy

 

Have you seen this yet?

http://www.colehersee.com/pdf/hot_fe...BatteryIso.pdf

 

IMO, the HD continuous duty solenoid is far and away the best way to couple two batteries. The ones used by Painless and ColeHersee are both very, very good so I would definitely use what you have.
The solid state isolators using diodes just waste to much energy for me.

Which battery to attach accessories to depends on how you're using the dual batteries.
Obviously, you absolutely want the engine to be running and using the output from the alternator when you are applying ANY serious electrical load.
The battery is nothing but a stop gap to keep things going VERY temporarily when the alternator is not available or inadequate.

For me, I keep BOTH batteries in parallel and on line almost all of the time. The only time they are not is when I want to take one off line to preserve it for restarting.
Like when operating stereo or lights for a long time with the engine off, or when I know I will be using winch hard and then shutting engine off immediately and not giving batteries time to recharge. Both are bad idea, but happen from time to time.

Therefore, I attach everything to primary battery. Since they are connected together 99.9% of the time, both batteries are sharing the load. When I (very rarely) isolate, I want NOTHING drawing off the reserve. That keeps it in reserve.

 

Oh, and I ALWAYS recommend adding an accurate volt meter! I use Datel units because they're simple, accurate, and durable. If your stereo/lights/fridge regularly pull your operating voltage down under 13.2 volts or so, you need to upgrade the charging system.
The winch will draw the batteries down, but the winch will be very intermittent use. Give the alternator at least 15 minutes to replace every 1 minute of use and you should be fine.

 

bp & mws,

bp,
Thanks for the link. The Colehersee looks slick with its almost full automatic system with only the boost button to mess with when needed. But I feel better protected with a manual system. It's nice to learn about the product though. I wouldn't be surprised if ended up using the Colehersee in the future.

mwsm,
Very informative information. Thanks for taking the time to set me straight.
I'm more than comfortable now sticking with the Painless system I have.
It sounds like (and makes perfect sense) I should use two volt meters (one for each battery). I always have my ScangaugeII showing volts along with a Cyberdyne Digital Voltmeter w/memory but I think I'll have to go with two Digital meters now. The Scangauge will not work properly reading the batteries individually.
I like the look of the Datel gauge you mentioned. I just might go with them if I don't decide to simply pickup another Cyberdyne.

RE: Alternator,
I do have a 200amp alternator in the truck now, but I've been thinking I should be looking at a minimum 250amp unit to help keep me out of trouble when up in the mountains.
I'll be posting a question for recommendations of alternators soon. I have a list of possible manufacturers I'd like to get some input on.

Rick...

 

mws,

The Datel meters do look nice. Very small. Those should actually work/fit nicely in the dash for me.

Which Datel unit are you using for your batterires?
(1/10 volt resolution / 8.0 - 50.0 VOLTS)
or
(1/100 volt resolution / 8.00 - 19.99 VOLTS)

The 8.00-19.99 volts would be fine for my needs. I don't see any reason to have the 8.00 - 50.0 volts.

What would the 8.00-50.0 volts be used for? (just curious)

What does the term Resolution mean for these meters? I've never heard the term used with volt meters.

Rick...

 

On a digital meter, resolution would be the difference between showing 13.2 volts, or 13.24 volts. The first is 1/10 volt resolution, the second is 1/100 volt. You obviously don't need 1/100 volt resolution, but it can be useful to monitor how fast a battery is depleting. I have a 1/100 volt in my travel trailer, but I would be just as happy with less resolution. However, with the 1/100 volt, I can see the difference in draw from an LED lamp versus an incandescent. So it is marginally useful.

 

The 1/100 gives a more detailed voltage reading/breakdown.

Simple enough.

Rick...

 

BPounds gave you the answer you needed.
I usually go with the higher resolution (.01 V), but I will point out that the last digit is usually fluctuating wildly when under signifant loads and/or engine running.... Some prefer to not see that digit to avoid the annoyance factor.

And why 8-50 V? Datel's main market is industrial monitoring equipment, and many systems there are not limited to 12 V. Also, the nature of meter technology is that the accuracy works out to be a percentage of the range. So you can have a meter with wide range and less accuracy/resolution, or a "fine tuned" mete with narrower range and more accuracy/resolution.

 

You have a 200 amp alternator now? I would be surprised if you need more.... That's almost 3000 watts and should power the fridge and whole bunch of lights! Put in the voltmeter and see if you really need it.
As current/power output goes up, the load gets heavier and belt/pulley slippage can get to be a problem. That's why most systems go to dual alternators when demand goes much over 150 amps.
I had a 250 amp on my tow van and it would squeal like a stuck pig when under full load unless I kept a fresh belt AND spray on dressing on the belt (8 rib on Chevy). Fortunately, it almost never needed full output. Just kept a can of dressing under the seat.

 

You seem like you want to learn as much as possible, so I'll share another tip:
Optimas are very, very good batteries and there is nothing "wrong" with them. They feature all the benefits of AGM technology and are widely available and mass produced which allows for decent pricing, but the cute spiral wrapping means a lot of wasted space in the case - which means less total plate surface area and less total capacity. You'll notice it's almost impossibe to find Amp-hour capacity figures for them. It's not so good. Maybe 50-60% of normal wet acid.

Myself, I am a total fan of Odyssey batteries. Not cheap and industrial based sizing can make it a bit trickier to fit... But they are even more durable and the capacity is usually MUCH greater than Optima. 1 Odyssey may equal two Optimas. Check them out for future applications:
Odyssey Batteries

 

Subscribing. Great topic.

 

mws,

I do have a Cyberdyne digital volt meter and my ScangaugeII also reads volts for me.
The Cyberdyne meter is a cheap unit. I tend to trust the ScanGauge over the Cyberdyne gauge. The Cyberdyne always reads a bit lower than the ScanGauge, but they pretty close to eachother.

It's been awhile since I tested, but from memory:

At Idle:
- Head Lights on high beam with the fog light mod (fogs on with high beams) and clearance lights.
- Heater fan on high
- Interior lights on
- Brake lights on
- Stereo cranked up pretty good (seperate amps. MTX-Thunder 404 for speakers & 421D for the dual subs)
- Power windows (two at a time) randomly running up and down.
- DVD player running both rear displays (video only)
- 400watt inverter plugged in running cell phone charger and laptop.
- NO FRIDGE or WINCH

I've never heard even a slight squeal from the belt. But in saying that I keep them pretty fresh. I've been changing them when they started to look even a bit worn. Needless to say I have a couple of used spare belts I keep in the parts box for the mountain trips.

The ScanGaugeII would drop to approx: 13.4 / 13.6volts

Would you consider that acceptable or maybe I should be considering a 250amp alternator?

Rick...

 

The problem I think with most bigger alternators is they need like 1500-2000 RPM to reach the higher output. I've been searching for a way to do a high idle on the 2v V10 but they only thing I found so far has been this.

http://www.penntexusa.com/IdlerAppGuide.pdf

To bad it's only for the E. Might be a way to make it work with the F though.