Battery Isolator Vs. Battery Solenoid ?

[Fish Chris]

Well first off, I have used a battery isolator, back in the day, for the regular truck battery in the front, and the dedicated stereo battery in the back. Worked great. I could pound on my system until the amps started shutting off, hit my ignition, fire the truck right up, off of the front battery which had been untouched, then charge the rear battery for how ever long it needed, and it was all good.

And btw, I do like to be able to sit parked here and there, and listen to the stereo for 30 minutes to an hour, at moderate to high levels........

However, the three amplifiers I used to have, wouldn't have drawn as much power as my RF power 1000 will now. Plus, I have heard that isolators will cause a drop in voltage to the auxillary {stereo} battery. Well obviously the last thing I want is a drop in voltage, before I have even drawn the first little bit of power !

{oh, and logically speaking, the fact that isolators have cooling fins makes it obvious that they are losing some power in the form of heat energy}

So, I need to know the full scoop with running solenoids. How do these work ? Would they keep my regular vehicle battery from being drawn from by my amplifier ? Are their different ways they can be set up ? Are their different power handling solenoids available ?

Would this one work for me; Doh ! ...... I thought this was a solenoid.... but it says "Relay / battery isolator" ??? .....but no heat cooling fins ? http://www.sonicelectronix.com/item_5287_PAC+PAC-200.html

What the difference between that one, and this one; {this was the kind I used before} http://www.rvpartscenter.com/ProductDetail...131&CID=395

In fact, now that I'm looking, I can't even find a straight up battery solenoid for car audio ?

Help please !

Peace,

Fish

[MECHMAN]

Well first off, I have used a battery isolator, back in the day, for the regular truck battery in the front, and the dedicated stereo battery in the back. Worked great. I could pound on my system until the amps started shutting off, hit my ignition, fire the truck right up, off of the front battery which had been untouched, then charge the rear battery for how ever long it needed, and it was all good.

And btw, I do like to be able to sit parked here and there, and listen to the stereo for 30 minutes to an hour, at moderate to high levels........

However, the three amplifiers I used to have, wouldn't have drawn as much power as my RF power 1000 will now. Plus, I have heard that isolators will cause a drop in voltage to the auxillary {stereo} battery. Well obviously the last thing I want is a drop in voltage, before I have even drawn the first little bit of power !

{oh, and logically speaking, the fact that isolators have cooling fins makes it obvious that they are losing some power in the form of heat energy}

So, I need to know the full scoop with running solenoids. How do these work ? Would they keep my regular vehicle battery from being drawn from by my amplifier ? Are their different ways they can be set up ? Are their different power handling solenoids available ?

Would this one work for me; Doh ! ...... I thought this was a solenoid.... but it says "Relay / battery isolator" ??? .....but no heat cooling fins ? http://www.sonicelectronix.com/item_5287_PAC+PAC-200.html

What the difference between that one, and this one; {this was the kind I used before} http://www.rvpartscenter.com/ProductDetail...131&CID=395

In fact, now that I'm looking, I can't even find a straight up battery solenoid for car audio ?

Help please !

Peace,

Fish

Battery isolators and relays are a good way to toast your alternator. By allowing one battery to be run down completely dead, and firing up the vehicle, the relay will swith over to the dead battery and cause the alternator to run wide open untill the dead battery comes up. This causes a lot of heat buildup in the alternator, and reduces the life of the alternator. Depending on the regulator circuitry that is used on the alternator, the under-load switching of the relay can take out regulators also. If the secondary battery bank is big enough, it can melt the alternator in a single charging cycle. The better long-term solution is to just parallel all your batterys together, install a switched voltmeter that you can monitor while the vehicle is parked, and simply start the vehicle up when the batteries start to fall below 12 volts.

Just my $.02

[Kranny]

Battery isolators and relays are a good way to toast your alternator. By allowing one battery to be run down completely dead, and firing up the vehicle, the relay will swith over to the dead battery and cause the alternator to run wide open untill the dead battery comes up. This causes a lot of heat buildup in the alternator, and reduces the life of the alternator. Depending on the regulator circuitry that is used on the alternator, the under-load switching of the relay can take out regulators also. If the secondary battery bank is big enough, it can melt the alternator in a single charging cycle. The better long-term solution is to just parallel all your batterys together, install a switched voltmeter that you can monitor while the vehicle is parked, and simply start the vehicle up when the batteries start to fall below 12 volts.

Just my $.02

bingo, hit it right on the head.

[Fish Chris]

Man, I really appreciate you guys replies....... But that just sounds really crappy to me. If my alternator can't handle it, I'll need a bigger / better alternator.

I really don't want to be bothered with watching a voltage meter. I had said that my Power 1000 will draw more power than all 3 of my amps, back in the old days did..... But ya know, come to think of it, probably not a whole lot more. Certainly not double.

Granted, I killed all kinds of stock alternators (crappy little 90 amp stockers for a Chevy S10) Then stepped up to an alternator out of an old Caddy (like 125 amps or so. It lasted longer.... maybe 6 or 9 months before it finally went. So then I had that one rebuilt by an old alternator pro. Don't know what all he did to it, but it came out to like just under 200 amps..... and it never failed again (probably 5 more years of pounding).

Not to mention all of the conflicting info I keep hearing about mixing batteries, and battery sizes......

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Tell you guys what, if I could afford it, I'd really like to just run another alternator, entirely, and not even have to touch the vehicles existing electrical system at all....... but even so, I "need" to be able to run my stereo battery(s) down to the point that the amp(s) shut off (not every time, purposely, but just in case I'm having a good time, and get carried away once in a while) and then fire the vehicle right up, and charge the battery(s) with no problems...........

Hmmmmm,

Fish

[missinglink]

Battery isolators and relays are a good way to toast your alternator. By allowing one battery to be run down completely dead, and firing up the vehicle, the relay will swith over to the dead battery and cause the alternator to run wide open untill the dead battery comes up. This causes a lot of heat buildup in the alternator, and reduces the life of the alternator. Depending on the regulator circuitry that is used on the alternator, the under-load switching of the relay can take out regulators also. If the secondary battery bank is big enough, it can melt the alternator in a single charging cycle. The better long-term solution is to just parallel all your batterys together, install a switched voltmeter that you can monitor while the vehicle is parked, and simply start the vehicle up when the batteries start to fall below 12 volts.

Just my $.02

This ^ x2

Without some sort of current limit, it is a very bad plan to just connect a nearly dead battery to a fully charged one.

On some EMS vehicles an isolator is used, with a relay to connect an isolated (and fully charged) batttery to the starter for emergency starts. As you already mentioned the isolator has a one volt (or more!) drop at high loads, and helps to serve as a current limiter. Even so, those emergency vehicles occasionally dump an alternator shortly after an emergency start.

We ask a lot of an alternator already, and adding several batteries was never on the original designer's mind. Upgraded alternators, additional alternators, and good battery managment are all things to consider when designing a multi-kilowatt system.

'Link

[Fish Chris]

Hey Link, I totally hear you, and the others, and I don't want anyone to think I disagree with you guys. On the contrary, I know your right.

It's just that I "need" to be able to pound on my system for 30 minutes, or an hour, with the truck not running.... then be able to charge that deep cycle back to full, on a fairly regular basis.

So what do I have to do / purchase, to make this happen ?

Do any of the super upgraded alternators have chips or circuitry which can handle this kind of thing better than a stock alternator ???

Hmmmm.

Fish

[raytard]

buy gas, and keep the truck idling

an isolator or whatever is fine and dandy, but its meant so the tv in your rv doesnt kill the starter battery, if you put one in you:

-get a current limitation and voltage drop

-give your tame system the ability to overload your power wire

-spend unnecessary cash on a device you dont need

-make your system more complex, and we all know to keep it simple

-put undue stress on the alternator

-draining a battery that low generally lowers the life and maximum voltage/reserve by destroying the plates

-operating your system at "moderate to high" levels while your current drops, which cant be good for the amps

just dont use it, leave your car idling

[missinglink]

Hey Link, I totally hear you, and the others, and I don't want anyone to think I disagree with you guys. On the contrary, I know your right.

It's just that I "need" to be able to pound on my system for 30 minutes, or an hour, with the truck not running.... then be able to charge that deep cycle back to full, on a fairly regular basis.

So what do I have to do / purchase, to make this happen ?

Do any of the super upgraded alternators have chips or circuitry which can handle this kind of thing better than a stock alternator ???

Hmmmm.

Fish

First, you can start with a little more info about the vehicle you want to do this with. Year/Make/Model/Engine. Number of batteries. Number & type of alternators.

Are you willing (and able) to install additional alternators?

Your three basic choices are:

1) A dedicated alternator with thermal managment for the depleted battery bank

2) A current limit resistor and relay for charging the depleted battery bank.

3) A dead loss system that you recharge from a 110v charger when you get home.

Charging through a current limit is simple & cheap, but may require longer to charge than you are willing to wait for. I would hold the current below 30 amps, which means a long drive to full charge.

A lot depends on your battery bank size, and charging capacity.

'Link

[Fish Chris]

Okay Link, my truck is an 08' F150 Supercab, with a 5.4L V8. The stock alternator is not too bad, as far as stock alternators go. 130 amps I believe.

I'd like to run the stock battery (nothing special) for the factory electrical system, for the truck itself. For the stereo, I'd like to run one, really big, heavy duty deep cycle... like a group 31, or, a couple of medium sized ones... maybe a couple of group 27's.

Am I "willing" to run multiple alternators ? Sure..... but not right off the bat. I have about $4000 worth of other stereo related stuff to think about first.

"Am I able" to install an additional alternator ? Me personally ? Hell no ! Wouldn't even consider it. Which is why its a good thing that I have a buddy who is a mechanical, and automotive electronic genious, to do all of that kind of stuff for me :-)

Anyway, I think I like this idea to start out with

2) A current limit resistor and relay for charging the depleted battery bank.

And then, maybe a bit later, this

1) A dedicated alternator with thermal managment for the depleted battery bank

BTW, where should I start looking for a "current limiter" ?

Oh, and BTW, what if I were to just replace my stock alternator, with an upgraded one... aren't those tougher / able to take the slam from charging drained down batteries, better than the stock alt ?

Thank you,

Fish

[missinglink]

Okay Link, my truck is an 08' F150 Supercab, with a 5.4L V8. The stock alternator is not too bad, as far as stock alternators go. 130 amps I believe.

That truck is a PCM controlled alternator. The stock alternator communicates with the PCM across the CAN bus.

I'd like to run the stock battery (nothing special) for the factory electrical system, for the truck itself. For the stereo, I'd like to run one, really big, heavy duty deep cycle... like a group 31, or, a couple of medium sized ones... maybe a couple of group 27's.

For repeated cycling look at a bank of golf cart batteries. They are made to be used like that, and 4 or 6 of them would give you a lot of capacity. Flooded cells, you must mount them outside of the cab...

Am I "willing" to run multiple alternators ? Sure..... but not right off the bat. I have about $4000 worth of other stereo related stuff to think about first.

"Am I able" to install an additional alternator ? Me personally ? Hell no ! Wouldn't even consider it. Which is why its a good thing that I have a buddy who is a mechanical, and automotive electronic genious, to do all of that kind of stuff for me :-)

He will need some good fabrication skills, that vehicle is not an easy one to add alternators on.

BTW, where should I start looking for a "current limiter" ?

You need a really effing big resistor. A 1 ohm, 400 watt unit should be just about right (cough). Probably easier to use a couple of 2 ohm 200 watt units in parallel - 3 units at the most. That would put you in the .6 ohm range. Roughly 20 to 30 amps out @ 14.7v input. They will get warm, don't bolt them to your gas tank...

2.0 ohm 200 watt resistor

Oh, and BTW, what if I were to just replace my stock alternator, with an upgraded one... aren't those tougher / able to take the slam from charging drained down batteries, better than the stock alt ?

Thank you,

Fish

Well, one alternator builder (mechman) just told you "nope". We don't make alternators, but have tested plenty. Many do not live up to the wild claims from the sellers. If you plan to slam the alternator with a load like that, tell your alternator vendor up front - and get his approval in writing.

Your stock alternator location will mate with a 3G / 4G or 6G unit. If you put an HO unit in there, make sure it is compatible with the PCM control in your truck. You should have a 6G in it now, rated at 105 amps.

A HO 6G can be built by a reputable builder to give you 140 to 200 amps reliably. It is important that you know the continous rating of the alternator @ 14.7 volts. a "300 amp" alternator that produces that current @ 12.6 volts is useless for recharging your depleted batteries - especially if it can only run that hard for a few minutes.

'Link