Battery Isolators,Separators, and Switches?

[Bbasso]

Originally Posted by jumpshowhigh

a company in California called Perfect Switch

care to share a link to it or product info?

[jumpshowhigh]

http://www.perfectswitch.com/

Originally Posted by Bbasso

care to share a link to it or product info?

[Bbasso]

interesting, thanks.

didn't see a $ tho...

[Scalf77]

Rockbender,
I agree with your assessment of the bidirectional mode and solar. I know there are members out there that have bot and are very happy. When I put this in WIKI I will add your information.

Ultrasport,
I use MS Visio for my drawings. I did put fuses in the diagram, I did leave off a fuse (circuit breaker) from battery to fuse box. Sportsmobile never had any fuses on my install, I don't know if they continue that practice. I have been lazy and never really put any in myself. The big problem is finding a fuse that is large enough to handle your app and it will still blow when needed. I have a 100 amp fuse between the battery and inverter and when I had a battery cable wear through to the frame it never went down.

Jumpshowhigh,
So i did cover FET based solutions, the perfectswitch is similar in most ways. I do really like FET's, I am just not convinced they are the best solution for this issue. If one is to go with a FET based solution it would be preferable to make sure it was installed in engine compartment or outside of the Van. Many of the sportsmobile units already were wired inside. Ofcourse if your building a new setup that is not a problem.

I was a little dissapointed to find them stateing inrush currents in milliseconds for this application, but it does look like a solid solution. My bigger concern is not how well it works, but what happens when it fails.
This is from the installation instructions:

"Should POWER-GATE cease to function correctly for any reason, it is
important to remove the device from the electrical circuit. Like any
component in an electrical distribution circuit, if it is not functioning
correctly, the POWER-GATE will dissipate heat as current passes through
it. If ignored, heat related damage could result if a faulty device is not
removed. Perfect Switch, LLC cannot be responsible in any way for
ancillary damage to the vehicle and equipment installed in, on, or about
the vehicle. Electronic components can cease to function at any time. It
is the operator’s responsibility to frequently assess the health of the
electrical system to insure a safe and reliable working environment."

-greg

[jumpshowhigh]

Typical lawyer language.....same issue with a failed battery, faulty cabling, or high resistant relay. If it fails, and you're pumping hundreds of amps through a failed device, it's gonna get hot so get it out of the system. If you're too stupid to notice the issue and do something about it, then buyer beware.

My decision process at the time of shopping was that I know solenoids will fail, but they are cheap and common. Solid state isolators that you find at West Marine or auto parts stores cost more and have no moving parts, but I know about the voltage drop and I have had them fail on me. Came across this POWER-GATE device in my late night searching. Called. Asked questions. Was impressed. Bought it. Been working properly so no complaints. Will it fail some day? Probably, but what on my rig won't eventually fail? I'm just looking for better efficiency and longer lifespan. Don't know much about inrush current except to say that whatever outrushes from my alternator and inrushes to the isolator ain't breaking it so far.

Originally Posted by Scalf77

Rockbender,

I was a little dissapointed to find them stateing inrush currents in milliseconds for this application, but it does look like a solid solution. My bigger concern is not how well it works, but what happens when it fails.
This is from the installation instructions:

"Should POWER-GATE cease to function correctly for any reason, it is
important to remove the device from the electrical circuit. Like any
component in an electrical distribution circuit, if it is not functioning
correctly, the POWER-GATE will dissipate heat as current passes through
it. If ignored, heat related damage could result if a faulty device is not
removed. Perfect Switch, LLC cannot be responsible in any way for
ancillary damage to the vehicle and equipment installed in, on, or about
the vehicle. Electronic components can cease to function at any time. It
is the operator’s responsibility to frequently assess the health of the
electrical system to insure a safe and reliable working environment."

-greg

[Ultrasport12]

Thanks for the replies.

Fuses are funny things you would think even a 100 amp fuse would blow with a dead short. I don't have anything on my Aux battery charging cable but I am going to do something even if its a fusible link like Ford has under the battery for the Battery Junction Box and in the Alternator charging line. I was going to use a 200 Amp breaker or ANL fuse but I want it under the van very close to the batteries and I am concerned about corrosion. The factory Ford aux battery system does not have any protection in it but its only 10 gauge wire from the relay to the battery, which might burn through eventually but I used #4 wire and have two batteries.

Again thanks for sharing what you have learned. I am sure a lot of people will benefit from it.

...Jamie

[moorefc]

What a great writeup! My vehicle is older, and uses the diode isolator. I don't really mind that when charging there is a loss, and since my alternator sense lead is at the car battery, the battery sees the full charging output of the alternator (~14.8v in my case).

I guess the question that comes up as to why change from isolator to a less lossy "contactor" is: what is the problem with the diode isolator using the energy of the voltage drop? The alternator has lots of capacity and the load the van presents represents a loss of 0.7v X 30A to maybe 0.7 X 90A ~21-63W -not that significant given that we are pushing a big vehicle down the road. Additionally battery charging loss is said to be about 30%, so we are dealing with a lossy system.

Maybe I am missing something...

Thanks again for the well written article that ties together a lot of information and the comments about the different newer products!

[Scalf77]

With a alternator ouput at 14.8 the voltage drop should not be an issue. It comes down to the actual voltage level that you are charging the battery with, not the power that is loss.

[shenrie]

damn, incredible writeup. thanks a ton! this will help me out so much!

quick question though. has anyone done the trombetta setup and instead of using a toggle to switch it on and off, connect it to the igintion? that way when the van is in the start postion its charging, and when the van is off, the house doenst have access to the van?

[Scalf77]

Yes, that was pretty much my set up, I went through a additional relay to add the capability to turn it on at other times if wanted. But you could run the coil wire to the "Run" circuit, it is hot when the key is in run mode. The "start" circuit is hot when the key is in the start position.

Greg