Solenoid vs Isolator

[Shotgun Willie]

Howdy Campers,

I'm about 1 month out from delivery of an ATC build. Working with Marty and Jeff, we've ironed out the bulk of my mods and build requests. Last bit is the battery charging schematic. I'm foregoing solar install initially as there are modifications to the wiring and panel mounting they don't / won't perform. Plus, I'm not afraid of some DIY, and in fact, enjoy it.

I'll be camping the weekend of delivery and need the truck to camper charging dialed-in optimally. I'm personally supplying the install with 8 ga marine grade duplex wiring, as ATC only supplies 10 ga. As a reference, here's the link: http://shop.genuinedealz.com/Marine%20Grade%20Wire/Flat%20Duplex%20DC%20Boat%20Wire/8%20AWG%20Boat%20Wire%20Cable%20RB/

My last bit of inquiry is whether to use the smart isolator that comes standard with their installs or to use a solenoid with a cut off switch. From the research I've done to date there are advantages and disadvantages with both set ups. My main concern is 1) isolator: while providing the advantages of not overcharging, results in voltage drops; and 2) solenoid: being mechanical can fail sooner, and can also over charge the house battery if not monitored when driving long distances. 3) If a solenoid is used, is it important to have the same batteries at truck and house? I'll be using an AGM group 27 at camper and the truck has a 2 year old flooded interstate.

No one has posted a link to the Aopec R12140B isolator used by ATC with their auxiliary battery installs. So here it is: http://p.globalsources.com/IMAGES/PDT/SPEC/946/K1040673946.pdf

The solenoid I'm considering is an Ametex SAS4201 : http://www.ametekswitch.com/Solenoids/Solenoid-Metal-Case-Family-Tabs.aspx

What's your advice? Aopec smart isolator? Or solenoid with manual cut off switch to avoid overcharging? Is the voltage drop with the Aopec negligible or significant enough to go a separate route? If you have a recommendation for a bettor solenoid, please chime-in with links provided. Lastly, please provide links to recommended manual cut off switches and photos of your switch mounting (if available).

Thanks in advance,

 

[Casa Escarlata Robles Too]

Howdy Campers,

I'm about 1 month out from delivery of an ATC build. Working with Marty and Jeff, we've ironed out the bulk of my mods and build requests. Last bit is the battery charging schematic. I'm foregoing solar install initially as there are modifications to the wiring and panel mounting they don't / won't perform. Plus, I'm not afraid of some DIY, and in fact, enjoy it.

I'll be camping the weekend of delivery and need the truck to camper charging dialed-in optimally. I'm personally supplying the install with 8 ga marine grade duplex wiring, as ATC only supplies 10 ga. As a reference, here's the link: http://shop.genuinedealz.com/Marine%20Grade%20Wire/Flat%20Duplex%20DC%20Boat%20Wire/8%20AWG%20Boat%20Wire%20Cable%20RB/

My last bit of inquiry is whether to use the smart isolator that comes standard with their installs or to use a solenoid with a cut off switch. From the research I've done to date there are advantages and disadvantages with both set ups. My main concern is 1) isolator: while providing the advantages of not overcharging, results in voltage drops; and 2) solenoid: being mechanical can fail sooner, and can also over charge the house battery if not monitored when driving long distances. 3) If a solenoid is used, is it important to have the same batteries at truck and house? I'll be using an AGM group 27 at camper and the truck has a 2 year old flooded interstate.

No one has posted a link to the Aopec R12140B isolator used by ATC with their auxiliary battery installs. So here it is: http://p.globalsources.com/IMAGES/PDT/SPEC/946/K1040673946.pdf

The solenoid I'm considering is an Ametex SAS4201 : http://www.ametekswitch.com/Solenoids/Solenoid-Metal-Case-Family-Tabs.aspx

What's your advice? Aopec smart isolator? Or solenoid with manual cut off switch to avoid overcharging? Is the voltage drop with the Aopec negligible or significant enough to go a separate route? If you have a recommendation for a bettor solenoid, please chime-in with links provided. Lastly, please provide links to recommended manual cut off switches and photos of your switch mounting (if available).

Thanks in advance,

In the summer of 2011 the surepwoer co.recalled some of their solenoid units due to over heating.Several of us had the models that fell within the overheating unit serial numbers posted .
After some talk to the surepower people I decided to search out another method.Marty came along and supplied the Aopec isolator which I installed and returned the Surepower unit for a refund.It was at that time that Marty started installing the Aopec units in the ATC campers.
There are some things I like with the isolator vs a solenoid. 1 the isolator doesn't get hot, 2 and the best part IMO if you have solar ,when the camper battery reaches it's full charge the unit will go on and charge the truck battery.Great whenever the truck is sitting for a long period.In my case my truck has the camper on all the time so it doesn't get driven except when camping.Now I always have a charged up truck battery.
There is a whole thread that Ugulyscout started about the solenoid problem.You might search it out for more info.
Frank

 

[pods8]

That Aopec unit is NOT an isolator. It is what is typically called an automatic charge relay or such. Blue sea marine makes similar units. An isolator means the batteries are ISOLATED via diodes and never can see each other regardless of voltage points, this in no way shape or form is that. It links the batteries up based on voltage levels thus they are combined and not isolated.

That said I like ACRs and dislike isolators. However if a company can't even name their product right you have to wonder if the engineers or the marketing folks are behind the helm...

 

[ntsqd]

I'm in the VSR/ACR camp. BT, DT with diode isolators and I'm done with those. Some ACR/VSR's are "dual sense" meaning that they sense battery voltage on both sides and will close if either side has reached the unit's voltage threshold, thus charging the other battery(ies). Some are single sense and must be installed with attention to polarity (i.e. where the single charging source is).

There are some really expensive solid state units that do much more than combine batteries. Hellroaring and perfectswitch come to mind. IMO those are too gimmicky for consideration. They also do things that aren't desirable or are unnecessary with a truck and camper. I believe that the National Luna product is in this same category, but I can't claim enough familiarity to state that with authority.

Blue Seas and BEP Marine are the two players that I'm most familiar with. The BEP products were recommended to me by an OZ fellow on Expo (John, "whatcharterboat") who does the wiring for primarily Mitsu Fuso based Outback tourist bus's and campers. If you can wade thru their page gigavac makes some really, really nice units, but most are designed for different uses though there is at least one that is voltage sensing and suitable for this use. Their stuff is mil-spec or nearly so and is in a price strata above the blue water marine stuff.

 

[pods8]

The BEP products were recommended to me


Just as an FYI, I noticed that BEP discontinued their VSR and have now introduced a DVSR (digital voltage sensing relay). (I haven't read up on it yet)

 

[Shotgun Willie]

Appreciate the feedback. Thanks guys.

 

[Casa Escarlata Robles Too]

I don't know much about all the technical ins and outs of the "isolator".All I know is that is what is being used by the builder of my camper,ATC and it works for me!
Frank

 

[garyoNC]

Instead of an isolator/solenoid, how about a charger? Is only on when charging, when charging is off the unit goes into a very high resistance state with no bleed-over. In other words, there is no electrical connection from battery to battery.

Something like this:

http://yandina.com/c160Info.htm

I have not used one, but looks very interesting. I think someone on here has used and liked his very much. Wish I could remember who first suggested it.

 

[ntsqd]

This is another take on the Voltage Sensing Relay (VSR) or Automatic Charge Relay (ACR) that has been discussed a lot on this forum. Name depends on the mfg.
I have a BEP Marine single sense VSR in our camper. It will only connect when the truck's batteries are nearly or fully charged. Any charge source topping off the camper batteries is ignored. This is fine until I install the solar system on the camper at which point I'll need to make the decision of whether to replace it with a dual sensing unit or not.

Instead of an isolator/solenoid, how about a charger? Is only on when charging, when charging is off the unit goes into a very high resistance state with no bleed-over. In other words, there is no electrical connection from battery to battery.

Something like this:

http://yandina.com/c160Info.htm

I have not used one, but looks very interesting. I think someone on here has used and liked his very much. Wish I could remember who first suggested it.

 

[Espresso]

I don't currently have a battery in my camper, in part because the options are bewildering and also because I don't have a deep understanding of 12V electrical. I do know making a mistake and frying the electrical system in a modern vehicle can be a very costly error.

I'm not sure if I will do solar, and if I do, I'm not sure if I want to mount it on the roof or have a tethered setup like RC Pilot's. The VCR/ACR looks simple enough...until I want to add a 2nd charging source, e.g. solar.

Does anyone know if the truck and camper batteries can be dissimilar? I have a standard lead-acid battery in my truck and I want to put a AGM in the camper.

 

[SunMan]

Does anyone know if the truck and camper batteries can be dissimilar? I have a standard lead-acid battery in my truck and I want to put a AGM in the camper.

Yes they can.

 

[camelracer]

I have 2 flooded cell batteries in the truck and 2 AGMs in the camper connected through a battery separator. I just added solar and haven't had any problems.

 

[ntsqd]

There needs to be made the distinction between a system that basically works and a system that has been optimized. A lot of apparently conflicting info here is due to this. For instance, a 10ga. charge wire works. It's been shown to do so over the years. But it will have less than ideal voltage drop so some of us have gone to much bigger wire (6 ga. in my case) to offset that voltage drop. It makes for a better system, but it's not an absolute requirement.

I have two AGM's in the truck and two flooded wet cells in the camper. Seems to be working just fine.

Re: dual charging, i.e. truck's alternator and solar. With any sort of device that connects/disconnects the camper from the truck's charge system a solar system will charge the camper battery(ies) first, and then depending on the particular version/type of device it may or may not then charge the truck battery(ies). Additionally some of the solar panel controllers have a dual output option so they can split the charge between the camper battery and the truck battery(ies). The Sunsaver Duo that I bought is selectable between 90(camper)/10(truck) and 50/50. I don't have to wire it that way, it will function just fine wired only to the camper batteries.

So what happens if they're both charging? The stronger charge source will dominate. Not to say that the lessor charge source will quit, it won't. Do they "fight" each other? I don't know. Yet there are many systems out there set up this way and they appear to work well. I have decided not to worry about it. The batteries are like a fuel tank, they'll only hold so much charge, really doesn't matter what the charge sources are, a full battery is a full battery and none them (when functioning properly) are going to convince the battery to take more than it can hold.