Battery Separator -

[David_h]

When I bought my '06 Hawk, I installed a Sure Power 1315 Battery Separator in the F150 engine compartment. Now, I've just discovered that FWC had the same 1315 unit installed in the camper. So, I have two separators. It doesn't seem like there is any harm in leaving it that way. Plus, it could be a little safer, since when the engine is off, there is no power in the cable that runs back to the camper connection. I'm inclined just to leave it alone.
David H
Mill Valley, CA

 

[Desert Rancher]

You need to find out if there is any voltage drop across the separator. If so, then you would not want to use both.
I would recommend a call to Surepower tech support.

 

[brianjwilson]

I'm not familiar with surepower isolators, but I agree, make sure there is not a voltage drop. Some isolators drop .6 volts or so, running two isolators and smaller wiring to the camper could easily be a 2 volt drop.

There is really no reason to have two. Keep the one in the camper if you think you may be moving it onto different trucks, or keep the one on the truck if not.
Hellroaring isolators, for example, only "open up" (connect the batteries) once over a certain voltage reaches the isolator. They explained to me that, if the isolator is too far away from the main battery or charge source, the resistance in the wiring may prevent the isolator from seeing the required voltage and may not connect the batteries to charge.

 

[K7MDL]

The Model 1315 anmd 1314 are solenoids so are mechanical contactors and will have very low to nil contact resistance. There are no diodes in the current path to drop voltage.

The tricky part is the Model 1315 is a dual sensing solenoid, meaning that it will close the contacts when it detects >13.2VDC on EITHER side of the solenoid. The 1314 senses only 1 side.

A battery being charged will be greater than 13.2VDC. One under load or sitting idle (no charge) will be less than 13VDC (probably 12-12.5 range).

With 2 1315s in series, If the camper battery is above 13.2V (such as a solar charger or shore power cable might cause) then the camper connector will be hot. If the truck engine is on when you hook it up, the truck side connector will also be hot. When you plug the 2 together you are connecting a live circuit. Since they are both about the same voltage, not much should happen though. If BOTH the truck engine is off and the camper battery is not charging, then both 1315 solenoids wil have their contacts open and the cable connector will be dead. When you turn on the engine or charge your camper (like when you plug in shore power) they will BOTH energize and one will charge the other (bidirectionally).

So there should be no problen with 2 of these in series, but I would prefer that the batteries on either end are not charging to minimize the chance of sparks when you plug the connector into your truck receptacle. The delay of the solenoids will ensure you have time to well seat the connector before they energize.

The advantage of using a 1315 with dual sense is that the camper battery can charge your starting battery or act as a boost if you have big enough wire and breaker or fuse.

I personally would bypass, or better, remove one of the solenoids, less to go wrong, and and turn off charging of both batteries so the contacts will be open while you make your camper connection with the truck.

For reference, the 1314 senses only 1 side. If you only had 1 1314 installed in the camper, if wired so that it senses the truck side, it will remain open (camper wire side will have no voltage) you plug it in to the truck, then it will have the truck staring battery voltage (about 12.5VDC) until you start the truck engine and the starting battery voltage rises above 13.2VDC. The solenoid will close and the whole system (both batteries) will now be at 14VDC or so while charging. So very similar to the 1315 case, it is all about the battery voltage; is it < or > 13.2V at the time you make the plug connection.

I just got a Grandby last weekend and I have a similar situation I am about to resolve today. I have a 1314 in the camper and a Blue Sea Systems ACR (automatic charging relay) in my truck with manual overide switch under my seat to power my radio gear when the camper is not installed. So I will bypass the 1314 in the camper to provide camper battery power to my radio gear (in the truck cab) when the starting battery is not charging. That way I will only drain down my camper battery while operating my radio gear, not my truck starting battery. I also have a solar charger on the camper battery.