Topic: BIM or other battery isolation in Unity (Read 3747 times) previous topic - next topic

I am confused as to what isolation or connection the house and chassis batteries have in the 2016 Unity.  I believe I was told they were isolated by the salesman on pickup but there is much confusion when surfing.  Either a BIM (battery isolation manager) or DC to DC charger are referenced as common features, but I have not been able to find out whether the 2016 Unity has either or instructions on their use.  In short, can the house battery be charged by the chassis engine?

My 2018 TB came with a BIM, but I was not sure that it was working right.  Rather than spend time trying to figure it out, I just replaced it.  In the past (on boats) I have used the Blue Sea Automatic Charge Controller (ACR) and have been happy with it.  There are several varieties.  I chose the basic 70 amp model.  It has two connections for the battery wires (which are already there) and it requires a ground connection.

The original BIM is under the passenger seat.  The seat is not hard to get out, but has unusual bolt heads.  I bought the special wrenches, but I don't know what they are called.  The bolt head is an eight point star shaped pattern.  Once the seat is out, installation is a piece of cake.  You just need to find a place to connect the ground wire.

If either battery is above 13.3 volts (charging) it connects the two battery banks together.  If neither is above 13.3, it disconnects them.  When the engine is running, I see 14.2 volts on the house (aka pleasure) batteries.  Since I installed solar panels too, it allows the panels to charge the engine start battery.

Tim

Thank you for your quick and understandable response.  I removed the passenger seat (BTW it turns out a 12 mm hex socket works fine in doing that--saw on another video).  What I found was a White Rogers 12V coil (pictured below), I'm assuming a solenoid.  The removal and replacement does appear straight forward as you mention, near by ground locations are plentiful. 

At your suggestion, I received a Blue Sea Systems 7611 AUTO CHARGE RELAY 120A 12/24V relay from Amazon today.  You mention you used a 70 amp relay (however 120 amp or higher were the only options).  How much current is likely to pass through the relay and will the lower current relays be reliable?  Also is it worth getting the remote LED to monitor function or is it just as easy to check charging voltages while the engine is running?

Thank you again, the battery connection has been a quandary from the purchase of the Unity.

David,

Glad everything worked out.  I think I went for the 70 Amp relay just to save money.  The engine has a 120 Amp alternator, but I have learned in the past that the alternator rating is achievable in only the best of conditions.  I doubt I will see even 70 Amps.  The LED monitor might be nice, but I just rely on voltage.  You can't lose with the 120 Amp model.

Everything is more sophisticated now than only a few years ago.  My charge controller for my solar panels is a Victron 100/30 meaning it will take 100 volts and put out 30 amps at 14.4 volts.  There are other Victron models that will put out a lot more.  They have a blue tooth output so that you can see what is going on using an app on your phone.  It's really nice.  I can see everything that has happened for the last month.  I recommend Victron if you get around to solar.

Tim

Removing the solenoid and installing the ACR is my plan for this morning, so not quite resolved. 

I do have 2 100 amp solar panels, haven't really started to investigate them, but does seem limited in amp generated.  Thanks for the advice on the solar controller and ACR.  Seems a bit too many things that can be learned on these vans.

I had the two 100 Watt solar panels.  The controller (don't remember the name) just had an LED on it.  It had no fancy blue tooth technology.  I could not really tell what was going on so I put an ammeter on my batteries and found a spot to mount it over the door with all the other stuff like tank levels and inverter controller.  I found that I was not getting a lot out of them.

So, first I replaced the, now forgotten, controller with the Victron controller.  It told me that, sure enough I was not getting much out of them.  I seem to remember a maximum of about 7 amps.  That's OK for keeping the batteries topped up while in storage, but I had dreams of dry camping.  So I removed the flexible panels and replaced them with four renogy 100 Watt panels.  They are $89 each on Amazon.  Solar is so cheap.

As a test, I switched the fridge to DC and left it overnight.  It uses around 10-12 amps.  So the next day, the batteries were down a good bit, and the panels were putting out around 25 amps.  About half that was going into running the fridge the rest into charging is suppose.  I am happy with the solar installation.  You can use the existing wiring if you wire the panels in series the keep the amperage down.  My panels are putting out around 40 volts maximum so the current will never be more than 10 amps going into the controller.  The existing wiring is 10 gage I think, so it will handle the power fine.  So far so good.

Tim

Hello, I have a 2016 Unity FX that is not charging the coach battery while driving. Sounds like the same problem that you were having. My unit also does not have a DC/DC charger. It has a White Rogers solenoid & a Omron Isolation Relay Delay. Did you remove them both when you added the Blue Sea Charging Relay or just the Isolation Relay? Are you able to charge your coach batteries? Thanks in advance to any advice you can provide.

I did the switch to the Blue Sea Systems 7611 AUTO CHARGE RELAY 120A 12/24V relay as noted, removing the solenoid and isolator.  I also added the remote indicator light (wiring is shown in the Blue Sea Systems materials) and it seems to indicate that charging is happening at least from the house to the chassis battery.  I haven't had a full opportunity to test out bottoming out either batteries yet, in part because I added an automatic generator starter.  Other than pulling the passenger seat (not the worse chore) it was relatively simple.  It appears that an ACR will not cross charge as fully as the coils/DC-DC but the installation is simple.

Good luck, I've moved onto the electrical water heater issue that I believe was there (along with many other overlooked upkeep items not noticed by the dealer) since I got the thing in June last year.  Huge education but still fun.

Thanks again. I've ordered  a Blue Sea Systems 7611 AUTO CHARGE RELAY. Should be here in a couple days. I'll let you know how it works for me. Jim

Just installed the Blue Systems 7611. The installation was very easy. Started my Unity in my driveway and it works perfectly.  Idles with the refrigerator on "battery" and charges the coach battery (Lithionics 320 amp lithium) at the same time. I've been trying to fix this for a couple years driving with the fridge running on propane. Thanks you both so much for the information.
Jim

Your input has been great, but I think I may still be in a quandary. 

I see the remote charge light illuminated when I run the generator or have the shore plug in, but I don't see the same for when the engine is running.  I also haven't seen the fridge convert to electric or increased input voltage while running.  So I assume the charge heads from house to chassis battery but not sure about the reverse.  Any ideas on how to check if the alternator to house battery is working?

I did check the voltage of the chassis battery, and it does change from 12. 6 to over 14 with engine idling, so not concerning the alternator failing me, so lost on the next steps.

Hopefully to cap off to this thread, the Blue Sea 7611 ARC is fine, but there is a 200 amp fuse (who knew) in the chassis battery fuse panel bolted adjacently to the chassis battery under the driver's feet.  Apparently it has been blown since I bought the van 1 1/2 years ago, but now the two batteries appear to be happy talking through the replaced ACR.  Be sure to check continuity between the chassis battery and the ARC (or DC to DC module) connection before changing out too many items (the fuse on Amazon was ~$5).