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timichango Samba Member
Joined: April 07, 2012 Posts: 858 Location: Squamish, BC, Canada
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Posted: Mon May 29, 2017 3:55 pm Post subject: Aux battery question / force-splitting Blue Seas ACR |
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Soooo, I'm hoping to find some advice about the best of several setup options for some mods I'm doing to my aux-battery install.
For the last 5 years, I've been running a pair of group-41 batteries under the seats: a "deep cycle" SLA under the driver's seat, and a cranking battery under the passenger's seat.
The rest of the system is fairly simple: both batteries have a fused wire running to a Blue Sea ACR under the sink.
Connected to the "B" terminal (house battery) of the ACR, I also have connected the pos. terminal from a single-bank ProSport shore charger, and also a wire feeding the pos. side of a blue sea DC distribution panel, which in-turn feeds the camper house electrics (ie. everything that's normally on the stock fuse-3 position in the '91 Vanagon, plus the kitchen, both on separate aux panel circuits).
When parked, the ACR splits the starter/house banks. When the engine is running, the alternator pushes charge voltage and trips the ACR into paralleling the two batteries. Similarly, when the ProSport charger throws charge voltage at the other side of the ACR, the batteries are also paralleled. This setup worked well with two batteries that essentially shared the same chemistry and charging demands.
So: here's the wrinkle: It was time to replace the Aux. battery, as the old one gave up the ghost. I decided on a Fullriver FT-560 (which is rather similar in all respects to an Odyssey 1200 AGM). Predictably, the Fullriver wants a different charge profile than the starter battery.
So, my plan is to run essentially the same system, but introduce an option for force-separating the banks in other words, forcing the ACR to split the banks when I'm charging from the ProSport (essentially ONLY using the charger to maintain the aux batt.), but allowing the ACR to combine banks when receiving alternator current, as before.
I've read threads that suggest adding a switch between the ACR ground terminal and ground to essentially shut off the ACR. That's one option.
Another option seems to be (potentially, unless I'm misunderstanding its function) running a fused positive wire to the "Start Isolation" terminal on the ACR to separate the banks via a switch (essentially using a standalone switch to mimic the ignition switch that terminal is intended to respond to).
Yet another option would be running a switch inline between the starter battery pos. wire going to the ACR and the ACR essentially allowing me to disconnect the starter battery from the charge relay altogether.
All three of these setups would seem to produce the same results: so which one should I use?
I'm attaching a schematic of the intended system, prior to including any switching to separate the batteries.
Thanks in advance for any advice!
-T _________________ . . . . . . . . . . . . . . . . . . .
Vroomhilde-San: Our 1991 Silver Vanagon Westy automatic + Subie EJ25
Last edited by timichango on Mon May 29, 2017 8:34 pm; edited 1 time in total |
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buildyourown Samba Member
Joined: March 01, 2009 Posts: 1668 Location: Seattle
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Posted: Mon May 29, 2017 6:17 pm Post subject: Re: Aux battery question / force-splitting Blue Seas ACR |
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I have this exact same setup. I used a relay to feed 12v to the "force separate" terminal on the ACR. When you plug into shore power, the 120v triggers the relay. This is the only way I figured out how since when you are running, every 12v is energized and would force separate your ACR.
I would really want this to function automatically. You mentioned manual switches but I'm the guy who would leave it separated.
This is the cheap relay I used:
https://www.amazon.com/gp/product/B0091WNX2K/ref=oh_aui_detailpage_o06_s02?ie=UTF8&psc=1
Been going strong for 2.5yrs now. I do leave it plugged in for several days at a time with the fridge running and it seems to do fine. Just did 3 very hot days after having the fridge run for 2 weeks straight. |
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timichango Samba Member
Joined: April 07, 2012 Posts: 858 Location: Squamish, BC, Canada
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Posted: Mon May 29, 2017 8:33 pm Post subject: Re: Aux battery question / force-splitting Blue Seas ACR |
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buildyourown wrote: |
I have this exact same setup. I used a relay to feed 12v to the "force separate" terminal on the ACR. When you plug into shore power, the 120v triggers the relay. This is the only way I figured out how since when you are running, every 12v is energized and would force separate your ACR.
I would really want this to function automatically. You mentioned manual switches but I'm the guy who would leave it separated.
This is the cheap relay I used:
https://www.amazon.com/gp/product/B0091WNX2K/ref=oh_aui_detailpage_o06_s02?ie=UTF8&psc=1
Been going strong for 2.5yrs now. I do leave it plugged in for several days at a time with the fridge running and it seems to do fine. Just did 3 very hot days after having the fridge run for 2 weeks straight. |
That's clever work with the 120v relay, actually. Makes sense. Where are you taking the 120v from to run across the coil? Do you have a photo of the setup?
I'll personally probably be fine with a manual switch we've got a reasonably regimented outbound/inbound checklist that we use when we head out camping, so it's just one more thing to add to the lists. I'm planning to run a wire for a remote LED from the ACR up to the dash area as well, so hopefully that indicator makes any blunders more obvious. In any case, I have a Blue Sea M-Series SPST switch lying around waiting to get used anyways (yeah, I know it's wayyyy overkill for the application).
Thanks for your input! _________________ . . . . . . . . . . . . . . . . . . .
Vroomhilde-San: Our 1991 Silver Vanagon Westy automatic + Subie EJ25 |
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buildyourown Samba Member
Joined: March 01, 2009 Posts: 1668 Location: Seattle
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Posted: Mon May 29, 2017 9:32 pm Post subject: Re: Aux battery question / force-splitting Blue Seas ACR |
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timichango wrote: |
Where are you taking the 120v from to run across the coil? |
I have a full westy so I utilized the stock hookup. The outlet by the floor is wired to the outside hookup with regular house romex. Pretty easy to tap in there. My charger lives under the old fridge cabinet |
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timichango Samba Member
Joined: April 07, 2012 Posts: 858 Location: Squamish, BC, Canada
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Posted: Tue May 30, 2017 9:53 am Post subject: Re: Aux battery question / force-splitting Blue Seas ACR |
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buildyourown wrote: |
timichango wrote: |
Where are you taking the 120v from to run across the coil? |
I have a full westy so I utilized the stock hookup. The outlet by the floor is wired to the outside hookup with regular house romex. Pretty easy to tap in there. My charger lives under the old fridge cabinet |
Nice. Yeah, I replaced the stock outlet with a GFCI in our van when we bought it back in 2012, and figured I could tie in there if I did decide to go the relay route. Was originally wondering if you'd tied in somewhere closer to the under-sink area, to minimize the length of the 12v run, though it now occurs to me that I don't even know where the rest of your installation is anyways.
I'm also realizing that the 120v relay could be installed adjacent to the back of the 120v outlet, with a fused 12v wire running behind the cabinetry to the ACR force-separate terminal.
Thanks for the idea I may actually decide to go this route, and save the big Blue Sea manual switch for something else.
cheers,
T _________________ . . . . . . . . . . . . . . . . . . .
Vroomhilde-San: Our 1991 Silver Vanagon Westy automatic + Subie EJ25 |
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timichango Samba Member
Joined: April 07, 2012 Posts: 858 Location: Squamish, BC, Canada
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Posted: Thu Jun 22, 2017 12:27 pm Post subject: Re: Aux battery question / force-splitting Blue Seas ACR |
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OK, so here's what I did...
I'd been accumulating parts and going through and generally cleaning up and redoing the electrical terminations that I did five years ago, now that I've got better crimping equipment. I wasn't happy with the original ring terminals that I'd used back then, as I've had a couple of them fail (ie. terminals actually breaking), and I replaced all of them with better quality terminals. Note to anyone in Canada: the big assorted multi-packs of electrical terminals they sell at Cambodian Tire have garbage terminals. Get better ones from a better FLAPS if you're doing electrical work. And a proper ratcheting crimper.
Anyways, I got that done, and got my layout and wire routing squared away, and then proceeded to address the force-disconnect control for my ACR (to force it to keep the batteries separated when using my shore charger / ensuring that the shore charger ONLY sees the house battery, and not the combined house/starter as a single bank).
I was hemming and hawing about putting any more holes in my cabinetry, and didnt' ultimately want to use my big Blue Sea M-series switch for a simple control circuit for the ACR, so I wound up rigging up a custom control box that I could mount to the outside of the cabinet behind the driver's seat.
One of the motivations there was not being able to find nice surface-mount switches in a small form factor (all of them seem to be flush mount or recessed panel mount) so I needed an enclosure to mount the switch, which also provided the ability to mount a remote indicator LED for the ACR, to review the ACR's status lights without spelunking into the under-sink cabinet where the rest of the setup lives.
I used a Hammond 1590A enclosure that I had lying around (for guitar pedal projects), and drilled the front for the switch's mounting barrel, and a wire passthrough hole in the lower face, to which I added a grommet.
I'm feeding three wires out from the under-sink cabinet, to the enclosure:
1) 12vdc power from a 2A fused supply on my aux distrubution panel inside the box, I rigged a 1000kohm resistor inline with the anode of the LED, and the cathode of the LED going out on wire #2 below
2) Return wire from LED cathode to the ACR's LED terminal
3) Return wire from the cold/switched side of the switch to the ACR's 'ignition isolate' terminal.
This way the LED on the box shows the ACR status (ie. not the switch position though it kinda does that indirectly based on the response from the ACR), and the switch connects/lifts the ignition isolation circuit on the ACR.
Switch in the "ON" position force isolates the batteries / the LED goes into blink mode, indicating that status.
Switch in the "OFF" position puts the ACR into default mode, which allows it to connect the banks when it sees over 13v on either side of the relay.
The nice thing is that the enclosure's mounting position facilitates two things:
1) it's easy to access when I'm hooking up a 110vAC cord to the side of the van just pop the door open, and flip to "force isolate" to target the house battery with the charger.
2) when I unplug the 110vAC, the next time I get into the van, there's a nice bright red LED flashing at me to remind me to flip it back into "standard/join" mode.
I attached the enclosure to the cabinet using industrial-strength velcro (it's extremely secure I've used this stuff for guitar pedalboards, and you need to really wrench at it to get it to budge once it's affixed). I've also left some slack in the cable run into the cabinet, spooled inside the cabinet, so if I ever want to move the enclosure elsewhere within a few ft. raduis of that position, I can. For example, if I need to troubleshoot something with the system, and monitor status while driving, I can simply stick more velcro in whatever spot I need to (or just zap strap the thing) in order to reposition it.
One arguable fringe benefit is that the blinking red light can double as a "fakeout" car alarm warning light. I'm not convinced that thieves actually pay heed to car alarm lights at this point, but hey, if it deters even one sketchbag... that's a bonus.
Really happy with how this turned out, and it's saved my big Bluesea switch so that I can repurpose it as a general kill-switch for the van's main electrical feed for security/emergency purposes.[/img] _________________ . . . . . . . . . . . . . . . . . . .
Vroomhilde-San: Our 1991 Silver Vanagon Westy automatic + Subie EJ25 |
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timichango Samba Member
Joined: April 07, 2012 Posts: 858 Location: Squamish, BC, Canada
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Posted: Thu Jun 22, 2017 5:38 pm Post subject: Re: Aux battery question / force-splitting Blue Seas ACR |
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Hahahahahah SHAZAM.
An early and unexpected benefit of this setup reared its head just now: I've been working from the van, at the beach, all afternoon to take advantage of the nice weather. At some point, I put on the cabin blower fan because I was having a cigarette (last day before quitting! Had to get in my final puffs...) during a phonecall with a colleague, and forgot to kill the blower afterwards (doh!).
Go to leave a bit later, and damn the starter battery is too drained to start the engine. Luckily, my lovely wife was able to swing by with my jumper cables (which I'd absentmindedly left out of the van after cleaning the van out yesterday), and give the van a jump.
Now that I can easily force-separate the aux/starter systems, I can make sure that all of my alternator current is going to the starter battery, and not getting shared with the aux battery.
Small victories, my friends... small victories. _________________ . . . . . . . . . . . . . . . . . . .
Vroomhilde-San: Our 1991 Silver Vanagon Westy automatic + Subie EJ25 |
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