Aopec smart battery isolator installed

[markopolo]

In preparation for a planned alternator upgrade I installed a relay type battery separator today. The new alternator is rated 140 amps and the diode type isolator in the van is rated 120 amps. It may have been OK to continue to use the 120 amp isolator but when I saw this smart "isolator" on the store shelf for $69.95 I had to buy it to try it out.

Aopec: http://www.aopec.cn/fac/en/home/
Isolators / Separators: http://www.aopec.cn/fac/en/htm-products/?type_id=5

I'd never heard of the brand before so hopefully it all works out for me.

Specs on the Aopec R12140B:

Continuous current: 140A
Intermittent current: 170A
Cut in voltage: 13.3v
Cut out voltage: 12.8v
LED on when engaged.

No cables included other than the attached small ground wire. I used two short runs of 4 gauge wire.



The circuit board is potted in silicone to protect it.





My van has two chassis or engine or starting batteries. One of those batteries (AGM) is located right behind the drivers seat. It butts right up against the seat base. I'm fairly certain that it was originally on the frame rail under the floor below where it is now. The guy that originally converted the van put the gray water tank in that spot under the van.

There is a closet right behind that battery and in the bottom of the closet I have two house or coach AGM batteries. The setup presented an easy installation option for the new smart battery isolator (SBI). I just mounted it on the outside wall of the close near the 1000W PSW inverter.





I had already purchased this when skagitstan posted this link: http://www.jaycorptech.com/pm-220-11-du ... relay.aspx in this forum topic: http://www.classbforum.com/phpBB2/vi...tart=22#p25990

It looked similar but it was bi-directional. Neither the instructions or website indicated that the unit I purchased was bi-directional so you can imagine my surprise when I connected the positive lead to the house batteries and heard the unit engage. I wondered if I had mixed up the wiring but didn't think I did because I put white tape on the cable that was to go to the starting battery. I continued with the install and connected the remaining cable to the starting battery.

I'm pretty sure the Aopec unit I bought is Bi-Directional. I put a load on all the batteries to get them below 12.8v. The converter / charger in my van runs through a marine type battery switch that allows you to choose: the house battery bank, the chassis battery bank, both battery banks or no batteries at all. I plugged the van in to power the charger and moved the switch from "no batteries" to engine bank and the Aopec unit engaged joining both banks. I moved the marine switch to "no batteries" again with a small load on the system. After 5 seconds or so the Aopec unit disengaged. I moved the marine switch from "no batteries" to house bank and the Aopec unit engaged joining both banks.

I did that a few times and the Aopec SBI engages when either the house or chassis battery bank voltage is 13.3v or more.

I like the bi-directional feature but I will try to figure out if I can turn it off if I want to (when charging from the solar panels for example). Booster put an overide switch on his Sure Power unit (link: http://www.classbforum.com/phpBB2/vi...hp?f=12&t=2028 ) but the Aopec is wired differently I think. The Aopec has a small gauge ground lead, one large gauge wire to the chassis battery bank and one large gauge wire to the house battery bank.

I'll have to check if breaking the ground connection turns off the unit. Maybe I should email the company and ask.

This should be a nice upgrade to the system in my van. The new unit has 4 gauge wiring, the marine type switch has 6 gauge wire and the old isolator has 4 or 6 gauge. A fair bit of current can flow when all of that it combined together. I left the old isolator in place until I decide what to do about it. I could just leave it in place as a hot spare. (edit: not jumpered over, that would defeat the purpose of it)

[booster]

A lot of the electronic separators have have an "ignition" input that is designed to disconnect them when the engine is turning over with over, or running if you want. It is the input that our Blue Sea charger goes to for isolating the banks when on the charger. It doesn't appear yours has that input.

It will be interesting to see if it goes open if you break the ground wire, once you have power on both sides. That might lock it up. Let us know how it turns out, as the interrupt ones are much more expensive than that.

[markopolo]

It's funny how I wanted a bi-directional unit. Then, after some recent forum discussions, I thought uni-directional would be fine. My van is stored plugged in and in my garage. The bi-diectional feature would be useful if stored outside not plugged in.

It might be OK the way it is on my van. 180W solar, 180ah house batteries, absorption fridge.

[booster]

We use the bidirectional in the garage stored to keep the starting battery full. I don't have it on all the time because the separator is the coil type and gets pretty hot for continuous use for months. I will turn it on when I plug in, let the shore charger fill the starting battery, and then disconnect the separator, leaving the coach batteries on float. 3 weeks later, I will do the same routine again.

[markopolo]

I have been using the marine switch for dual bank charging.
I'll have to check to see if this Aopec unit gets warm over time.

[booster]

Ah, I forgot you have the manual bypass, which is much better for when in storage.

[skagitstan]

I'll very likely use the BlueSea unit https://www.bluesea.com/products/762..._-_12V_DC_500A that Marcopolo pointed me to (whilst using this parenthesis as a short and easy way to avoid ending my sentence in a preposition ).

I also still like the Sterling http://www.sterling-power-usa.com/Pr...p12vor24v.aspx.

The BlueSea is a bit overkill in current handling and is less configurable, but should be more readily available. The Sterling has better overcurrent protection and sensing.
Both have build in remote start capability. The BlueSea has the cutout switch, and is latching. Both have low idle and parasitic current.

I will probably dither back and forth between the 2 until my Transit shows up...anywhere from late April to July, if I'm lucky.

[booster]

The Blue Sea with the manual disconnect is a very nice unit. The manual switch is a good feature that you don't see all that often.

[markopolo]

Originally Posted by booster

Ah, I forgot you have the manual bypass, which is much better for when in storage.

That manual switch is also the battery disconnect switch for the RV. One problem with that is when there's a prolonged power outage and the switch was on not left in the off position. (Switch is on to charge both banks). The propane detector would eventually drain all the batteries. That could apply if I unplugged the RV for some reason and forgot to plug it back it or if a breaker tripped in the garage etc..

I've been pulling the LP gas detector fuse as a precaution when storing the van for longer periods.

I was thinking of leaving that manual switch in the house battery position and letting the Aopec handle the joining of the house and chassis battery banks.

I checked the Aopec yesterday and it was warmer than surrounding materials but not by much. It was 32F in the garage though so not the best day to check.

[markopolo]

I wonder if the chassis grounding for both house and engine batteries is allowing the Aopec R12140B to function as a bi-directional unit?
I sent an email to Aopec asking if putting a switch on the ground wire will disable the unit or lock it up.

[markopolo]

I got a prompt reply from Aopec.

#1 putting a switch on the ground wire and using it to break the ground connection will not disconnect the unit.

#2 breaking the positive connection will not harm the unit

So #2 gives a few options; relay + small switch, manual switch or battery post type switch etc.

I think I'll do nothing until I've seen the voltage from alternator after running the van for a few hours. I run the fridge off the inverter while driving so that will be taken into account.

Something interesting occurred today. The cut-in voltage for the Aopec is 13.3v and the float voltage from my Progressive Dynamics charger is 13.2v. I put a brief test load on the inverter that caused the system voltage to drop below the 12.8v cut-out voltage of the Aopec. When the load was removed voltage immediately returned to 13.2v float voltage which wasn't enough to trigger the Aopec to cut-in.

The PD charger in my van will boost to 14.4 volts DC for 15 minutes every 21 hours so that will trigger the cut-in and engage the Aopec unit again. It would remain engaged through the next and future float cycles because the cut-out voltage is 12.8v.

When the van is seen to be in use by the PD charger it will up the voltage to 13.6v.

Interesting to see how these things interact.