Sure Power Isolator to Blue Sea 7622

[Ocsmb]

Superb info guys. Thank you.

I'm a novice so I have to ask. The wire from the alternator to my toasted 3 post Sure Power isolator (FYI located in the engine bay driver side) will now install on the start battery postive post? Does it need a fuse near the start battery?

The wire from the battery junction box to the isolator just toss?

[Scalf77]

That sounds correct, you don't need a fuse from the alternator to the starting battery. I fuse the cable from the starting battery to the Bluesea ACR on both ends,
-greg

[Ocsmb]

Originally Posted by Scalf77

That sounds correct, you don't need a fuse from the alternator to the starting battery. I fuse the cable from the starting battery to the Bluesea ACR on both ends,
-greg

Got it thanks!

[malcolmkegel]

Hi greg. Look like a great setup. I have a 2004 Sportsmobile and don't think it has a battery disconnect. I have to replace my house battery so I was thinking of killing two birds with one stone.
Any chance you have a more detailed diagram of your wiring?
Much appreciated!

[Scalf77]

Sure, this should be a good starting point Van Battery Connects.pdf. In reality I don't really disconnect the battery, but instead I disconnect the power distribution. I also have a separate manual disconnect for always on power.

In any case I use the BlueSea 7713 for this disconnect. I have the switch wired in to provide manual control, but basically if the 7713 has 12 volts on the control input it stays connected. remove 12 volts and it disconnects. Between that switch I have a relay that is controlled by my Pentametric Battery monitor, this relay is triggered by a low voltage setting in the battery monitor. Obviously this is optional. The power for the Blue sea control switches come from the always on circuit, this allows them to turn the switch back on. The downside is that even if I throw a low voltage disconnect via the Pentametric I have power draw from the always on devices.

I do have a separate disconnect for my solar input, but the inverter/charger does not have a separate disconnect.I use a Bluesea 7701 for that, mainly because it is what I had, it is much more difficult to use a "controlled" disconnect, but is fine as a disconnect switch. I use Bluesea ML series Link Bus "9160" to connect the three switches together. I also use Bluesea MRBF terminal fuses for various power distribution. There is one going to the van battery I have a similar fuse on the van battery since the power cable is bidirectional. The next fuse is for the Power Distribution fuse panel, and then the third is for the Always on Power distribution. The house battery has a class T fuse close to the battery and also a class T fuse is on the output/input of the inverter/charger per their recommendations.

The 7622 ACR also has a relay between the switch and the unit, this is totally optional, and comes down to a personal preference. This relay puts the 7622 into auto-mode when the van is running, when the van is not running it goes by what ever position the switch is in. By default I normally have the switch off, disabling the ACR, If I want to top off my batteries with solar or the house charger I will set the switch to auto. With this setup, I do not find the need for the ignition lockout wires of the ACR, I suspect that I would wire them in if I was not using this extra circuit.

In theory, I set it up this way to provide the low voltage disconnect, but also provide the ability to power the distribution fuse panel via the van alternator via the 7622 ACR. I can manually disconnect the fuse panel via the switch while still providing power to the items that I use while driving. This allows me use solar for a better charge profile then the alternator provides, also a better float voltage while long drives. This was impart done with a future thought of lithium batteries.

Other thoughts, the solar has a fuse at solar controller, but since there is some heft to that wire , in the future I may add a another MRBF fuse to the solar side of the disconnect switch. Although power should not feed this direction, there is a subsequent amount of current valuable on that side, it is fused at the battery and inverter, but in the case of a short it may be a issue.
Also, I may look at also having some control over the always on power with the Low Voltage disconnect provided by my battery monitor.

I hope this helps, and feel free to ask any follow up questions, I probably should have had more coffee before answering this.

-greg

[malcolmkegel]

WOW!!! I love this forum. People like you make it great!!! Thanks so much for the very thorough explanation.
Malcolm.

[Flux]

One thing I can't figure out is if the 7622 actually combines the batteries during alternator charging, or if they are isolated and charging.

My thought is that you would never want to combine 2 battery banks in parallel that are completely different in size, type, and voltage in anything other than an emergency.

[daveb]

Originally Posted by Flux

One thing I can't figure out is if the 7622 actually combines the batteries during alternator charging, or if they are isolated and charging.

My thought is that you would never want to combine 2 battery banks in parallel that are completely different in size, type, and voltage in anything other than an emergency.

Many RV's keep the house and vehicle batteries separate for that reason. Some keep the solar split (one array for the house and one for the starting batteries) but it seems rare to see this on the standard SMB build. I don't worry so much about splitting the solar because the house bank is so large compared to the starting batteries and my prime goal is to get the house system charged while in camp. I do have an idea that constant solar charging standard wet cell batteries takes a toll on them. I went through several Motorcraft batteries before switching to all AGM starters. Because AGM's will usually hold a storage charge for about a month, I'm wanting to add full control of the solar charging. My vans shore charger keeps a constant 12.9v level while plugged in so while it's sitting there at home on the driveway I really don't need the solar even though the controller jumps into a float mode while in a no-use/full sun situation.

The way the 7622 separator works is bidirectional so yes, when it sees a charge voltage coming from the engine alternator it will connect (close) and charge both systems. Any time one or the other battery systems drops to a voltage about 12.7 or so the separator opens. The separator (in my case) also works in reverse when charging from shore power. The 7622 has full controls on the unit itself but can be setup with a remote switch.

So far my setup has been working fine and I rely on a 7622 with remote to separate the banks. The charging parameters between the AGM starting and house batteries are close enough that I'm not worried but there's always room for improvement.

[Flux]

Thanks for that daveb. I am trying to dot all my i's and cross all my t's before throwing money at a house battery system and there is a lot of dubious info and products out there. I thing there are simple solutions that will work, but I don't think they get the most out of their systems.

I had a genius solar/electronics guy in at work today and I talked to him about this "combining" issue. He agreed but the conversation was kind of quick as it was an aside to our business talk. I am gonna try to pick his brain further. He also mentioned that he had some "stuff" laying around and could get me a few things for a solar system......so I got that going for me.

I'm sure that combining batteries with the alternator charging them isn't too bad, but you'll never get full capacity on that AGM like you would with a smart charger feeding from solar or battery charger feeding from shore. This is what I am gathering from the info I can find.

A couple things I have considered:

For sure using the same types of batteries for house and starting. AGM.

A parallel charging system from the alternator through an isolator is necessary for redundancy and doing the bulk of the charging.

The Blue Sea 7622 is a nice piece of the puzzle.

I have considered a 12V power supply that runs from shore power to feed the house loads. Like 40Amps or so. Then have a smart battery charger on board that goes to work on the house batteries, but the solar could do that as well. A simple switch to cut the house batteries from the bus over to the power supply.

I need to learn more about the solar chargers and how all this ties together.

[Bbasso]

I took Dave's advice a while back and my 7622 has been flawless in operation.
If my van has been sitting for a while I'll hit the connect button that way all four of my batteries get charged up from my solar array. I have 2x155ah AGM house batteries and two interstate 850cc starter batteries.
And while driving I'll also connect them so the dual alternator setup has some fun lol.
It's a worthy piece of equipment.