Dual battery w/isolator and winch question

[iptman]

Here's a crude schematic of what I thought I was going to do but now I'm concerned and need some help from the electrically savvy on here...

Battery 1+ ->6 gauge wire ->Blue Sea ACR-SI ->6 gauge wire-> Battery 2+

Battery 1+ -> 1/0 wire -> post 1 on Blue Sea switch
Battery 2+ -> 1/0 wire -> post 2 on Blue Sea switch
M12000 -> 1/0 wire -> Output post on Blue Sea switch

So if I have the switch turned to '1' (or 2 for that matter) which connects battery 1 to the winch, and the truck is running (therefore the isolator is connecting both batteries trying to charge them) I have continuity from battery 1 to switch to winch as well as continuity from battery 2 to isolator to battery 1 to winch. That second part is what makes me worried. How does the ACR not get fried in this scenario? I've seen some people put 80 amp fuses on the ACR line but why don't these pop any time the winch needs more amperage? What am I not getting here? I was initially thinking to connected the start isolation input on the ACR to both the starter and possibly to a small terminal on one of the winch solenoids but now that I think of it wouldn't that trigger the starter to fire off? So I'm at a loss here. I know I could put a circuit breaker on the ACR line and jut manually break the circuit any time I winch for one or the other batteries but this seems overkill. I could also upgrade to the Blue Sea 7622 ACR that has a manual and remote disconnect and can handle 500 amps but again that seems overkill as well. Thanks for any input or thoughts.

 

[coax]

Not sure I have an exact answer to your question but here's a few thoughts. The ML you were looking at has an intermittent rating for 5 minutes of 210amps. Even using a winch through that device you'd have to have a winch pulling 420+ (Factor in the alternator output) for a 5 minute winching session to come close to the rating. 420 amps is a fairly large winch at full power draw (my EP9 will only pull 350 or so). I'm also not sure how the bus voltage may be affected by that much power draw from winching, so its possible it may drop enough that the latch would separate the batteries on low voltage.

In the end, I figured that winching was one of the times I'd want to have two batteries in parallel, and ended up with the blue sea 7622 because it will 1.) give you the manual option to join the batteries and 2.) handle more amps than just about any recreational winch would draw during normal operation. 500 continous (Way more in fact as really only ~half the power draw would flow through the Isolator.) 3.)Its one part, not two.


That warn 12k looks like it has a draw of 440 amps at 12000 lbs. Do you plan on doing long duration, high line pulls? If thats the case, just remember to flip the manual switch to 1+2 and avoid the issue would be one way to solve it
hth


Just for reference, I put the Isolator here, and have a blue sea switch before the winch just as an emergency disconnect.

 

[caanuck]

Iptman,

I ran a setup similar to what you are planning for years. I used a baintech smart isolator (40amp i think)with a manual blue sea dual battery isolation switch and a 9500 lb winch. I always liked the setup because the charge controller didn't need to be rated for a large amperage,I could simply switch the dual battery isolator switch into 1+2 position to jump start.

I ran the winch with batt1 or batt2 in testing and light pulls, however I always used both batteries when the going got tough. i never thought about it but this would prevent any high potential across the charge circuit. In one situation I had a wire melt inside the winch solenoid control box and the winch stayed engaged. It pulled the batteries down to where the whole truck electric system reset and nearly wrecked the truck before I got to the isolator to switch it off but it didn't affect the charge controller.

You will be safe to put the fuses in the charge circuit, plan to winch using both batteries and carry spare fuses just in case.

 

[iptman]

I thought about 1+2 for winching but my goal of the second battery was to backup the primary for start purposes exclusively. I wouldn't want a situation where I needed the winch for a heavy pull only to be stuck with electrical issues after the fact.

I thought about the 7622 but wanted the switch under the hood to disable the winch. I figured I could get the 4 way switch vs. 2 way and save a few ducketts with the 7610 ACR. I also didn't want to buy more 1/0 gauge cable than I had to. With the 7610 all you need is 6 gauge.

-Patrick

 

[caanuck]

I thought about 1+2 for winching but my goal of the second battery was to backup the primary for start purposes exclusively. I wouldn't want a situation where I needed the winch for a heavy pull only to be stuck with electrical issues after the fact.
-Patrick

My experience was different I guess, i used the setuo to winch with batt 1+batt2 alot and as a backup start battery very little. it broke down into four main winching situations;

1.when you get stuck deep enough
2. get over an obstacle that you could avoid
3.pulling others out
4. utility work( pulling logs, deer etc)

in case 1 and 3 you would need batt1+batt2 and likely take the chance that you may cause an electrical issue, this would be the least of your worries especially if there is water/flooding/tides involved that either prevent the engine from running while you winch or potentially flood the vehicle.

In case 2 and 4 i would take the chance because that's why I went out that day or took that trail

In any case I think you are planning the right setup, and the use of batt1+batt2 for a winch eliminates you having an electrical issue with the charging circuit.

 

[iptman]

So if I connected a diode on a lead from the starter relay and also from the output on the Blue Sea switch and connect both these leads to the Start Isolation terminal on the ACR-SI I should be able to achieve what I want. Basically disconnect the batteries if either the starter is engaged or if the winch has power while stopping current from flowing from the winch through the start isolator terminal to the starter relay (to not inadvertently engage the starter motor). Anyone see a problem with this possible setup? Anyone know how to size a diode for this application?

 

[coax]

I thought about 1+2 for winching but my goal of the second battery was to backup the primary for start purposes exclusively. I wouldn't want a situation where I needed the winch for a heavy pull only to be stuck with electrical issues after the fact.

... I also didn't want to buy more 1/0 gauge cable than I had to. With the 7610 all you need is 6 gauge.

-Patrick

So if I connected a diode on a lead from the starter relay and also from the output on the Blue Sea switch and connect both these leads to the Start Isolation terminal on the ACR-SI I should be able to achieve what I want. Basically disconnect the batteries if either the starter is engaged or if the winch has power while stopping current from flowing from the winch through the start isolator terminal to the starter relay (to not inadvertently engage the starter motor). Anyone see a problem with this possible setup? Anyone know how to size a diode for this application?

If you are going for simplicity and reliability I would think that adding diodes and a bunch of associated wiring will take you down the opposite road.

As for the extra 1/0 cable necessary for the larger blue sea switch, I think it would actually be a lower amount. You'd need bat1 to isolator, bat 2 to isolater, and winch to bat 1 or 2. No need (IMVHO) to use 1/0 for such a short run between batteries. (Voltage drop between 2 gauge wire and 1/0 gauge wire for 200 amps over 6 feet is only 1.2% difference...) Maybe use it only for batery to winch. With the 2 component blue sea setup, you have 2 runs of 6 gauge, 2 runs of heavier gauge to the switch, and then 1 run of heavy gauge from switch to winch.

Not trying to sell you on a specific model but I did go through all the scenerios you did and the larger isolator seemed like the logical choice. Easy to separate, easy to join, 3 isolation wires, etc.

Good luck with the install whatever option you go with!

 

[iptman]

I think I'm finally seeing the light on the 7622. I didn't realize it had 3 separate isolator connections. Plus the manual and remote overrides are pretty nice feature.

 

[coax]

One other note that folks may find useful. The 7622 is rated at IP66, while the smaller 7610 is rated ip67. (Second digit is water). So if you plan on dunking the truck up and over where you mount the ACR, the smaller one with a manual switch may be better.

I mounted my 7622 at about the air intake height, so if I'm that deep, the dizzy is wet and there's probably water in the intake already....


6 Powerful water jets Water projected in powerful jets (12.5 mm nozzle) against the enclosure from any direction shall have no harmful effects.

Test duration: at least 3 minutes
Water volume: 100 litres per minute
Pressure: 100 kPa at distance of 3 m


7 Immersion up to 1 m Ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion).

Test duration: 30 minutes
Immersion at depth of at least 1 m measured at bottom of device, and at least 15 cm measured at top of device