Dual Battery Install Completed. Blue Sea ML-ACR and Odyssey PC1200s

[BulletHead]

Forgot about this thread. Finished it up a while ago. Hers a final picture.

It looks like to me your starting battery is the one on the left (looking at pic), and the winch is powered by your right battery (aux), am I wrong to assume that the winch should ALWAYS be wired to the main battery as that would be the shortest electrical path to the alternator since it requires high current draw at full load?

Are you relying on the 7622 to handle that current draw and if there is a voltage drop, the 7622 would combine the batteries? Curious.

 

[Umbrarian]

am I wrong to assume that the winch should ALWAYS be wired to the main battery as that would be the shortest electrical path to the alternator since it requires high current draw at full load?

There are a variety of situations where it (and other stuff) should not be wired to main battery. There is no one way is the correct way. A lot depends on what you have and how you plan to use it.

 

[BulletHead]

There are a variety of situations where it (and other stuff) should not be wired to main battery. There is no one way is the correct way. A lot depends on what you have and how you plan to use it.

I'm just trying to get an idea as to WHY it was wired that way. I need to wire mine in and I'm not sure how I should/would wire mine. Maybe I am overlooking some scenarios.

 

[DaveInDenver]

Indeed, always is a strong word. I prefer wiring the winch to the starting battery but arguments for the aux are valid. My reasoning is that this is the battery that has the alternator feeding it full time and with the engine running the battery is doing less work. Plus there's no chance of the isolator clicking open or arcing terminals mid-pull.

But assuming those arguments are up to debate (and I admit they are), one thing you probably don't want is the winch running from an aux battery that isn't starting capable. Dual use like Odyssey, Blue or Yellow Top, etc. aren't a problem but a true deep cycle wouldn't like being asked to power a heavily loaded winch at its full rated current.

Sometimes repurposed telco or golf batteries would not be appropriate. Have to read the specs and if a cranking amps specification is not given you might be careful powering a winch with it. Telco UPS batteries can tolerate a very short high amp discharge, maybe 5 seconds maximum, but sustained current is expected to be much lower, 25A or 75A.

 

[Umbrarian]

I'm just trying to get an idea as to WHY it was wired that way. I need to wire mine in and I'm not sure how I should/would wire mine. Maybe I am overlooking some scenarios.

I can tell you why I do it that way. Mine is more experience based than theory based. I tried the theory and it did not work well. So I have changed based on actual experience. I am a long time 4-wheeler, and have done hundreds of winchings over the years.

My vehicle is setup with a dual battery isolater system. Winching is usually the option of last resort (tow strap is fast and easy), so if I am winching, I am stuck good. I winch with the batteries isolated, off the aux battery. This allows me to winch till battery is dead, and still have juice in the primary to start (or keep going) the vehicle . There is no alternator than can overcome heavy winching in real time. More than once, I have winched aux battery dead, and stop to re-charge aux battery and then winch again. That does not work if you winch is connected to your primary battery, IME.

I have also found, through actual measurement (V/CCA/RC), my aux is consistently better charged than the primary. The more stuff you hang off the primary, the weaker it is over time. So by using the aux, I am likely to have more winching power. Modern cars hang lots of stuff off the primary (alarms, computers, clocks, etc) from the factory, and end-users hang even more.

So this covers the major reasons for me.