Howdy, I'm new here & I'm looking for pro-tips.

I have a '71 Blazer that I had previously wired for dual battery and winch about 20 years ago. I was never happy with my setup but it worked just fine. Since then I stored my beast, recycled its old batteries and a not-so-friendly neighbor stole my winch. Looking for an economical and smart solution.

I'll attach an image of my plan. Thoughts?


Bigger image: https://drive.google.com/file/d/1W86...ew?usp=sharing

 

That will work, but I would do it (and did it) a little differently. Instead of an isolator, I have a large continuous-duty solenoid connecting the batteries together, and energized by the ignition. My winch and other loads (refrigerator, auxiliary lighting, etc.) are connected to one battery, and my "starting" battery powers the Blazer and its factory equipment so that, if I run the "accessory" battery down, I can still start the vehicle. When it's running, both batteries are connected together through the solenoid, so they both charge from the alternator. The nice thing about this setup is that I have both batteries available for starting and, if I leave the engine running, both batteries plus the alternator output to run the winch.

 

Thanks for the reply, Tom.

Isolator vs Solenoid vs ACR?
Are you running something like a BSS L Solenoid 9012? I'm just not clear on pros and cons of isolator vs solenoid vs ACR since my understanding is that the diodes in the isolator should also protect the starting battery from discharge while allowing the generator to charge both.

Placement?
I'm not confident that I have my proposed placement of the Isolator/Solenoid correct. I'm trying to tie the Aux battery directly to the winch plus feed the loads tied to the fuse block with it as well. Just not sure that will happen because I'm trying to maintain the original wiring between the factory voltage regulator & fuse block. Hope so since it makes the most sense to have isolator/solenoid between the batteries.

Ignition?
I'll attach the schematic because I'm also not sure how the ignition plays into this apart from being wired to the starter

 

An ACR basically does the same thing as a solenoid, but it's switched based on charging voltage, rather than ignition switch position. The isolator will protect your second battery from discharge, but it won't let you draw high current from both batteries at the same time. Neither the isolator or the ACR will let you "jump start" a weak battery from the stronger battery, which a solenoid does whether you want to or not. Personally, I just prefer the simplicity of the solenoid, since I've seen several failed isolators.

As far as moving your fuse box loads to the auxiliary battery, it seems like it should be as simple as moving the 10ga.(?) wire that supplies it to the auxiliary battery. But you'll need to make sure the circuit that energizes the starter solenoid is powered by the starting battery if you still want to be able to start with a dead auxiliary battery (unless you're using a charge solenoid that will connect the batteries in parallel when you turn the key on). It's been a while since I worked on anything with an external voltage regulator. If it were mine, I would probably upgrade to an internally-regulated alternator unless you're trying to keep it all original.

 

Thanks for the info, Tom. I really like the idea of using both batteries for a large current draw & the jump start so I'll investigate a solenoid a bit further.

I found the idea of a smart isolator intriguing at first because it has some of these features but I'm trying to keep the computerization low.

As far as the voltage regulator, the wiring is a hot mess in some places so I'm just taking an "if it ain't broke don't fix it" approach. I'll put a more modern charging system on my list though

I've read that flooded cell batteries are still best for starting and AGM are good for heavy loads like winches, etc. Does that make sense to you?

 

To be honest, I really don't know. I doubt there's a huge difference either way. Personally, I prefer AGM because they're maintenance-free and they won't leak, even if you end up upside-down. If you have the batteries inside the vehicle (like I do), that can be pretty important. I've been looking at lithium batteries, mostly for the light weight, but they do NOT seem to like high-amp draws. So, that's kind of a deal breaker, even if I could afford them, lol.

 

Oh, sweet. Do you have your batteries inside because of weight distribution?

 

That's a nice side effect, but it's mostly because there just isn't any room under an S10 hood for another battery. The original battery barely fits in there, lol.