Somewhat related to this posting. I'd like to add 2nd battery w/single engine... any link to kit to do so which includes cables?
thanks

It is a Twin Power brand. Cannot remember who I ordered it through. I've had it for about 3 years now. Installed in a 2017 Road Glide Special, 107" with Red Shift cam & S&S oil pump.

You just triggered one of my dead brain cells from school to come back alive! ("triggered" Ha! aint that an overused word now a days! LOL)
anyway i believe that's referring to Lenz's law...how to go look it up again but here's the gist of it:

"Lenz's law, in electromagnetism, statement that an induced electric current flows in a direction such that the current opposes the change that induced it. This law was deduced in 1834 by the Russian physicist Heinrich Friedrich Emil Lenz (1804–65)"

So the larger the current draw on the alternator the more the alternator tries to fight that current with the magnetic field its generating thus trying to slow it down...

No, because cable lengths needed varies boat vs boat , rigger vs rigger.

Good news, many online co’s will make cables for you with any connector ends.

PA,

As SB suggested, there are far too many variables to account for for anyone to provide a kit that wouldn't include a crap ton of excess wire. You're on your own. Luckily, it ain't rocket science. It just takes some planning and about a day's work (for me, anyway...)

Our previous boat actually already had two batteries in it when we bought it, but they had them wired in parallel, which means we didn't actually HAVE two batteries. We had ONE, with double the capacity and double the potential for total battery failure. We reconfigured them, replacing all wiring, including the ground wire, and added a switch. We went with the Perko switch, and were advised to use #4 welding wire for both the hot and the ground wire. We used non-insulated crimp terminals, soldered on after crimping (pre-tinning is a really good idea). We wired both batteries to the two input posts of the switch and the entire boat runs off the single output post; starter, accessories (including the amp for the stereo) and charge circuit. This setup has proven bulletproof for us so far. I Just have to make sure to alternate which battery is active every so often. It doesn't have to be each time you take the boat out, just so long as you don't get in the habit of using one battery all the time. Our current boat was rigged this way when we bought it. Switch placement matters. I wouldn't advise mounting it under the engine hatch if you have a powered lift that is attached both top and bottom. You laugh, but I've seen it in several boats, and it's a nightmare if the batteries ever fail. In our previous boat, we mounted the switch under the rear seat. I also added in a couple of contact points, direct wired to the sundeck lift, that I could connect jumper cable to and lift the sundeck with another boat's batteries. In our current boat, since I can lift the sundeck off the powered lift, the switch is mounted in the engine well. It's a PITA, as the sundeck is FARQING heavy, but I can do it.

Thanks. Brad.
(937)545-8991

This has been an interesting read. Thank you.

I have a single engine with 4 batteries. I added 4 amps to the stereo, so I added 2 more batts for a house bank and have 2 batts on the perko switch for starting/running accessories.

I have been charging the house batts strictly from an onboard charger plugged in 120V. (Dual Pro 3 bank charger)
https://www.batterymart.com/p-dual-p...0602816c06cbb4

I bought Power pole "charge" in hopes of being able to charge all the batteries while on the go, AND charging them all from shore power via the same unit. After receiving it, I found out it only worked with a 24 or 36 volt trolling motor set up with a 12V staring battery. So, if anyone has a 12v starting and 24V house bank system, this is an option.
https://www.westmarine.com/power-pol...-19933290.html

I now have a 160 amp alternator from Mechman that I will be installing now and was wondering how to wire it up.

After reading the above replies, it looks like I will be just running 2 banks of 2 batts off the Perko switch unless someone has a better idea.

I do also have a Sure Power battery separator I used on my last boat I may work into my set up. It's capable to run 200 amps continuous. The Blue Sea is only good for 120 amps or 500.
Sure Power 1315-200 Battery Separator

Powering an entire hospital is a little different then recharging a 12 volt battery, your analogy is not valid... while a larger load may consume an extra HP or so in no way is it going to make the belt slip is my point.

1 horsepower = 746 watts. 50 amp alternator @ 12 volts = 600 watts. Enough said

You never said belt slip in your original quote nor did I.

But an alternator with a large load does have more turning resistance VS one without.
Enough to make a properly tensioned belt slip? More than likely not.
Enough to make you lose 5 MPH? NO

Higher amp alternators and belt slip info

https://www.mechman.com/faqs/

You peeps notice most afmkt alternators come with dumb easier to slip pulleys in them now vs steel ??

Swap steel over from bad one if you can. They grab belt way better.