24v Winch by adding another battery?

[o2batsea]

amateur electrical tinkerer reply... that would work if you put Diodes on those cables to the 2nd battery, otherwise the whole system becomes 24v. 24v feed comes off the 2nd battery that is run in series, leaving the feed to the vehicle off only the first at 12v.... It works in my head anyway.

I recently put a 2nd battery in my boat and used http://www.bepmarine.com/home-mainme...lusters-manual
and will at some stage use the same for Andy the Landy, was ridiculously cheap less than 1/5th the cost that auto electricians were talking about, and all marine grade.

again, in my head, you should be able to get a 24v feed off the two batteries and leave the rest of the outputs at 12v, you would need diodes etc, but is doable. worst case would be inverter to get it up to AC voltage then step it back down to 24

Um, no. Go try it.
It's how gazillions of trolling motors are connected.

[NC_Mule]

amateur electrical tinkerer reply... that would work if you put Diodes on those cables to the 2nd battery, otherwise the whole system becomes 24v. 24v feed comes off the 2nd battery that is run in series, leaving the feed to the vehicle off only the first at 12v.... It works in my head anyway.

I recently put a 2nd battery in my boat and used http://www.bepmarine.com/home-mainme...lusters-manual
and will at some stage use the same for Andy the Landy, was ridiculously cheap less than 1/5th the cost that auto electricians were talking about, and all marine grade.

again, in my head, you should be able to get a 24v feed off the two batteries and leave the rest of the outputs at 12v, you would need diodes etc, but is doable. worst case would be inverter to get it up to AC voltage then step it back down to 24

I kind of feel like it would work to but I'm not ready to bet my wiring harness on it. Guess I'm thinking household wiring. Like when the electrician wired our hot tub. He ran 240v (two 120V lines)from the breaker box to a disconnect outside near the tub then wired the tub into the disconnect on a breaker. Take a hot lead from each battery to a "fused disconnect" of sorts then down stream of your panel would be 24V. Wire the winch to that. I just wonder if 24V could find it's way up stream of the disconnect somehow and fry everything, guess diodes would stop that. As for charging I would charge the 2nd battery the same way the first is charged because at that point it's just 12V.
Thanks for the link to these switches. I'm also going to research how trolling motors are wired. Still waiting on the Warn model number so I can price out a 12v motor conversion.
pb

[o2batsea]

[NC_Mule]

Wow, nice pic man!
So the positive red line out of "winch" is that 24v? If I run the rest of the truck off of "house" I assume that will still be 12V even though the negative side of "winch" is hooked up to the positive side of "house"
Thanks for the thoughts on this.

pb

[o2batsea]

Wow, nice pic man!
So the positive red line out of "winch" is that 24v?

Yes. The second battery will not "leak" back to the first. Both sides use common negative, but different positive.

If I run the rest of the truck off of "house" I assume that will still be 12V even though the negative side of "winch" is hooked up to the positive side of "house"

What you would be doing is connecting two 12V batteries in SERIES to create 24V, no different than loading batteries end to end in a flashlight. The "house" battery remains at 12V since you aren't taking power from the downstream battery at all.
The main drawback to this, in my opinion, is that the second battery is not isolated from your start battery.
As the winch draws down both batteries, the charging system is putting voltage into the start battery. The voltage to charge the winch battery is "leaked" to it. I doesn't get a direct charge. The negative consequence of this is that you can quickly flatten both batteries. If you are without means to get restarted, you could get stuck.
For extended winching with 24V, you should really add a second 24V alternator and battery system that is completely separate from your 12V electrics. 24V has many advantages.

Oh and you would want a big fat Schottky diode to isolate the second battery as it will reduce voltage drop if you were really worried about any current backflow. A properly sized one will run you about $50 at digi-key or mouser.

[NC_Mule]

Yes. The second battery will not "leak" back to the first. Both sides use common negative, but different positive.


What you would be doing is connecting two 12V batteries in SERIES to create 24V, no different than loading batteries end to end in a flashlight. The "house" battery remains at 12V since you aren't taking power from the downstream battery at all.
The main drawback to this, in my opinion, is that the second battery is not isolated from your start battery.
As the winch draws down both batteries, the charging system is putting voltage into the start battery. The voltage to charge the winch battery is "leaked" to it. I doesn't get a direct charge. The negative consequence of this is that you can quickly flatten both batteries. If you are without means to get restarted, you could get stuck.
For extended winching with 24V, you should really add a second 24V alternator and battery system that is completely separate from your 12V electrics. 24V has many advantages.

Nice man, thanks for a clear explanation. I think I understand what you are saying. I see what you mean about having a seperate
24v system and alternator as being the best option. I'll run the numbers and put a $$ on my options.
Can you explain some of the advantages of having 24V?

[o2batsea]

sure.
24V means you slice your current draw in half. So, a winch motor that would draw 100 amps on 12V draws 50 amps on 24V. In addition, voltage drop over a given wire length is also halved. 24V motors tend to last longer since they are loaded half as much, and so on and so on.
With batteries, you get a double bonus as doubling batteries lengthens their lives by more than 120%, as long as you discharge them and recharge them with enough "wiggle room" (generally not below 50 percent so that you aren't constantly recharging at high amps = cooking). Sizing batteries isn't rocket science. Basically you stuff in the largest, heaviest batteries you can.
Get a copy of "The 12 Volt Bible", an very reader friendly introduction to batteries, management and power usage. It's directed at boaters, but useful for anyone who has a 12V system.