Adding another battery

[DBCooper]

Just bought a jet ski lift that goes in the back of the truck. It has two 2500 lb Warn winches to lift 2 jet skis onto bunks. It has a battery box in the back near the tailgate to run all this stuff. My question is what is the easiest or best way to wire the battery in so my truck will charge it? It would suck to pull the ski up to the truck and not be able to get it up to the bunks. I assume a battery isolator is mandatory. Thanks for any input.

Dan

 

[klenger]

Plug it into the trailer connector.

 

[DBCooper]

I thought about that, but I'll have a trailer plugged into the trailer connecter.

 

[Matt400]

I think some more questions need answers. .

• How many times in one day will you use the winch
  
• How long is the on time of the winch
  
• How many miles will you drive after use of the winch
  

We could get more technical like winch amp draw and such but for now just curious about the other. If your alternator is not up to the job maybe yet another battery at home on a trickle charge so you can swap a fresh one in every so often.



If it looks like your alternator will not be overworked you could make up a 2 wire harness with disconnect that splices into the trucks travel trailer harness "behind" your trailer plug.

 

[klenger]

Since you will be using the trailer connecter, I would recommend splicing into the back side of the trailer connector and installing a simple molded 4 pin trailer connector. The new trucks come that way now. Given the purpose of the winch, I don't see any problem with this setup.

 

[DBCooper]

Matt, to answer some of your questions, I would like to think that once I drop into the water I would be in for the day, however 2-3 times a day may be required. It takes about 30-45 seconds of run time per winch (not at the same time) to lift a ski up. Mileage after each use is between 5 and 500. No kidding. I have no idea what the draw is on each winch... sure I can find out. I doubt I need to worry too much about that.

What would be the result if I put the 3rd battery in like the two under the hood, parallel style? I can put a plug near the battery to unplug over night. I think I'd rather isolate it though.

 

[SnoKing]

Matt, to answer some of your questions, I would like to think that once I drop into the water I would be in for the day, however 2-3 times a day may be required. It takes about 30-45 seconds of run time per winch (not at the same time) to lift a ski up. Mileage after each use is between 5 and 500. No kidding. I have no idea what the draw is on each winch... sure I can find out. I doubt I need to worry too much about that.

What would be the result if I put the 3rd battery in like the two under the hood, parallel style? I can put a plug near the battery to unplug over night. I think I'd rather isolate it though.

Only like, size, age and amp hr batteries should be paralleled. If you have nice heavy power leads from the truck batteries to run this setup, I would not worry about it. There is a lot of reserve capacity in the existing two batteries. If your engine is running while you load, you may not even be dipping into the batteries at all. SNOKING

 

[K5IP]

As said,

just plug it into your present battery set up. The current draw from winch is proportinal to the load you are pulling (though not directly proportinal). The jet ski load is quite small. I would estimate about 100A for that load. So, if you operate the winch for four minutes, your alternator (120A) can bring your batteries back

up in just a few (theoretically, but not actually 5) minutes. Don't worry about it and you don't need the hassle of the extra battery.

Understand though, that if you bring some extra wires back to the battery, they need to be big enough to handle the load without excessive voltage drop. Probably something between a #10 and #6 wire. (you can use the truck frame for the return (negative). Connectors also need to be quite heafty. This high peak load is why the trailer connector idea is not such a good idea

Rog

 

[Matt400]

I think what I would do is get rid of the battery that came with the lift and add this on:

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Connect the short end (red & black cables) to your lift unit and the long end to one of the truck batteries. Cut the clamps off the orange leads to proper length and crimp on eye connectors, then you can use the quick disconnect when you remove the lift. Making this a permanent fixture to the truck is nice because you could get another cable that you could use for jump starts from that same socket. Or if you get a long enough set all you will have to do is add another connector to the alligator clamps you cut off.



This eliminates having to recharge a battery way back there and use an isolator. Also eliminates trying to run a 3rd battery in parallel as they should all match.

Leave the truck running for the off load and reload.



You can find those here just typ in "cables" in their search box.

 

[DBCooper]

Wow... sometimes I wonder how I can be so blind. That is a really good idea. The truck will be running most of the time since it's pretty much a mad dash at the boat ramps around here anyways. I don't see any problems with a set up like that. Nice and simple. Thanks to the four of you for your input.

Dan

 

[Matt400]

I don't see any problems with a set up like that.

Well maybe one. .

When running cables like that remember you have allot of amperage available from your truck batteries that is on the line at all times so just be sure to make a nice install and insulate any areas that could possibly chafe or burn the cable. A short circuit could easily cause a fire.



Check out the amp draw on your winch, maybe you could add one of these for safety.