Powerboost Winch Battery Question

[Mszczewski]

So, I have a couple of questions for the gurus on this forum regarding adding a Winch to my 2021 Powerboost. I hope to get input from the likes of @HammaMan @Snakebitten and others who have done extensive work in the community around these fantastic vehicles.

I plan to add a 12k winch to my vehicle soon. I plan to install it in a receiver-based winch cradle and change out the front tow hooks for receiver tubes to swap the winch around as needed. That part is all fairly straight forward. My questions come in around powering this setup.

My current plan includes running a set of power cables to both the front and rear bumpers of the truck, terminating in some Anderson Connectors to make the connection quick and dummy-proof. I am planning to include a high-amperage solenoid powered on the low side by my existing Garmin PowerSwitch to energize the cables as needed to ensure that if I get into an accident or have some rubbing, I don't burn my truck down.

As a bonus to this configuration, I plan to modify some of my existing jumper cables to terminate one end in an Anderson Connector to make jumping others (or myself) dummy-proof.

I've got a couple of questions about best practices:

1. Should I plan to run a negative line back to the frame ground in the engine compartment, or is it okay to send 450 amps back through the frame with a shorter negative termination on the back of the truck?
2. With the battery configuration in these trucks, the 12v starting battery, the 12v under-the-seat battery, and the DC-to-DC step-down converter from the 48V traction battery (in place of the alternator), I think I'll have plenty of oomph to drive the winch. However, I wondered if upgrading the under-the-seat battery to something larger would be prudent.
   1. If I go this route, what are your thoughts on battery chemistry? I was looking at lithium batteries based on their energy capacity, though the high amp draw might rule them out.
3. I am currently planning to have a single solenoid energize both the front and back connections at the same time; this would allow me to use the truck as a passthrough in some edge cases or add a battery to the Anderson Connector that isn't hooked up to the winch to provide some extra reserves.
   1. Are there any advantages to installing a pair of dedicated solenoids that control the connectors separately?
4. Based on the draw of a winch like this (450 amps at peak), I think (based on the charts I've seen) I need to be up in the 4/0 space for the wire run to the truck's rear. That seems big, but again, I would rather not burn the truck to the ground. Am I oversizing this cable, or can I safely get away with something smaller?

Thanks in advance to everyone for their thoughts and input!

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[Tall Tail]

4. The higher your amps and the smaller your cable and the longer your wire runs, the lower your voltage will be which will reduce your winches capacity proportional to the voltage reduction. for example, if your voltage drops from 12 VDC to 8 VDC, multiply your winches capacity by 2/3.
Based on my research, 4/0 or larger would preserve more of your voltage and winch capacity. I have a post explaining this if you search winch and my handle.

https://www.calculator.net/voltage-drop-calculator.html
https://www.southwire.com/calculator-vdrop


https://www.f150gen14.com/forum/threads/winch-to-battery-connection.24772/#post-466350

 

[HammaMan]

Haven't seen the DC/DC maxed out with high loads like that. It shouldn't be phased by it but we've got no data yet to go off of yet. It's water cooled. Wouldn't touch your batteries for this. If this is a summertime activity, adding in a high-amp capable LFP in parallel would help out significantly. This is the only high-amp sustained battery that I know of up to the task https://www.amazon.com/SIEKON-Low-Temp-Protection-Trolling-Off-Grid/dp/B0CYKT8DGM.

Here's its test. W/ 4/0 coming back from the AGM combined w/ DC/DC output, this will keep the winch at rated capacity as the system should be able to hold 12+ volts like a champ. Just need to find a way to connect it to your 4/0 maybe with some small 3 way terminal blocks w/ batt in the bed? It will even help w/ winch in the front backfeeding energy via the 4/0.

If it weren't for the reversed terminal locations, I'd already have put this under the hood of my truck. They also have a group 24 version that's just a smaller package. As you can see from the teardown, there's quite a bit of free space in the case. Just wish it had a heater relay to program during charging to first pre-heat the cells. Need to message Will and ask him if it's got a heater port (often BMSs are built for several use-cases - might contact the MFG and ask them to make a heated version)

 

[FaaWrenchBndr]

I wouldn’t mess with the aux battery under the seat. A few have tried with stereo equipment and have had electrical gremlins pop up.

use the AGM battery in the engine compartment, just like all winches are operated

 

[Mszczewski]

Here's its test. W/ 4/0 coming back from the AGM combined w/ DC/DC output, this will keep the winch at rated capacity as the system should be able to hold 12+ volts like a champ. Just need to find a way to connect it to your 4/0 maybe with some small 3 way terminal blocks w/ batt in the bed? It will even help w/ winch in the front backfeeding energy via the 4/0.

To make the connection, I would think I would need something like this:
https://www.northcoast.com/product/detail/427200/nsi-industries-iplw250-3

It is rated for large cables and some degree of weather resistance. That would allow me to run a single 4/0 from the starter battery back to the rear of the truck and then tuck this up under the bed with a leg to the bumper for the winch and a leg up into the bed for the extra battery.

The only worry I have with that connector is the last line about fine-stranded wire; I was planning to use welding wire, which is fine-stranded, for both the extra physical protection and better conductivity. However, I suppose I could use standard 4/0 and tuck it into the frame for physical protection.

 

[HammaMan]

Does that accept smaller diameter? To current limit that specific LFP battery, I'd suggest connecting to it with 2 gauge to that splitter. You can leave that battery continually connected to the 12v bus of the truck to bolster your reserve 12v capacity and keep it charged. By using 2 gauge you're essentially vdroop current limiting the battery to the rest of the 12v system.

 

[Mszczewski]

I think I will attempt the first pass of this build with the truck's existing batteries. If, in testing, the existing batteries and converter don't seem to be able to keep up with the winch's demands, I can look at adding an additional lithium or AGM battery to supplement.

What are your thoughts on the negative leg of this system? Is it better to run a dedicated 4/0 wire back to the engine compartment ground point, or can I rely on a frame termination in the rear of the truck?

 

[Mszczewski]

I am bumping this thread to see if anyone has any thoughts on using a frame ground point in the back of the truck on the rear leg for this system versus running a dedicated 4/0 wire back to the engine compartment for the negative.

 

[HammaMan]

I am bumping this thread to see if anyone has any thoughts on using a frame ground point in the back of the truck on the rear leg for this system versus running a dedicated 4/0 wire back to the engine compartment for the negative.

If you want to use the frame, stiffen the frame bond with a parallel conductor

 

[Mszczewski]

If you want to use the frame, stiffen the frame bond with a parallel conductor

Do you mean I should attach a run of the 4/0 cable for the negative to two points on the truck's rear?

 

[travisN000]

I am bumping this thread to see if anyone has any thoughts on using a frame ground point in the back of the truck on the rear leg for this system versus running a dedicated 4/0 wire back to the engine compartment for the negative.

https://www.f150gen14.com/forum/threads/installed-12v-power-in-bed-ppob-2-4kw.23729/post-451201

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