Which battery should I connect a winch to

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lightning series3

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I have just fitted a tmaxx split charge system to power a second battery. The second battery is running the lights and a few other bits.
I have a winch now and im not sure which battery to connect it to .
What do people think . Thanks
 
I'd have thought the best plan would be to have one battery for the starter and the other for the winch. So that if you flatten the battery winching, you can still start the car.
 
We've got split battery systems on the trailer, 55AH for the winch and engine bay lights, 110AH for the habitation side, and 4 X 80W solar panels and 2 X 26A chargers.

The winch should come off the auxiliary battery, so as said, you can't put yourself in a silly position.

The Tmaxx system isn't powering the winch, it's just the link to put power into the auxiliary battery from the vehicle side of things.

Peter
 
Just remember that the winch load will be passing thru that tmax relay which might not be upto the job. A winch at full load might be pulling 400a +
 
mikeh501 said:
Just remember that the winch load will be passing thru that tmax relay which might not be upto the job. A winch at full load might be pulling 400a +
Click to expand...

The winch should be directly on a battery, so the scenario is that the auxiliary battery will take the load, the Tmaxx only operates when the car is moving under its own power?

Peter
 
I believe if you have 2 batteries in parallel connected to each other any load placed on it will be transferred by both batteries. Hence the winch load will be satisfied by both the aux and starter batteries when the relay has them connected. The issue therefore being you may destroy a relay not made to take the load because the load will be going through that relay.

That's how I understand it anyhow. My dual battery relay to s rated at 500a continuous and connected with 40mm cables.
 
If two batteries are connected in parallel the battery with the lowest internal resistance will supply a higher proportion of the load current. CCA is normally a good indicator of internal resistance (higher CCA = lower resistance). However just to complicate things slightly the resistance of the relay and wiring will also need to be considered as it will effectively be added to the battery internal resistance of battery that doesn't have the winch leads attached to it. All things being equal with two identical batteries the battery with the winch connectors attached will supply more than half of the current to the winch and the second one slightly less due to the relay/lead resistance. All bets are off if you have two different batteries or ones of different ages though. Best way to check would be with a clamp ammeter and measure the current through the relay wires when a load is on the winch. HTH
 
Ok it sounds like I better connect the winch to the main battery as the tmaxx wont be powerful enough to have it running of the aux battery unless I upgrade all wiring . The engine will be running while winching so it keeps the power flowing .thanks guys
 
Kwakerman said:
If two batteries are connected in parallel the battery with the lowest internal resistance will supply a higher proportion of the load current. CCA is normally a good indicator of internal resistance (higher CCA = lower resistance). However just to complicate things slightly the resistance of the relay and wiring will also need to be considered as it will effectively be added to the battery internal resistance of battery that doesn't have the winch leads attached to it. All things being equal with two identical batteries the battery with the winch connectors attached will supply more than half of the current to the winch and the second one slightly less due to the relay/lead resistance. All bets are off if you have two different batteries or ones of different ages though. Best way to check would be with a clamp ammeter and measure the current through the relay wires when a load is on the winch. HTH
Click to expand...

Really good explanation. Thanks for that :)

Also agree that the winch should definately be connected to the AUX battery; but to be sure you wont burn out the tmax relay it would need to be upgraded.

Lots of variables however, and just because a winch can draw 400a load doesnt mean it will do it every time you use it, or whether your relay can support the odd jolt of a few hundred amps if its rated at 100a etc etc.....

connect it to your AUX battery and use it. Worst that can happen is you melt your relay lol. Keep a fire extinguisher handy :D
 
An other option could be to fit a fusible link in the relay wiring, if the relay is rated at 100 Amps fit a 100 Amp link. Check it after you have done some heavy winching, if its blown then you know the relay is being overloaded and needs uprating.

FYI it will take more than 100 Amps for a few seconds to blow a 100 Amp link but a 100 Amp relay should be able to survive that short time.
 
Put a load bypass switch in.
Alongside my fused 200amp relay I use one of these to connect the two batteries and feed off to the winch. Connect using heavy gauge welding cable. (500amp+)

As you can see the switch has a few different positions.
Off/ Battery 1/ battery 2 and both.
High amp ratings too.
When you're engines running flick the switch to both battery's and it will share the load directly from the batteries through the big cable and less through the charging relay and small cables etc.
plus it acts as an isolator for the winch.

http://www.reliancemarine.com/Produ...E-/View.aspx?gclid=CPO8r8jbsb8CFVHMtAod0C0AyQ
 
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