Battery Disconnect with dual battery switch

[kman67]

I got a battery disconnect switch to use with my 2 batteries and their dual battery switch. I think I figured out where to put it in the system, but wanted to run it by you guys.
This is what I have:
Main battery powers my winch.
Dual battery switch to turn off my auxiliary battery if wanted and turns the auxiliary battery off when the ignition is off.
https://painlessperformance.com/product/250-amp-dual-battery-control-system-part-no-40102/
Blue Sea battery disconnect with Alternator Field Disconnect:
https://www.bluesea.com/products/3001/HD-Series_Heavy_Duty_On-Off_Battery_Switch_with_AFD
Fused distribution block that has power coming in from battery and alternator and feeds the main fuse panel, engine fuse box and stereo fuse box:

Littelfuse 07985003ZXS MIDI® & MEGA® PDM Fuse Holder​

https://www.waytekwire.com/product/...kqiROukK3hJcpb1gWf4JtFE7t765jigRoCVUMQAvD_BwE
Explorer 4G alternator. Routing #914 green with red stripe through the Blue Sea AFD terminals then to the alternator.

How does this schematic look?
Thanks

 

[DirtDonk]

Don’t have too many opinions on it yet, but subscribing to see what germinates.
The only thing I see at the moment that seems a little off to me, is the way you have the fuse panel wired between the battery and starter relay.
I would power it from the starter relay, certainly, but not sure I want to fuse in between the starter and the battery.
Is that what you intend? What rating of fuse if so?
Are you intending to use the fuse panel as a
“starter interlock/antitheft switch“ of sorts?

 

[Jdgephar]

In your diagram, the battery disconnect will be disabling the starter for sure, and I'm assuming everything else in the main fuse box of Bronco, if the power for the fuse panel comes off of the starter relay lug.

I'm assuming you want the two batteries tied together when the engine is running, thus charging both the main and auxiliary batteries. Is that correct? If so, you want the painless 40102 to be on when the engine is running. There are better devices that I have used for this. I like the voltage sensing relays that detect when the voltage is elevated above ~12.5 volts, which means the engine is running and the alternator is working. Something like one of these. It will disconnect the batteries when the engine turns off and/or charging stops.

Your choice of the painless 40102 relay means that you have to turn on the switch when the vehicle is running to make sure the aux battery charges. Then you have to remember to turn it back off so that you don't drain the battery (from the solenoid being left on). The voltage sensing ones do that automatically. The one I linked can be manually turned on with an additional toggle switch wired in as well, if for some reason you need both batteries on at the same time, and the engine is off, or the alternator dies.

I'm not sure what you want to do with the aux. battery. Most like to run the winch and/or radio and aux. items that you run with the engine off using the aux. battery. That way the main battery does not get depleted, and then you can't start the engine. The way you have drawn the wiring, the main battery can be depleted with heavy winching, and you have to carefully choose how to wire your painless relay so that it will actually turn on and allow you use the aux. battery to "jump start" your engine with a dead main battery.

If you wire the winch and other items you use with the engine off to the aux battery, then you don't have to do anything to be able to start your engine. Just turn the battery switch to on.

I've wired several boats with an aux battery and the voltage sensing relay. When the radio is on all afternoon, you don't have to worry about being able to start the engines back up.

That's my $0.02

 

[Jdgephar]

You can also get 500amp rated ones with a built-in over-ride switch to combine the batteries:

https://www.amazon.com/dp/B00P0DECL0/?tag=classicbroncos-20

 

[ntsqd]

Goals for the system would be handy to know.

If the battery switch is simply to be able to turn the vehicle OFF and not for combining the batteries for heavy loads, self jump-starting, or other uses, then put it between the grounds for both batteries and the frame. They do go to the same bolt, right? If they don't, they should be.

I'm with Jdgephar, much prefer an Automatic Charge Relay (ACR) or Voltage sensitive Relays (VSR) to a simple contactor. And much prefer the use of blue water marine components to anything else. Which for parts like these means either Blue Sea Systems or BEP Marine are going to be the easiest brands to get.

 

[kman67]

Paul, maybe my diagram is a bit confusing. There is no fuse between the battery and the starter relay. The Littlefuse box is connected to the same terminal on the starter relay as the battery power.
I have used this type of dual battery solenoid in the past (Good Samaritan Dual Battery kit from Wild Horses), so that is why i went with this kit. This kit works in this way:

The selector switch has three positions, which operates the system.
Switch centered ; the main battery is used only for vehicle operation. The solenoid is not activated and the auxiliary battery will not be charged(or discharged).
Switch Up, activating green light position ; the main and auxiliary batteries are connected for charging/discharging and starting and the green light is illuminated when the key is in the on position, when the ignition is off or in accessory position, auxiliary battery is disconnected, saving it's power.
Switch down, activating the red light position ; the main and auxiliary batteries are connected together and the red light is illuminated at all times regardless of ignition switch position. This can be used to have the auxiliary battery jump start the main battery.

The goal of the battery disconnect switch is to shut off power to the Bronco without having to get out a 1/2" wrench and opening the hood. 99% of the time, the dual battery switch will be in the up/green position, which charges and discharges when running, but disconnects the auxiliary battery when the vehicle is off or key in accessory position.
Thanks

 

[ntsqd]

If you turn the battery off are you going to lose things like radio station pre-sets or ECU learned info?

You schematic will leave the aux battery fully functional. Is that the plan, or do you want it turned off as well?

 

[kman67]

Yes, if I turn the battery disconnect switch off, I would loose radio station pre-set/ecu learned info. That is why I would only use it in an emergency such as a fire, starter motor not stopping or a crash where the fuel pump inertia switch didn't work, etc. I guess I could run those radio memory wires before the battery disconnect, but wasn't planning on it.

I thought that if I have the battery disconnect switch after the dual battery switch, both batteries would be disconnected.

The painless switch controls the dual batteries. The Blue Sea switch disconnects the power coming from the dual battery switch.
Thanks

 

[ntsqd]

That would depend on if the aux battery's only connection to anything on the + side was to the dual battery switch. Frequently it is not. If it is then yes, the disconnect will isolate it.

 

[Jdgephar]

If I'm reading this correctly, the only purpose of the aux battery is to jump start the truck if the main battery goes dead when the truck is off. I see in the instructions for the Painless kit that this is how they recommend to connect everything. I'm sure they've also figured out that when the switch is down (red light position), the switch needs to power the solenoid off the aux battery else the relay may not turn on if the main battery voltage is too low.

 

[ntsqd]

If that is all that the aux battery is there to do it would be far easier to simply carry a Li-Ion jump-starter.

 

[Johnnyb]

Yes, if I turn the battery disconnect switch off, I would loose radio station pre-set/ecu learned info. That is why I would only use it in an emergency such as a fire, starter motor not stopping or a crash where the fuel pump inertia switch didn't work, etc. I guess I could run those radio memory wires before the battery disconnect, but wasn't planning on it.

I thought that if I have the battery disconnect switch after the dual battery switch, both batteries would be disconnected.

The painless switch controls the dual batteries. The Blue Sea switch disconnects the power coming from the dual battery switch.
Thanks

I have a similar setup, with similar goals. I regret not running a separate low power wire to maintain memories as I have found frequent reasons to disconnect batteries for general service. Of course for welding and such, you want everything disconnected (especially the electronics), but for other services I plan on installing a low power bypass.
I also installed a ground side knife switch on both batteries for complete isolation.

-JB

 

[ntsqd]

I put the actual disconnect in the ground cable. Run both battery's ground cables to the switch, ground on the other side. For keep-alive memory I jumper across the switch with a weatherpack single ATO fuse holder and the smallest amperage ATO fuse that I can find.

 

[kman67]

So it seems better to put the battery disconnect on the negative side. A jumper wire with quick disconnect is a good idea.
Thanks
Kyle


Sent from my iPhone using Tapatalk

 

[ntsqd]

Not a jumper wire as those will fry uncontrollably, a fuse holder. I tend to use these with a 1A or 2A fuse in them:
Weatherpack waterproof fuse holder

Can pull the fuse if you need complete shut-down, but any load that draws more power than the memory keep-alive circuit(s) will pop the fuse. Say that you're also using the battery switch as part of your anti-theft system. Trying to hot-wire the truck will pop the fuse. When I'm using the battery switch for that function I buy one of the Hella switches with a removable key.

This is the 500A version, they also make a 1000A version with a huge metal 'key':
Hella Keyed Battery Switch

 

[ntsqd]

Can also go with Rincon Power's LOTO enabled battery switches:
https://www.rinconpower.com/product-models/battery-disconnects

 

[kman67]

Not a jumper wire as those will fry uncontrollably, a fuse holder. I tend to use these with a 1A or 2A fuse in them:
Weatherpack waterproof fuse holder

Can pull the fuse if you need complete shut-down, but any load that draws more power than the memory keep-alive circuit(s) will pop the fuse. Say that you're also using the battery switch as part of your anti-theft system. Trying to hot-wire the truck will pop the fuse. When I'm using the battery switch for that function I buy one of the Hella switches with a removable key.

Ok, thanks for clarifying.
I won't be using this as a theft device, I have another kill switch for that.
Thanks
Kyle