Dual battery/isolator/aux fuse box question...

So I thought I had a clever way to make this work, but I seem to have caught a snag...

My initial plan was to run an auxiliary battery off of my starting battery, with a dual battery isolator relay. Pretty much got that working. The next part is where my snag comes in...

I wanted to run the aux fuse panel off of the auxiliary battery, but instead of the direct current causing it to be 'always on' even when the car is off, I wanted it to trigger on when the car is on. So I ran another battery relay isolator from the aux battery to the aux panel, that is triggered to the 30a fuse for the radio in my main fuse panel to turn on when the car is on. The thing is, when this is all set up, and I test my aux panel, it still has constant power even when the car is off.

What am I doing wrong? Is the second isolator too redundant/messing things up? Is there another way to trigger the aux fuse panel to come on when the car is on?

Sorry if my explanation of things isn't clear, let me know if I need to add more detail to help explain better. Any help is appreciated. Thank you

 

My uneducated thoughts, You need to run the relay before the aux battery, as the aux battery is always on.

 

Well, I have 2 isolator relays, one between the dual batteries, and the next between the aux battery and the aux panel. My thought was that the second relay would be used to trigger on the aux panel at start up. The aux battery is always on, which in my mind, if I didnt have the second relay, would make the aux panel always on.

 

my schematic is like this:


Main Battery -> Isolator relay -> Aux battery
Aux battery -> isolator relay -> aux panel

 

K, didn't pick up on the first relay.

 

I woke up thinking about this.

1-not sure a relay is the right thing to use. First, does the relay allow some energy to pass through and then when switched on, allows more juice to flow. Or does it only allow energy to flow when switched on? I think I have seen folks using a solenoid to control the flow.
2-I'm don't believe you need both relays. I would remove the one between aux bat and aux fuse box.

 

Also, dont you need to tap into an ignition feed wire for your relay?

 

If you're only feeding the aux fuse panel with 30 amps, you can use a bosch relay. Using terminals 87 and 30 to switch the power to the aux fuse panel. Wire the feed from the battery with a fuse, to terminal 87. Terminal 30 connects to the fuse panel feed. If you reverse these 2 terminals then terminal 87a becomes hot when the relay is turned off. Terminals 85 and 86 are the coil that turns on the relay. Ground one and use a switched 12v on the other to turn the relay on with the key.

 

this is how i have my acr set up, i have a ignition isolator running to the acr so it delays it to the house battery and its accessories

 

You initial set up should have worked - using an ignition-on component to trigger the isolator. Maybe, you connected the wire to the wrong side of the fuse? Disconnect the wire and see if power to the isolator is disrupted. Use a voltmeter to make sure there is no power at your connect point when the power is off.

What isolator are you using? Most use power to close the points, allowing power to run through; some are the other way around, using power to open the points; thus, power goes through when no power is applied to the isolator.

 

if I were to remove the relay between the aux battery and fuse box, then the fuse box would always be on, which is kinda what i'm trying to avoid. I'm definitely gonna look in to the solenoid option

 

I think you're right, i'm gonna have to do more testing to see if the wires on the isolator are set up correctly. I'm using this iso in between my aux batt and aux fuse box:

$30 Stinger SGP38 80-AMP Battery Isolator and Relay,BLACK

https://www.amazon.com/gp/product/B001HC6UJ0/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

this is my aux battery:

$37 Chrome S Pro iGel YTX12-BS Battery – 180 CCA, Gel Electrolyte, LCD Display, 12V 10Ah – Fits ATV, Motorcycle, Scooter, Jet Ski, Dirt Bike, UTV, Snowmobile & More – T3 Nut & Bolt Terminal

https://www.amazon.com/gp/product/B00IUWLZMW/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

the isolator didnt come with instructions on which wire to hook up to and where, and I guess i just figured like my initial and larger isolator between the cranking battery and aux battery, on which the instructions noted that the hook up between the trigger and the ground didnt really matter. I'll have to do some more testing on this. Thanks to you all for the input, I really appreciate it

 

Not that its creating your problem, but that battery is NOT what you want to use for an aux... you need to find a deep cycle battery.

If you want to find a small battery for aux you might look into wheelchair batteries.

 

Really? Is this one considered a cranking battery? will this one damage my components?

 

Won't damage anything, you're battery just isn't designed to be drained and recharged like you have it set up.

 

I was thinking that if you weren't supplying juice to aux battery, it wouldn't supply juice to aux fuse box. I seemed to forget that the aux battery will still hold juice.

 

@hammertaco11 That solenoid should be fine. It doesn't matter which of the smaller connections go to the ground source. Your issue is going to be with the wiring. I think you tapped into a live wire.

I have a similar setup, using a second solenoid to run juice to a fuse panel. However, my setup is all manual; I'm using a DPDT switch to manage both solenoids. But, I have thought about running the second solenoid to an ignition-on source. Using a voltmeter I found an available connection in the fuse box. Some day, when I run out of projects, I may re-wire it.

 

Interesting, I do not at all profess to be an expert in this stuff - in fact quite the opposite. I would be very interested to hear where you gathered the info about gel batteries having deep cycle capabilities (no sarcasm) .

My career for the last 8 or so years has been building custom motorcycles and I can only speak from what I have observed, these little batteries DO NOT like to be discharged over and over, it kills them very quickly. Be it AGM, Li-ion, or standard lead acid. While the former might have a little more resilience than a standard lead acid, they still seem to hate a discharge of more than 70% or so repeatedly..

Again I really have no science based info to back this up personally, just purely observational.


Edit: out of curiosity just went and looked at one of the li-ion batteries pamphlet and it clearly says not to allow it to discharge on the front. All the AGM batteries I have had say the same



Another Edit: reading the page on his battery I came across this so I dont know maybe he will be fine Saying it can be re-charged that many times kind of alludes to the fact that it can be dis-charged that many times.

 

Sir, you correct. I was thinking AGM. I have a Deka Intimidator which is not designed for complete discharging but can recuperate better than a standard battery from a discharged state. I edited my entry; thanks for correcting me.