Install auxiliary battery disconnect in 5 minutes

[jebiruph]

@J Sierra

I installed a set-up few years ago. Works great!

I can see voltage of both Aux and Main.... can separate batteries.... can charge separately .... and I have Aux bypassed. I can toggle Aux if I opt to.

Thanks again, @jebiruph who assembled the kit for me.

If anyone is interested, this is the thread that lead to this setup that @Rhinebeck01 posted. It's a good read if you are bored. https://www.jlwranglerforums.com/forum/threads/ess-dual-battery-management.60034/post-1287541

Here is the new simplified version with one voltage gauge and one switch and without the jumper or battery switch.

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[J Sierra]

This is the ground for the aux battery. The shunt is 75mv at 150A. 80mv is 160A peak for the aux ground.

 

[jebiruph]

Something is amiss - accuracy or whatever.
I can believe a microsecond spike in the hundreds of amps, but no way these pull more than a 4.5" massive Motorcraft starter cranking over a cold 390 for any period of time perceivable by man.
800 is a pretty large spike considering all that the current does is:
Operate the pull-in and hold-in windings of the solenoid, after which time the pull-in windings are taken out of circuit (if these solenoids even HAVE two windings)
And - operate the armature of the starter since there are no field windings.
It's an initial 'short' when the armature is connected by the solenoid and stationary, as soon as it moves, that changes. (not truly a short, but for all practical purposes it appears as such)

Wouldn't the dual batteries, the higher voltage of the AGM battery, the high compression of the 3.6 and a smaller starter all contribute to higher starting current?

 

[ShadowsPapa]

Wouldn't the dual batteries, the higher voltage of the AGM battery, the high compression of the 3.6 and a smaller starter all contribute to higher starting current?

The AGM batteries are only 12.7-12.8 volts.
A standard non AGM L/A battery is a bit over 12.6 when fully charged, something like 12.64 or whatever.
So that's small fractions of a volt, and I'd bet he's not running this on freshly topped off AGM batteries with the surface charge just removed.

The 3.6 is high compression in theory - they take the volume at BDC and compare it to the volume at TDC.
That's how they get "advertised compression ratio".
The fact is - if the intake closing is retarded at all, you can't use those numbers for reality as some air will bleed off as the piston comes up before the valve fully closes. So in effect, they can achieve lower cranking compression - Open late, close late, and you have a lower real compression.
The cylinder isn't totally sealed off at BDC.
And if you have an engine with better than 100% pumping efficiency, say the Honda 4 valve engine, that gets about 114% pumping efficiency, the dynamic compression can be a lot higher because you have more air in the cylinder than would otherwise exist at rest.
You can drastically change the volumetric efficiency of an engine with how well the head and intake flow, valve timing, lift, duration, overlap.............

I bet the numbers change a heck of a lot on these based on the valve lift mode, cam timing and other factors between cranking, running idle, running redline, running load, no load and so on.

 

[J Sierra]

Now add the clamp on meter. Channel 2 is shunt, channel 3 is clamp on.

 

[J Sierra]

Shunt reads 75mv = 150A peak, and clamp on reads 154A peak.

 

[J Sierra]

Starter cable channel 2, aux ground channel 3. Next is main ground 2 and aux ground 3. Next two images

main ground 2 and alternator 3.

 

[J Sierra]

Battery test, top is main next is aux

 

[ShadowsPapa]

Battery test, top is main next is aux

What device is giving battery test

 

[J Sierra]

Battery tester/charger Topdon TB6000

 

[ShadowsPapa]

Battery tester/charger Topdon TB6000

Thanks. I will look that up and see what they are all about.
My battery testing involves an antique carbon pile and my documents from GM training on battery testing.

 

[J Sierra]

What it does is put a small load then a larger load and with ohms law figures the internal resistance of the battery.

 

[ShadowsPapa]

What it does is put a small load then a larger load and with ohms law figures the internal resistance of the battery.

Dang, it gets decent reviews.

I like to have multiple tools for some things - you might not believe - or maybe you would, how many different volt meters I have, at least 6 torque wrenches, and so on.

 

[J Sierra]

Manual charging mode in TB6000, complete control of charging.

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