Powerboost 12v battery charging tip

[Snakebitten]

From my testing the only time that isolator opens is on flywheel starter engagement.

I have a quote from the service manual screenshotted somewhere and it states exactly what you mentioned. It's purpose is to provide 12V power to the entire 12V system for the few seconds that the AGM is isolated to the bendix starter loop during Cranking Event.

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[HammaMan]

I have a quote from the service manual screenshotted somewhere and it states exactly what you mentioned. It's purpose is to provide 12V power to the entire 12V system for the few seconds that the AGM is isolated to the bendix starter loop during Cranking Event.

I still think the most surprising thing when I had nothing in the AGMs and the DCDC ran the belt starter to engage the ICE. Did not expect that. I need higher frequency sampling to see that in action.

 

[Samson16]

I’m looking at the sparse wiring diagram in the modifiers guide and it shows the AGM is charged via the starter/generator.

 

[Samson16]

From the guide. Notice Charging System line labeled AA as it goes to sheet 2.

 

[Samson16]

I have a quote from the service manual screenshotted somewhere and it states exactly what you mentioned. It's purpose is to provide 12V power to the entire 12V system for the few seconds that the AGM is isolated to the bendix starter loop during Cranking Event.

The Auxiliary Battery Isolator actually isolates the main AGM battery from the Battery Junction Box(BCMC) during the traditional starter event according to the diagram. The DC/DC 12V output and the 12V auxiliary battery remain connected. That circuit is labeled BB as it goes between sheets.

 

[Davexxxx]

By voltage alone your 12v system was already at a low

Yes, I was a bit surprised to see it that low. So far, the truck has given me no warnings of, or reduced functions of any kind.

" I found the conditions and shared them so that anyone who may have weird issues will know how to for-sure enable 12v generation "

Of course and thank you. It still seems like a weird, outlier type hack to me. Fan speed at 5 to to fully charge the batts?

"Due to the LFP keeping the 12v AGM floating at 100%"

Can you explain the why of that? If the factory cut off is 80% and forscan is often bumped to 90-95%, how is your LFP and it's BMS, over-riding all of that to achieve 100% on the starting batt?

Related, it has been mentioned that the 2 batts are only truly paired at starting circuit energization.

Guess I'm trying to assure I haven't picked up wrong info. I thought the small batt was for running the ancillaries, so the starting batt didn't get worn down by all the electronic goodies of modern vehicles.

Guess I'm looking for a, leg bone connected to the hip bone, type order of things.

My current ability to measure DC amps, is limited to the 20 amp swing. of my meter. It won't always be that way but it is today.

 

[Samson16]

There appears to be a Battery Monitoring Sensor for the main AGM and a Battery Current Sensor for the Aux Battery.

 

[Samson16]

Related, it has been mentioned that the 2 batts are only truly paired at starting circuit energization.

I defer to others, but I think the Main AGM is isolated from the "DC Bus"(which includes the auxiliary battery and the DC/DC 12V supply) only during the starter event when the AGM is providing cranking Amperage to the traditional flywheel starter.

I think the statement is incorrect. The 2 batts are isolated from each other during starting circuit energization. Main AGM and Starter----isolator----Aux Bat and DC/DC 12V supply

*The statement not Your statement. Apologies.

 

[turbopilot]

I defer to others, but I think the Main AGM is isolated from the "DC Bus"(which includes the auxiliary battery and the DC/DC 12V supply) only during the starter event when the AGM is providing cranking Amperage to the traditional flywheel starter.

I think your statement is incorrect. The 2 batts are isolated from each other during starting circuit energization. Main AGM and Starter----isolator----Aux Bat and DC/DC 12V supply

Given that the 2023 PB "Stop Safely" events are happening when pushing the start button I wonder if we are beginning to understand what may be happening with these battery switching events.

 

[Samson16]

Given that the 2023 PB "Stop Safely" events are happening when pushing the start button I wonder if we are beginning to understand what may be happening with these battery switching events.

With the Modifier's guide schematics I can see part of the basic power layout. I can see there is also something called the Module Communications Network but I need more information. Hamma, Snake, and the guys are doing a great job working backwards by observation and testing.

Backwards Forwards and sideways actually lol. Whatever it takes

 

[Davexxxx]

We drove a 50 or 60 mile round trip yesterday.

Just now checked the engine batt. 12.5V.

Pulled the cover off the rear batt. Same reading.

 

[Snakebitten]

Unless the battery isolator is in isolation mode, you should get the same reading at both batteries since they are connected.

As far that so-called Belt Drive Starter Generator........ The 12V battery cable harness to the 12V AGM under hood battery does indeed travel to both the traditional 12V bendix starter AND the Belt Drive Starter Generator. So when the "Cranking Event" isolates the AGM from the rest of the truck, it's actually isolating both starters too, since the battery cable is the only power harness connecting to the starters. Forgive the required pinch/zoom to read this :

 

[Snakebitten]

Battery Isolator

 

[Snakebitten]

The entire 12V battery cable. (High DC amperage cable)
Look closely and it travels to both starters.

 

[turbopilot]

Thanks @Snakebitten. Why two starters?

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