Testing an Aux batt solution...

[HammaMan]

BMS - yes. It is about 9mm thickness, so I need to account for that. It might be underrated - bought the Daly 15A 4s before I was certain about my configuration. We'll see. Tough to find a small BMS with temperature protection.

Thanks for the image of the sensor squeeze. That helps me visualize possibilities.

That'll work for this application in parallel. It'll just turn charging on and off repeatedly until amperage isn't exceeded. You shouldn't notice it.

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[RedDragon65]

Finally got my Bluetooth Voltmeter installed, after a long day of driving yesterday/should be fully charged, this am after temp in the high teens, SOC = 12.35v, I have never had any battery issues so far, but stock battery coming up on 3 years old, time to take action on the underhood, underseat, or both recommended?

 

[Snakebitten]

12.35v (resting) is still high enough to avoid the typical low voltage issues.

Or at least on mine, I've never experienced disabled features or any kind of alerts, as long as the resting voltage was above 12.3V

But it's not the healthiest SOC, that's for sure.

 

[RedDragon65]

Thanks - will definitely put I on the list to address before next winter - or if it gets any worse

 

[RedDragon65]

12.35v (resting) is still high enough to avoid the typical low voltage issues.

Or at least on mine, I've never experienced disabled features or any kind of alerts, as long as the resting voltage was above 12.3V

But it's not the healthiest SOC, that's for sure.

One more quick question for the experts here - ran the Charge test from the app a few times - it is stating level is too high - reading between 15.13 - 15.18 - anything to be concerned with or need to have the dealer look at it before I go out of warranty?

 

[HammaMan]

That's the peak voltage at times while trying to charge the AGM. That's just the truck's behavior. So long as you're protecting the LFP with its own BMS, fan 5 can be used to charge the LFP properly. If the truck is putting out 15v, the LFP can't eat that. However when it tapers down outside of traditional charge behavior, fan 5 will keep it in the mid 14s else it will sit a hair under 13v.

 

[UGADawg96]

And back to 12.9 again while flashing. Guessing this thing does that continually as part of the process.

Even with turning off approach lighting and killing the lights as soon as the truck turns off, resting voltage overnight drops to 11.8v. I think I'm either going to need to set up one of these LFP parallel workarounds or just replace both 39 month old batteries. hrmmmm.

 

[RedDragon65]

That's the peak voltage at times while trying to charge the AGM. That's just the truck's behavior. So long as you're protecting the LFP with its own BMS, fan 5 can be used to charge the LFP properly. If the truck is putting out 15v, the LFP can't eat that. However when it tapers down outside of traditional charge behavior, fan 5 will keep it in the mid 14s else it will sit a hair under 13v.

Cool - thanks again for all the insights/recommendations!

 

[scott011422]

I'm also working on implementing this, Tired of the low voltage and HammaMans feedback on realistic cold weather behaviour I can certainly live with. While looking at battery mounting locations I was doing the math to see if the feeder wire to the aux battery was large enough to take the load of both batteries if I connected the LFP battery to the AUX battery like so many are doing when I had a thought.....

I'm not sure the aux battery actually does anything at all on the Powerboost. What does the Aux battery do? It runs the trucks electronics during cranking events. Sounds important. However, on the PowerBoost, The DC\DC converter is running the truck. While the factory aux battery is large enough to run all the electronics on the truck, I cant think of a single reason why it would ever have to?? If there isn't enough power in the HVB to run the DC\DC converter the truck wont even try to start. We've seen this at dealers when they have drained the HVB working on the trucks and they have had to wait for special chargers.

Now I'm not saying remove the battery. I'm just saying, As a thought experiment, What's really the point of that battery on the Powerboosts?

FYI, These PowerBoosts are soooo packed, There really isn't anywhere else to mount this battery closer to the underhood fuse panel. Still looking, But not looking promising.

 

[hpwjr]

First opportunity for me getting a good test on having put in the LFP in parallel to the AGM auxiliary battery. Last time I was gone for a while (4 or 5 days) when I came back my main battery registered 11.9 volts. Admittedly, it was a little cold for here—in the upper 40s. Yesterday I came home after 8 days gone from the truck—but after having installed the LFP battery. It was a little warmer, for sure—around 68–but the battery voltage was holding at a resting voltage of 13.01! I declare problem solved.

 

[tsigwing]

I'm also working on implementing this, Tired of the low voltage and HammaMans feedback on realistic cold weather behaviour I can certainly live with. While looking at battery mounting locations I was doing the math to see if the feeder wire to the aux battery was large enough to take the load of both batteries if I connected the LFP battery to the AUX battery like so many are doing when I had a thought.....

I'm not sure the aux battery actually does anything at all on the Powerboost. What does the Aux battery do? It runs the trucks electronics during cranking events. Sounds important. However, on the PowerBoost, The DC\DC converter is running the truck. While the factory aux battery is large enough to run all the electronics on the truck, I cant think of a single reason why it would ever have to?? If there isn't enough power in the HVB to run the DC\DC converter the truck wont even try to start. We've seen this at dealers when they have drained the HVB working on the trucks and they have had to wait for special chargers.

Now I'm not saying remove the battery. I'm just saying, As a thought experiment, What's really the point of that battery on the Powerboosts?

FYI, These PowerBoosts are soooo packed, There really isn't anywhere else to mount this battery closer to the underhood fuse panel. Still looking, But not looking promising.

When installing mine I accidentally blew the 125A fuse at the aux battery. Truck ran fine for two days without it while I waited for my dealer to get one in stock. Not sure under what conditions it is "needed", but I am sure it is included for some reason. Replacing the AGM with the LFP was not a HUGE deal, you just have to gut the existing box to mount it, and cobble together the wiring.

 

[HammaMan]

I'm also working on implementing this, Tired of the low voltage and HammaMans feedback on realistic cold weather behaviour I can certainly live with. While looking at battery mounting locations I was doing the math to see if the feeder wire to the aux battery was large enough to take the load of both batteries if I connected the LFP battery to the AUX battery like so many are doing when I had a thought.....

I'm not sure the aux battery actually does anything at all on the Powerboost. What does the Aux battery do? It runs the trucks electronics during cranking events. Sounds important. However, on the PowerBoost, The DC\DC converter is running the truck. While the factory aux battery is large enough to run all the electronics on the truck, I cant think of a single reason why it would ever have to?? If there isn't enough power in the HVB to run the DC\DC converter the truck wont even try to start. We've seen this at dealers when they have drained the HVB working on the trucks and they have had to wait for special chargers.

Now I'm not saying remove the battery. I'm just saying, As a thought experiment, What's really the point of that battery on the Powerboosts?

FYI, These PowerBoosts are soooo packed, There really isn't anywhere else to mount this battery closer to the underhood fuse panel. Still looking, But not looking promising.

The aux batt is a transient buffer for the DC/DC when the system isolates the large AGM to perform a rolling start of the truck while in hybrid mode. When the ABS accumulator triggers, it hits w/ ~50a pulses.

 

[tsigwing]

Installed a bluetooth battery monitor, checking this morning, getting 12.7V

 

[hpwjr]

Something has changed though I’m not sure it matters. My resting voltage is now varying from 12.6 to 12.8 instead of the 13.1 I was getting. My Lithium X2 says it’s at 98% full. What has this changed. We are in warmer weather now. Is that a factor?

 

[HammaMan]

Something has changed though I’m not sure it matters. My resting voltage is now varying from 12.6 to 12.8 instead of the 13.1 I was getting. My Lithium X2 says it’s at 98% full. What has this changed. We are in warmer weather now. Is that a factor?

What does the app show? Cell balance?
Are you using fan 5?

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