Does it have an auto shutoff function?
Builds Moonshine - A Build Thread (12 Viewers)
- Thread starter GLTHFJ60
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- Thread starter
- #4,002
The BMS does have an auto shutoff function. It will detect low cell voltage and prevent discharge below that point.
- Thread starter
- #4,003
76* today, SOC dropping off quickly now. Renogy monitor now registers 0, BMS says 33%. So we won't get a month, but I'm happy if we get two full weeks with mild weather!
Hey. Remember this?
I got the blue beast out of hibernation this spring. Lots of work getting the brakes back on line, but otherwise she fired right up and is chugging along. A little exhaust work to reattach an 02 sensor, but after that I’ll be inspected and street legal.
I got the blue beast out of hibernation this spring. Lots of work getting the brakes back on line, but otherwise she fired right up and is chugging along. A little exhaust work to reattach an 02 sensor, but after that I’ll be inspected and street legal.
I think the biggest problem is that you're keeping your Bud Light at 38*. Waaaay too warm. You need to drop that to 28* right now!
Just kidding (kinda...I like cold beer). Nice job!
Just kidding (kinda...I like cold beer). Nice job!
- Thread starter
- #4,006
Flashback! Holy crap man, how the hell are you? Still in NY?
- Thread starter
- #4,007
Came out this morning and the Renogy monitor was off, which is expected when the BMS is shut off, or shuts itself off:
The BMS bluetooth app shows discharging has been turned OFF, due to the reason "Protection Cell Undervoltage", meaning the cells have gotten too low:
The BMS bluetooth app shows discharging has been turned OFF, due to the reason "Protection Cell Undervoltage", meaning the cells have gotten too low:
- Thread starter
- #4,008
After flipping on the battery join feature of my PowerGate battery isolator, the AGMs are connected in parallel with the LiFePO4 array, and the array instantly starts charging. Interestingly enough, the LiFePO4 array was drawing ~30a from my AGMs with the battery join feature only (truck still off):
A few seconds later, the Renogy monitor came back to life, indicating that the LiFePO4 array was charging from the AGMs:
I then started the truck with the battery join feature still on, and we can observe via the Renogy that the LiFePO4 array is now charging at a rate of ~74a. This is combined alternator amperage, as well as draw amperage from the AGMs. The Renogy is wired to ONLY monitor amperage in/out of the LiFePO4 array:
After this SUCCESSFUL test, the battery join switch was turned off, but the batteries are still joined by the PowerGate, since the PowerGate automatically joins the batteries while alternator voltage is present.
FINALLY, the truck was shut off, and we can see that the LiFePO4 array absorbed 0.08AH, low voltage protection is off, and discharging is now disabled. SUCCESS!!!
A few seconds later, the Renogy monitor came back to life, indicating that the LiFePO4 array was charging from the AGMs:
I then started the truck with the battery join feature still on, and we can observe via the Renogy that the LiFePO4 array is now charging at a rate of ~74a. This is combined alternator amperage, as well as draw amperage from the AGMs. The Renogy is wired to ONLY monitor amperage in/out of the LiFePO4 array:
After this SUCCESSFUL test, the battery join switch was turned off, but the batteries are still joined by the PowerGate, since the PowerGate automatically joins the batteries while alternator voltage is present.
FINALLY, the truck was shut off, and we can see that the LiFePO4 array absorbed 0.08AH, low voltage protection is off, and discharging is now disabled. SUCCESS!!!
- Thread starter
- #4,009
So, what does this all mean? Let's go over the wiring concepts once more.
- Two AGM batteries (wired in parallel) charge via the alternator through the PowerGate MOSFET battery isolator.
- LiFePO4 battery array charges through via the alternator through the PowerGate MOSFET battery isolator
- While the truck is OFF (alternator not charging) the two battery banks are isolated
- While the truck is ON (alternator charging) the two battery banks are connected via the battery isolator, and charge in parallel
- The AGMs supply power ONLY to the engine starter, and winch
- The LiFePO4 array supplies power to the vehicle 12v harness (factory fuse box, ignition, etc), as well as all accessory loads (fridge, lights, etc)
In conclusion:
1. When the LiFePO4 array is drawn down by loads to zero, the BMS shuts off discharging to protect the LiFePO4 array.
2. When this occurs, the truck has no power (expected)
3. The Battery Join feature, activated by a carling switch on the dash, connects the AGMs to the LiFePO4 array (in parallel) in order to self-jump
4. In this scenario, I can then start the truck and the alternator charges both battery banks as expected.
Conclusions:
- I love this whole thing.
- The system is maintenance-free, and redundant.
- Nearly two full weeks of fridge use with the truck off in mild weather.
- I expect that to drop down to maybe 5 or 6 days in the dead of summer, or when I'm using the lights more
- I expect the battery life to extend a bit when the fridge is more full, or the weather is colder.
- The Renogy monitor may not need to be recalibrated, as after it reported 0AH remaining, there was only a few hours left of charge in the LiFePO4 array.
HUGE thanks to @J Mack for blazing the trail with LiFePO4 batteries, at least for me. This is far and away the best possible #broverland power system. Thank you Jim!!!
- Two AGM batteries (wired in parallel) charge via the alternator through the PowerGate MOSFET battery isolator.
- LiFePO4 battery array charges through via the alternator through the PowerGate MOSFET battery isolator
- While the truck is OFF (alternator not charging) the two battery banks are isolated
- While the truck is ON (alternator charging) the two battery banks are connected via the battery isolator, and charge in parallel
- The AGMs supply power ONLY to the engine starter, and winch
- The LiFePO4 array supplies power to the vehicle 12v harness (factory fuse box, ignition, etc), as well as all accessory loads (fridge, lights, etc)
In conclusion:
1. When the LiFePO4 array is drawn down by loads to zero, the BMS shuts off discharging to protect the LiFePO4 array.
2. When this occurs, the truck has no power (expected)
3. The Battery Join feature, activated by a carling switch on the dash, connects the AGMs to the LiFePO4 array (in parallel) in order to self-jump
4. In this scenario, I can then start the truck and the alternator charges both battery banks as expected.
Conclusions:
- I love this whole thing.
- The system is maintenance-free, and redundant.
- Nearly two full weeks of fridge use with the truck off in mild weather.
- I expect that to drop down to maybe 5 or 6 days in the dead of summer, or when I'm using the lights more
- I expect the battery life to extend a bit when the fridge is more full, or the weather is colder.
- The Renogy monitor may not need to be recalibrated, as after it reported 0AH remaining, there was only a few hours left of charge in the LiFePO4 array.
HUGE thanks to @J Mack for blazing the trail with LiFePO4 batteries, at least for me. This is far and away the best possible #broverland power system. Thank you Jim!!!
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Way to overcomplicate some batteries bro. Lol jk. That's a pretty neat system and it's cool that's all working properly.
Are you still running the stock Dodge 120A alternator?
- Thread starter
- #4,012
Yes sir, with one of those internal regulator kits.
My mind is hurting trying to follow this entire system. I have the standard Blue Sea 7622 ACR in the 62. I'm trying to decide if I want to invest in something like this for the 4Runner.
So far my arb fridge isn't a problem on trips with a single battery. I have a 100W solar panel going up on the roof rack which should help with any issues.
So far my arb fridge isn't a problem on trips with a single battery. I have a 100W solar panel going up on the roof rack which should help with any issues.
- Thread starter
- #4,014
Having a solar panel would extend your battery run time for sure.
In short, it all depends how often you travel to places where you set up camp for a week or more at a time without driving.
I don't plan on having the truck sit still for more than 1-2 days and worst case I can start the car for 15 minutes each day. Seems like your setup is a bit more robust than my needs.
Yep. Still in New York. At an engineering firm now. The truck has sat for 3-4 years, but I did get a rebuilt transmission put in it. probably be a bunch of small issues as I get some miles on it, but I’ve got a lift at my shop now, so the jobs will be way easier.
I get a discrepancy with mine too but haven’t had time to dig to find out why, because the BMS is actually monitoring individual cell voltage estimate capacity I’ve been just using that number for my baseline.
Moonshine is a beast, I hope to be able to see it in person some day!
- Thread starter
- #4,018
Awesome man!! Super cool that you're getting back into it. My truck has changed quite a bit since you last saw it! Must have been 13 years ago now?
Thanks Jim! Glad to hear I'm not the only one with a mismatch.
- Thread starter
- #4,019
Took the truck for a drive yesterday, and I did find one hiccup. When the array SoC is very low (0-2%) according to the BMS, the array will draw over 120A from the alternator+AGMs to charge when at any RPM **above idle**. This trips the over current protection within a second or two:
This happened while driving yesterday. I noticed the issue because my Renogy monitor showed 0a charging while driving, which I've never seen before.
The lock icon in the center of the screen can be used to disable charging and discharging, which then resets the protection modes. When locked, left for 5 seconds, then unlocked again, the protections reset, and allows the array to charge and discharge again. Super cool unintended consequence of my wiring; due to the fact that I have my vehicle harness fusible link connected to the PowerGate terminal that feeds the LiFePO4 array, the truck can continue running when the LiFePO4 array is shut off / disconnected / broken, as long as one of the two conditions are met:
1. Vehicle running, meaning both outputs of the power gate are connected for charging via alternator
2. Battery Join switch is activated, which allows the fusible link to draw solely from the AGMs.
Of course, this wiring config also means that the vehicle harness is fed from the LiFePO4 array when the engine is off and the battery join feature is *not* activated.
So, failure mode is redundant as well!!!
What's the fix for this condition?
Well, at idle, the array draws ~70A from the alternator/AGMs, and within a few minutes, the array comes up above 5%, and it no longer draws >100A while driving.
Idling at low SOC:
After a few minutes, driving around >5% SOC, the array only pulls 60-70A:
This happened while driving yesterday. I noticed the issue because my Renogy monitor showed 0a charging while driving, which I've never seen before.
The lock icon in the center of the screen can be used to disable charging and discharging, which then resets the protection modes. When locked, left for 5 seconds, then unlocked again, the protections reset, and allows the array to charge and discharge again. Super cool unintended consequence of my wiring; due to the fact that I have my vehicle harness fusible link connected to the PowerGate terminal that feeds the LiFePO4 array, the truck can continue running when the LiFePO4 array is shut off / disconnected / broken, as long as one of the two conditions are met:
1. Vehicle running, meaning both outputs of the power gate are connected for charging via alternator
2. Battery Join switch is activated, which allows the fusible link to draw solely from the AGMs.
Of course, this wiring config also means that the vehicle harness is fed from the LiFePO4 array when the engine is off and the battery join feature is *not* activated.
So, failure mode is redundant as well!!!
What's the fix for this condition?
Well, at idle, the array draws ~70A from the alternator/AGMs, and within a few minutes, the array comes up above 5%, and it no longer draws >100A while driving.
Idling at low SOC:
After a few minutes, driving around >5% SOC, the array only pulls 60-70A:
Last edited:
- Thread starter
- #4,020
Conclusion Addendum:
1. I could add a higher current BMS to prevent this ~120a overcurrent condition. The same BMS model comes in 120A configurations as well as the 100A configuration I have currently.
overkillsolar.com
2. 120a alternator is more than enough capacity for this truck.
3. If the LiFePO4 array completely fails for some reason, I can still run the truck completely and entirely off of the AGMs via the PowerGate battery isolator.
LOVE IT
1. I could add a higher current BMS to prevent this ~120a overcurrent condition. The same BMS model comes in 120A configurations as well as the 100A configuration I have currently.
4s BMS 120a LifePo4 with M6 Threaded Terminals – Overkill Solar
overkillsolar.com
3. If the LiFePO4 array completely fails for some reason, I can still run the truck completely and entirely off of the AGMs via the PowerGate battery isolator.
LOVE IT
