Tyler-98-W68
Well-Known Member
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I’m sure everyone has seen Brandon Haneline’s video of him running a power inverter on his 4xe. This was a great video that showed how the HV battery topped up the smaller 12v battery (providing the HV battery had sufficient charge).
The 4xe has a 2.5KW (2500w) DC/DC Charger/Converter which charges the 12v battery.
2500W / 12v = 208 amps. So in theory a 4xe is a 208amp “alternator” to charge the 12v battery.
There also is a Bosch IBS (intelligent battery sensor) which can be monitored to show all the aspects of the 12v battery and it’s operating parameters. The IBS measures the State of charge and then adjusted voltage/amperage to the battery. Which is what I’m displaying on the OBDlink software.
In Brandon’s video it showed the voltage dropping down to the low 11’s and then the HV battery kicking in and charging the 12v battery back up. That’s perfect and operating as designed but how much of the 208amps that the DC/DC charger can produce is the battery receiving? I was able to test and monitor that out today. Now I don’t have my cables set up for my inverter quite yet so I couldn’t run high draw devices like Brandon did, so I chose to drain the battery down a fair amount and then monitor how many amps the battery would get from the DC/DC charger.
If you didn’t already know. Any time the hood is popped the 12v battery is disconnected from the HV battery. So the way I drained the battery down was to have the vehicle in RUN (without starting it) hood up and then plug in my devices, which really wasn’t much. Combined with the headlights on HVAC on max, I was able to get a constant power draw of 42 amps at 12v or around 500w. Really not much power but over time it would drain the 12v battery.
I’ve attached a few pictures to show power draw on the 12v (not the HV battery)
Simply having the vehicle in the RUN position with nothing else on (HVAC off) no headlights simply just being on draws 18amps.
Cranking up with HVAC turning on the headlights = 31amps.
When I added in my small inverter in the rear I got a 42amp draw. With the hood open the battery had no way to charge and was draining down.
Upon closing the hood and having the HV battery able to charge the battery again I was able to measure a peak of 85amps immediately after closing the hood and progressively lower the charge.
I then tried to start the vehicle up without having the ICE come on, however it did come on and continued to charge at a rate around 40amps. What was interesting (and off topic) is that it said EMU came on but the PID’s I had monitored did not change so there is another parameter for battery charging that locks out Electric only mode.
This behavior very closely resembles the battery charging behavior in my 2014 Grand Cherokee with a 240a Alternator, except with a bit of an issue which I found in my next test.
I forgot to show the PID for SOC or state of charge in the first test so I did another test, I wanted to show this to see how fast or slow the SOC of the 12v battery would recover while charging.
For the second test I drained the battery down to 49% SOC then closed the hood and recorded the battery behavior while being charged. I got an even higher peak charge rate of 129amp which then progressively lowered but then it dropped a very large amount to around 20amps of charge rate. This behavior is not ideal and not like my Grand Cherokee, Which has the same IBS and a 240a alternator. In my Grand Cherokee I could recover almost 50% SOC in 20 minutes because of the large amperage going in to the battery and it did not drop off the charge rate like in the 4xe.
Here is a video of the 4xe during the second charging test
(the video is sped up 8x)
This is a video of my Grand Cherokee charging the battery up much quicker (video is also sped up) for comparison
You can see that the Grand Cherokee sustains a higher charge longer, now yes the SOC started much lower, but there was no large drop in charging current.
I ended the 2nd Charging test at 55% SOC. However even though I stopped monitoring, the battery did continue to keep charging. I ended up going to a drive in electric mode and whether the vehicle was driving or not did not change the charge rate. After 2.5 hours the SOC was 75% and minimal current going in to the battery as shown in the picture below.
A few reasons why this may have happened.
The one thing I found during these tests is that the factory 12v is pretty much junk for any type of serious power use. I understand it’s not meant for deep and constant cycling because it’s backed by the HV battery (except if the HV battery is depleted). But the voltage drop even with a 40amp load is quite high. I’m used to having high quality AGM deep cycle batteries in my vehicle. I’ve been using Northstar batteries in all my vehicles for a few years. A quality battery can handle larger loads without as great of voltage drop under load.
With all the battery failures seen on the 4xe (and other jeep models), I don’t trust the factory mopar batteries for anything. The battery in my vehicle is the H6 size since I don’t have the tow package but the difference in specs H6/vs H7 aren’t that great and they are still the same mopar junk used in other vehicles.
Related to the battery failures, one contributing factor could be that the battery is getting drained down to a low SOC and then not really being charged up properly or high enough, progressively leading it to be drawn down and left in a drained state to the point of failure. But using the data I have from my other vehicle it would seem the charging algorithm is to blame(on the 4xe) and could be causing the batteries to fail. Only way to know is if others monitor their SOC and report back their findings.
If anyone is planning on using their vehicle in an overlanding type setup or wanting to run high draw devices (like a power inverter) it would be wise to invest in a high quality deepcycle battery. For a few reasons.
I’ve got much more testing to do but at least it’s a start.
Should anyone want to look at IBS behavior in my Grand Cherokee they can read my post here
https://www.jeepgarage.org/threads/...e-monitoring-from-ibs.234560/#post-2021319226
The 4xe has a 2.5KW (2500w) DC/DC Charger/Converter which charges the 12v battery.
2500W / 12v = 208 amps. So in theory a 4xe is a 208amp “alternator” to charge the 12v battery.
There also is a Bosch IBS (intelligent battery sensor) which can be monitored to show all the aspects of the 12v battery and it’s operating parameters. The IBS measures the State of charge and then adjusted voltage/amperage to the battery. Which is what I’m displaying on the OBDlink software.
In Brandon’s video it showed the voltage dropping down to the low 11’s and then the HV battery kicking in and charging the 12v battery back up. That’s perfect and operating as designed but how much of the 208amps that the DC/DC charger can produce is the battery receiving? I was able to test and monitor that out today. Now I don’t have my cables set up for my inverter quite yet so I couldn’t run high draw devices like Brandon did, so I chose to drain the battery down a fair amount and then monitor how many amps the battery would get from the DC/DC charger.
If you didn’t already know. Any time the hood is popped the 12v battery is disconnected from the HV battery. So the way I drained the battery down was to have the vehicle in RUN (without starting it) hood up and then plug in my devices, which really wasn’t much. Combined with the headlights on HVAC on max, I was able to get a constant power draw of 42 amps at 12v or around 500w. Really not much power but over time it would drain the 12v battery.
I’ve attached a few pictures to show power draw on the 12v (not the HV battery)
Simply having the vehicle in the RUN position with nothing else on (HVAC off) no headlights simply just being on draws 18amps.
Cranking up with HVAC turning on the headlights = 31amps.
When I added in my small inverter in the rear I got a 42amp draw. With the hood open the battery had no way to charge and was draining down.
Upon closing the hood and having the HV battery able to charge the battery again I was able to measure a peak of 85amps immediately after closing the hood and progressively lower the charge.
I then tried to start the vehicle up without having the ICE come on, however it did come on and continued to charge at a rate around 40amps. What was interesting (and off topic) is that it said EMU came on but the PID’s I had monitored did not change so there is another parameter for battery charging that locks out Electric only mode.
This behavior very closely resembles the battery charging behavior in my 2014 Grand Cherokee with a 240a Alternator, except with a bit of an issue which I found in my next test.
I forgot to show the PID for SOC or state of charge in the first test so I did another test, I wanted to show this to see how fast or slow the SOC of the 12v battery would recover while charging.
For the second test I drained the battery down to 49% SOC then closed the hood and recorded the battery behavior while being charged. I got an even higher peak charge rate of 129amp which then progressively lowered but then it dropped a very large amount to around 20amps of charge rate. This behavior is not ideal and not like my Grand Cherokee, Which has the same IBS and a 240a alternator. In my Grand Cherokee I could recover almost 50% SOC in 20 minutes because of the large amperage going in to the battery and it did not drop off the charge rate like in the 4xe.
Here is a video of the 4xe during the second charging test
(the video is sped up 8x)
This is a video of my Grand Cherokee charging the battery up much quicker (video is also sped up) for comparison
You can see that the Grand Cherokee sustains a higher charge longer, now yes the SOC started much lower, but there was no large drop in charging current.
I ended the 2nd Charging test at 55% SOC. However even though I stopped monitoring, the battery did continue to keep charging. I ended up going to a drive in electric mode and whether the vehicle was driving or not did not change the charge rate. After 2.5 hours the SOC was 75% and minimal current going in to the battery as shown in the picture below.
A few reasons why this may have happened.
- Poor quality battery, IBS didn’t like some parameters and did not keep feeding the high amperage to recharge the battery
- Limitation of the IDCM or DC/DC Charger which won’t put out large amounts of current for extended periods of time.
- The first test the SOC wasn’t monitored but the battery wasn’t also as low of SOC so maybe there is a threshold that will keep “fast” charging going, I simply exceeded that in my second test.
The one thing I found during these tests is that the factory 12v is pretty much junk for any type of serious power use. I understand it’s not meant for deep and constant cycling because it’s backed by the HV battery (except if the HV battery is depleted). But the voltage drop even with a 40amp load is quite high. I’m used to having high quality AGM deep cycle batteries in my vehicle. I’ve been using Northstar batteries in all my vehicles for a few years. A quality battery can handle larger loads without as great of voltage drop under load.
With all the battery failures seen on the 4xe (and other jeep models), I don’t trust the factory mopar batteries for anything. The battery in my vehicle is the H6 size since I don’t have the tow package but the difference in specs H6/vs H7 aren’t that great and they are still the same mopar junk used in other vehicles.
Related to the battery failures, one contributing factor could be that the battery is getting drained down to a low SOC and then not really being charged up properly or high enough, progressively leading it to be drawn down and left in a drained state to the point of failure. But using the data I have from my other vehicle it would seem the charging algorithm is to blame(on the 4xe) and could be causing the batteries to fail. Only way to know is if others monitor their SOC and report back their findings.
If anyone is planning on using their vehicle in an overlanding type setup or wanting to run high draw devices (like a power inverter) it would be wise to invest in a high quality deepcycle battery. For a few reasons.
- Superior cycling capability (drain it down over and over again)
- Ability to start the vehicle from a very low voltage (My northstar will start my 5.7 Hemi below 11v)
- If your HV battery does get depleted you can draw down the 12v battery without being stranded in a no start situation.
- A high quality battery can take large amounts of current for a long period of time.
I’ve got much more testing to do but at least it’s a start.
Should anyone want to look at IBS behavior in my Grand Cherokee they can read my post here
https://www.jeepgarage.org/threads/...e-monitoring-from-ibs.234560/#post-2021319226
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