12V Battery replacement with H4

[carys98]

Is a LVB Voltage Reading of 12.47 considered Normal on a truck sitting overnight?

I’m not really an expert on this but I don’t really trust using the voltage to determine SOC. If you search around there are various sources and they don’t all agree but it looks like 12.47 is somewhere around 80-90% SOC. The other concern is that unless you disconnect the battery you don’t know if there is a load that might be dropping the voltage.

Here is one chart that I found.

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[jwrezz]

Personally I'd say that's pretty normal.

Both my trucks LVB and my backup battery (also 30Ah AGM) are both at 12.5V right now and they've been sitting for about a day.

You have a backup battery? How is it wired and where do you keep it?

 

[Adventureboy]

I’m not really an expert on this but I don’t really trust using the voltage to determine SOC. If you search around there are various sources and they don’t all agree but it looks like 12.47 is somewhere around 80-90% SOC. The other concern is that unless you disconnect the battery you don’t know if there is a load that might be dropping the voltage.

Here is one chart that I found.

This chart would be fairly accurate if the battery were disconnected. The battery voltage will read lower for a given SOC while it is powering up modules, which is always the case if the frunk is open.

 

[Adventureboy]

@mr.Magoo when you get a minute, can you check what part number is on your Battery Management Sensor? I had the CSP done a while back, but the part number on mine is ML3T-10C652-BA and doesn't match the CSP. I think the part is just a dumb current shunt so it should be ok, but I'm concerned because my voltage at the battery post is high compared to what you are seeing.
Last night, my charge cycle was 2 hours and it held ~15.28v for the full 2 hours. Last weekend, my charge cycle was 7 hours and it started around 15.25 v and ended at 14.99v. Driving today ranged from 15.21-15.23v (on/off for about 2 hours)
Figured I'd verify the voltage, so I started the truck and it read 15.18v on the monitor, but only 15.0-15.05v on the CarScanner. I figured, ok, makes sense because there is probably a minor loss through the wires to the module if they are carrying the current to run the module and my monitor is measuring on the posts. Got the multi-meter out and it matched the monitor (actually read about 0.02v higher than the monitor, which is close enough). SOC was 83% on the ODB reading when I did this.

Interesting dynamics while doing this. Sitting in the seat, the voltage was over 15v frunk open. When I went to the frunk, the voltage dropped to just over 13v. Thought that was weird, so I went back and sat in the seat - it jumped back to 15v. Definitely have some complex algorithms going on here...

 

[mr.Magoo]

You have a backup battery? How is it wired and where do you keep it?

OK, so it's not a backup for the truck itself, it's a backup for my data logger / dash cam.
It's placed where the OEM jack used to be and I have a separate DC/DC charger to maintain it.

 

[mr.Magoo]

@mr.Magoo when you get a minute, can you check what part number is on your Battery Management Sensor? I had the CSP done a while back, but the part number on mine is ML3T-10C652-BA and doesn't match the CSP.

I'm pretty sure I have a ml3z10c679b, at least that's what I ordered.
I never waited for the CSP, I just replaced it myself at the time.

I've seen some weird stuff with mine lately but I don't know if it's because of my battery (Diehard H3) is almost two years old or if it's because I accidentally drained it completely like 0% SoC and 9V (that was a long time ago though) plus a few deep discharges (sub 40%) that was more on purpose, or if there's other things going on.

I did see scenarios where it would maintain 15V for a VERY long time even though the battery wouldn't take any charge (current), but it was also cold-ish at the time so who knows what's going on.

 

[dingmah]

I actually just finished the same H4 upgrade tonight and took some reference photos. Since you’ve already posted a guide, I’ll just drop my pictures there instead of making a new thread.

 

[Airforce]

I actually just finished the same H4 upgrade tonight and took some reference photos. Since you’ve already posted a guide, I’ll just drop my pictures there instead of making a new thread.

I understand that the cause of the Bulging battery is because of being Overcharged and to remedy this issue is to use a Trikle battery charger?

 

[RLXXI]

I understand that the cause of the Bulging battery is because of being Overcharged and to remedy this issue is to use a Trikle battery charger?

The plastic cases these batteries are built with will bulge slightly, it's normal, no need to do anything special or buy anything extra.

 

[Adventureboy]

I figured I would post my H4 replacement results after the first week. I didn't need to drive this past week, but I have to do the driveway shuffle twice per day to let the wife in/out of the garage. We know this is particularly hard on the 12v because it lights up all of the modules for a while before putting them back to sleep without giving the 12v any significant charge time.
The H4 is much more tolerant of that abuse. Tracking the voltage for 4 days with no charge cycles, the H4 did exactly as it was supposed to do. The voltage dropped steadily through the 4 days and after the 8th driveway shuffle on the 4th day, the Lightning charged the H4 to 100% - no drama. My 2-year-old H3 would cycle after 24 hours and even when new, wouldn't make it more than a couple of days.

The monitor I'm using also calculates SOC, but it always under calculates the SOC value compared to the ODB2 SOC. It said 40% SOC when the truck started charging. In this case, because of the larger H4, there is no way to tell what the real SOC was on the H4 when the truck charged it. There is no way to tell what the BMS SOC was, since that requires you to be in the truck with the modules on. I estimate the ODB SOC to be around 50% when it triggered the charge cycle based on the knowledge that my monitor undercalculates by about that much.
Note the major SOC steps line up with my driveway shuffles. The steps are about -5% SOC for each driveway shuffle on the H4. On the 2-year-old H3, they were about -15% SOC.

I'll report back if anything goofy happens, but for now, I'm very happy with the swap, and I have a 5-year free replacement warranty.

 

[mr.Magoo]

The plastic cases these batteries are built with will bulge slightly, it's normal, no need to do anything special or buy anything extra.

So you're saying that a little bulge is OK, but a big bulge is creepy - I mean - bad ?

 

[chl]

Same here big difference from Ancel 200 compared to car scanner. Removed and returned to Amazon.

Comparing apples to oranges I think.
Ancels are supposed to be highly rated and accurate.

But did you use it to bench test the battery, i.e., with the battery disconnected from the truck and allowed to settle for at least an hour after the last charge to 100%, before testing?

Not sure what the OBD data is telling CarScanner about the 12v battery when it is still connected - it could be telling your what the BMS says the SOC is, a coulomb counting system that could stray from the truth.

 

[chl]

I figured I would post my H4 replacement results after the first week. I didn't need to drive this past week, but I have to do the driveway shuffle twice per day to let the wife in/out of the garage. We know this is particularly hard on the 12v because it lights up all of the modules for a while before putting them back to sleep without giving the 12v any significant charge time.
The H4 is much more tolerant of that abuse. Tracking the voltage for 4 days with no charge cycles, the H4 did exactly as it was supposed to do. The voltage dropped steadily through the 4 days and after the 8th driveway shuffle on the 4th day, the Lightning charged the H4 to 100% - no drama. My 2-year-old H3 would cycle after 24 hours and even when new, wouldn't make it more than a couple of days.

The monitor I'm using also calculates SOC, but it always under calculates the SOC value compared to the ODB2 SOC. It said 40% SOC when the truck started charging. In this case, because of the larger H4, there is no way to tell what the real SOC was on the H4 when the truck charged it. There is no way to tell what the BMS SOC was, since that requires you to be in the truck with the modules on. I estimate the ODB SOC to be around 50% when it triggered the charge cycle based on the knowledge that my monitor undercalculates by about that much.
Note the major SOC steps line up with my driveway shuffles. The steps are about -5% SOC for each driveway shuffle on the H4. On the 2-year-old H3, they were about -15% SOC.

I'll report back if anything goofy happens, but for now, I'm very happy with the swap, and I have a 5-year free replacement warranty.

Over time, going down to 50% or 40% before topping off will take its toll.
Going below 90% for 4 days is not a good thing for the battery.

One way to know for sure what the low SOC is would be to disconnect the battery and put it on a good quality battery tester.

The best thing for lead-acid batteries is to keep them at 100% as much as possible and us a low charging current when topping off.

That big jump from 50% or 40% to 100% indicates a large current spike. Also not good for lead-acid batteries.

The Lightning Battery Manglement System at work on your new battery.

 

[Pitbull2o08]

I did what I saw some others had done an put a small hole in the plastic near the charge port door hinge and ran a wire to the battery compartment, Easy to reach in when the frunk is open to route the SAE charge wire - I had a spare with a built in fuse I used.

I bought a NOCO Genius1 - it has a proprietary charge plug on it so had to also get the adapter for the SAE standard ($15 groan), and I got a 15ft SAE extension cord so I could put it in my garage next to my FCSP EVSE and run the wire next to the CCS1 cable to my driveway.

Here are some pics:

The port door closes fine with the SAE cord there.

I had used a plastic bag and some twist ties to cover the CCS1 and the SAE wire connection when we had a snow and ice storm - kept them dry very well.

Inside my garage I can plug the NOCO in out of the weather.

See this thread for other ideas on ways to use a maintainer with the Lightning:

https://www.f150lightningforum.com/forum/threads/charging-12v-battery.16979/

I thought the 12 V was charged during plug-in charging?

 

[chl]

I thought the 12 V was charged during plug-in charging?

It is but apparently that isn't enough in many cases to keep the battery healthy, and one might only plug-in charge once a week for example, while the 12v battery will keep going down to maybe as low as 50% or so, and then then the charging current when it comes will be very high, also not a good thing.

Best to keep lead-acid batteries like our AGMs at 100% as much as possible for longevity.

PS: that seem to be what the OP is seeing in his data.

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