Better late than never!

[JohnnyCLE]

Thanks Dr.!, Markopolo, I will take that as no one has admitted to trying.

I guess I will be the first then as I plan to move to a slight variation of GSM's approach while my existing 6v batteries have life, and then to a slight variation of Booster's approach as they reach EOL and need to be replaced. The slight variation is to continue with the front pair of batteries, likely in series as they are.

Resigned that for the near term my AC run time will continue to be limited. Probably replace the 50amp lead breaker in the 110v service box with a 30amp one so that no one is tempted to pull 5000 watts out of the inverter at one time!

[JohnnyCLE]

Detail on how and why to best care for your batteries was missing from, or at best glossed over, in the Owner's Manual for the 2014/+ AGM E-Trek's. I have attempted to write this section of the manual and paste a link to the .pdf here.

(See attachment below!)

Hopefully this link works! It is a link to a public Microsoft OneDrive folder.

This is targeted at existing owners as a starting point to understand how to care for their E-Trek batteries. It also should be useful for someone who is considering purchasing a used E-Trek. It may be useful for owners of other AGM based systems.

There are some horror stories posted about E-Treks. After 5 years, I still like my E-Trek, but have discovered that I have not taken very good care of the critical batteries. I hope to do better in the future and continue the learning process. The somewhat pioneering capabilities of the E-Trek and some correctible engineering weaknesses, combined with many first time owners, and poor training / documentation was an unfortunate mix.

Many thanks to the much discussion which has gone into the understanding summarized in this document. Any proofing or editorial comments welcome!

[booster]

Originally Posted by JohnnyCLE

Detail on how and why to best care for your batteries was missing from, or at best glossed over, in the Owner's Manual for the 2014/+ AGM E-Trek's. I have attempted to write this section of the manual and paste a link to the .pdf here.

https://1drv.ms/b/s!Apbr3zGy2xSEldwK...exrEw?e=TzfEGw

Hopefully this link works! It is a link to a public Microsoft OneDrive folder.

This is targeted at existing owners as a starting point to understand how to care for their E-Trek batteries. It also should be useful for someone who is considering purchasing a used E-Trek. It may be useful for owners of other AGM based systems.

There are some horror stories posted about E-Treks. After 5 years, I still like my E-Trek, but have discovered that I have not taken very good care of the critical batteries. I hope to do better in the future and continue the learning process. The somewhat pioneering capabilities of the E-Trek and some correctible engineering weaknesses, combined with many first time owners, and poor training / documentation was an unfortunate mix.

Many thanks to the much discussion which has gone into the understanding summarized in this document. Any proofing or editorial comments welcome!

Definitely a good idea and should be useful as there is a lot of missing and bad information floating around on the etreks and how they work and should work.


The One Drive folder access will be a problem for some of us as, like us, they either aren't signed up for One Drive or have bailed on it because of it's intrusiveness into our privacy. I found that even though I would disable it so it could only be used for saving certain files, it would turn itself back on with Windows Updates, and download everything on the computers. On top of that, it took many files and put them on One Drive only without saving copies to the computer even though set to do the copies. When I tried to access them, it would then again go into downloading everything else it hadn't seen since the last time on. Horrible thing for privacy and actually "owning" your files. They appear to want to get as much data of yours as they can to make you go over your free space limit and then hold the files hostage so you sign up for the paid service.


I assume you probably have a pdf or doc file? or could save the information to one? If so, you can just use the "manage attachments" button that show up in the additional options section when you do a reply and then upload the file to the this site. Just copy the uploaded location it gives you into a post and everybody should be able to see it pretty easily by clicking the link.

[JohnnyCLE]

Much better approach! Thanks!

[JohnnyCLE]

This may be of interest to battery people and owners of Sprinters who may have batteries in the engine compartment as well as in a back undercarriage.

Today I was scheduled to have a Victron battery monitor installed in my E-Trek. Because of dual ground issues and much discussed E-Trek battery concerns I decided, for the interest of science, to have two monitors installed, with temperature probes, both in the engine compartment and in back.

First data from the 2 hour drive home! Started out in in-town driving and the engine compartment quickly heated up to 15 degrees F above ambient air, which was 85 and humid. The rear battery compartment slowly warmed up but for the first 30 minutes was 5-6 degrees above ambient air. A 10 degree difference.

A major change happened when I hit more open road - mph 55-70. The engine compartment cooled off to 6 degrees above ambient and the rear battery compartment warmed up to 15 degrees above outside air. The Sprinter seems to do a good job of pushing engine heat underneath the coach and the emissions system runs hotter than the engine. At highway speeds it was the rear batteries which got warm - reading of 99 degrees vs 84-85 outside.

Just one data point, but different than what has been presumed.

[booster]

Originally Posted by JohnnyCLE

This may be of interest to battery people and owners of Sprinters who may have batteries in the engine compartment as well as in a back undercarriage.

Today I was scheduled to have a Victron battery monitor installed in my E-Trek. Because of dual ground issues and much discussed E-Trek battery concerns I decided, for the interest of science, to have two monitors installed, with temperature probes, both in the engine compartment and in back.

First data from the 2 hour drive home! Started out in in-town driving and the engine compartment quickly heated up to 15 degrees F above ambient air, which was 85 and humid. The rear battery compartment slowly warmed up but for the first 30 minutes was 5-6 degrees above ambient air. A 10 degree difference.

A major change happened when I hit more open road - mph 55-70. The engine compartment cooled off to 6 degrees above ambient and the rear battery compartment warmed up to 15 degrees above outside air. The Sprinter seems to do a good job of pushing engine heat underneath the coach and the emissions system runs hotter than the engine. At highway speeds it was the rear batteries which got warm - reading of 99 degrees vs 84-85 outside.

Just one data point, but different than what has been presumed.

That is really interesting, and is so far away from any temps I have ever seen in engine compartments that it is sort of hard to grasp.



We have two alternators that when not working hard tend to run at just above the ambient around them, in our Chevy. Ambient tends to track the radiator temperature pretty closely in pattern and temp. We always see at least 30* or more above ambient with them. Of course, they are on the engine, not away from it like batteries.



It would be very interesting to see where the monitor temp sensor is mounted in relation to the batteries. It is very common, in starting batteries at least, for the manufactures to have some often hard to see ducting from the grille or headlight areas to the battery for cooling, and there is often even a shroud around the battery to direct the cool airflow around the battery. The fact that it went so low on the highway seems to indicate it may be reading the temp of road air, which would commonly be at least 6* warmer than normal ambient most of the time. In general, on warm days most of the air into an engine compartment comes through the radiator so is heated by the radiator so the temp of he water should be directly related to the compartment temps. Radiators run hotter on the inlet side and cooler on the outlet side. If you have an infrared temp gun in would be interesting to get the radiator temps if you can get at it well enough around AC condenser.



We have heard a lot about early battery failures on the front two batteries in the etreks, and very often the stated cause is high temperatures, so lots of contradictory information there.



The rear battery temps sound similar to what we see on ours in similar location, about 15* above ambient in warm weather. I think most of the rear heat comes from the rear axle which runs about 150* on the center case area at highway speeds.

[JohnnyCLE]

Re the Victron installs. The temperature readings are from the respective positive battery terminals. I had the install done by the closest authorized Vectron dealer. I will take some pictures and post.

I am looking forward to running some tests, after the holiday weekend. I am thinking the most consistent amp draw will be running the 12v vent fan and the 110v AC, fan only.

Any suggestions on unique things I should be looking for? Or settings I should check?

[booster]

Originally Posted by JohnnyCLE

Re the Victron installs. The temperature readings are from the respective positive battery terminals. I had the install done by the closest authorized Vectron dealer. I will take some pictures and post.

I am looking forward to running some tests, after the holiday weekend. I am thinking the most consistent amp draw will be running the 12v vent fan and the 110v AC, fan only.

Any suggestions on unique things I should be looking for? Or settings I should check?

What you get for reading will be very interesting, as I am not certain which grounds will be reading which batteries and in what voltage.


I would need to go back in the archives and try to find the homemade wiring diagram that another user had posted to see exactly how the strings are wired, I think that the shunts could be seeing current going to only the 12v section of batteries and also current going to the 24v batteries and since the shunts are in the negative line, they won't know the difference. How that is going to apply to the accumulation of amp hour use from any given battery, that is good for any real monitoring, is certainly a question. It may depend on where the battery sense is connected for voltage, and if the meters are set for 12 or 24v for the watt-hr calculations.


Need to go find that diagram....

[booster]

Here is a link to and earlier thread that started as a monitor add and got into a bunch of other things etrek and batteries if you haven't seen it. It does have a wiring diagram of a system that Roadtrek added a balancer to.


https://www.classbforum.com/forums/f...tall-3984.html


Long and inconclusive, but points out a lot of the items that are in question, I think.


Another here with similar stuff


https://www.classbforum.com/forums/f...nt-3947-2.html


The monitor being able to do anything really useful is in question through a lot of these threads, unless the system is taken to pure 24v with a 24 to 12 converter.

[JohnnyCLE]

Thanks! Yes, I have read through that thread multiple times. It will be interesting to see how the current flows. Pulled and pushed 24v at the head, bridged and tapped in the middle with potential flows from the smart solenoid. Eight batteries, two locations, potentially charged from four sources and pulled at two levels. It is a marvel of engineering!

[booster]

"marvel of engineering" would be one way to describe the system, although I can also think of many other ways

[JohnnyCLE]

I am just somewhat impressed that it works at all, at some level.

Attached is my best attempt to model it:

I am hopeful that a solution will evolve where all of the 24v can be in back, as you suggested long ago, supplemented by two additions for 12v in the front. Connected by a DC - DC converter / charger. This contributed to installing the two battery monitors.

I have not found an AGM 8v GC2 battery. The ones I have found have been FLA. Am I missing them somewhere?

[booster]

Originally Posted by JohnnyCLE

I am just somewhat impressed that it works at all, at some level.

Attached is my best attempt to model it:

I am hopeful that a solution will evolve where all of the 24v can be in back, as you suggested long ago, supplemented by two additions for 12v in the front. Connected by a DC - DC converter / charger. This contributed to installing the two battery monitors.

I have not found an AGM 8v GC2 battery. The ones I have found have been FLA. Am I missing them somewhere?

Here is one for you:


Motive T875-AGM | Trojan Battery Company

[booster]

Here is another one from the old posts and appears to be th e200ah version.


https://www.batterystuff.com/batteri...gc8-45968.html

[JohnnyCLE]

Thanks for the links!

Attached are photos of the Victron shunt and temperature probe installs. The monitoring units are tucked away in the driver's side wheel well cabinet as I will be accessing via bluetooth.

[JohnnyCLE]

Attached are the Victron readings while charging using shore power at night with all loads disconnected. The charger is set to push 28.4 v, which shows up in the solar voltmeter. The 24v monitor shows close at 7.04v / battery, but the 12v monitor shows substantially less at 6.45v / battery.

Any guess as to why? Would length of cabling have this effect or could this be caused by a battery issue. I would have expected to see a more consistent charge current across all batteries.

[JohnnyCLE]

Attached are temperature readings from the respective grounds in the engine compartment for 12v and in the battery compartment for 24v. These were after a 3 hour interstate drive with ambient air around 86 degrees F.

[JohnnyCLE]

Attached are pictures which show how current is pulled for 24v demand and 12v demand across the split E-Trek grounds. Current flows are measured for each bank at the respective grounds. This is for a system without a battery balancer.

[themexicandoctor]

An observation; I don't have a Dog in this discussion but wanted to remark that its refreshing to see both the Engagement & the Data that is being shared ...

[JohnnyCLE]

Thanks Doc! The AGM E-Treks have a remarkably unique battery arrangement. It occurred to me that I have one of the few "virgin" models without a battery balancer, and probably the only one of those with the ability to gather data from the two banks and grounds.

I am now leaning towards having a balancer installed this winter, but thought that it would be of interest to gather actual data on the behavior of the original design. Something Roadtrek probably should have done and published when people began to have issues with battery life and there was a lot of speculation as to why.