Ecotrek batteries won't fully charge.

Moto Vita

Active member
After some research it appears I may be able to turn off power from the solar charger to the batteries using my MT 50 meter. I will look into that this morning,
 

RT.SS

Active member
Where are you measuring the 16-volts, from the discharge or charge post? Unlikely from the charge post, the inverter is directly connected to the charge post (if rewired) via 4/0 wire, and you mention reading 14-volts at inverter DC terminals, that is a huge voltage drop. Also, the AGM kicker will be boiling over at 16-volts.

If the Ecotrek discharge post is reading 16-volts, then likely that is the culprit why the charge relays are offline. You have to trace the inverter DC connections if it’s indeed rewired to the Ecotrek charge post as recommended by RT, this prevents backdoor charging of the Ecotreks resulting to overcharging.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
Where are you measuring the 16-volts, from the discharge or charge post?

That may be part of a design problem. Inverter/charger combo units share the same connection to the battery, so they can't make any distinction between a charge and discharge port. But the battery's BMS thinks otherwise.

Which port did the solar get connected to?
 
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Moto Vita

Active member
Where are you measuring the 16-volts, from the discharge or charge post? Unlikely from the charge post, the inverter is directly connected to the charge post (if rewired) via 4/0 wire, and you mention reading 14-volts at inverter DC terminals, that is a huge voltage drop. Also, the AGM kicker wilasl be boiling over at 16-volts.

If the Ecotrek discharge post is reading 16-volts, then likely that is the culprit why the charge relays are offline. You have to trace the inverter DC connections if it’s indeed rewired to the Ecotrek charge post as recommended by RT, this prevents backdoor charging of the Ecotreks resulting to overcharging.
I measured at the terminal to the right of the negative terminal, I don't know which that is, the voltage there reads the same as the output terminals on the inverter/charger. I also measured voltage at the terminal to the left of the negative terminal, I can't remember now but it was either the same or zero (my only excuse is that I'm in severe pain when crawling under the van). I will check it again.
The AGM kicker has some sort of seperation that I don't understand. The voltage reading at the AGM is slightly different than system voltage and when the Ecotrek batteries are switched off the AGM voltage doesn't read on the voltmeter and the lights won't run off the AGM (if they would I could probably get to AZ just using the AGM).
Edit.
I just looked at a photo on the LS2 website and it shows the right hand terminal as the charge port on the current batteries.
 
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Moto Vita

Active member
That may be part of a design problem. Inverter/charger combo units share the same connection to the battery, so they can't make any distinction between a charge and discharge port. But the battery's BMS thinks otherwise.

Which port did the solar get connected to?
I haven't seen where the solar power ties into the system. I ran through the functions of the MT50 meter on the controller, I thought it would let me shut the system off but it doesn't. I did verify all the settings and I noticed that the battery voltage reading on the MT50 meter is lower than what I measure at the batteries.
 

Moto Vita

Active member
Where are you measuring the 16-volts, from the discharge or charge post? Unlikely from the charge post, the inverter is directly connected to the charge post (if rewired) via 4/0 wire, and you mention reading 14-volts at inverter DC terminals, that is a huge voltage drop. Also, the AGM kicker will be boiling over at 16-volts.

If the Ecotrek discharge post is reading 16-volts, then likely that is the culprit why the charge relays are offline. You have to trace the inverter DC connections if it’s indeed rewired to the Ecotrek charge post as recommended by RT, this prevents backdoor charging of the Ecotreks resulting to overcharging.
The 16 and 14V readings were with the system unloaded and loaded respectively.
 

Moto Vita

Active member
Where are you measuring the 16-volts, from the discharge or charge post? Unlikely from the charge post, the inverter is directly connected to the charge post (if rewired) via 4/0 wire, and you mention reading 14-volts at inverter DC terminals, that is a huge voltage drop. Also, the AGM kicker will be boiling over at 16-volts.

If the Ecotrek discharge post is reading 16-volts, then likely that is the culprit why the charge relays are offline. You have to trace the inverter DC connections if it’s indeed rewired to the Ecotrek charge post as recommended by RT, this prevents backdoor charging of the Ecotreks resulting to overcharging.
With the batteries switched off and the inverter/charger on I'm getting 17.1V at the charge terminal on the Ecotrek battery and 0 at the discharge post. When I turn the inverter off the voltage at the charge terminal drops to 16.4V. The solar charger shows 13.4V at the battery with very low amperage since it was almost dark. Logic tells me that the 16.4V must be coming from the battery although the onboard voltmeter shows 12.9V when I turn the batteries on. The DC accessories in the coach seem to work normally, I'm assuming that they will draw the battery down to it's cutoff point since I don't show charging voltage on the onboard meter (unlesss I hold the reset button down). It seems that that Roadtrek rewired the system to current specs and the system worked fine for 5 years after they last worked on it.
I'm at a loss.
 
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Nic7320

Solera 24S on a 2011 NCV3 chassis
If you charge a battery through a MOSFET (the internal switch inside a BMS) and then disconnect the charger, what you measure at the battery input is the battery voltage minus one diode drop (about 0.7 volts) from voltage back feeding through the body-drain diode that is part of the MOSFET.

In other words, the MOSFET is not a perfect on/off switch and your measurements of 17.1V and 16.4V make perfect sense.

But that leads me to a more serious question with potential safety issues. Is your lithium battery pack really getting charged to 17 volts? If so, your charger is providing an overvoltage and your BMS is not doing its job.

Double check one thing before we go any further. What is the voltage between the battery negative post and the vehicle's chassis ground? You might just have a bad ground strap, which would explain why both banks failed simultaneously. One easy test for this is to take your battery jumper cables and parallel a second battery negative connection to chassis ground connection. Doing this will short out your current shunt (if you have one) but that also might be part of the problem.
 
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Moto Vita

Active member
If you charge a battery through a MOSFET (the internal switch inside a BMS) and then disconnect the charger, what you measure at the battery input is the battery voltage minus one diode drop (about 0.7 volts) from voltage back feeding through the body-drain diode that is part of the MOSFET.

In other words, the MOSFET is not a perfect on/off switch and your measurements of 17.1V and 16.4V make perfect sense.

But that leads me to a more serious question with potential safety issues. Is your lithium battery pack really getting charged to 17 volts? If so, your charger is providing an overvoltage and your BMS is not doing its job.

Double check one thing before we go any further. What is the voltage
between the battery negative post and the vehicle's chassis ground? You might just have a bad ground strap.
You've exceeded my electrical knowledge by bringing up MOSFETs.
You mean between the center ground stud on the Ecotrek battery and the chassis, right? I don't understand why I would find voltage there, but I can check in the morning.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
You're exactly right, there should be very little voltage there. Even with a current shunt, there should only be about 0.1 volts or less. But if there is more than that, then that explains your high voltage readings. You might be reading about a 13 volt battery in series with a highly resistive pathway to ground that creates an additional voltage drop (or voltage rise, in this case).

When you measured the battery charging input, what did you use for a negative reference on your meter? The battery post, or a more convenient chassis point?
 
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RT.SS

Active member
Keep in mind that the AGM kicker battery is connected to the Ecotrek charge terminal; without a charging source (solar, shore, UHG), and with Ecotrek switched off, you are reading the AGM battery voltage. It is unlikely that the 12-volt AGM will hold a surface charge of 16 volts. It's possible that your multimeter's internal battery is low; many multimeters will produce a false high reading when its battery is low. Verify the multimeter reading by checking a battery with a known voltage.

With Ecotrek turned on and if properly working, you should get same voltage reading at the discharge and charge terminals against the battery negative post. A voltage drop at the DC house load could indicate a bad ground or poor connections.

Here's a simple way to see if the Ecotrek charge terminal relay is working and if the inverter is wired to the Ecotrek charge side. Without shore and with engine off, switch off both Ecotreks, then power on the inverter. If the inverter powers on, then it’s wired into charge side and it is being powered by the AGM battery. At this point, the 3kW inverter can supply a small load and will shut down from low voltage when a larger load is applied (ex: microwave).

With the Ecotrek turned on, see if the inverter can now power the same high demand appliance (ex: microwave); if so, the Ecotrek charge relay is operational and not in protection mode. At this point, the Ecotrek is powering the inverter via the charging terminal relay. If the charge relay is indeed operational, the Ecotrek should be getting charge current from any of the available chargers (UHG, solar, and shore). I hope that makes sense to you.

FYI: Ecotreks BMS does not use MOSFETs, the charge and discharge terminals are switched by internal relays.
 

Moto Vita

Active member
You're exactly right, there should be very little voltage there. Even with a current shunt, there should only be about 0.1 volts or less. But if there is more than that, then that explains your high voltage readings. You might be reading about a 13 volt battery in series with a highly resistive pathway to ground that creates an additional voltage drop (or voltage rise, in this case).

When you measured the battery charging input, what did you use for a negative reference on your meter? The battery post, or a more convenient chassis point?
I was using the center battery post.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
Ecotreks BMS does not use MOSFETs, the charge and discharge terminals are switched by internal relays.

Most BMS boards on the market do use MOSFETs, but I do recall an early specification that pretty much mandated safety relays. So considering the age of the Ekotrek, this piece of information helps but becomes another very puzzling clue.

Since MV is measuring directly at both battery terminals, it rules out a bad ground connection external to the battery. It was a nice theory that was dashed by two facts; one, they use relays rather than FETs, and two, he's measuring directly on the battery terminals instead of using a ground connection somewhere downstream.

And 0.7 Volts of voltage drop was a very odd coincidence. But it's also way too high of voltage drop for internal relay contacts and the intrinsic battery resistance, especially since the voltmeter draws negligible current to create any IR drop.

And these inconsistent readings between the two meters is a problem. Maybe get a better meter and get data that agrees with one meter or another.
 
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Nic7320

Solera 24S on a 2011 NCV3 chassis
What's the chance your charger got glitched into a higher voltage setting, and your BMS is doing exactly what it should do, that is, shut down when there’s too much input voltage.

This is the reason I design in redundant safety layers to lithium batteries. All it takes is one Single Event Upset to change a software setting, and then your system ends up doing something it shouldn't ever do.


But that doesn't explain the UHG overvoltage, unless it uses the same charge regulator.
 
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Moto Vita

Active member
What's the chance your charger got glitched into a higher voltage setting, and your BMS is doing exactly what it should do, that is, shut down when there’s too much input voltage.

This is the reason I design in redundant safety layers to lithium batteries. All it takes is one Single Event Upset to change a software setting, and then your system ends up doing something it shouldn't ever do.


But that doesn't explain the UHG overvoltage, unless it uses the same charge regulator.
I/m waiting for daylight to do the suggesting testing. meanwhile heres a pic of my inverter panel.
1698934344932.jpeg
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
That shows you're in bypass mode and shore power or UHG is going straight to your outlets through the internal transfer switch. .

A couple odd things I see; It isn't saying 60 Hz line frequency, but rather "AF" Hz. Also, it thinks you're at 100% charge, but only shows two bars with room for more

Is there another page to see your bulk/absorption/float voltage settings?

Getting another meter, preferably with a DC current clamp, would help here a lot.

This one is well priced:
 
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Moto Vita

Active member
That shows you're in bypass mode and shore power or UHG is going straight to your outlets through the internal transfer switch. .

A couple odd things I see; It isn't saying 60 Hz line frequency, but rather "AF" Hz. Also, it thinks you're at 100% charge, but only shows two bars with room for more

Is there another page to see your bulk/absorption/float voltage settings?

Getting another meter, preferably with a DC current clamp, would help here a lot.

This one is well priced:
I wonder what "AF" Hz means? I guessed it might be automatic frequency, I'm also confused by the sine wave directed at the battery, I guess that indicates the charger?
I think the 100% charge that's not full is my problem. I need to look for a manual for my inverter.
I put that meter in my Amazon cart but I'll be on the road for a few days.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
I would interpret the Sine wave to battery icon to indicate the charger is getting power. It doesn't necessarily mean it's charging if the charger thinks it's full.

"AF" might mean "altered frequency," but I'm only guessing. They show units of Hz (Hertz), but it might not be a true frequency counter if it's simply looking for 60 Hz or indicating something it doesn't like. Hopefully RT can help us there.

State of Charge estimators can be erroneous. They don’t measure SOC directly; they keep track of current coming and going and make a SOC estimate based on that. SOC estimators can and do drift. They're sort of like trying to keep track of your bank account balance by adding up your deposits and withdrawals, with a few errors along the way. SOC estimators need a way to synchronize to 100% SOC when some criteria are met.

Also, remember State of Charge is not a measure of State of Energy. An Ah (Ampere hour) at full voltage has more energy than an Ah at a lower voltage. Electric cars don't use SOC for this reason because it doesn't track remaining miles of range.

Amazon lockers are available while you're on the road.
 
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Moto Vita

Active member
Keep in mind that the AGM kicker battery is connected to the Ecotrek charge terminal; without a charging source (solar, shore, UHG), and with Ecotrek switched off, you are reading the AGM battery voltage. It is unlikely that the 12-volt AGM will hold a surface charge of 16 volts. It's possible that your multimeter's internal battery is low; many multimeters will produce a false high reading when its battery is low. Verify the multimeter reading by checking a battery with a known voltage.

With Ecotrek turned on and if properly working, you should get same voltage reading at the discharge and charge terminals against the battery negative post. A voltage drop at the DC house load could indicate a bad ground or poor connections.

Here's a simple way to see if the Ecotrek charge terminal relay is working and if the inverter is wired to the Ecotrek charge side. Without shore and with engine off, switch off both Ecotreks, then power on the inverter. If the inverter powers on, then it’s wired into charge side and it is being powered by the AGM battery. At this point, the 3kW inverter can supply a small load and will shut down from low voltage when a larger load is applied (ex: microwave).

With the Ecotrek turned on, see if the inverter can now power the same high demand appliance (ex: microwave); if so, the Ecotrek charge relay is operational and not in protection mode. At this point, the Ecotrek is powering the inverter via the charging terminal relay. If the charge relay is indeed operational, the Ecotrek should be getting charge current from any of the available chargers (UHG, solar, and shore). I hope that makes sense to you.

FYI: Ecotreks BMS does not use MOSFETs, the charge and discharge terminals are switched by internal relays.
I checked my meter by checking the battery of a car parked in the garage overnight. 13.2V
The van had the inverter/charger running overnight,
Underhood AGM measured 14.V
Voltage at the inverter output, which should be system voltage was 15.6V
My onboard meter read 12.8V
My solar charger panel (MT50) shows battery voltage as 13.7V
As I said I think there is something between the AGM and the rest of the system that, among other things, seems to protect it from high system voltage.

"Here's a simple way to see if the Ecotrek charge terminal relay is working and if the inverter is wired to the Ecotrek charge side. Without shore and with engine off, switch off both Ecotreks, then power on the inverter. If the inverter powers on, then it’s wired into charge side and it is being powered by the AGM battery. At this point, the 3kW inverter can supply a small load and will shut down from low voltage when a larger load is applied (ex: microwave)."
Yes

"With the Ecotrek turned on, see if the inverter can now power the same high demand appliance (ex: microwave); if so, the Ecotrek charge relay is operational and not in protection mode. At this point, the Ecotrek is powering the inverter via the charging terminal relay. If the charge relay is indeed operational, the Ecotrek should be getting charge current from any of the available chargers (UHG, solar, and shore). I hope that makes sense to you."

Yes. I had to reconnect shorepower to get the Ecotreks to turn on, I'm not sure why.
During this test the heating element in the portable heater I was using for a load died, coincidence I think, so I switched to a hair dryer.

I still have the battery and ground checks to do that I have to crawl underneath for, I was stalling since it's raining.
 
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