New to RVs and Hopeful Warp Core RoadTrekkers

[Davydd]

Last night before I left I did do what he said with the 5 second reset button press for each battery. This morning when I came back, one of them was online and that allowed me to get shore power to the rest after I reset it and the inverter kicked on.

Taking care of paperwork stuff around town but will head back to the unit to "learn" some more

Once you reset a battery bank you then have to charge it. That takes time as said. Once you reset if you did not charge it enough, the parasitic draw will take it back down to the 20% threshold and you will have to start over with reset and charge again. It is the BMS. At 20% your lithium batteries are not discharged.

 

[BBQ-ClassB]

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Don't charge all the banks at once.

Charge one at a time.

 

[BBQ-ClassB]

In one of the home build lithium threads here, we did get a look at that, and I think the net conclusion was that stopping the charging at about 13.8v or so was probably a good spot, as they would be nearly full but wouldn't be at 100% or held at full charge voltage which is not good. The AGM profiles will be at about 13.5v, so will be lower SOC. The knee in the curve is very steep, so not a lot of change in SOC once you get past that 13.5v, IIRC. There will be no change in charging speed, as the charger is maxed out anyway, with the voltage still in the climbing toward absoption stage of 14.4v. If it bumps to float earlier, it will just sit there at the lower voltage, which I don't think we have ever seen an answer to if that is bad, or if the charger(s) should be shut off.

That explains why so many users report they could never get their ecotreks fully charged.

 

[booster]

That explains why so many users report they could never get their ecotreks fully charged.

I think a lot of it will also depend on how far down the batteries are, and how long the absorption and total charge cycle times are set. If it stays in absorption to 14.4v, they will get nearly 100%, but if it bumps to float at 13.5v they will lower. Again, we just don't really know how they do it, but the parts the use would certainly indicate there are a lot of compromises in the system that make it less than optimum in operation or battery control.

A multistage charger is really not the right one for lithium, from what we see now from the battery folks, as they would prefer a full shutoff charger at the SOC you desire, but less than totally full and not with a float charge. Although we haven't seen any real data on the full shutoff penalty if not there.

 

[wincrasher]

Absorption?!

Lithiums should bulk charge only. No absorption phase, and no floating.

 

[Davydd]

We are talking about Lithium Ion here aren't we? There is no absorption and they can be fully charged easily.

Hammill asked where the 20% SOC number came from? What is the cut off? I thought Roadtrek originally said 10%.

Why are you staying in hotel or even running all your batteries down at once? You ought to be experiencing your Roadtrek.

 

[booster]

Absorption?!

Lithiums should bulk charge only. No absorption phase, and no floating.

Yep, that is the point exactly, so why use an AGM multistage profile in the charging systems?

 

[wincrasher]

Well, how do we know that is what they are doing? Why would you try to charge with shore power anyways? Why not get it out on the highway and fast bulk charge with the GU?

 

[booster]

Per Greg earlier

From everything I have seen, it appears that the charge profiles of all the chargers are set to an AGM tailored charge profile which will get max life out of the AGM with some potential penalty with getting the Ecotrek batteries all the way to full charge. How full do the Ecotreks get? No accurate info available to tell that presently but for most users I suspect getting close to full will be acceptable in terms of their use of the system.

 

[booster]

Well, how do we know that is what they are doing? Why would you try to charge with shore power anyways? Why not get it out on the highway and fast bulk charge with the GU?

I think I would turn that around also to "why would you go drive all day when you can just plug in overnight". All depends on the situation.

 

[wincrasher]

Well I would think if you are just testing, then trying to get one unit to full charge would be a pretty simple exercise using the GU. Should take less than an hour.

What Greg put out is probably speculation, but it may be true on the inverter/charger. The GU should only be doing bulk charging.

The inverter manual has a custom profile that I was looking at trying to determine if it was CV/CC like others out there. Couldn't tell.

 

[gregmchugh]

Well I would think if you are just testing, then trying to get one unit to full charge would be a pretty simple exercise using the GU. Should take less than an hour.

What Greg put out is probably speculation, but it may be true on the inverter/charger. The GU should only be doing bulk charging.

The inverter manual has a custom profile that I was looking at trying to determine if it was CV/CC like others out there. Couldn't tell.

Given that RT doesn't reveal anything about the details of the system, everything is pretty much speculation. I have seen no reports from owners that would lead me to believe that any of the chargers are set up for a lithium charge profile but given the dearth of detailed data it is surely possible that RT has made changes to get a lithium profile. On the other hand, I don't recall any reports of the auxiliary AGM needing to be replaced which would probably be the case if a lithium charge profile was used.

I can speculate that my speculations may not be perfect...

 

[WingedRyno]

In order to get regulated 12v DC power in the coach you need to have at least one Ecotrek online. With no Ecotreks online the GU is not connected to the load side of the battery bank. The inverter will operate without any Ecotreks online when connected to shore power but the 12v D.C. is very unstable with no batteries connected to the charger circuit. The inverter needs to be on to pass shore power through to the coach.

So to use the GU to charge lithium, one needs to be online. That's very good to know.

So he should have 110v to the coach but not 12v if all modules are off or dead? Makes sense.

Where is the AGM in the picture with all this, I thought it was parallel to the lithiums? If so, it would go dead, also and then totally out of luck as mentioned earlier.

Maybe best to carry and old school basic battery charger to hook up and charge the AGM up to get it back up to voltage so the big chargers will work.

This AGM is the one that is under the hood, right? During the walk around I was told that was a lithium battery but upon inspection today it's only 110 AH and appears to be an AGM. So what exactly is its function if it's not the chasis battery under the driver?

As you know, every RT seems to be wired differently...

In the most common configuration, the charge side of the Ecotreks is connected to the GU, the auxiliary AGM, and the solar charge controller. The load side of the Ecotreks is usually only connected to the inverter/charger and the 12v distribution through the battery disconnect relay. With no Ecotreks online, the charge side is isolated from the load side and you cannot get 12v power from the GU or the AGM into the coach.

With the Ecotreks off, the AGM gets charged from the GU or Solar.

You mean the aux AGM right? Is that the one under the hood (not the chasis battery)? Do the litihums get charged by the solar or just this aux battery? Is this aux battery charging lithiums?

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Don't charge all the banks at once.

Charge one at a time.

What is the advantage of doing this, to avoid the BMS parasitic drag of all the batteries at the same time? Or is there something else? Seems like good advice unless you know you're driving for enough time or on shore power overnight or something.

We are talking about Lithium Ion here aren't we? There is no absorption and they can be fully charged easily.

Hammill asked where the 20% SOC number came from? What is the cut off? I thought Roadtrek originally said 10%.

Why are you staying in hotel or even running all your batteries down at once? You ought to be experiencing your Roadtrek.

I don't know what the cut off is. I'm running down my batteries to test how long it takes to run them down and charge them up, before I get too far away from the dealership. Since yesterday was the first day I've laid eyes on my RT I think I've got time to live as you think I should after I test it out.

Well, how do we know that is what they are doing? Why would you try to charge with shore power anyways? Why not get it out on the highway and fast bulk charge with the GU?

I plan to do that after testing out the shore power that was readily available.

 

[BBQ-ClassB]

...

This AGM is the one that is under the hood, right? During the walk around I was told that was a lithium battery but upon inspection today it's only 110 AH and appears to be an AGM. So what exactly is its function if it's not the chasis battery under the driver?

...

see post 209

 

[WingedRyno]

Not the Chassis battery.

There is another AGM battery -- a house AGM battery that is used to control your ecotreks. If you had ran the ectreks dead, the AGM will also be dead (not a good thing), you will need to recharge it first before you can wake up your ecotreks.

If you open the hood, you will see the house AGM on the right side of the engine bay.

The chassis AGM is under the driver's seat.

Thanks. The AGM can't "control" the ecotreks, right, it can just supply power to something that does control them. If I'm right, I wonder what it is? I was under the impression that the battery BMS controlled itself.

 

[Davydd]

If you are hovering around your dealer why aren't you going back to them with your questions? Did they not explain the system to you and give you an orientation? Does Roadtrek provide any operating procedures?

 

[BBQ-ClassB]

Thanks. The AGM can't "control" the ecotreks, right, it can just supply power to something that does control them. If I'm right, I wonder what it is? I was under the impression that the battery BMS controlled itself.

If you look at the ecotrek modules,
you will notice there are 2 inputs and 1 outputs.

 

[WingedRyno]

If you are hovering around your dealer why aren't you going back to them with your questions? Did they not explain the system to you and give you an orientation? Does Roadtrek provide any operating procedures?

Who says I didn't go back to them. Did you see the time I posted these questions? They're not around late into the night. This ain't ARV up in here, and it's not Vietnam, Davy. There are rules.

 

[cruising7388]

I think I would turn that around also to "why would you go drive all day when you can just plug in overnight". All depends on the situation.

If you were employing a converter like a Magnum et al that could deliver 100-125 amps that would be true but the RT converter is rated at 45 amps and incredibly, this is what is supplied regardless of the ah capacity of the coach. At 45 amps, assuming you are pulling 15 amps for your appliances etc at rest, that leaves 30 amps available for battery charging and if the converter is looking at a discharged 1600ah battery bank, you could grow old waiting for a full recharge.

 

[booster]

If you were employing a converter like a Magnum et al that could deliver 100-125 amps that would be true but the RT converter is rated at 45 amps and incredibly, this is what is supplied regardless of the ah capacity of the coach. At 45 amps, assuming you are pulling 15 amps for your appliances etc at rest, that leaves 30 amps available for battery charging and if the converter is looking at a discharged 1600ah battery bank, you could grow old waiting for a full recharge.

The website literature shows a 3000 watt inverter, but it is a 45 amp charger? I thought they were a combined unit, like a Magnum, so that would be really odd.