ecotrek batteries using 6 internal amps

[gregmchugh]

Originally Posted by cruising7388

The ARV BMS operates without any parasitic drain?

There is a "parasitic drain" due to the battery management system on any lithium battery system but most have a drain that is not significant relative to the usable amp hours from the battery bank.

[cruising7388]

Originally Posted by gregmchugh

There is a "parasitic drain" due to the battery management system on any lithium battery system but most have a drain that is not significant relative to the usable amp hours from the battery bank.

The question was only half serious. Requiring 3 amps to support a lion BMS would deplete the practical capacity of a 200 ah battery about 40% over a 24 hour period which is outlandish if that is actually the case. If it is, why would RT be prompted to implement a BMS so power hungry if "most" of the marketed systems have insignificant power drains?

Does anyone know if ARV uses latching power relays in their design?

[Davydd]

Originally Posted by cruising7388

The ARV BMS operates without any parasitic drain?

Nothing like is what is being discussed about the Roadtrek lithium battery banks. With the Silverleaf Coach Controller I have a constant readout of every lithium cell voltage and temperature along with a readout of amps going in or out at any given time. So I can see the effects of how much load the inverter, refrigerator, and everything else is. I can even observe when cell balancing is taking place. When the refrigerator is running amp drain is 5-6. The inverter is a steady 3-4. If I turn those two off the parasitic total is going to be about 2-3. Typically with inverter and refrigerator always on the draw will vary from 6 to 14 amps. I also have on all the time a wifi router system and Trik-L-Start. Then there is the Silverleaf monitor screen, other idiot lights, cooling fans for the refrigerator and inverter, the sound system, wired detector alarms, etc.

When I charge I can see shore power adding about 110 amps. Solar at noon probably at best 16 amps in Minnesota right now off a 420W solar bank. Engine idling with key start is about 100 amps. Fast idle via keyless Autogen is hitting 230 amps which makes a good case for having the fast idle option. Driving at 50 mph is around 280 amps charging. I've seen it hit 330 amps. I could plug into shore power in the sun and fast idle and be well over 300 amps charging as they all work in parallel. The BMS will shut everything down when fully charged.

Last week I stayed in a cabin in northern Minnesota. I left our B parked and unused where I could get some sun, turned off the inverter, left the refrigerator on to cool my beer and some extra food, and after 96 hours the battery drained to a SOC of 50% or a drop of about 320 ah. That was a 3.33 amps per hour drain. I surmised the solar pretty much balanced the refrigerator which I had on the low 2 setting. Daytime temperatures got up to around 75 degrees.

When you understand what you are dealing with it can be a no-brainer, no energy conservation worry, AC power 24/7 system without ever plugging into shore power. I plugged into shore power on the road 19 out of 152 nights last year mostly because I paid for the site with shore power. Friday, at Grand Marais, I didn't bother to plug in. By the time I drove off the 55 mile dead end Gunflint Trail I was 100% charged after those 4 days.

There is nothing I am aware of that is proprietary about Advanced RV's system. All the parts are well known. What they have done is they have written a lot of software to make the parts function properly in partnership with several companies as they stated way back. That is probably what could be considered proprietary or something a one off builder or another company would have difficulty duplicating.

[cruising7388]

Originally Posted by Davydd

Nothing like is what is being discussed about the Roadtrek lithium battery banks. With the Silverleaf Coach Controller I have a constant readout of every lithium cell voltage and temperature along with a readout of amps going in or out at any given time. So I can see the effects of how much load the inverter, refrigerator, and everything else is. I can even observe when cell balancing is taking place. When the refrigerator is running amp drain is 5-6. The inverter is a steady 3-4. If I turn those two off the parasitic total is going to be about 2-3. Typically with inverter and refrigerator always on the draw will vary from 6 to 14 amps. I also have on all the time a wifi router system and Trik-L-Start. Then there is the Silverleaf monitor screen, other idiot lights, cooling fans for the refrigerator and inverter, the sound system, wired detector alarms, etc.

There is nothing I am aware of that is proprietary about Advanced RV's system. All the parts are well known. What they have done is they have written a lot of software to make the parts function properly in partnership with several companies as they stated way back. That is probably what could be considered proprietary or something a one off builder or another company would have difficulty duplicating.

Thanks for the details on the ARV setup. Are you using multiple batteries and if so can you take an individual battery on and off line?

Absent any other load, what is your estimate of what power the BMS consumes?

[gregmchugh]

In many cases I expect that the power draw of the BMS may not be included in the reported charge/load amps data shown by a display derived from the shunt on the battery bank since the connections are many times going to be internal to bank rather than on the other side of the shunt where they will be read. I expect ARV can provide the info on the BMS load if it is not read by the shunt and info on the relays used. They are pretty open about the design. Elite Power Systems probably publishes the amp draw of the main BMS controller which I believe is the basis for the ARV battery controller.

[cruising7388]

Originally Posted by gregmchugh

In many cases I expect that the power draw of the BMS may not be included in the reported charge/load amps data shown by a display derived from the shunt on the battery bank since the connections are many times going to be internal to bank rather than on the other side of the shunt where they will be read. I expect ARV can provide the info on the BMS load if it is not read by the shunt and info on the relays used. They are pretty open about the design. Elite Power Systems probably publishes the amp draw of the main BMS controller which I believe is the basis for the ARV battery controller.

All of which begs the question: why would RT spend the time and resources to put together a proprietary BMS that, in compliance with Murphy's law, inevitably would have bugs and hiccups in its initial development stage? What does their system do that hasn't been previously designed and vetted and available in the market place? Surely Silverleaf would have written software to support their system that would have filled the bill for RT. NIH?

[Davydd]

Originally Posted by cruising7388

Thanks for the details on the ARV setup. Are you using multiple batteries and if so can you take an individual battery on and off line?

Absent any other load, what is your estimate of what power the BMS consumes?

Our 800ah li-ion battery bank is one assembly controlled by one BMS. It consist of 16 3.2 volt 200ah cells. four cells are assembled in series for one 200ah 12v battery and four 12v batteries in parallel for a total of 800ah. So no, you take the whole assembly off line if you need to. The BMS estimate is negligible or undetected as I said. The batteries are served with a 4/0 cable from the battery and the same to the 2800w inverter.

My system may be out of date already. Advanced RV is revamping their battery system as they never stand still. They learned a lot from mine as I was the first build and probably put a lot of stress on them from temperatures down to -5 degrees to 96 degrees so far over 42,000 miles of travel. They did change the charging profiles I have reported on in my Advancing Alvar thread and I also got that programming upgrade. I did opt for their new Delco Remy 320 second alternator upgrade last spring (previously had the Nations 270) that is twice as big as the Nations Roadtrek uses. ARV basically found in the southwest warm weather where owners desired to run their house air conditioning while on the road that the Nations could not keep up. That is a function I doubt I would ever use but do love the higher power output with little to no degradation from heat.

The point of all this is what Roadtrek is doing is not gospel or has to be accepted if they are doing it, but I am not so sure all this speculation is accurate. I would think if Etrek owners had to manage their batteries as has been speculated here that there would be a full-scale mutiny of owners. If that were true, I doubt Mike Wendland would be able to control it in his Facebook Roadtreking: The Group.

[gregmchugh]

Originally Posted by cruising7388

All of which begs the question: why would RT spend the time and resources to put together a proprietary BMS that, in compliance with Murphy's law, inevitably would have bugs and hiccups in its initial development stage? What does their system do that hasn't been previously designed and vetted and available in the market place? Surely Silverleaf would have written software to support their system that would have filled the bill for RT. NIH?

Silverleaf does not make the BMS portion of the system, Elite Power Systems does the BMS.

I guess you would have to ask Roadtrek why they did what they did...

No one here can do anything but speculate on their reasoning for developing yet another version of a lithium battery system...

[Davydd]

Originally Posted by cruising7388

All of which begs the question: why would RT spend the time and resources to put together a proprietary BMS that, in compliance with Murphy's law, inevitably would have bugs and hiccups in its initial development stage? What does their system do that hasn't been previously designed and vetted and available in the market place? Surely Silverleaf would have written software to support their system that would have filled the bill for RT. NIH?

Silverleaf is a whole coach management system. Roadtrek doesn't use it. Advanced RV is the only Class B converter with the Silverleaf system and it is usually found on Class A rigs in the $500,000 and up range. It is a reporter and touch feedback system. It is not a BMS. Its use is dependent on the RV converter to interface with it.

[cruising7388]

Originally Posted by gregmchugh

I will have to remember to simply ignore your questions from now on and not waste my time trying to provide answers to you inquiries unless you would be so kind as to include the smiley face on the ones where you are simply being cute and no smiley face on the ones where you are actually seeking information...

You are the other recent poster who triggers my troll detector much too often, I will have to listen more often to that detector and simply ignore your musings...

I'm a recent arrival to this forum and want to respect its traditions. But the reason for this vitriol totally eludes me. I'm not interested in tangling with or trolling anybody. I'm here to learn and contribute. So can anyone clarify for me what this guy's problem is?

[gregmchugh]

Originally Posted by cruising7388

I'm a recent arrival to this forum and want to respect its traditions. But the reason for this vitriol totally eludes me. I'm not interested in tangling with or trolling anybody. I'm here to learn and contribute. So can anyone clarify for me what this guy's problem is?

I deleted it, just continue with the regularly scheduled programming...

[cruising7388]

Originally Posted by Davydd

Our 800ah li-ion battery bank is one assembly controlled by one BMS. It consist of 16 3.2 volt 200ah cells. four cells are assembled in series for one 200ah 12v battery and four 12v batteries in parallel for a total of 800ah. So no, you take the whole assembly off line if you need to. The BMS estimate is negligible or undetected as I said. The batteries are served with a 4/0 cable from the battery and the same to the 2800w inverter.

My system may be out of date already. Advanced RV is revamping their battery system as they never stand still. They learned a lot from mine as I was the first build and probably put a lot of stress on them from temperatures down to -5 degrees to 96 degrees so far over 42,000 miles of travel. They did change the charging profiles I have reported on in my Advancing Alvar thread and I also got that programming upgrade. I did opt for their new Delco Remy 320 second alternator upgrade last spring (previously had the Nations 270) that is twice as big as the Nations Roadtrek uses. ARV basically found in the southwest warm weather where owners desired to run their house air conditioning while on the road that the Nations could not keep up. That is a function I doubt I would ever use but do love the higher power output with little to no degradation from heat.

The point of all this is what Roadtrek is doing is not gospel or has to be accepted if they are doing it, but I am not so sure all this speculation is accurate. I would think if Etrek owners had to manage their batteries as has been speculated here that there would be a full-scale mutiny of owners. If that were true, I doubt Mike Wendland would be able to control it in his Facebook Roadtreking: The Group.

When I previously suggested that hopefully RT would mitigate BMS losses by developing a master BMS, some folks chimed in that a master BMS would not work well but by your description, you have four paralleled batteries maintained by a single BMS that is working flawlessly.

Did the 320 amp Delco alternator require using different belt widths and different pulleys or any change in pulley ratios? Is the frame size the same as the Nations 270? What regulator supports it?

Re the southwest environment, I'm puzzled why the 270 amp Nations would not provide 2800 watts to the inverter even under this condition. To fall short, even at its hot rating, does it actually derate more than 30%? Does the unusually high ambient temperature lower the hot rating even more?

I don't think any definitive conclusion regarding the RT setup can be made until it's wrung out under controlled conditions devoid of cockpit error....a syndrome of which I am painfully familiar.

[gregmchugh]

I don't recall anyone saying that a central BMS would not work well just that it does not fit into Roadtrek's decision on the system architecture using modular components...

[Davydd]

Originally Posted by cruising7388

When I previously suggested that hopefully RT would mitigate BMS losses by developing a master BMS, some folks chimed in that a master BMS would not work well but by your description, you have four paralleled batteries maintained by a single BMS that is working flawlessly.

Did the 320 amp Delco alternator require using different belt widths and different pulleys or any change in pulley ratios? Is the frame size the same as the Nations 270? What regulator supports it?

Re the southwest environment, I'm puzzled why the 270 amp Nations would not provide 2800 watts to the inverter even under this condition. To fall short, even at its hot rating, does it actually derate more than 30%? Does the unusually high ambient temperature lower the hot rating even more?

I don't think any definitive conclusion regarding the RT setup can be made until it's wrung out under controlled conditions devoid of cockpit error....a syndrome of which I am painfully familiar.

The Roadtrek 200ah battery banks are built from 3.2v li-ion cells the same way. They just chose to keep them as separate banks instead of combining them all in one. It could be to do so and be able to turn them on and off at will created more relays and switches thus more parasitic drain. I dunno. I am not an expert on this stuff.

What Advanced RV did with Elite Power Systems GBS brand batteries and BMS is not much different than what Technomadia put together four years ago. The major differences are Advanced RV was benefitting from improved batteries and more sophisticated electronics to monitor and balance cell voltage and temperature. So, if you had ever read up on Technomadia's progress and reports you would have a fair understanding.

As for the Nations Alternator with the Balmar regulator it is subject to quick drops in power output from heat to the point that if you are running a 140 amp draw air conditioner the alternator power output can drop below that in the extreme hot weather when air conditioning is needed while driving. I was able to monitor this output drop off effect over two seasons in the southwest in temperatures that never came close to the 100+ degree summer temperatures that drew the complaints. The Delco alternator stays steady in output or at least to the point you fully charge an 800ah battery bank. Who knows beyond that because I'll never encounter it. The Delco is better all around, but it is considerably more expensive. It fits in a Sprinter barely. I have heard it would not fit in a Promaster.

I don't know how one would know how a Nations alternator performs in a Roadtrek. Do they have the means to monitor it? I see real-time constant readouts from the Silverleaf monitor with an iPhone app that mirrors the screen right at my dashboard.

Mercedes Benz sells a factory option bracket for a second alternator. The Nations fits that. The Delco requires a custom made bracket. Advanced RV designed and had theirs made. I don't know if there is an off the shelf option for others to use the Delco.

This is Advanced RV's take on the alternator improvement.

https://www.youtube.com/watch?v=XANYxoEF_HY

[avanti]

I provided some real-life data on the performance of my Nations' Alternator in message #2 of this thread:
http://www.classbforum.com/forums/f2...html#post46481

The weather was in the 90s that day.

You can see in the second chart what I presume is the throttling of the alternator by the Balmar regulator in order to keep things cool. As you can see by eyeballing it, the system was definitely averaging around 200 amps, even with the throttling. I have never had the need to run the A/C while driving (the dash A/C is more than adequate to cool our Sprinter under all conditions that we have experienced), but I can't imagine that this wouldn't be adequate -- possibly at the expense of slower battery charging for the brief period of all-out bulk charing. My reading of ARV's new alternator is that it is just an example of their "if we can make it bigger and better, let's do it, regardless of cost" philosophy. Not that there is anything wrong with that...

[Davydd]

Originally Posted by avanti

My reading of ARV's new alternator is that it is just an example of their "if we can make it bigger and better, let's do it, regardless of cost" philosophy. Not that there is anything wrong with that...

If you say so.

I've had both alternators in my B. I think I have a feel for the performance difference and it is significant. By your own chart you were bouncing up and down for an hour below 140 amps and than after an hour steadily declined below the 140 amps I mentioned to prevent a "death spiral" of battery drain as ARV told me. I guess you probably don't visit Arizona and Texas in the summer but that Nations was proving inadequate and I understand in some cases failing. I believe ARV still offers both solutions since a dual alternator is standard, but if you live in the south the Nations may well prove inadequate if you depend on whole coach air conditioning for pets or longterm boondocking. I like to think Advanced RV listens to its customers and responds with solutions.

[cruising7388]

Originally Posted by Davydd

The Roadtrek 200ah battery banks are built from 3.2v li-ion cells the same way. They just chose to keep them as separate banks instead of combining them all in one. It could be to do so and be able to turn them on and off at will created more relays and switches thus more parasitic drain. I dunno. I am not an expert on this stuff.



As for the Nations Alternator with the Balmar regulator it is subject to quick drops in power output from heat to the point that if you are running a 140 amp draw air conditioner the alternator power output can drop below that in the extreme hot weather when air conditioning is needed while driving. I was able to monitor this output drop off effect over two seasons in the southwest in temperatures that never came close to the 100+ degree summer temperatures that drew the complaints. The Delco alternator stays steady in output or at least to the point you fully charge an 800ah battery bank. Who knows beyond that because I'll never encounter it. The Delco is better all around, but it is considerably more expensive. It fits in a Sprinter barely. I have heard it would not fit in a Promaster.

I don't know how one would know how a Nations alternator performs in a Roadtrek. Do they have the means to monitor it? I see real-time constant readouts from the Silverleaf monitor with an iPhone app that mirrors the screen right at my dashboard.

Mercedes Benz sells a factory option bracket for a second alternator. The Nations fits that. The Delco requires a custom made bracket. Advanced RV designed and had theirs made. I don't know if there is an off the shelf option for others to use the Delco.

This is Advanced RV's take on the alternator improvement.

Man, that thing is HUGE !

With respect to discrete BMSs vs. a master BMS, maybe there are some tradeoffs. It's a no brainer that a master control system is going to be more energy efficient. But perhaps there is some redeeming virtue in discrete controllers. If one of the batteries in your system developed some problem that affected the status of the other batteries, would your BMS isolate the offending battery permitting the other batteries to keep on chugging or would it shut the whole works down? With the RT system, any specific battery can be isolated without affecting the managment of the others. If you are willing to live with multiple management loads, perhaps there something to be said for this approach.

Your assessment regarding the Nations 270 indicates performance that ain't too terrific. You've determined pretty much that the output capacity rating of the Nations 270 under hot weather conditions drops as much as 50%.

[Davydd]

Originally Posted by cruising7388

Man, that thing is HUGE !

With respect to discrete BMSs vs. a master BMS, maybe there are some tradeoffs. It's a no brainer that a master control system is going to be more energy efficient. But perhaps there is some redeeming virtue in discrete controllers. If one of the batteries in your system developed some problem that affected the status of the other batteries, would your BMS isolate the offending battery permitting the other batteries to keep on chugging or would it shut the whole works down? With the RT system, any specific battery can be isolated without affecting the managment of the others. If you are willing to live with multiple management loads, perhaps there something to be said for this approach.

Your assessment regarding the Nations 270 indicates performance that ain't too terrific. You've determined pretty much that the output capacity rating of the Nations 270 under hot weather conditions drops as much as 50%.

You can create a lot of redundancy that will never be used. For instance I have never used a spare tire in over 170,000 miles of Class B RV travel. I no longer carry a spare.

One thing ARV does is it monitors each and every 3.2v cell for voltage and temperature. It also has built in cell balancing. It has top and bottom SOC control. That gives me more confidence than knowing I can take a bank offline but have no idea why.

The Nations alternator is more than adequate for general coach use even if output does drop 50%. I do think heat is its achilles heel and ARV has determined it to be wanting with their southwest customers. Besides, that is about all that is available from third parties right now.

[BBQ]

.

That's one mama of a second alternator.

[avanti]

Originally Posted by Davydd

I've had both alternators in my B. I think I have a feel for the performance difference and it is significant. By your own chart you were bouncing up and down for an hour below 140 amps and than after an hour steadily declined below the 140 amps I mentioned to prevent a "death spiral" of battery drain as ARV told me.

???
Yes, it repeatedly dropped briefly below 140 amps, but as I said, it AVERAGED around 200 amps, which is what matters. That is WAY more than enough to run the A/C. As for your "death spiral", that is simply the normal charge curve of my AGM batteries.

I guess you probably don't visit Arizona and Texas in the summer but that Nations was proving inadequate and I understand in some cases failing.

As happenstance would have it, those data were collected in Texas in the summer.

I cannot see any way in which the output that I have documented would be inadequate for running an A/C, although, as I said, I find that totally unnecessary, even in Texas. ARV may have had a problem with their system, but it is not present in mine.

As for failing, I can't speak to that--maybe mine will fail some day. But, it would have to do it a LOT for the ARV upgrade to be cost-effective.

As I have said many times, if someone wants to pay ARV prices for the absolute best specifications available, I think that's great. It's just that I myself am more of a cost-effectiveness kind of guy.