ecotrek batteries using 6 internal amps

[gregmchugh]

Originally Posted by gerrym51

Is the poster still a member? if you can't highlight their name they've been kicked out


cruising 7388 has a 210 eco800 on order. seems he should inquire.

Post disappeared quickly and poster was not removed. I sent a message to the poster to see what happened but no response yet...

[mumkin]

You techie guys really get into this stuff. LOL Be nice if RT gave their owners a clue...

Originally Posted by Davydd

BTW, Mumkin, did you ever get a clear response and answer with what went wrong with your lithium battery setup?

I never got any response. Haven't spoken to them since I got clearance to replace them with the AGMs. Two or three months after my problems, they finally came up with putting in an AGM to have a source to jump start the lithiums.

[booster]

Originally Posted by mumkin

You techie guys really get into this stuff. LOL Be nice if RT gave their owners a clue...



I never got any response. Haven't spoken to them since I got clearance to replace them with the AGMs. Two or three months after my problems, they finally came up with putting in an AGM to have a source to jump start the lithiums.

It does seem that the "armchair engineers" have more of a concern about having the Roadtrek customers get good products and information than Roadtrek itself does, which is kind of sad.

[cruising7388]

Originally Posted by gerrym51

Since there is still time to change your ecotrek 800 order or not change it-why not address this directly to roadtrek-maybe it is not correct or you can get clarification

Done. I'll pass on any iinfo I get.

[booster]

Expanding a little on the relay discussion here. It wasn't mentioned, but one of the big issues in using bistable relays is that they normally need a momentary input (on and off so two switches), only long enough to switch them. Much tougher to supply in many auto activate systems than a simple power turn on.

To get around that problem, and provide a true drop in for standard relays, Blue Sea came up with a bistable relay that switches when power applied and unswitches when power is removed, just like a plain old relay. It isn't a true zero power relay when sitting, using 8ma when open and 13ma when activated, but is lower than most anything else around that I have seen. Also will switch 300 amps live, and 500 rated continuous, 1 million cycle life (mechanical parts). This would be a true drop in for any 12v controlled relay in a setup like Roadtreks, I think, and get rid of almost all parasitic losses. $200 retail an Amazon, so probably under $100 OEM in quantity. This would be ideal for mojoman, as it has a manual override, so no shim or jumper needed to close it in case of electrical failure.

https://www.bluesea.com/products/771...-Release_-_12V

[gerrym51]

L ooked at the video again.

In the first 5 minutes alot about the battery.

Full BMS in each battery-lots of stuff that needs powering-might not just be relays

https://www.youtube.com/watch?v=LH507_7rSZE

[mojoman]

My BMS takes a 2amp fuse and it powers the old school inefficent relay/contactor.

[booster]

Originally Posted by mojoman

My BMS takes a 2amp fuse and it powers the old school inefficent relay/contactor.

That relay must take less than the 3 amps you mentioned earlier, then , so you're better off than I thought you were.

[cruising7388]

Originally Posted by booster

Expanding a little on the relay discussion here. It wasn't mentioned, but one of the big issues in using bistable relays is that they normally need a momentary input (on and off so two switches), only long enough to switch them. Much tougher to supply in many auto activate systems than a simple power turn on.]

Actually, not a whole lot tougher. Take the Intellitec Battery disconnect relay. It uses only two terminals and the relay state changes simply by reversing the polarity of the driving source. For those that need a visual example of how these latching relays work:

https://www.youtube.com/watch?v=UGxJs5XaSWY

There is a less apparent but equally great advantage in using latching relays which is the great flexibility in designing the driving voltage. Take a standard 12 volt relay. It requires 12 voltsl or reasonably close to it to pull in and 9 volts (mas o menos) to hold in. The coil has to survive a 100% duty cycle.

With a latching relay because the duty cycle is close to 0% you can design the relay for as little as 3 volts which means that the relay will continue to respond under greatly degraded applied voltages, a condition not all that uncommon with coach batteries in an RV. Even subjected to 12 volts, a 3 volt latching relay will survive because it's subjected to any applied over voltage for just a few milliseconds. Most people don't realize it, but that's how the starter is typically designed for an automobile. It's actually a 9 volt device and hitting it with 12 volts provides beneficial increases in rotation speed and torque, the trade off of course being that you better not do it too long.

[booster]

The Intellitec would be considerably tougher to implement into an on/off circuit in an application like a battery system that is automatically triggered. You we need to to trigger a short pulse to activate it, and then another short pulse, on a different circuit, to deactivate it. This is compared to just triggering a single 12v continuous signal to activate, and shutting it off to deactivate. The Blue Sea was designed because all the boaters were asking for it for just those reasons. It is also a drop in for any standard relay as it works off the same signal.

We may have different definitions of latching relays in our heads. To me a latching relay is triggered by one circuit and then held in place by a second circuit. The purpose is that the first circuit can then be shut off, and the relay can only be released by the second circuit. They are often used to generate a multistep process where one button starts it, and it stops once the last process or switch is completed. Again, much more circuitry than just on/off 12v as with a standard relay or the Blue Sea.

Reduced hold current relays would work similar to a latching relay, except there is no second external circuit that is switched to once activated. They basically just add a resistor or other component to reduce the coil amperage once activated. They would still release once the original circuit voltage is removed, just like a plain old relay.

IMI, if you can afford them, a relay like the Blue Sea is the way to go.

[cruising7388]

Originally Posted by booster

The Intellitec would be considerably tougher to implement into an on/off circuit in an application like a battery system that is automatically triggered. You we need to to trigger a short pulse to activate it, and then another short pulse, on a different circuit, to deactivate it. This is compared to just triggering a single 12v continuous signal to activate, and shutting it off to deactivate. The Blue Sea was designed because all the boaters were asking for it for just those reasons. It is also a drop in for any standard relay as it works off the same signal.

We may have different definitions of latching relays in our heads. To me a latching relay is triggered by one circuit and then held in place by a second circuit. The purpose is that the first circuit can then be shut off, and the relay can only be released by the second circuit. They are often used to generate a multistep process where one button starts it, and it stops once the last process or switch is completed. Again, much more circuitry than just on/off 12v as with a standard relay or the Blue Sea.

Reduced hold current relays would work similar to a latching relay, except there is no second external circuit that is switched to once activated. They basically just add a resistor or other component to reduce the coil amperage once activated. They would still release once the original circuit voltage is removed, just like a plain old relay.

IMI, if you can afford them, a relay like the Blue Sea is the way to go.

I agree that a drop in improved relay that's compatible with the existing address protocol is a real advantage because it embraces the KISS principle.

I agree that any latching relay will require dual inputs that can be differentiated by the relay. But, for example in the Intellitec relay, can't this be done elsewhere with just one circuit by designing the relay to recognize a shift in signal polarity?

I agree that Blue Sea is the best of the breed with respect to anything they manufacture. What particularly impresses me is that you can use any of their products for decades and if it quits, the only thing Blue Sea wants to know is where to send the replacement.

That said, there is no hard information at the moment that quantifies what portion of the standby load is attributable to any relays. All we know at this point is that someone at the factory presumably acknowledged that the standby load on their lithium battery is 6 amps with no details regarding what actually contributes to the parasitic load and in what proportion, i.e. the battery monitoring module, the battery management module, relays, heaters etc

A distantly related question: Flooded cell batteries can't be placed in an unvented compartment in an RV because of hydrogen vented during the latter stages of charging. AGMs have the same constraint because (although they normally don't) they could vent hydrogen when overcharged. What about Lithium ion batteries? Could they be stowed some place in the interior of the coach to mitigate the temperature control requirements?

[Davydd]

You don't mitigate temperature control requirements unless you control your RV 24/7/365. The inside of a B in most climates in the United States can be an overheated oven when unattended in warm months. Lithium ion batteries are going to stay way cooler in an underfloor insulated box. Vice versa in the winter. It is easier to heat a small box than an entire van to protect batteries.

Then there is the space issue. 800ah of lithium ion batteries will essentially take all under bed back storage space available. That's a big sacrifice in a B. Heck, go look at the space hogging 200ah lithium ion battery bank in Pleasure-ways.

[gregmchugh]

Originally Posted by gerrym51

L ooked at the video again.

In the first 5 minutes alot about the battery.

Full BMS in each battery-lots of stuff that needs powering-might not just be relays

I guess it might seem that there is a lot of stuff going on in that BMS and it takes power to do stuff but here is what is likely in any BMS...

A microcontroller (computer with built-in input and output circuits to read voltages / digital signals and to control digital outputs) that can be very low power. The microcontroller software handles all the stuff that seems complex. The microcontroller reads the cell voltages and cell temperatures and maybe a shunt current then has control logic to activate the relays to control the connection of the high power charge and load devices to the battery bank.

It does not appear that the battery heaters are controlled by the microcontroller but likely there is a thermostat of some sort to handle the battery heater on/off function.

There is some type of cell balancing implemented but this does not typically require any significant power.

There are relays which could consume power as per the discussion here and battery heaters that use 4 amps but the rest of the stuff such as temperature sensors and hopefully a shunt and anything else typically in a BMS does not use significant power.

RT wants you to believe that the Ecotrek module is some sort of highly complex state of the art system like you might find in a Tesla but reality is that it is a very simple system which is much less complex than the least complex software based controller in a modern automobile, which is typically a body computer controlling lights, locks, seats, etc.

[cruising7388]

Originally Posted by Davydd

You don't mitigate temperature control requirements unless you control your RV 24/7/365. The inside of a B in most climates in the United States can be an overheated oven when unattended in warm months. Lithium ion batteries are going to stay way cooler in an underfloor insulated box. Vice versa in the winter. It is easier to heat a small box than an entire van to protect batteries.

Then there is the space issue. 800ah of lithium ion batteries will essentially take all under bed back storage space available. That's a big sacrifice in a B. Heck, go look at the space hogging 200ah lithium ion battery bank in Pleasure-ways.

Sheesh! I can see clearly now. They can't be too hot and they can't be too cold and for their AH capacity they're awfully big and they have to be constantly managed and they cost an arm and a leg with the dubious redeeming virtue that they'll outlast an octogenarian like me who is down to one year subscriptions for my magazines.

Your points seem to add up to a pretty persuasive argument for not embracing a fiercely expensive technology that seems to involve as many or more problems and constraints than the technology resolves. Stable and well tried and tested AGMs don't seem to have any of these headaches. And on a coach that eliminates the Onan generator for the under hood alternator, there is a pretty good sized space that opens up for adding as many AGMs ad you could ever want. I really like cutting technology but the kludge being marketed to date looks more and more like an invitation to endless frustration and annoyance. Could be that Mumkin is the smartest pilgrim in the room.

[cruising7388]

Originally Posted by gregmchugh

There is some type of cell balancing implemented but this does not typically require any significant power.

If the ECO800 owner takes the suggestion of shutting down three of the four batteries when at rest to eliminate three parasitic loads, what kind of balancing do you think will occur when the owner subsequently activates three fully charged batteries to a common bus that also has the deeply discharged fourth battery connected ? What controls the current inrush to the depleted battery?

[gregmchugh]

Originally Posted by cruising7388

If the ECO800 owner takes the suggestion of shutting down three of the four batteries when at rest to eliminate three parasitic loads, what kind of balancing do you think will occur when the owner subsequently activates three fully charged batteries to a common bus that also has the deeply discharged fourth battery connected ? What controls the current inrush to the depleted battery?

I think the strategy could be to bring one battery online then put the depleted battery offline, avoid adding multiple charged batteries in parallel with a depleted battery. Or something like that...

[gregmchugh]

Originally Posted by cruising7388

Sheesh! I can see clearly now. They can't be too hot and they can't be too cold and for their AH capacity they're awfully big and they have to be constantly managed and they cost an arm and a leg with the dubious redeeming virtue that they'll outlast an octogenarian like me who is down to one year subscriptions for my magazines.

Your points seem to add up to a pretty persuasive argument for not embracing a fiercely expensive technology that seems to involve as many or more problems and constraints than the technology resolves. Stable and well tried and tested AGMs don't seem to have any of these headaches. And on a coach that eliminates the Onan generator for the under hood alternator, there is a pretty good sized space that opens up for adding as many AGMs ad you could ever want. I really like cutting technology but the kludge being marketed to date looks more and more like an invitation to endless frustration and annoyance. Could be that Mumkin is the smartest pilgrim in the room.

Not sure you should base a decision to avoid lithium and to stick with AGM on Roadtreks system. The ARV implementation is pretty bulletproof. For the same battery capacity they are smaller and much lighter than AGM. They can be charged faster requiring no absorption phase and are not bothered by not getting a full charge. Lots of advantages except for the price at the moment but prices will come down. Not for everyone, clearly, but not something that is very risky now...

[booster]

Regarding the power drain and relays. The conversation has drifted a bit to imply that relays are the definitive cause of the power drain. My original thoughts were that it was the only thing I could think of that would use that much power, but there is no proof of it and it could be something else.

I agree with Greg that the lithiums do have some big advantages. Especially in the Roadtrek setup, they also have some disadvantages. The same is true for the AGMs in the Roadtrek systems. The lithium downside is somewhat known from this discussion. I would have to hope that the power drain problem will be fixed in the future, now that it is seeing the light of day and getting exposure. I don't see how Roadtrek could ever continue to make them with that kind of loss (if true) and have any happy customers other than the fan girls and boys. Of course, we also don't know if they have any other skeletons in the closet, too. They have not been out long enough to know long term durability. They also don't have any monitoring system in place so you don't know what is going on.

AGMs in Roadtreks have a lot more history, but IMO the Roadtrek system is certainly not state of the art. State of charge information is very important for AGMs to assure you get to full charge on a periodic basis. Roadtrek does not have any battery monitor in the system, so you are flying blind on that. Their chargers are also straight timer models, so they will not be able to consistently handle getting the batteries to full on shore power, and either over or under (most likely) charge. The same is true for their solar chargers from what I have heard. The Shurpower separator they use is a relic, that we have just discussed and will eat a lot of your solar power both by it's losses and what it sends to the van components. I think in non etrek vans, the AGMs would probably be relatively trouble free, but have shortened lives and decreased capacity over time. The e-trek AGM system is very poorly designed.

Tough choice, to be sure.

[Davydd]

Originally Posted by cruising7388

Sheesh! I can see clearly now. They can't be too hot and they can't be too cold and for their AH capacity they're awfully big and they have to be constantly managed and they cost an arm and a leg with the dubious redeeming virtue that they'll outlast an octogenarian like me who is down to one year subscriptions for my magazines.

Your points seem to add up to a pretty persuasive argument for not embracing a fiercely expensive technology that seems to involve as many or more problems and constraints than the technology resolves. Stable and well tried and tested AGMs don't seem to have any of these headaches. And on a coach that eliminates the Onan generator for the under hood alternator, there is a pretty good sized space that opens up for adding as many AGMs ad you could ever want. I really like cutting technology but the kludge being marketed to date looks more and more like an invitation to endless frustration and annoyance. Could be that Mumkin is the smartest pilgrim in the room.

I don't own a Roadtrek so can't speak to their design. But I do own an 800ah lithium ion battery, underhood second alternator and high capacity inverter and have a year and a half experience under my belt. I wasn't speculating with my comments. Having now had three Class Bs I think I know full well the capabilities of what you can and cannot do on the road. It has made a major difference in how I travel, where I go and where I stay, which I like and very much enjoy compared to my previous Bs. Too hot or too cold is not going to be an issue for me as I know what I am dealing with. I would not trade my setup or go back to AGMs.

But here are the facts. To equal an 800ah lithium ion battery setup with AGMs to have the same useable capacity no matter how well designed, you would have to have an equivalent of 13 standard 12v AGM batteries. They are much larger and much heavier and I quite frankly doubt you could make that many fit inside or under a Sprinter van and still have a functional and capable RV. Do the weight math and layout design. I have. Considering I have had AGM house batteries barely last a season or a magazine subscription, I think I will stick with lithium ion.

I've accepted the pioneering role in this. I look at it this way. Those who speculate the technology might be more viable in 5 years (a common refrain for all new technology) or whatever are missing out on 5 years now and may not be around in 5 years or RVing then.

[gerrym51]

I see your posts about lithium and agm--but don't forget the middle ground

tppl agm

thin plate pure lead agm batteries like in the zion