ecotrek batteries using 6 internal amps

[gregmchugh]

Originally Posted by gerrym51

I think Roadtrek wants to be able to mix and match ecotrek and agm among their many models.

Having each battery basically 'stand alone' with their own bms and relays actually makes sense if that is the goal.

this system however cannot get around the effect of using up power of each battery.

If it was all batteries tied to to 1 set of relays and one bms like in Davydd's i'm sure power consumption would be far less.

There is no technical reason they need 6 amps, likely will cost more for lower power relays if they are an issue and replacing whatever else is sucking up the power...

[Davydd]

Originally Posted by gerrym51

I think Roadtrek wants to be able to mix and match ecotrek and agm among their many models.

Having each battery basically 'stand alone' with their own bms and relays actually makes sense if that is the goal.

this system however cannot get around the effect of using up power of each battery.

If it was all batteries tied to to 1 set of relays and one bms like in Davydd's i'm sure power consumption would be far less.

That is saying company before customer. If all this topic speculation is true then the pigeons are coming home to roost. Granted this technology is not cheap right now in comparison but other companies are eventually going to get in and history may not sit well for Roadtrek.

I still wonder if those on the Roadtrek Owner's group understand what they are talking about, at least what has been presented here. I have a hard time believing you can lose 72% of you battery charge by 4 AM. That seems not possible to me despite the discussion of relays and all as if picking lint out of your navel. Analytical electrical details overwhelm my electrically dyslexic mind but direct observations don't.

Gregmchugh, Do you think Roadtrek would answer the simple question that if you turn Voltstart off that the batteries will disconnect at 10% SOC and save them from fully discharging? That seems an important point to know. The Yan Seiner LaMesa video was mentioning 20% for Voltstart. Is that a recent change? I thought they were originally mentioning 10% for Voltstart. I know from testing there are delays and if running an air conditioner and heavily using your batteries you can overrun close to 10% and that made me more conservative in my settings.

BTW, for comparison, if I turn everything off at night like the inverter as Roadtrek recommends (per my LaMesa discussion with a rep) and just had the refrigerator on, from about 10 PM at lights out, TV off to 4 AM I would lose maybe 30ah off my battery. That would be about 5% of my available battery amp hours (640ah of an 800ah battery bank.) That's why I can't believe or understand how relays could add 67% more to this equation. A typical frugal stop overnight to getting underway the next morning could be 20% drop in SOC and a relaxed cooking and not worrying stay overnight could be about 30%.

The inverter turn off comment puzzled me at the time because I never turn my inverter off though it is easy to do so at the Silverleaf monitor vs opening the back door of the van and flipping a switch at the inverter as they showed me. I now wished I asked more questions.

There's got to be more to the rest of this story.

[mojoman]

You can't mix AGM and lithium batteries in the same system. The AGM battery will inevitably cook if connected together and charged at the lithium voltage of 14.6v. There are systems that connect a small amount of lithium batteries to lead batteries but only to handle surges and short high demands of inverters. They are usually setup to cut in at around 11.5v and it lengthens the life and AH of the lead batteries. They act similar as a start capacitor.

[booster]

Originally Posted by mojoman

You can't mix AGM and lithium batteries in the same system. The AGM battery will inevitably cook if connected together and charged at the lithium voltage of 14.6v. There are systems that connect a small amount of lithium batteries to lead batteries but only to handle surges and short high demands of inverters. They are usually setup to cut in at around 11.5v and it lengthens the life and AH of the lead batteries. They act similar as a start capacitor.

I think if you had a full cutoff charger, set at less than 100% full of 14.6v (maybe the 14.3v AGMs like) you would probably be OK with the mix, or a lot better anyway. Both would be charged to 14.3v and then the charger would shut off, the lithiums would quickly drop to mid 13 volts and stay there for a long time, which is also good float voltage for the AGMs in the system. The AGMs would not supply much power until the lithiums were near dead, I think.

[gerrym51]

davydd-why do you insist on comparing your system to the roadtreks.

Nobody said you lost 72 percent by 4am.

What i did say is several people mentioned their voltstarts coming on around 4 am.

Since we have no idea how charges they batteries were originally we don't know.

what we do know is that each battery uses up 6 amps per hour once they are turned on. assuming the battery has 180 ususable amps before the battery shuts itself off thats 30 hours with NO loads. with a 4 amp refrigerator-18 hours obviously.

[booster]

If you use cheap, non reduced power hold, 500 amp relays, they can easily be 3 amps apiece, or 6 amps for two of them, or 144ah in 24 hrs in one 200ah module. For 4 modules, that is 576ah in 24hrs for an 800ah four module system, plus whatever the frig uses, so over 600ah in 24 hrs.

By comparison, a Blue Sea bistable relay uses zero amps except when moving so in 24 hrs you would use essentially no battery capacity to them, no matter how many of them you had. There is a high cost to the customer if the parasitic we are hearing about is because they chose to save a couple of bucks on relays, but it sounding pretty possible.

[Davydd]

Originally Posted by mojoman

You can't mix AGM and lithium batteries in the same system. The AGM battery will inevitably cook if connected together and charged at the lithium voltage of 14.6v. There are systems that connect a small amount of lithium batteries to lead batteries but only to handle surges and short high demands of inverters. They are usually setup to cut in at around 11.5v and it lengthens the life and AH of the lead batteries. They act similar as a start capacitor.

BTW, in a test I ran for my new Delco alternator I reported in my Advancing Alvar thread I noted the charge voltage was topped out and stayed at 14.2 volts for the hour of charging. Once 100% SOC was reached the voltage dropped back to 13.6. Programmable with the Balmar voltage regulator? I don't know.

To observe, I connect my iPhone 6 via internal wifi with the Silverleaf monitor and mount it on my dashboard so I can continuously see it using an information mirroring RVCair app.

[Davydd]

Originally Posted by gerrym51

davydd-why do you insist on comparing your system to the roadtreks.

Nobody said you lost 72 percent by 4am.

What i did say is several people mentioned their voltstarts coming on around 4 am.

Since we have no idea how charges they batteries were originally we don't know.

what we do know is that each battery uses up 6 amps per hour once they are turned on. assuming the battery has 180 ususable amps before the battery shuts itself off thats 30 hours with NO loads. with a 4 amp refrigerator-18 hours obviously.

Context and comparative purposes. If I didn't people might assume reading all this lithium ion battery systems have a fatal design flaw. That's not true. I didn't say someone said I was losing 72%. Booster used that figure for Roadtrek and I have a hard time understanding it. Thus my comparative context.

I have a hard time believing Roadtrek would design a system where 6 amps per hour were being sucked out of each 200ah battery bank as Booster says is possible for not much beneficial reason. But if all that was true I wouldn't be apologizing, sucking up and defending them. I'm questioning what that Facebook group is reporting and your repeating it here. You said it, "no one knows" but negative fuel is being added to the fire via your contribution of creating the topic.

[gerrym51]

Originally Posted by booster

If you use cheap, non reduced power hold, 500 amp relays, they can easily be 3 amps apiece, or 6 amps for two of them, or 144ah in 24 hrs in one 200ah module. For 4 modules, that is 576ah in 24hrs for an 800ah four module system, plus whatever the frig uses, so over 600ah in 24 hrs.

By comparison, a Blue Sea bistable relay uses zero amps except when moving so in 24 hrs you would use essentially no battery capacity to them, no matter how many of them you had. There is a high cost to the customer if the parasitic we are hearing about is because they chose to save a couple of bucks on relays, but it sounding pretty possible.

Booster what kind of price difference are you talking about with these relays?

[gerrym51]

Originally Posted by Davydd

Context and comparative purposes. If I didn't people might assume reading all this lithium ion battery systems have a fatal design flaw. That's not true. I didn't say someone said I was losing 72%. Booster used that figure for Roadtrek and I have a hard time understanding it. Thus my comparative context.

I have a hard time believing Roadtrek would design a system where 6 amps per hour were being sucked out of each 200ah battery bank as Booster says is possible for not much beneficial reason. But if all that was true I wouldn't be apologizing, sucking up and defending them. I'm questioning what that Facebook group is reporting and your repeating it here. You said it, "no one knows" but negative fuel is being added to the fire via your contribution of creating the topic.

Since i;m the one who posted it in the first place-i;m not defending them,

why don;t you join the wensite and look yourself, i will say very few people are talking about this. most roadtrek owners on that site don't have ecotreks

[Davydd]

Originally Posted by booster

If you use cheap, non reduced power hold, 500 amp relays, they can easily be 3 amps apiece, or 6 amps for two of them, or 144ah in 24 hrs in one 200ah module. For 4 modules, that is 576ah in 24hrs for an 800ah four module system, plus whatever the frig uses, so over 600ah in 24 hrs.

By comparison, a Blue Sea bistable relay uses zero amps except when moving so in 24 hrs you would use essentially no battery capacity to them, no matter how many of them you had. There is a high cost to the customer if the parasitic we are hearing about is because they chose to save a couple of bucks on relays, but it sounding pretty possible.

Is this something an owner could easily check or are those relays locked up inside those steel lithium ion holding boxes? I should have taken more detailed photos of that LaMesa display. They had plexiglass covers showing the guts in those boxes. I have to admit I wouldn't have known what I was looking at anyway.

[booster]

Originally Posted by gerrym51

Booster what kind of price difference are you talking about with these relays?

The cheap relays put the current needed to activate them on the coil, it activates, and then they leave the current on full to hold the it in position. Reduced current hold relays have circuitry and design that allows them to reduce the current significantly once the relay has moved, as some of the examples given pointed out (.040 amps instead of 3 amps for instance). A bistable relay only uses current when switching, and then the current is shut off completely, so they use no current when just sitting activated. IMO, there is no excuse to use full current relays in an RV battery system, especially one touted as state of the art, if that is what Roadtrek did (still unknown). The price difference is significant in some cases. Cheap relays maybe $15-20, reduced current ones maybe double that, bistable Blue Sea are like $150 retail, so probably $90ish to and OEM. These are all guesses, though.

[mojoman]

I have old tech style Contractor/relay, it uses 3amps, I may change it out to a modern one but this one allows me to manually operate it, if it fails I can hold the contacts closed manually with a shim. I kinda like that feature. Old school.

[booster]

Originally Posted by mojoman

I have old tech style Contractor/relay, it uses 3amps, I may change it out to a modern one but this one allows me to manually operate it, if it fails I can hold the contacts closed manually with a shim. I kinda like that feature. Old school.

With any of the others, you could just make a jumper for them if they failed.

[gerrym51]

Originally Posted by Davydd

Is this something an owner could easily check or are those relays locked up inside those steel lithium ion holding boxes? I should have taken more detailed photos of that LaMesa display. They had plexiglass covers showing the guts in those boxes. I have to admit I wouldn't have known what I was looking at anyway.

I wouldn't know what a relay looked like if it bit me in the a--?

Let alone tell an expensive from a cheap relay.

[Davydd]

Originally Posted by gerrym51

I wouldn't know what a relay looked like if it bit me in the a--?

Let alone tell an expensive from a cheap relay.

See. We have things in common.

I think a couple of links have been posted in this thread showing relays.

[gerrym51]

Davydd

who knew

https://www.youtube.com/watch?v=O9uxu-kyX5Q

[gregmchugh]

Originally Posted by Davydd

Is this something an owner could easily check or are those relays locked up inside those steel lithium ion holding boxes? I should have taken more detailed photos of that LaMesa display. They had plexiglass covers showing the guts in those boxes. I have to admit I wouldn't have known what I was looking at anyway.

Yes, relays are inside the sealed box along with the battery cells and all the components of the battery management system including cell balancing.

[cruising7388]

Originally Posted by Davydd

I don't know and why I was asking in a roundabout way. If they were to disable Voltstart then does the battery bank auto disconnect or does it run down to full discharge? If they auto disconnected you would know. You would basically have a steel tent with no electricity. Not all that dire of a situation other than your refrigerator contents which probably would not be a problem once you woke up and took care of the situation. If the batteries fully discharged that would not be good for lithium ion batteries.

Apparently there is indeed a defeat switch for VoltStart and enabling it does not shut down the batteries until they discharge to the point where the BMS says enough is enough and shuts down the discharge path but somehow keeps open a re-charge path. I'm hazarding the guess that the AGM battery addition provides a fall back recognition load for the UH generator or the charger and perhaps even stimulates some logic to the BMS to permit a recharge process even though the discharge path is shut off.

[gregmchugh]

RT has always said they would discharge the Ecotreks down to 10%

The Voltstart trigger point appears to have changed from the original spec to a higher voltage (it has no measure of actual battery charge level) but if you look at the typical usage profile it turns out the trigger point is not critical. The trigger voltage needs to be high enough to avoid inverter low voltage and Ecotrek low voltage shutdowns and low enough to avoid triggering before the battery bank has discharged the power provided by a single Voltstart engine run cycle. The total energy available using Voltstart from a fully charged battery bank will be 90% of the battery capacity plus the energy from the total engine run time of the Voktstart cycles as long as the trigger voltage meets the limits above.

Bottom line, Voltstart trigger voltage point does not seem to be a critical parameter...