ecotrek batteries using 6 internal amps

[Davydd]

Originally Posted by gregmchugh

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.

The ARV battery heaters are controlled by a thermostat to turn on and off determined by the temperature in the battery box. This is not a BMS function to my knowledge. It seems to be very effective as it is designed to keep temperatures above 41F (5C) which is supposedly optimum. As I mentioned before the heaters (5a electric pads embedded between battery banks. I have two pads.) generally don't come on until air temperatures drop to about 20F and they don't stay on continuously at that temperature. I can tell when they are on by the increase in amps used on the Silverleaf readout. I now know positively with a flame icon that comes on when the heat is on. That was an upgrade I got with the Silverleaf last October. This would have no bearing on a complaint written up in June if Roadtrek was similar and not tied to the BMS. Regardless, wouldn't energy output only occur when heat was needed?

Cell balancing is not a constant operation in an ARV. I haven't figured out how frequently it occurs but when it is happening you know it is going on. I have only observed it once when plugged into shore power. But I don't see that as a contributor to the constant 6 amps per hour drain Roadtrek is supposedly experiencing.

[Davydd]

Originally Posted by 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

Are the tppl AGM batteries being used in the Roadtrek Ecotrek designs?

[booster]

I think everyone needs to understand that you can't transfer results and design robustness from the ARV system to all the others. ARV has basically a cost is no object style system and it is very good, and very expensive, compared to what else is being offered by others.

That said, the information that davydd has posted about how many AGM batteries would be needed to be equivalent to his lithiums is not how I would portray the same comparison. Most of the time, the comparisons are done, like davydd has done, assuming the AGMs can only be discharged to 50% or they fail very quickly. We had a very good discussion of this on the board a few months ago, and the actual data we were able to find was very interesting, to be sure. Yes, you get about 1/2 the number of total recharge cycles at 80% discharge when compared to 50%, but if you look at the total number of amp hours in and out over the life of the battery, which is what really counts, the difference drops to only 10%. If you have even a moderate number of shallow cycles, the 10% also disappears. The same data indicated lithiums to be more susceptible to losing cycle life, based on total amp hours in and out over the life of the battery, do to deep discharges, than AGM, although they still have considerably longer life than AGMs.

Based on that information, I think the more realistic and fair comparison would use the 80% discharge capacity of the AGM batteries. That would make 800ah of AGM batteries have 640ah usable, which is about the same as davydd has usable in his setup. That could be four big six volt AGMs that would weigh about 500#. Davydd's batteries will be lighter, but he also has a very heavy insulated frame and case, so the difference is reduced some.

Using the 80% discharge also allows faster recovery of daily use, as you are in the high acceptance rate area of the battery more of the time, basically from 80% DOD to about 20% DOD. Lithium still wins here as they stay in the high acceptance until almost full.

Using the 80% discharge does not change the fact that you need to get a full charge on the AGM batteries every 70-10 cycles or so, and should be done with charging methods much better than the ones Roadtrek, or most others, offers. You need good equipment and at least 12 hours of reliable charging power to do it. IMO, this is the biggest downside of the AGMs.

The lithium systems are getting better, and cheaper, and likely will be taking over most of the RV market, unless there is something new showing up, but most of the RV manufacturers are still learning how build them. Roadtrek is a prime example of this, as they have had a very rough rollout of their lithium systems. Of course, the e-trek AGM systems had/have lots of issues, too.

I would love to have a lithium system, but it would need to be of the ARV level of durability, although with simplified systems. It is getting to be closer all the time to having the parts available to put together a basic, reliable lithium system off the shelf, which should change things a bunch for the manufacturers.

[gregmchugh]

Except for the battery heater function and some customization and the underfloor packaging, I believe the ARV lithium sysytem is pretty much an off the shelf Elite Power lithium system such as these. Readily available system...

RV Lithium Battery

[booster]

Originally Posted by gregmchugh

Except for the battery heater function and some customization and the underfloor packaging, I believe the ARV lithium sysytem is pretty much an off the shelf Elite Power lithium system such as these. Readily available system...

RV Lithium Battery

You are probably correct in that the parts are mostly available. I do wonder how much of the software and control programming are ARV specific, as well as how the parts are integrated. We do know davydd has had a couple of "programming" upgrades, but we don't know if they were generic or ARV based.

The link you post does have vendor progamability, IIRC, so depending on how good that is you may get close to the ARV system. I don't think they address cold weather and heating, though.

It is interesting that they say in the link that their relays use 2.8 watts each, so they would have a parasitic loss of about 1/2 amp from them whenever activated (batteries on). The appear to be of the reduced amps hold variety.

[gerrym51]

Originally Posted by Davydd

Are the tppl AGM batteries being used in the Roadtrek Ecotrek designs?

no-just the standard battery in the zion

[gregmchugh]

Originally Posted by booster

You are probably correct in that the parts are mostly available. I do wonder how much of the software and control programming are ARV specific, as well as how the parts are integrated. We do know davydd has had a couple of "programming" upgrades, but we don't know if they were generic or ARV based.

The link you post does have vendor progamability, IIRC, so depending on how good that is you may get close to the ARV system. I don't think they address cold weather and heating, though.

It is interesting that they say in the link that their relays use 2.8 watts each, so they would have a parasitic loss of about 1/2 amp from them whenever activated (batteries on). The appear to be of the reduced amps hold variety.

Yes, ARV likely uses the CAN interface to get to the Silverleaf and has battery heaters and has some customized software but the system is pretty good in the base version.

[gregmchugh]

I posted this before, but here is an example of an Elite Power lithium install

The Big “Beastly” Solar/Battery Upgrade Part I – Why? – Wheeling It

[WJones]

Originally Posted by booster

We had a very good discussion of this on the board a few months ago, and the actual data we were able to find was very interesting, to be sure. Yes, you get about 1/2 the number of total recharge cycles at 80% discharge when compared to 50%, but if you look at the total number of amp hours in and out over the life of the battery, which is what really counts, the difference drops to only 10%. If you have even a moderate number of shallow cycles, the 10% also disappears.

Booster, I remember that discussion very well, and yes, it was enlightening. I think that we should call it the "50% myth". Unfortunately, I doubt it will ever die. I just keep seeing it crop up everywhere!

[gregmchugh]

And, if you are willing to spend a lot more for a lithium system you can go with one of the marine grade systems from Victron, I don't think they include battery heaters but quality and reliability is very good. I notice that AM Solar is no longer building their own lithium system and are selling the Victron systems.

Lithium Batteries — AM Solar

[gregmchugh]

Originally Posted by WJones

Booster, I remember that discussion very well, and yes, it was enlightening. I think that we should call it the "50% myth". Unfortunately, I doubt it will ever die. I just keep seeing it crop up everywhere!

I try to spread the word to the Roadtrek Owners that it is outdated, maybe never really was valid but sure sold a lot of unneeded AGM batteries. I also suspect it will continue to be gospel with no hope of making it an urban legend...

[gregmchugh]

Originally Posted by 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

TPPL AGM do still require an Absorption phase during charging don't they?

They are an improvement over standard AGMs but still have some of the issues that Lithiums don't have...

[booster]

Originally Posted by gregmchugh

TPPL AGM do still require an Absorption phase during charging don't they?

They are an improvement over standard AGMs but still have some of the issues that Lithiums don't have...

From all I have seen, TPPL still need the full absorption stage and it is best if they are taken to an amp reading to indicate full charge like AGMs and wet cells. The last segment of the absorption charge also slows a lot like AGMs. There is a lot of contradictory information about if, and how much, different the slow down is compared to AGMs. Some say it is similar, some say they go through the section faster. Either way, you are still looking at many hours of charge cycle more than lithium, like with AGM, and nearly all the extra time is spent in the final 20% of the charge cycle. Most everyone with a classb can't supply enough amps to have any real difference in the early charging, on a large battery bank, so all three types are quite equal in getting from 20% to 80% state of charge.

[gerrym51]

Originally Posted by booster

From all I have seen, TPPL still need the full absorption stage and it is best if they are taken to an amp reading to indicate full charge like AGMs and wet cells. The last segment of the absorption charge also slows a lot like AGMs. There is a lot of contradictory information about if, and how much, different the slow down is compared to AGMs. Some say it is similar, some say they go through the section faster. Either way, you are still looking at many hours of charge cycle more than lithium, like with AGM, and nearly all the extra time is spent in the final 20% of the charge cycle. Most everyone with a classb can't supply enough amps to have any real difference in the early charging, on a large battery bank, so all three types are quite equal in getting from 20% to 80% state of charge.

tppl agms have a charge acceptance rate 6 times higher than standard agm.

they are very fast charging-closer to lithium than agm. However they are still forms of agm. however it's a middle ground from agm to lithium

I get most of my info from people who use them is cruiser forums and boat supply sellers

[booster]

Originally Posted by gerrym51

tppl agms have a charge acceptance rate 6 times higher than standard agm.

they are very fast charging-closer to lithium than agm. However they are still forms of agm. however it's a middle ground from agm to lithium

I get most of my info from people who use them is cruiser forums and boat supply sellers

If an AGM will take 200 amps, and that is what your alternator will do, what good is having a battery that will absorb 1200 amps?

[gerrym51]

Originally Posted by booster

If an AGM will take 200 amps, and that is what your alternator will do, what good is having a battery that will absorb 1200 amps?

it charges faster just like a lithium-thats the point-on cruising boats they use smaller battery banks and quick charge in tppl agm.

where sizing of standard agm is 2 to one compared to lithium

tppl agm is 1-1. as far as charging.

Don't take my word. If you do multiple searches of tppl agm -which i have-because i got one i learned this .

tppl agm is not lithium-however it does not need all the lithium protection either

[Boxster1971]

Looks like US Navy moved to valve regulated lead acid (VRLA) batteries using its thin plate pure lead (TPPL) technology batteries about ten years ago...
http://www.prnewswire.com/news-relea...-74152832.html

GO NAVY!!

[Boxster1971]

Originally Posted by gerrym51

... ... I get most of my info from people who use them is cruiser forums and boat supply sellers

I've also read a lot of battery info on the cruiser forums. From what I read the main issue with AGM batteries is their need to be kept fully charged at least every few days for them to last. The big advantage with LiFePO4 batteries is they are happy to live in a partial state of charge, not requiring a regular full charge. That's a sweet spot for the cruisers who can't always get their batteries fully charged.

[booster]

Originally Posted by gerrym51

it charges faster just like a lithium-thats the point-on cruising boats they use smaller battery banks and quick charge in tppl agm.

where sizing of standard agm is 2 to one compared to lithium

tppl agm is 1-1. as far as charging.

Don't take my word. If you do multiple searches of tppl agm -which i have-because i got one i learned this .

tppl agm is not lithium-however it does not need all the lithium protection either

We have had this discussion before, and I have done lots and lots of reading on TPPL. The amount of capacity you need is the same as AGM as the life if the same at 80% and 50%, although the 50% rule really doesn't apply to either of them. They only charge faster is you can supply that much. Our AGMs will take all that our 250 amp alternator will put out, so there is not benefit to be had. The speed of the charge above 80% is where the question. I did find an article a while ago by Nigel Calder that said he had been changing his ideas on the TPPL do to early loss of capacity, and was shifting towards absorption charge cycles of something like 18-24 hours to prevent the losses, and stressing that TPPL has to be taken full periodically just like AGM. If you have a small battery and big alternator, then you would gain from extra charge exceptance, but very, very few people would have the capacity to charge at 6C for their bank size. TPPL also have the same issues if cycled in the middle of state of charge as AGMs, thus the get full regularly rules.

[gerrym51]

Originally Posted by Boxster1971

I've also read a lot of battery info on the cruiser forums. From what I read the main issue with AGM batteries is their need to be kept fully charged at least every few days for them to last. The big advantage with LiFePO4 batteries is they are happy to live in a partial state of charge, not requiring a regular full charge. That's a sweet spot for the cruisers who can't always get their batteries fully charged.

thats true-i am not saying tppl agm are superior-just that they are an option closer to lithium than standard agm and don't require all the extra care.

tppl is uses by telecom companies for a variety of reasons-and they are very restistant to outside elements.