Lithium Batteries / voltstart.

[gerrym51]

I talked to my Roadtrek dealer today when i was picking up the check for the zion i sold. He says he's heard nothing either way

[cruising7388]

Originally Posted by Davydd

Idleling to charge batteries is stupid thus Voltstart is stupid.

I don't get this. If the plan is for driving soon and you have sufficient battery capacity, idle charging when briefly camped doesn't make much sense. But if you are boondocking for a while, eventually you are going to run out of suds and periodic recharging at idle seems sensible to me, particularly if you have the enhanced charging capacity of a Delco or Volta alternator. What's stupid about this? I think the pros and cons of Voltstart is a separate issue.

[gregmchugh]

Originally Posted by cruising7388

I don't get this. If the plan is for driving soon and you have sufficient battery capacity, idle charging when briefly camped doesn't make much sense. But if you are boondocking for a while, eventually you are going to run out of suds and periodic recharging at idle seems sensible to me, particularly if you have the enhanced charging capacity of a Delco or Volta alternator. What's stupid about this? I think the pros and cons of Voltstart is a separate issue.

Maybe only select people think it is stupid, seems OK to me with fast idle if possible...

[cruising7388]

Originally Posted by avanti

You know, if there really is 60 watts of continuous parasitic loss, that would translate to a LOT of heat. It would be like having a 60 watt light bulb burning full time inside the enclosure.

I agree that it's difficult to envision the BMS chewing up five amps. Even the relay on the Surepower 1315-200 amp separator only pulls 1.5 amps (18 watts) and its solenoid is too hot to touch. If 60 watts is being dissipated within the battery case, if the battery is active, I doubt that the <32F heater control would ever activate.

[BBQ]

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From the horse's mouth


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[gerrym51]

Originally Posted by BBQ

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From the horse's mouth


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thats the original-since that time they supposedly have improved it.


BBQ-are you ever going to clarify your comment?

[gregmchugh]

Originally Posted by cruising7388

I agree that it's difficult to envision the BMS chewing up five amps. Even the relay on the Surepower 1315-200 amp separator only pulls 1.5 amps (18 watts) and its solenoid is too hot to touch. If 60 watts is being dissipated within the battery case, if the battery is active, I doubt that the <32F heater control would ever activate.

Any good marketing person would claim the load is a feature, not a problem. Helps keep the batteries warm...

[booster]

I think a "rough", but more applicable to the real world, answer to the parasitic loss is for those with lithium batteries to just turn on a module with no load on it and see how long it runs before it cuts out on low voltage. We won't know for sure how much power it used because we don't know for sure how much it holds full or when they cut off at empty, but at least folks would know how long they can expect a module to last when sitting, and also guess at parasitic based on the module claimed capacity.

That Roadtrek has chosen to not have any real battery SOC monitoring system in the lithium applications is either really naive, stupid, or deceiving, I think, as they should have one.

It is probably pretty likely that they will not ever put one in until the parasitic drain gets to normal levels, as with a monitor the users would actually see that they only get to use a small % of the power they store in the batteries.

One huge downside for the users of the systems is that they can't just turn on all the modules and have 4/8/16 hundred amp hours available to run stuff while they are away, as they all will kill themselves in a couple of days. Having to turn the modules on one at a time to use them because of the losses is pretty much a big kludge. This is likely the biggest reason Roadtrek wants a Voltstart in every unit, to mask the battery issues

[gerrym51]

Originally Posted by booster

I think a "rough", but more applicable to the real world, answer to the parasitic loss is for those with lithium batteries to just turn on a module with no load on it and see how long it runs before it cuts out on low voltage. We won't know for sure how much power it used because we don't know for sure how much it holds full or when they cut off at empty, but at least folks would know how long they can expect a module to last when sitting, and also guess at parasitic based on the module claimed capacity.

That Roadtrek has chosen to not have any real battery SOC monitoring system in the lithium applications is either really naive, stupid, or deceiving, I think, as they should have one.

It is probably pretty likely that they will not ever put one in until the parasitic drain gets to normal levels, as with a monitor the users would actually see that they only get to use a small % of the power they store in the batteries.

One huge downside for the users of the systems is that they can't just turn on all the modules and have 4/8/16 hundred amp hours available to run stuff while they are away, as they all will kill themselves in a couple of days. Having to turn the modules on one at a time to use them because of the losses is pretty much a big kludge. This is likely the biggest reason Roadtrek wants a Voltstart in every unit, to mask the battery issues

you are correct. An effective battery monitor would enable people to know they are not getting the amount of battery time they were promised

[booster]

Originally Posted by cruising7388

I don't get this. If the plan is for driving soon and you have sufficient battery capacity, idle charging when briefly camped doesn't make much sense. But if you are boondocking for a while, eventually you are going to run out of suds and periodic recharging at idle seems sensible to me, particularly if you have the enhanced charging capacity of a Delco or Volta alternator. What's stupid about this? I think the pros and cons of Voltstart is a separate issue.

I certainly would not go as far as saying the idling is stupid, but I would hope for everyone's sake that it is mostly unnecessary. A big lithium system of 800 or more AH should give nearly everyone at least 4 days of use unless they are running the AC, and trips to do something or dump tanks usually have similar time spans so a big alternator, especially at Volta level outputs, can get you back quickly.

I really hope we don't get into a situation where we have RVs running all over the campgrounds to run AC or other huge loads all the time as it will be as bad the noisy, stinky, generators we deal with now.

Of course, the large parasitic on Roadtrek systems makes them much more dependent on running the engine to keep from running out of power.

[cruising7388]

Originally Posted by booster

That Roadtrek has chosen to not have any real battery SOC monitoring system in the lithium applications is either really naive, stupid, or deceiving, I think, as they should have one.

I don't think the presence or absence of an SOC meter was a matter of choice. It's more the result of the multiple battery design.

If you are dealing with one battery, providing a shunt driven SOC meter is simplicity itself. The parasitic BMS loss could be accounted for by the meter recognizing that the battery is active and programming that loss in addition to measuring what passes through the shunt.

Where it gets sticky is when you have multiple batteries with discrete ground paths. Even if that is successfully addressed there is still the requirement that when using a shunt based SOC meter, you have to start with initially calibrating the meter by inputting the fully charged battery ah capacity. With a single battery, that's a simple input. But with multiple batteries, even though the initial calibration might be accurate, it depends on all those batteries remaining in the loop. Unless you recalibrate the SOC meter every time you turn on or shut down discrete batteries, you are going to get erroneous state of charge readings from the meter which is a likely result for a user that doesn't understand that. RT probably decided that it was better to keep you in the dark than to include a SOC meter prone to giving inaccurate readings.

[gregmchugh]

Originally Posted by cruising7388

I don't think the presence or absence of an SOC meter was a matter of choice. It's more the result of the multiple battery design.

If you are dealing with one battery, providing a shunt driven SOC meter is simplicity itself. The parasitic BMS loss could be accounted for by the meter recognizing that the battery is active and programming that loss in addition to measuring what passes through the shunt.

Where it gets sticky is when you have multiple batteries with discrete ground paths. Even if that is successfully addressed there is still the requirement that when using a shunt based SOC meter, you have to start with initially calibrating the meter by inputting the fully charged battery ah capacity. With a single battery, that's a simple input. But with multiple batteries, even though the initial calibration might be accurate, it depends on all those batteries remaining in the loop. Unless you recalibrate the SOC meter every time you turn on or shut down discrete batteries, you are going to get erroneous state of charge readings from the meter which is a likely result for a user that doesn't understand that. RT probably decided that it was better to keep you in the dark than to include a SOC meter prone to giving inaccurate readings.

I won’t attempt to conjur up Roadtrek’s reasons for not including SOC info in the basic Ecotrek system but I would guess it is a matter of cost (due to the modular design) and their assumptions that their owners are not, for the most part, interested in the details of the systems.

It is possible that each Ecotrek module may have a shunt and is keeping track of the current battery capacity for that module. The Coach Connect system may connect to a network using the communication ports on each Ecotrek and be able to get the overall SOC at any time for display on the Coach Connect display. This would be a possible approach that they built into the system but they may have some other less accurate method for displaying SOC on the Coach Connect system.

[booster]

I just took a look at the battery power management instructions on the Roadtrek website, and they still list the parasitic loss as 60 watt per module. If it were really lower than that, I would certainly think that document would have been changed as it is very poor advertising.

[cruising7388]

Originally Posted by gregmchugh

I won’t attempt to conjur up Roadtrek’s reasons for not including SOC info in the basic Ecotrek system but I would guess it is a matter of cost (due to the modular design) and their assumptions that their owners are not, for the most part, interested in the details of the systems..

I believe Dan Neely did install a system on an Etrek that resolved this. IIRC it involved a lot of 4/0 cable and addition shunts, meters with a build cost that went into thousands of dollars.

I think that there is an increasing contingent of RV owners that are uninterested in how their systems work and are mostly interested in whether or not they are working. It sort of has a parallel in the evolution of computers. Early on, computer owners did express interest in how their computers worked and had some skills in resolving problems. Today it seems like most computer users couldn't care less how their equipment works. They are pretty much only interested in whether or not it works and rely on customer service and tech support to get stuff.back into an upright condition. Mea culpa.

[booster]

I would agree that many just want it to work, just like your car, turn the key and go. No problem there.

But....would you ever buy a car without a gas gauge and no warning until the car wouldn't move? That is basically what Roadtrek is doing with their power systems with no SOC gauging. That is going to simple, and gets the point of causing more problems than a complicated system.

Roadtrek has tried to cover this fault with Voltstart set a artificially high voltage to assure folks don't run out of power, but they now have the vans starting all the time. I don't see that as simpler.

[gerrym51]

Originally Posted by booster

I just took a look at the battery power management instructions on the Roadtrek website, and they still list the parasitic loss as 60 watt per module. If it were really lower than that, I would certainly think that document would have been changed as it is very poor advertising.

If it were any other company than roadtrek i'd agree with you-however my zion manual has never been updated or corrected. many of the specs in other areas of the site stay wrong.

I can believe it

[BBQ]

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There is a video on youtube where a guy cornered one of the RT engineers at a show and asked him about this parasitic draw. The engineer beat around the bush to avoid the answer. Finally, under repeated questioning, he gave a non-committal answer that the draw is less than the 60w now. But he would not give a figure.

I wish I have a link to that video.

[<<B-Guy>>]

Wow, this has come a long way from my original post but has been very helpful - really thinking twice now about ordering lithium and voltstart if we do go ahead with a purchase, especially given the way we will likely use the van. Sounds as though AGM's should work fine for us - at considerably less $$.

If I read the RT literature correctly, it looks as though for the RT 210 pop, if you order the underhood gen. option (which I think we would) then part and parcel of thet option is two extra batteries - that would be for a total of four (non lithium).

I believe that with just two batts - they go in a tray that pulls out externally.

If you get the underhood generator with the two additional batteries, I am wondering where they go - I suspect they take up valuable storage space under the rear sofa but I don't know.

Can anyone advise?


The 210 looks quite attractive to me for a number of reasons compared to other makes/models, but there are a couple of other things I have not yet been able to confirm.


(1) The 210 looks very low - I presume maybe because it has a dropped floor - is it in fact much lower than other models? We won't be doing any serious off roading /boon docking, but I wonder if this could be a problem in normal camping situations.


(2) I would rather avoid the "continental" tire kit but would like to carry a spare if possible.

If you d not opt for the continenal kit does the spare have to go inside the van at teh rear or is there provision to carry it underneath?

Thanks for any advice /help!

Brian.

[booster]

The two extra batteries would go in compartments behind the rear wheels last I heard, and wouldn't cost you space.

The spare would go inside the van without the tire carrier, which is not very nice, IMO.

All the Roadtrek Chevies have low road clearance, but can fairly easily be lifted about 2" by changing the front springs and adding airbags to the rear (or changing the rear springs) Quite a few of us have done it, and Ron J Moore has a thread going on it right now.

[<<B-Guy>>]

Great, thanks for the info! Good news about the batteries!

As for the spare tire, I think I'd like to have one to be more self sufficient, so I guess I would go with the continental option.

I suppose I could still put a rack for two bikes on the back with an extension - or maybe get a font hitch as we have done on our last three tow vehicles for our trailers - that has always worked ok for us.

I am told you cannot put a front hitch receiver easily on a Promaster but should be ok on the Chev I would think. Had them on Safari van, 1500 pickup, and now on 2500HD pickup

I will certainly look into more detail of increasing ground clearance if we do wind up with a 210 and encounter problems! Hopefully that sort of modification would not have any impications of warrantee on a new vehicle.

For now we still need to see a 210 first hand! It sounds as though it could be a good fit for us, but I would probably have to order one with 5 month delivery
and wouldn't want to risk that just based on brochures and videos!

Should be able to see a fairly current one somewhere nearby - that is my next step

Brian.