ecotrek batteries using 6 internal amps

[gerrym51]

we had a post on roadtrek owners facebook about ecotrek batteries.

he was questioning why his solar could not jkeep up with his compressor fridge

it appears that each 200 amp ecotrek battery uses internally 6 amps per hour

i am reprinting his entire post of email that was sent him


Norm Schlachter OK, here is the deal. EACH of the lithium modules has an internal self-draw of about 6 Amps per hour, 24 hours per day. The solar setup can provide about 20 Amps per hour for as long as there is bright sunshine on it (6-8 hours at the most. So, 6x4=24 Amps draw x 24 hrs = 576 Amps draw per day, just doing nothing. Solar is 20x7 = 140 Amps per day charge.

576 Amps out, 140 Amps in = net loss of 436 Amps per day from an 800 Amp bank. This is without anything running. If the fridge is running that is another 3 Amps per hour draw, 24 hours per day.

So, the secret is… turn off three of the batteries if the vehicle is unattended. If the solar can put 20 amps into the battery, and there is only 6 amps draw (or 9 with the fridge), then it can keep that battery charged while there is sun on it. Each module is 200 Amps so for the rest of the night it will be able to keep going until the sun comes up again. 9Amps x 18 hrs is 162 Amps. This, too will achieve a net loss (7 hrs daylight x 11 Amps solar charge (20-9) = 77 Amps). But much more slowly, plus there are still 3 batteries fully charged left over.

Ideally if the vehicle is just going to sit unused, it should either be turned on and plugged in to keep everything charged, or everything turned off. If the idea is to just have the fridge running, plug it in and turn the inverter on.

[booster]

Holy cr*p, that makes davydd's ARV look like it absolutely sips power. The talk about being able to use all the battery capacity instead of 50%, and then they waste even more than they save. You would have more available power with AGMs that didn't use that much idling.

That just can't be right. And why do they talk about amps per hour instead of amp-hours for power and amps for draw?

[Boxster1971]

That is just crazy - what could they have in that battery module?

Actually on second thought it sounds like an internal heater when the battery temp is below 40 degF. It would be interesting if this was a cold weather condition.

[gerrym51]

Originally Posted by Boxster1971

That is just crazy - what could they have in that battery module?

Actually on second thought it sounds like an internal heater when the battery temp is below 40 degF. It would be interesting if this was a cold weather condition.

according to the poster-no =it has nothing to do with the heaters. several roadtrekkers including a few in southern california and 470 watts of solar with multiple ecotrek batteries could not understand how they could be running out of power so quickly with just the fridge on.

the e-mail i posted is what the user said

[booster]

So that was an e-mail between users. I wonder what Roadtrek has to say about that.

[gerrym51]

i posted it exactly as it was given.

for several months there have been questions about power. we chalked it up to the inverter.

however today this post seemed to put the issue in a different light.

Greg McHugh knows all about this maybe he will post.

the biggest issue to me is anybody who has just 1 ecotrek

[gerrym51]

Originally Posted by booster

So that was an e-mail between users. I wonder what Roadtrek has to say about that.

No-the e-mail was from roadtrek engineering to the poster explaining to him why he was having issues and what to do,

since he has 4 batteries he was told to shut off 3 so that all solar would go to just 1 battery and slow down the loss.

he was told to only turn on the other 3 when using high wat device for longer period-most likely air conditioner

[booster]

If this is true, it sure explains why Roadtrek doesn't put a battery monitor in their units. I don't think the customers would be really happy about seeing that much power going to waste.

[Davydd]

That email makes no sense to me. If the batteries are losing amps then something has to be drawing the power and that seems way too much. If you shut them down would they not still be losing power if an external draw isn't involved?

[markopolo]

Correct - if shut down then no parasitic loss to BMS/monitoring etc. But no lights or fan etc. either! He proposed to shut down unneeded modules.

You have to rotate the in use module so as to balance the wear.

It would seem that it is early days still in their tech if the info given in the post is accurate.

[gerrym51]

I copied Norm Schlacters post exactly. Since I don;t have ecotrek i cannot say i have first hand knowledge. several other posters did claim same issue but until Norm received that e-mail from roadtrek engineering it was all guessing.

I also don;t know if it's correct.

another indication might be voltstart.

I have seen posts of questioning why voltstart works so often.

people with 800 amps having voltstart go on at 4 AM even though they only had fridge on

weird

[gerrym51]

I copied this from another post this morning, I do not know if he has solar though and if he has voltstart to solve this



Garnet McBride My 2016 Zion with a 200 lithium never lasts more then 12 hours, even in warm weather, with everything turned off (fridge,inverter etc.). If I leave it overnight (starting fully charged) it will shut down around 12 hours. I am guessing battery management is consuming significant power.

[booster]

Looks like there may be another rough spot for Roadtrek to get through, if this is really what is going on. It definitely would explain all the switches to turn the modules off. It makes one wonder if they used full coil power relays instead of bistable or reduced hold versions. In many of the other systems I have seen, like the Elite based one Greg posted a while ago, it they have low/no current hold relays they tout it. I can't imagine where else they could use that much power. Of course I am just an armchair engineer.

[gerrym51]

Originally Posted by booster

Looks like there may be another rough spot for Roadtrek to get through, if this is really what is going on. It definitely would explain all the switches to turn the modules off. It makes one wonder if they used full coil power relays instead of bistable or reduced hold versions. In many of the other systems I have seen, like the Elite based one Greg posted a while ago, it they have low/no current hold relays they tout it. I can't imagine where else they could use that much power. Of course I am just an armchair engineer.

i am not an engineer. the post said it was internal battery stuff.remember roadtrek mix and matches agm and ecotrek among it's many models in many configurations. Maybe each battery pack has certain devices/equipment in themthat start using this power when turned on. it May not actually be the BMS perse

[Davydd]

I leave my inverter on and have a fairly large compressor refrigerator. I also have 24/7 internal wifi, cell phone booster and Trik-L-Start on. That and all the parasitic energy draw is an assumed 10 amps per hour draw as my planning rule of thumb. Then on top of that you have your usual energy usage which you can manage. Say, if you stop at 4 pm and leave the next morning by 8 am you have 16 hours. That is a draw of 160ah from your battery if you do nothing. So yes, if you brew a cup of coffee, turn on your lights, exhaust fan, water pump, water heater, watch TV, etc. most likely you will not get through 12 hours on a 200ah li-ion battery bank that has 160ah available. Roadtrek, in my opinion, should be selling nothing less than 400ah lithium ion ecotrek systems to perform as promised. Otherwise you would be spending way too much money for a system that gives you not much more than a traditional Class B electrical system.

[gerrym51]

Originally Posted by Davydd

I leave my inverter on and have a fairly large compressor refrigerator. I also have 24/7 internal wifi, cell phone booster and Trik-L-Start on. That and all the parasitic energy draw is an assumed 10 amps per hour draw as my planning rule of thumb. Then on top of that you have your usual energy usage which you can manage. Say, if you stop at 4 pm and leave the next morning by 8 am you have 16 hours. That is a draw of 160ah from your battery if you do nothing. So yes, if you brew a cup of coffee, turn on your lights, exhaust fan, water pump, water heater, watch TV, etc. most likely you will not get through 12 hours on a 200ah li-ion battery bank that has 160ah available. Roadtrek, in my opinion, should be selling nothing less than 400ah lithium ion ecotrek systems to perform as promised. Otherwise you would be spending way too much money for a system that gives you not much more than a traditional Class B electrical system.

davydd-i'm sure your lithium system does not waste the power roadtreks does.

[gerrym51]

Originally Posted by gerrym51

I copied this from another post this morning, I do not know if he has solar though and if he has voltstart to solve this



Garnet McBride My 2016 Zion with a 200 lithium never lasts more then 12 hours, even in warm weather, with everything turned off (fridge,inverter etc.). If I leave it overnight (starting fully charged) it will shut down around 12 hours. I am guessing battery management is consuming significant power.

I conversed with Garnet Mcbride.

he does not have voltstart on any solar. he says he drives just about every day and the engine generator quickly recharges his battery.

My tppl agm Has a very high charge acceptance rate. i actually think i'm better off than he

[booster]

Originally Posted by gerrym51

I conversed with Garnet Mcbride.

he does not have voltstart on any solar. he says he drives just about every day and the engine generator quickly recharges his battery.

My tppl agm Has a very high charge acceptance rate. i actually think i'm better off than he

I would have to agree with you on that, and most of us with AGMs and big alternators would also be better. At this point, the only thing he has an advantage in would be not needing to do a top off charge once a week, which takes something like 4-8 hour for our AGMs, or your TPPL.

[Davydd]

Originally Posted by gerrym51

davydd-i'm sure your lithium system does not waste the power roadtreks does.

That's my point. If I had just 200ah of lithium ion I would not expect to get through the night with normal expected and promised use.

Question? I have one single BMS for an 800ah battery bank. Does a Roadtrek have a BMS on each 200ah battery bank?

My expectations such as a late stop at a Walmart, eat at a restaurant and get up and go in the morning would expend about 120ah. A normal late afternoon stop at a campground and get up and go next morning will exceed 180ah. I can cook, brew coffee, turn on heat, watch TV, etc. and use around 250ah but not much more. Regardless, normal use would not be met with a 200ah battery bank with 160ah available.

I forgot to mention some of my energy draw is from my Silverleaf controller and its rather large LCD monitor. When they add Coach Connect they will have similar draw.

[gerrym51]

Originally Posted by Davydd

That's my point. If I had just 200ah of lithium ion I would not expect to get through the night with normal expected and promised use.

Question? I have one single BMS for an 800ah battery bank. Does a Roadtrek have a BMS on each 200ah battery bank?

My expectations such as a late stop at a Walmart, eat at a restaurant and get up and go in the morning would expend about 120ah. A normal late afternoon stop at a campground and get up and go next morning will exceed 180ah. I can cook, brew coffee, turn on heat, watch TV, etc. and use around 250ah but not much more. Regardless, normal use would not be met with a 200ah battery bank with 160ah available.

I forgot to mention some of my energy draw is from my Silverleaf controller and its rather large LCD monitor. When they add Coach Connect they will have similar draw.

I have no idea. i know each battery has an on and off switch. i know they give a built in volt meter. other than that i'm clueless