Life after RoadTrek: Ecotrek, rebuild Ecotrek module, or DIY?

[Johnnyfry]

Battleborn batteries are selling 100 amp hour modules for $950. The batteries have an internal BMS whive has a much lower parasitic draw compared to what RT used. They claim that the BMS draw is in the under 1 mA range. It would be worth an inquiry.

 

[RV-RDer]

Hi chris_g19
hope is not too late and you have disassembled your batteries, I think before that you may want to reach out the batteries manufacturer, they're offering support after EHG/RT send them a message: service@ks2corp.com

 

[gregmchugh]

Battleborn batteries are selling 100 amp hour modules for $950. The batteries have an internal BMS whive has a much lower parasitic draw compared to what RT used. They claim that the BMS draw is in the under 1 mA range. It would be worth an inquiry.

Battle Born does seem to be the most popular option at the moment, lot’s of installations...

 

[cmellone]

I would be glad to help. I'm an EE/CS with 10 years of EV battery electronics design experience and a Zion of my own. One of my modules is also acting strange and I was wondering what I'd have to do about it. Looks like you beet me to too it. There's no way I'd pay anywhere close to $7000 for a module that should have been under warranty.

First step is to see where the problem lies. My experience says there's a connection or other electronics issue. Let me know how a I can help.

Charlie

 

[chris_g19]

Hey Charlie!

I removed one if my modules but haven't dove into it yet.
I can share the design of nearly the entire electrical system shortly, I just pride my work and want to clean up the schematic a bit first.

The cells appear to be 3.2V 100AH prismatic like the Winston ones. Maybe even the Winston ones, not sure yet. Colors don't match. Once I get it apart I should find a reference number. They are in a 2P4S configuration, giving 12V and 200AH per module.

My current working theory for why these ecotreks are failing after 1-2 years is back to the C-rate. Max C-rate with the alternator settings I had is over 1.2.

Cells like Winston should handle that fine, but not for everyday use.

I was recommended by RT to use one module at a time, however jumping on the highway, with only one module charging, gives that super high C rate, and I think this is why mine failed.

I've only taken a few actions to date.l amstill in investigation mode, hoping my last and final ecotrek doesn't fail. To protect it as much as possible until I fix the whole system, I reduced the maximum allowed alternator field by 50% which should keep the C-rate down and last for a while longer. Getting plenty of solar now that it's spring anyways.

So yeah. Most likely I'm going to harvest the raw cells from the two ecotreks, then charge them up. After that I'll balance the cells. Then I will do a load test with the balancer still on and logging the Watt hour data. From the watt hour data I'll know how much the cells have degraded. I might replace all of them (about 2,000$), which would be the worst case financially speaking.

I'm going to redesign this thing with a C-rate 0.5 or lower and probably get more solar which will also help smooth out the charge profile.

I think with a good redesign, I can make it last 10-20 years no problem.

I understand why RT designed it the way they did. It makes sense now. However for a heavy user like me, a modular design has so many drawbacks. I need a DIY solution for my situation, so I'm not bitter now. I mean, I literally boondocks 365 days a year...... So..... Yeah.

BTW, to replace the BMS I'm probably going with smart 123. They have some nice features and I like being able to get detailed metrics via Bluetooth since the batteries will remain under the van.

Ok, back to my day job!

 

[stevegoldfield]

I just saw a document on the Roadtrek and Hymer group on Facebook with two Emails from Anthony Scappaticci (anthony@ks2corp.com). KS2 is the manufacturer of the lithium ion batteries Hymer NA used. In the first Email, he just says that 13.5V for all 3 values is the best setting for the battery system. In the second Email, he says that KS2 will honor a 3-year warranty on the batteries. He advises owners to contact our dealers and direct them to Kendra@ks2corp.com. They are also contacting dealers, but use that if your dealer has not yet been contacted. This is excellent news.

 

[chris_g19]

Hey Steve,

The three year warranty they are referencing is if you buy batteries from KS2 directly. They are not honoring the road trek warranty.

So you'd have to spend the 7,000 dollars to get new batteries with the 3 year warranty. They are only warrantiying the latest Revision of the battery, which I think is rev "I"

I have one rev H and one rev HR. :-(

By the way, anything below 3.5V per cell is ok for this battery chemistry, regardless if what they recommend. This is a LiFePO4 chemistry without the Mn. So for a 12V system 14V max. That's not as important as the C-rate though since the internal reistance of these batteries is so low the alternator can't get it that high anyways.

That said, I'll change my bv, av, and fv values all to 13.5V and see what happens . Certainly can't hurt!

The really important question is what are they setting the BMS and to cutoff at? Probably higher, like 13.8V or maybe more. I would love to know, but this information will be hard to come by, and I'm not going to bother testing it to find out.

 

[chris_g19]

Ok. I just changed my bv to 13.6, it was like 14.8 before. av I changed to 13.6, and float to 13.5. we'll see how it does the next few days. I'm expecting it to charge slower, but still in the range that makes sense does the voltstart duration of like 30 mins.

I also noticed RT seems to have installed the alternator temp sensor wrong. I'm getting an error code for that. Need to fix that ASAP before it gets hot out again.

So fun to tinker.

 

[ContinuousImprovement]

After lots of investigating I've decided to stay with EcoTrek batteries and fix Hymer's installation mess. I opened both my Aktiv's rev H and rev L1. L1's are great and keepers. Rev H are older, not at all the same and not as robust as the L1. If your rev H breaks see if KS2 would give you some credit for your dead H.

KS2, the manufacture, is offering service but they I don't know the value of a hacked Ecotrek (I made that mistake).

The links shared our on-going work on an Aktiv.
https://sites.google.com/view/suiet-hacks-llc/programming-an-aktivs-ecotrek-system?authuser=4

https://sites.google.com/view/suiet-hacks-llc/rewiring-aktivs-ecotrek-system?authuser=4

 

[chris_g19]

Cool! Thanks for the info for sure. Sounds like great news for most people, maybe KS2 is really committed to working out all the bugs now, since without this product there is no KS2!

I decided before diving in that I'm going full DIY. I want a system I designed and am familiar with so I can fix and prevent downtime in the first place.

If you have the time and willpower I recommend DIY everything. I'm putting in many upgrades as well that KS2 can't do for me, like Bluetooth to the Bus and datalogging for some diagnostics to address maintenance early before issues come up.

I've also redone some plumbing issues, it's so much easier to DIY in the long term then deal with stress of RV companies.

 

[ContinuousImprovement]

Cool! Thanks for the info for sure. Sounds like great news for most people, maybe KS2 is really committed to working out all the bugs now, since without this product there is no KS2!

I love DIY too. I view my aktiv's electrical system as DIY now that Hymer is out of the way. The KS2 batteries have a BMS comm port and some have already reversed engineered the protocol. Rumor is KS2 will offer a monitor but its just a rumor since I haven't seen one posted yet. I'd like to have that.
I'm now master of the whole system without buying new batteries, BMS, Balmar, etc. Today I'm adding a feature so the cabin runs directly off the engine when the weather is too cold for Lithium to immediately power up. Now that the solar panels charge the AGM, they will also charge the engine's starter battery when I choose. I'm having fun on the cheap. Perhaps I'll spend big bucks later but today I'm satisfied just to know the whole system and its reliable.

 

[cruising7388]

Today I'm adding a feature so the cabin runs directly off the engine when the weather is too cold for Lithium to immediately power up.

What feature needs to be added for GU support of the cabin loads with the battery charge terminal shut down? Won't the GU do this as is?

 

[ContinuousImprovement]

What feature needs to be added for GU support of the cabin loads with the battery charge terminal shut down? Won't the GU do this as is?

Ecotrek Aktiv cabins are only powered by the GU through an ecotrek. Both charge and discharge relays must be closed. Are Ecotrek RTs different?

 

[cruising7388]

Ecotrek Aktiv cabins are only powered by the GU through an ecotrek. Both charge and discharge relays must be closed. Are Ecotrek RTs different?

After looking at the electrical diagram, it looks like you are correct. The GU powers the battery charge port which is common to the discharge port and cabin loads. But if the battery charge port shuts down in a low temp situation, the GU can't see the cabin loads.

 

[gregmchugh]

After looking at the electrical diagram, it looks like you are correct. The GU powers the battery charge port which is common to the discharge port and cabin loads. But if the battery charge port shuts down in a low temp situation, the GU can't see the cabin loads.

So, you just add a switch to connect the AGM to the Load side. Maybe one with a low voltage disconnect to protect the AGM, look at the Blue Sea one that can have a remote switch to control it to see if it makes sense.

 

[ContinuousImprovement]

I didn't find a simple undervolt protector at blue sea.

This would work
Victron BatteryProtect 12/24V-65A https://www.amazon.com/dp/B01N6ATT8C/ref=cm_sw_r_cp_apa_i_5E9LCbS1WD3S9

The DC max 50amp and hopefully subzero cold is a rare problem. How about a $15 50 amp CB used as a switch? The UG will be running at the same time if we are powering more than the led lights.

https://www.amazon.com/gp/aw/d/B07FFBGGLC?psc=1&ref=ppx_pop_mob_b_pd_title

 

[markopolo-ClassB]

One consideration I'd guess is to not impede the primary function of the AGM boosting the LFP's. Could a low voltage disconnect ever interfere with that for example?

I noticed this:

An existing cabinet cable and 150 amp sealed circuit breaker is relocated under the ProMaster beside an Ecotrek discharge-side. A new 6-gauge cable is routed from the 150 amp CB, through the floor and to the battery ON/OFF latching relay.

here: https://sites.google.com/view/suiet-hacks-llc/rewiring-aktivs-ecotrek-system?authuser=4

Was the 150A a typo - should that have been 6 AWG & 50A and not 6 AWG & 150A?

 

[gregmchugh]

I didn't find a simple undervolt protector at blue sea.

This would work
Victron BatteryProtect 12/24V-65A https://www.amazon.com/dp/B01N6ATT8C/ref=cm_sw_r_cp_apa_i_5E9LCbS1WD3S9

The DC max 50amp and hopefully subzero cold is a rare problem. How about a $15 50 amp CB used as a switch? The UG will be running at the same time if we are powering more than the led lights.

https://www.amazon.com/gp/aw/d/B07FFBGGLC?psc=1&ref=ppx_pop_mob_b_pd_title

Here is the Blue Sea but the Victron ones have more options and some kind of Bluetooth interface also so I would go with Victron...

https://www.bluesea.com/products/7635/m-LVD_Low_Voltage_Disconnect

 

[ContinuousImprovement]

One consideration I'd guess is to not impede the primary function of the AGM boosting the LFP's. Could a low voltage disconnect ever interfere with that for example?


Was the 150A a typo - should that have been 6 AWG & 50A and not 6 AWG & 150A?

Good questions.
1) The low disconnect or CB will be installed between the AGM and main fuse panel so those functions are not affected when its it open or closed.

2) Aktiv's main panel delivers a max of 50 amps so it is not obvious why Hymer installed a 150 amp sealed CB in the cabin. It was "free" so it was relocated under the chassis. Six-gauge was chosen for the new wire after the CB. 6-gauge was chosen based on NEC 70 table 250.122 which rates 6-gauge wire for 200 amps. That much current will only flow if the 6-gauge wire is shorted but that's a good enough reason.

You clearly read closely. Thanks. Anymore comments?

 

[gregmchugh]

One consideration I'd guess is to not impede the primary function of the AGM boosting the LFP's. Could a low voltage disconnect ever interfere with that for example?

I noticed this:



here: https://sites.google.com/view/suiet-hacks-llc/rewiring-aktivs-ecotrek-system?authuser=4

Was the 150A a typo - should that have been 6 AWG & 50A and not 6 AWG & 150A?

If you locate the low voltage disconnect on the connection from the AGM to the load side of the system for use when the the Ecotreks are offline then it shouldn’t interfere with any of the normal functions of the AGM. You would also want a way to switch that connection off completely when any of the Ecotreks are online since you are providing an alternate path from the chargers to the lithium cells so you could get overcharging without any way for the BMS to prevent it. At least that is how I see it working...