Problem Charging Relion in Cold

[robertj1961]

I wanted to see how the charging would work when temperatures were a little colder given Relion states you can do that down to -4.
Temperature was 25 degrees so was hoping would not be too much of a problem.
Wrong!
I decided to start the Onan generator instead of plug in to the 30 amp circuit.
Generator started a little slower than normal but didn't seem to mind the cold temperature. It was running normally and as usual, after about 30 seconds, heard the "click" sound that is the inverter/charger energizing. Mastervolt display showed "bulk charging" which is normal with the batteries being at around 40% SOC. Generator ran normally for about 1 minute and then abruptly shut down and all DC power was lost to the van.

I checked the circuit breaker on the generator that had tripped and reset it but that just protects the generator and still no DC power in the van. Checked all "known" circuit breakers and nothing had tripped. There is a 50 amp breaker underneath the van near the low point drains that was fine and had not tripped. Not sure what the 50 amp breaker is for? I decided to plug the van in to my 30 amp power source to see if that would reset or work.
It did not. Still no DC power with no lights or anything working that was DC powered. When I plugged in however, the Mastervolt display came on and said the voltage was 5.6 volts? That was also confirmed on the BM Pro display.
Decided to call Thor who tried to be helpful but honestly had no idea what could cause this. Tech guy said the suspected he 250 amp fuse had blown that is not resettable but has to be replaced. That fuse is located near the 50 amp fuse.
I was hoping the Relion BMS system was the problem and would reset correcting the problem as temperatures warmed up. I decided just to unplug from the 30 amp source and deal with it later. I re-checked the van about two hours later and everything was back to normal showing 12 volts and working normally again.

Any ideas on this appreciated? I suspect that supplying the charging source (generator) during cold weather caused a "shutdown" of the Relion BMS for some reason. The batteries are "supposed" to heat up when a power source is supplied and then start charging when the temperature is high enough but obviously this did not happen.

No idea why the Mastervolt would show 5.2 volts when shore power was supplied?

Was wondering if anyone has had similar problems trying to charge the Relion batteries when temperatures are cold?

I suspect Thor has not "thought this thru" with regard to how the Relion System works with regard to the inverter/charger supplying the power to heat the batteries prior to them accepting the charge?

I realize that 95% or the Tellaro's out there have the underhood generator (UHG) with the Relion setup but mine is somewhat unique with the Onan 2800i "IN PLACE OF" the UHG. It is possible this is a problem unique to my setup and thought I would mention that.

For now plan not to charge in cold weather until I get this sorted out. Luckily I am in North Carolina where cold weather is not as much of an issue as many other areas.

[DavidEM]

When you say that your Onan generator “abruptly shut down” do you mean it stopped producing power or actually stopped running. If the later then maybe the BMPro losing DC power triggered this.

Overall it sounds like the Relion’s BMS tripped due to low temps and when it warmed up a bit it started supplying power. Was the warm up due to ambient temp increases or was it caused by the Relion’s internal circuits? Not sure.

David

[robertj1961]

The Onan actually stopped running. When it did the breaker on the generator tripped also.

I agree it sounds to me like the Relion BMS tripped due to the low temperatures. I was "hoping" that the Relion working together with the Mastervolt/Charger and generator would allow the batteries to be heated, and then charged but guess it won't work that way.

The warm up was caused by ambient temperature increase as our temperature rose during the day to around 50 degrees. I also disconnected the shore power because I did not want to leave it plugged in given I had to leave my residence etc.

I feel fortunate it started working normally again as when this happened was afraid that was not going to be the case.

It is possible I suppose, that if I left it connected to shore power that the batteries would have been heated and then charged within an hour or so?

I could not for personal reasons wait that long however to find out. It was also strange to me that I lost all DC power to the van and the Mastervolt display was showing 5.2 volts but only when plugged in to shore power. With it not plugged in, all displays (Mastervolt and BMPRO) were "blank" and receiving no power.

I suppose it could be that was the voltage used to heat the batteries but I am not the expert on these and chose to unplug everything. Thanks for reply.

[fourthgear]

Hard to say what did what & when with out some sort of monitoring & a history of what & when . Everything goes through the Inverter , 12vdc/or 120vac from SP or Genset .I had issues with my ATS & was doing about the same thing , but I still had 12vdc , just no 120vac & it didn't always happen when switching to SP or 120vac . I think when the Inverter senses 120vac supply, be it Genset or SP , it switches over to SP/gen.120vac , it may not have 120vac it may switch over even if 120 Vac or there is some way the ATS communicates with the MasterVolt Inverter & the Inverter senses it enough to switch over to SP/genset internally even though its not there .( 5.6V)

My Sanctuary system diagram shows everything goes through the Inverter , from the Inverter both 120vac & 12vdc then go to the Distribution panel , be it 12vdc or 120 vac .( same panel on mine )

You may have more then one issue , just happened at the same time , Testing is needed when & if it happens again & you can see what is where , its the reason I am documenting my system , so I can see any history or changes in the settings or inputs . All of these MV systems should be set up so the system can be seen .

There could be a couple reasons why the Genset tripped a Breaker & may not had anything to do with the MV system , well maybe . LOL

[RonRM]

I have a UHG, so a bit out of school on this one. I don't think there is a lot of difference in how the system operates with or without...and you are absolutely correct "this was not a well thought out system".

Couple of things, that correlate with your findings and the others suggestions in the posts.

I keep reading that the Relion's actually stop delivering supply when they are heating. Haven't confirmed this with my rig, but sounds like that's what happened to the Relion's. The fact they came back, is probably due to them heating up and 'turning back on'.

You saw 5.2volts on the MV panel...if you didn't disable your solar (didn't pull the fuse), it's a chance that's where that came from. But, that also means nothing else was supplying 12vdc- not the batteries, nor the inverter/charger.

The BMPro should stay running even without a supply, it has an internal battery. Dunno, what it does when when it senses less than 12vdc. The internal battery is another issue Thor overlooked. I emailed BMPro, they stated the obvious, dont charge the BMPro in less than 30F temps, you can use it down to -4f...just dont charge it...how the heck does that work?

Did you by chance, have the MV set to draw less than 30amps from its source (generator in this case)? MV limited might explain less than 12vdc. Don't know what it actually does when the limit is hit. The manual says it throttles it's charging when the AC limit is hit...doesn't explain the details of Power Sharing mode.

What's odd is why there was no 12vdc (your MV showing only 5.2), even without the Relions, I thought the MV inverter charger should have supplied 12vdc.

Looks like it's time to move to warmer weather if we want these things to operate without having to have 25 page flow chart of if-this-then-that conditions along with an MS in electrical engineering, PhD in battery chemistries, master electrician certification and a whole ton of common sense (clearly the people who designed this had none of these). They were just not thought through for temps less than 30f.

ron

[robertj1961]

Good information. I would agree about the possibility of solar supplying the 5.2 volts if it was showing that without the AC cord hooked up to the 30 amp source. The only time I would get 5.2 volts was when plugged in which I thought very odd. When it was unplugged, no BMpro power or Mastervolt power. No DC anywhere. I looked at the lights on the Combi and all dark with no power to the inverter unless plugged in.

The Thor Tech seemed to think my 250 amp Big Boy fuse had blown. That just shows how little they know about these. If the DC didn't come back on however that is where I would start I suppose. There is also a 50 amp fuse located near the Big Boy fuse that is resettable and not sure what that one does but it had not tripped.

I think you and DavidEM are 100% correct about the RELion BMS shutting everything down DC. I suppose when that happens it does not supply any DC until it resets and not sure how long that takes or if it has to warm up before power comes back?

The only other thought I had when plugged in was the 5.2 Volts possibly related to the battery heaters? I should have just have left it plugged in for an hour or so to see if it reset and started working normally I suppose but didn't have time that day to deal with it. It seems stupid however that the Relions would not supply any power at all while heating. I get the reason for not charging until heated but once they shut down like they did forget about any power for a while. That would suck if I was camping somewhere because no heat or warm water would be available either.

I really need to figure out how to drop the battery boxes and disconnect the power from there but looks like it could be a pain.

For now, I am fortunate to be in North Carolina and will not try and charge the batteries when cold. I am afraid however this will happen again anytime below 41 degrees and that is unacceptable IMO. I would think generator and shore power should react the same but this may be possibly just related to the Onan generator and hope that the case for all those with the UHG.

The MV was set to draw 25 amps when this happened with the generator so I don't think that could be the cause but anything is possible...

Happy to have others around who understand the electrical side of all of this much better than I do and thanks for replies! I am all about "trial and error" but try not to repeat the same mistakes twice. Pretty obvious Thor also engineers with "Trial and Error" rather than testing all of this ahead of time.

[Chance]

Originally Posted by robertj1961

I wanted to see how the charging would work when temperatures were a little colder given Relion states you can do that down to -4.
Temperature was 25 degrees so was hoping would not be too much of a problem.
Wrong!
I decided to start the Onan generator instead of plug in to the 30 amp circuit.
Generator started a little slower than normal but didn't seem to mind the cold temperature. It was running normally and as usual, after about 30 seconds, heard the "click" sound that is the inverter/charger energizing. Mastervolt display showed "bulk charging" which is normal with the batteries being at around 40% SOC. Generator ran normally for about 1 minute and then abruptly shut down and all DC power was lost to the van.

I checked the circuit breaker on the generator that had tripped and reset it but that just protects the generator and still no DC power in the van. .....cut.....

Multiple problems here in my opinion. The first is that you need to differentiate between Fahrenheit and Centigrade temperature scales because a number without units means very little. You also need to confirm that temperature data you quote is for charging temperature versus discharging. I believe -4 C is very close to 25 F so who knows if your battery was right at the critical temperature, particularly if the van had been parked outside prior to test and previous temperatures were even colder. It takes time for cold batteries to warm up gradually, and it lags ambient temperature rise.

Discharge Temperature of -4° F to 130° F is often quoted for various lithium batteries, but charging is usually limited to 30~32 F. Best to keep it above freezing temperature of water. Better yet is to follow specs and add a little temperature for safety.

Lastly, your van probably has Onan 2800i “inverter” generator, and if I had to give an educated guess, it doesn’t appreciate a sudden hard disconnect of loads. It’s likely the battery bank started charging, and once the BMS sensed that batteries were about to get damaged, it cut them off abruptly.

I am “guessing” this only because I know that one of the main reasons 48 VDC house batteries have not been adopted faster is that 48 VDC (nominal) dedicated alternators are often damaged when lithium battery BMS open circuit abruptly. I know you don’t have 48 VDC, but Onan inverter generator may have similar protection for internal electronics. My portable inverter generator came with a warning not to unplug devices under load for this reason.

[robertj1961]

All temperatures I have referred to are fahrenheit. The Relion LT batteries are designed to be able to be charged to -4 F according to their literature. They are equipped with internal heaters that should heat them first, and then charge. I suspect you are correct that the batteries did shut everything down using the BMS and the Onan sensed this and also shut down to self protect. Thanks for reply.

[16ACE27]

Originally Posted by robertj1961

All temperatures I have referred to are fahrenheit. The Relion LT batteries are designed to be able to be charged to -4 F according to their literature. They are equipped with internal heaters that should heat them first, and then charge. I suspect you are correct that the batteries did shut everything down using the BMS and the Onan sensed this and also shut down to self protect. Thanks for reply.

The Onan generators require constant 12 VDC to operate the controller. Unlike a car that has it's own 12 VDC alternator, the Onans rely on the house batteries to supply the 12 VDC while running. If 12 VDC goes away, the generator engine shuts down.

[robertj1961]

Originally Posted by 16ACE27

The Onan generators require constant 12 VDC to operate the controller. Unlike a car that has it's own 12 VDC alternator, the Onans rely on the house batteries to supply the 12 VDC while running. If 12 VDC goes away, the generator engine shuts down.

Ok. That would confirm that most likely the Relion BMS shut the DC power down for some reason. I sent a request to Relion for possible explanation of why the heaters in the batteries and then the charger would not come on given those conditions and will post when/if I hear back from them. Thanks.

[RonRM]

Wow, putting this all together in my head...it's about to explode.

You can't charge the batteries with UHG - under 32f (that's a function of the temp sensor for the regulator mounted to the outside of battery).

If you have a gen/inv, can't charge the batteries under 40f (internal to the battery), because Relion kills the 12Vdc output while heating (pretty sure that's true - check that with Relion). Generators dies during this process.

Can charge with shore power, at any temp. I can guarantee that works...I'm at 100%SOC - been like that for months in the driveway even with many -20f days.

Sure seems like a warm weather machine, or it needs shore power on a regular basis.

I was thinking the other possibility for the 5.2v could be the MV limiting dc output. There is mention of the output being limited in certain conditions. I don't know where the MV measures voltages. Dropping 12v to 5.2v would take near 90amps of constant load. I think the heaters are around 100watts each. No conclusions, it will be interesting to understand. Probably need to put a meter on the output of the MV (both current/volts).

ron

[robertj1961]

I have sent a "technical request" to Relion a couple of days ago regarding this but have not heard anything back. Will post when/if I hear back.

I agree the 5.2 volts is strange. You could be right on the MV doing that for some reason. For now, you are 100% correct about it being a "warm weather machine". If that were the case, Thor should have saved their money and not installed the expensive "LT" batteries. At least it is working when connecting the shore power but I have not personally tested this and don't leave mine plugged in.

Relion has suggested that these batteries are better off not on "float" but seems to be no way to do that in very cold weather. Since yours stays plugged in, seems to be working as it should. At least when plugged in.

I wonder however if you lost power and the batteries got cold and then had to heat up, in if you would loose DC power during the startup/heat process?

Thanks for the reply and still learning quite a bit about how this van does/ or in many cases does not work as it should.

[Chance]

Originally Posted by robertj1961

.....cut....

I wonder however if you lost power and the batteries got cold and then had to heat up, in if you would loose DC power during the startup/heat process?

Thanks for the reply and still learning quite a bit about how this van does/ or in many cases does not work as it should.

Are your lithium batteries located inside coach? If so, as is the case with most RV Lithium batteries I have seen, you can start the vans engine and warm the inside of the van like you would any car until it reaches a comfortable temperature around 70 F or thereabouts. Given a little time batteries should also warm up enough to allow charging. After initial cold start, house heater (whether propane or gasoline) can keep inside of van warm enough for camping in cold weather, which should also keep batteries fully functional for charging.

Unless batteries are located outside camper, I don’t see this being a significant problem for cold weather camping as long as there are safeguards to prevent charging a cold battery bank.

I’m not saying Thor did an adequate job because I have no idea how they wired safety interlocks to protect batteries from damage. In many cases batteries can be charged from shore power, generator, alternator and or solar, so there is a lot to consider. From my perspective easiest solution is to make certain batteries remain above 40 F before any charging is attempted.

[robertj1961]

The batteries on the 200ah systems (like mine) are located outside the coach underneath the van and just in front of the rear axels so they are somewhat difficult to access. The 400ah and 800ah option Tellaro's have them mounted inside which makes the cold weather scenario much more useable.

The RV technician who delivered the van stated that removing the batteries were a pain when I asked the question on delivery.

I am fortunate to not be in a super cold area (North Carolina) so in most cases I can work around the issue but feel for people in colder climates where it would be more difficult.

In theory, I was hoping the system would work better when temperatures were lower given that these Relion batteries are "supposed" to heat the batteries up first, and then charge but this didn't seem to happen in my case. At least with the Onan generator.

[RonRM]

Originally Posted by Chance

Are your lithium batteries located inside coach? If so, as is the case with most RV Lithium batteries I have seen, you can start the vans engine and warm the inside of the van like you would any car until it reaches a comfortable temperature around 70 F or thereabouts. Given a little time batteries should also warm up enough to allow charging. After initial cold start, house heater (whether propane or gasoline) can keep inside of van warm enough for camping in cold weather, which should also keep batteries fully functional for charging.

Unless batteries are located outside camper, I don’t see this being a significant problem for cold weather camping as long as there are safeguards to prevent charging a cold battery bank.

I’m not saying Thor did an adequate job because I have no idea how they wired safety interlocks to protect batteries from damage. In many cases batteries can be charged from shore power, generator, alternator and or solar, so there is a lot to consider. From my perspective easiest solution is to make certain batteries remain above 40 F before any charging is attempted.

ditto - 2023/20L batteries are under the coach - 9/10 degree of difficult to remove. Thor just repurposed an AMG system added sophistication and didn't consider the combinations of situations and care/feeding required by lithium.


So, just to recap.

Batteries have hard wires to both +/- always powered devices (they do not cut off with master DC switch). So, batteries can never be 'stored'...they will discharge to 0 in a few days. Modification of wiring needed -- at your own risk.

Stock solar even on the brightest day, is not enough to run the heaters in the batteries. Best if it is disco'ed in cold. No way to do that, without pulling a fuse - good luck finding it and then once you see it...requires very specific yoga poses to remove.

Temp is measured on UHG (on non gen models) - this feed back regulates alternator field and keeps UHG in temp range. Good stuff, keeps the smoke inside the alternator where it belongs .

Temp is measured on outside of battery - this is feed back to the UHG regulator. Prevents UHG output when temp is below 0C. Marginally stupid - since BMS handles this. In theory, this protects from a couple of other conditions...but that's going out on a limb (read below field dump issue). It's mostly just stupid.

Temp is measured by the internal BMS - this feedback is internal, no interface no bluetooth...nada. At threshold, it diverts charge to heaters, until internal battery temp is 40f+. It appears the 12vdc output is cut off when heating. Nice, but...without this information being available to the charging devices, can actually cause other issues (read below field dump)

It appears on gen units, when the battery goes into low temp cutoff, it kills the generator as there is no 12vdc when heating.

On UHG units, UHG (via regulator temp low temp cutoff) will never deliver charge to batteries below 0C. So, no way to charge (via UHG) below 0C with regulator at low temp cutoff - solution modify low temp cutoff on regulator...easy to do, but please be careful...at your own risk.

UHG/regulator does not have 'field dump' protection. If the UHG is charging and the battery BMS cuts off 12VDC (technically both batteries would have to disco) - instantaneous field dump may occur, pretty much guaranteeing 12VDC device damage throughout coach. Balmar now sells a device (around $65) to protect from this (big zener diode in waterproof case). This can occur if the battery outside temp is above low temp cutoff (above 0C regulator will deliver charge) and the inside temp goes below BMS low temp cut-off...hard to imagine it is even possible...but if it happens there is nothing to protect from what happens next. Given where/what and accuracy of temp measurements - there can be differences in temps, causing an issue.

When on shore power, everything is done with voltages...none of the devices feed back/talk to one another. MV inverter/charger just does it's thing and the batteries do their thing...batteries, when internally are below 0C, divert change to heat, MV is suppling 12vdc so coach 12vdc stuff stays alive - even if batteries are not delivering 12vdc. When at 40F+, batteries charge...they never get above 13.5/13.6 - top end charge voltage set on MV. MV continues to 'float' or bounce back and forth between battery heat and charge cycle,...not ideal by any means.

For me, too cold out to fix. I'll have to live with the consequences of being plugged in all winter. First chance, I'm going to yank all the crap directly wired to the batteries, add disco switch, so I can completely disconnect them. Second, install new parts that will provide a bit more intelligence about what happens when (shunt, monitors, Rpie with some ESP32's - I've got a smart RV project on the board for spring). Tweak the UHG low temp cutoff. Add the Balmar zener diode pack ($65 field dump protector). While I'm under there, replace all the connectors/splices etc. with waterproof marine grade stuff. Oh yeah, the connector on the UHG has only 2 wires in a 4 wire connector -- apparently the Thor assemblers do not plug those MT holes...water gets into connector...plug those with silicone or better.

If $$ was no object...I don't think I'd buy a different unit, might be stupid on my part...but I kinda like the Ram and most of the Thor stuff on the inside. It's just the power system that is an issue in cold temps (setting aside all the abysmal manufacturing practices/execution). My $$ is going into fixing/adjusting the battery system (replacement would be pretty expensive).

The 20L actually might have enough room behind the fuse panel ,and near the water pump to move the batteries (or additional) inside...that's an option too.

rm

[RonRM]

Found this YT for reference...2:15 - confirms output disabled when heating

https://www.youtube.com/watch?v=Q5S4c0GcmFw

Interesting method to 'wake up' dead Relion's.

[Chance]

Originally Posted by robertj1961

The batteries on the 200ah systems (like mine) are located outside the coach underneath the van and just in front of the rear axels so they are somewhat difficult to access. The 400ah and 800ah option Tellaro's have them mounted inside which makes the cold weather scenario much more useable.

......cut......

Thanks to you and Ron both for confirming battery location under floor, and temperature problems it magnifies. To me that’s a deal breaker because it complicates and compromises operation. I like simple, so prefer inside in air conditioned and heated space.

Lithium-iron-phosphate batteries (I assume that’s what they are?) operate best in same temperature range that is comfortable for humans and pets. Outside under floor they can get too cold or also too hot much easier. Temperatures near pavement in stop-and-go traffic can get pretty high on a sunny summer day.

I’m curious how they find location inside van for larger 400 and 800 Ah battery? Are those different floor plans? Guess I could look at specs.

[fourthgear]

Yes , different floor plans , different Van Chassis & RV layout use , my Sanctuary 19P ( Sprinter 4x4 ) 400 AH System is inside & under the rear seat in the back of the RV .

[robertj1961]

Very Interesting way to "wake up" the batteries. I have not yet used my emergency start switch and may give that a try at some point. In my case, the Balmar was showing voltage when I started the generator however, but then abruptly shut down once the Mastervolt turned on. I will not try that again in cold weather. I suppose just need to plug in to shore power when it is that cold.

My question about this is if I plug in and the batteries are too cold to charge, is the Mastervolt smart enough to not go in to "bulk charging" mode and the BMS shuts everything down? I know in Ron's case who is keeping his plugged in batteries are staying warm enough to maintain charge, but what happens if the batteries are too cold and a heat up period is required prior to charging which could be as much as an hour. Will the BMS cut all DC power to the van? It appears so. The only time I know for sure this happened my display was showing 5.2 volts and nothing DC including lights etc would work normally.

I am also wondering what should be displayed on the Mastervolt display while the batteries are heating up and not charging? I have not tested that yet on 30 amp. Could it be the display is showing "bulk charging" when in actually batteries are just being heated up? If that is true then that would explain why the Balmar shows 0 amps "going in" while the mastervolt still displays "bulk charging"

Also wondering if the BMS requires ambient temperatures to rise or when it resets to start supplying DC power again once it shuts down?

If the mastervolt shuts down, batteries will not be able to heat up which is what I thought was happening but could be wrong.

Thanks for the video about the wake up of the Relions as that is very interesting. I have not had mine "go to sleep" however due to temperature that I am aware of. They have shut down once power is applied however.