Voltage limits on Mini's

We have a customer that using running solar and at times seems voltage climb as high as 31.5 VDC in extreme cold weather,

The specs state the Mini range up to 28 VDC… I am sure the fuse will not pop right after 28 VDC…

So the question is… is 31.5 VDC going to be ok

What is the real upper level before failure

I’m not sure, but I’d hate to see a solar surge kill the unit.
I’d recommend putting some device that can limit the input to keep the device safe.
Like this V05E25AUTO - AUMOV® Series - Radial Leaded Varistors - Littelfuse
Do you own testing, with a power supply, solar, and voltmeter.
You could also do a solar controller to the battery and then connect the pepwave to the battery.

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the customer has controllers… but as stated he has seen spikes up to 31.5.

Again looking to see if 31.5 VDC is ok for the MINI.

if he switches over to peplink from another company…he does not want to have to replace 5000 controllers also

I’d recommend ordering and testing the littlefuse.
I don’t know that there is a fuse inside the pepwave.

Adding @sitloongs
What are your thoughts?

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What’s the setup? Is the customer plugging the solar panel PV output directly into the Mini? That would be… unusual. If they have a charge controller, but are running a 24VDC system, then the bulk charge voltage would typically not be above 29.2V.

Can you provide more details about the setup?

@MRW-CRS

I have discussed with Hardware Engineering team, power surged up to 31.5 VDC is fine for MAX BR1 Mini. I’m agreed with @soylentgreen, it better to understand why the controller have such spikes up to avoid any unexpected power issue for the deployment.

If this is a big project, i suggest you can have a test BR1 Mini device to run using the controller to verify any issue for the power.

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In this case the setup does not matter… here is why… the customer uses the equipment they use and they (in very cold weather see spikes) …what they asked me to find out was would 31.5 volts damage peplink Mini’s… they are currently using another vendors hardware that will handle the spike. They are NOT interested in using a different controller -

Customer has 1,000’s of sites they are not going to change their working set up in order to deploy peplink devices… they want to know if peplink will work with the setup the currently

would temperature have an effect on the variation in voltage… IE - would 31.5 be ok at -10 or + 115

the customer asked
“So, they have tested it throughout their temperature range at the higher 31.5 VDC? I know it will work under normal 77 degree F, but wasn’t sure when temp in enclosure would go to 120 or so. I was thinking normal specs/testing was generally to like 140 degree, but that is something I would have to look at in specs.
Just want to make sure that it will function normally at 31.5VDC throughout the entire temp range we are accustomed to without conditioned enclosures.”

I would suggest not putting an electronic device directly on a variable power source. I use 12/12 transformers some times to get a clean 12v level from a 12v source. On my networking setup, I use a couple different step up / step down transformers to get the proper V to the electronic from a 12 or 24v source.

see the original post question

@MRW-CRS ,

Please open a ticket to allow us to review your setup. It’s not easy to advice without knowing how the device being deployed. Please include the forum link in the ticket so that support team aware the discussion.

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Again, set up or other devices used has nothing to do with the the question.

The question is will 31.5 VDC harm the device at different temps.

We have been told 31.5 VDC is ok…

is 31.5 VDC ok at -10
is 31.5 ok at 115

the equipment it is connected to has no effect on IF 31.5 is ok at -10.

The customer is not trying to solve the problem of voltage spikes he is trying to find out if 31.5 VDC will be harmful/destructive

right now they are using sierra rv50(x)'s with no problem!!! they want to know if they start replacing them with Mini’s will they have problems with the voltage.

they are not going to replace 5,000 controllers or add 5,000 power supplies to make the switch to Peplink

You’re asking a more complicated question than you realise I think - or your underestimating the complexity of getting an answer to a non standard question like this that has commercial ramifications if answered incorrectly.

The SW rv50 is advertised as supporting 7-36V. The BR1 Mini datasheet says 12-28V.

As such, it’s very unlikely that a BR1 mini has ever been tested at higher ambient temperatures whilst powered at 31.5V specifically. So there isn’t a standard test document that support can look at to answer you immediately. (Devices are temp tested at normal voltages though of course).

I’ve stood next to Peplink’s computer controlled ovens they use for PCBA assembly testing - they are big and expensive to spin up to temp and need to be closely monitored when used.

You are asking Peplink to either go and warm up an oven to your temperatures to test a BR1 Mini at your specific voltages, or you are asking them to verify and analyse the deployment scenario and give an educated guess - which requires questions.

Support will ask you questions, they will go ask the hardware engineering team to verify and effectively underwrite your use of a BR1 Mini outside of normal power/voltage conditions, that team will ask questions back because you said 5000 units and not 5, and no one sensible in engineering will answer one way or another until they know as much as they need to to do so confidently, so you’ll get more questions. Then you’ll get an answer.

Don’t be frustrated by the questions - they show that support and engineering are trying to help.

Good luck! - hope you win the opportunity!

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@MartinLangmaid

Thank you for helping to explain the difficulties especially for a certain conditions that beyond the lab environment that will always performed :heart: :heart:.

@MRW-CRS ,

Seen this is a big project including around 5000 devices and I have discussed again with Hardware Engineering team and they willing’s to help test based on the extreme conditions (Extrema Power surged 31.5 V, cold & hot temperature ). That should cover the -40degC to 60degC.

This may take some before we can revert back the results (1-2 weeks). Hope it will help you to Win the project.

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Martin

I understand questions and wanting to understand things - i troubleshot things all day long

However, the question I asked had nothing to do with how the equipment received the power… It had to do with the how the MINI handled the power levels once received.

solar panels, controllers, types of wires used, fuses, breakers, etc… do not matter

I would believe that if the spec sheet says it will operate between temps x and y, and voltages a - b- then the device has been tested at those temperature ranges using varying voltages…
I would also think that there should have been some voltage level which did not work - I would also think that somewhere somebody has a record of a test that says at x degrees and y voltage the units start to fail
When you say they are temp tested at normal voltage - that assumes a known normal voltage… how was that normal voltage discovered? What is normal voltage?

in our area normal is 12, 24 , or 48 vdc and temps inside an enclosure sitting on a gas/oil pad run a wide range. We actually had a couple of minis stop working due to high temperatures inside a box…interestingly enough they started working again when temps dropped

I thank you for your answer and as always enjoy your insight and input

@sitloongs thank you. it would be nice to get these guys using Peplink, they are one of the larger gas and oil companies in the USA.

They just purchased another company who we helped deploy a large number of Mini’s in their SCADA setup

Indeed. But that questions in turn generated additional questions from anyone who read it.

Here are the questions I had as this thread progressed:


  • More than 30V DC is outside of nominal / charging voltages for 24V systems - what gives? Is that a screwed charge controller maybe? I wonder what model it is and if there is a datasheet online I can check - don’t want this guy to fry a BR1 mIni because of faulty power controllers.

  • I wonder how variable the voltage is. Those cellular modules in the BR1 Mini can be temperamental on quick voltage changes.

  • If it was me I’d stick a voltage regulator before the BR1 mini I wonder if he has considered it.

  • 5000 units! Gee we’d better get this right otherwise there will be trouble.
  • Exactly what I was thinking. 31.5vdc is a weird upper voltage limit… It’s not a 36V system then, but 31.5vdc is over voltage for every 24VDC battery system I’m aware of. Hope this guy isn’t walking into a shitstorm.

See what I mean? You’re on a forum with people trying to help and understand so that your Peplink project is successful.

I don’t know you, you could be a rocket scientist and have deployed 10,000 Peplink units already and know everything there is to know about running Peplink using solar power. Or you could be any old Joe who’s just been given the job of upgrading some black boxes he’s never really used and doesn’t know enough to ask tough questions of the customer. Its why we ask these questions that you think of as redundant, because we want to help and learn how others are doing stuff and why they do it that way.

This thread alone might cause the hardware team to redesign DC voltage regulation on a BR1 mini to cope with your scenario - but only if they get answers to their questions.

The system has been designed to support 12-24v nominal voltages and then there will be safety margins built in too.

I expect there is a report somewhere that says this device failed at this high voltage when at this temp, but that information still needs to be found by the engineering team and confirmed, and I bet the response will be ‘yes but - why, whats the conditions, the humidity, whats the source of the power etc’ because that’s how engineers think.

In most of my areas this is true too. Never seen 31.5VDC as an upper limit voltage on a 24V nominal system though which is what caused all the head scratching and questions I think.

Me too. I design and build custom enclosures. Anything deployed in direct sunlight for extending periods gets active cooling for that reason, and I use passive cooling (thermal mass and heat pipes typically) everywhere else.

No worries - that’s what this place is all about.

@sitloongs will do his thing and get answers for you I’m sure. If not I’ll go put one in the oven on a variable DC PSU and live stream it :wink: Either way you’ll get an answer.

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@MRW-CRS

Hardware Engineering team reverted the test results for the following conditions:

VDC 31.5 with -40degC to 65degC

Results : Passed.

:wink: Hope it will help you for your project.

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