148A from a 60A supply!!! Oh wait ...

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Bill_G
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Joined: Thu Sep 17, 2009 5:00 am

148A from a 60A supply!!! Oh wait ...

Post by Bill_G »

Yesterday, I replaced a -48VDC PCP charger and battery string circa 2001 with a Newmar Centurian II. I've used this product several times in the last five years. It's actually an Enatel DC plant out of New Zealand that Newmar Power rebrands in the USA. Good price, and so far a solid product.

I logged into it this morning to check the stats, and was surprised to notice the overall status screen reporting 148A from the rectifiers and to the load.

OMG!!! What did I burn down?

Oh, wait ... it's a small site that barely pulls 30A max when all stations are up. So, I put in a 50A master breaker to the load and set the rectifier to current limit at 60A. All the equipment is online. So, obviously the breaker didn't trip. It can't be exceeding 50A. When I interrogated the individual modules, their current measurements were much lower. Add them up, and move the decimal point to the right one place, and there you go - a giant number. OTOH, the event logger agrees the reported large number exceeds the alarm setpoint, and duly logs the overcurrent event once a minute.

I have a tech support question into Newmar on how to get a decimal point. Maybe it's a purchased entitlement or something.
com501
Posts: 1088
Joined: Fri Nov 02, 2001 4:00 pm
What radios do you own?: Over 50 - All Motorola

Re: 148A from a 60A supply!!! Oh wait ...

Post by com501 »

They'll probably tell you to buy a new one, or that support has ended.
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Bill_G
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Joined: Thu Sep 17, 2009 5:00 am

Re: 148A from a 60A supply!!! Oh wait ...

Post by Bill_G »

Well, I have two more to put in sometime before the end of the year. So, I'll get some practice reading the current remotely. The front panel meter was correct yesterday when I left.

BTW - I was able to swap out the chargers and batteries without taking the site down. Yesterday was a test run, and it went as planned. I brought along another rectifier rated at 120A, McGuivered it to the mains, dialed in it's voltage to match the existing site distribution, attached the cables, threw it's disconnect, nothing smoked, then I shut down the existing charger, took it apart, got it out of the room, wheeled in the new rack, wired it up, fired it up, and then took the temporary out. Two guys, ten hours including travel time. Woohoo.
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Bill_G
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Re: 148A from a 60A supply!!! Oh wait ...

Post by Bill_G »

Okay. Figured it out before tech support had a chance to call back - the current shunt cal settings (which makes sense ... kinda).

So, this product series has two ways to access it - via web browser or their app. Through the web, you can log in as admin or user, and through their app you can log in as factory, expert, or customer. I've always used the browser because it's straight forward, and gets what I need done. The app is slower, and a little buggy. It will hang for no reason leaving you with a scrolling circle, and a message (not responding) at the top. But, the app let's you drill a little deeper, and let's you get to places like the measurements calibration settings. Comparing other location settings, the current shunt was different by a factor of 10. Write a new value, and now the status screen summed rectifier current and load current displays were correct.

Someone must have fat fingered the values during factory QC, but I could swear the front panel values looked correct when I was on site. So, it could have been a bad bit set during one of my numerous hung app sessions while trying to set the SNMP strings. It was blowing up big time for a while, but finally settled down. The app is also the only way to save a configuration, or write it back. Hard to say. Fixed now. Just another pretty face soon to be forgotten amoung all the others.
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