[RE-wrenches] Conext xw+ 6848 inverter 1.5 minute voltage increase

[Ray]

Good Call Drake,  I've definitely had that problem before too. Neutral 
became disconnected, and the voltage on one leg got so high it damaged 
some equipment: garage door opener, heating controls, microwave, oven 
controls....  Funny thing was when the loads were roughly balanced, 
everything seemed normal; close to 120 vac on each leg, and 240 vac 
loads were not effected.

Ray Walters
Remote Solar
303 505-8760

On 8/13/18 7:04 AM, Drake wrote:
> This problem might be due to a neutral connection problem in the 
> electrical system. Loose neutral connections can put 120 V loads in 
> series.  It puts loads on both line 1 an line 2 in series for 240 V. 
> The high resistance load (the one with the low draw) gets high voltage.
>
>
> At 06:23 PM 8/11/2018, you wrote:
>> I am placing this inquiry out to see if anyone else has experienced a 
>> similar experience. An electrician friend near Taos, NM, installed a 
>> Conext XW+ 6648 inverter on a large 2nd seasonal (remote stand alone 
>> PV supplied) vacation home, (used less than 10 weeks per year), it 
>> has a large 48 VDC AGM battery (40+kW-Hr) and almost a 7.0 kW PV 
>> Array and a back-up LP gen-set. It has a Xantrex accessories : 
>> Com-Box, charge controllers, bat monitor, etc. The anomaly this 
>> system exhibits is that - when the owners are infrequently present - 
>> during each evening, for about 90 seconds -  the 120vac lights get 
>> noticebly brighter. After this brief event, the lights exhibit normal 
>> behavior. No lights or appliances are functionally damaged. It is 
>> more of a nuisance than an actual problem. This usually happens 
>> between 9:30 and midnight. The timing seems to be arbitrary - as no 
>> known load either turns on or turns off in conjunction with this 
>> event. Xantrex has been consulted and the inverters firm ware has 
>> been upgraded and they even sent a replacement inverter control 
>> board, which after its replacement nothing changed. As this is quite 
>> late at night and has been happening both in winter and in summer 
>> months, it is not presently believed to be associated with the PV 
>> modules or charge controller. Conventional wisdom implies, that if 
>> there is some significant load was cycling in the background - the 
>> lights would dim - not brighten. I have never heard of anything like 
>> this and was wondering- if any had. There are no known large 
>> capacitive loads on the system. Any one seen anything similar, I was 
>> asked - as I have been doing systems in New Mexico since 1995 and I 
>> guessed it was a well/ water pressure bladder tank system related 
>> issue  . . .  but the installer has witnessed this, at night when the 
>> water pump and well remained off.   ? Item 2) some weeks ago, it was 
>> noted on this RE-Wrenches thread that some ballast blocks, 4” x  
>> 8” x 16” were starting to suffer decomposition and a solution was 
>> sought, I guessed that this might be due to water seepage and 
>> repeated freezing and thawing. Has anyone used an inexpensive masonry 
>> sealer painted on the blocks, to stop water wicking to the concrete 
>> ballast blocks? There is very thick cinder block paint (UGL) for 
>> cinder block foundations that would be quite expensive and 
>> polyurethane is very pricey too - I would like to recommend that 
>> works successfully and is economical for existing installations 
>> rather than replacing hundreds of blocks? Thanks, Daniel O. Duffield 
>> NABCEP Certified PV Installation Professional (2005) NM licensed 
>> Commercial Electrical Contractor EE98/ER01 IEEE member 23 years 
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