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

[Ray]

Also check the inverter syncing,  if they aren't in sync you can have 
the wave forms become additive and have higher voltages too.

Ray Walters
Remote Solar
303 505-8760

On 8/13/18 12:03 PM, Ray wrote:
> 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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