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General Category => System Design and Layout => Topic started by: Powerplay on November 02, 2016, 08:39:36 PM

Title: Converted system to 48V today
Post by: Powerplay on November 02, 2016, 08:39:36 PM
Hi Gang.  I took advantage of the nice weather around here today to swap in a 48V inverter and reconfigure my battery bank to 48V.  I had taken screen shots of all the Local App config pages to record the settings on my two Classic 150s for a reference when I configure them for 48 volt follow-me charging.  The solar panel strings on one of my Classics was reconfigured into 95V strings a few days ago and had been charging the 24V bank at about 93VmP for the last few days.

I noticed the Classics didn't auto-detect the 48V bank when they booted back up, but the Local App (And screen shots from before) made it very easy to configure the Classics for 48V.  The sun was starting to set by the time every thing was in place but everything seemed to be running well.  I've already noticed the 48V inverter self-consumes about 9W less power at night.

Now my 2 Awg main charging circuit (also supplies daytime power direct to the inverter(s) can carry about twice the power as before.  I'm a happy camper as things went very well.  I did feel a twinge in my back when I was lifting one of the inverters at the end of the day.  Time to take a break.
Title: Re: Converted system to 48V today
Post by: CDN-VT on November 02, 2016, 10:04:05 PM
Sounds Great .
After all readings recorded & a voltage change I have done a factory reset ,and started fresh by setting the battery voltage on the start up screen .

factory reset= VMM Vulcan Mind Melt as some call it here.

Reset all my picked setting & poof , Harvest was quicker on the higher voltage.

VT
Title: Re: Converted system to 48V possible fly in the ointment
Post by: Powerplay on November 04, 2016, 12:37:35 PM
Everything is looking good today and the system is running the loads well and charging the bank at 59.1 V (T-comped).  There might be a fly in the ointment though.  I think some of the battery interconnect cables might be the 60V rated variety.  This was never an issue on the 24V bank but now we're possible to exceed 60V on colder days.  I changed the classics to set max output voltage at 59.9 V while I sort this out.  What say the experts about this?  I'd guess there is very little leeway on this rating and I'll be looking to install some higher voltage rated interconnect cables into the battery bank.  There should be no issues for any other cables in my system including the big wires that connect the bank to the inverters.  But I'm double checking just to be sure.
Title: Re: Converted system to 48V today
Post by: Westbranch on November 04, 2016, 01:22:44 PM
What is the max Voltage stamped on the cables, and temp rating?
Title: Re: Converted system to 48V today
Post by: Powerplay on November 04, 2016, 02:17:27 PM
Opened the bank to look in and saw 600V or AWM A/B 105C 1000V on the 00 short wires.   ;D  Guess I'm covered in the bank.  They must have miss-printed the invoice to say 60V rated and left off an important zero.   :o  It's been a year since I installed them and was sorting through the records.  There is still a wire elsewhere in the system I'm going to check out but I guess I can lift my voltage restriction.  The new configuration got the batteries into float on the double today.  It is where they're setting right now.

Guess I thought my belt or suspenders snapped but neither one did. 
Title: Re: Converted system to 48V today
Post by: Vic on November 04, 2016, 02:21:07 PM
Powerplay,

Forget where you are located ...

If your system will be re-inspected,  the V rating of the battery interconnect cables might possibly be an issue.

What is the Type of cable?
Is the cable Fine-Stranded  (it is usually for large cables)?
What gauge is it? it is Welding cable,  but even that should be just fine,  voltage-rating wise.   It is very difficult to make cables with ratings below about 300 V.

Where are the batteries and electronics located  --  in a residence,  or ...?

EDIT:  AWM cable is about the best,  for this application,  and a 105 C temp rating is great,  am sure the 00 gauge cable will serve well.   It IS good that you are thinking about the fine details of the system.   Enjoy ...<

My opinions,   Vic
Title: Re: Converted system to 48V today
Post by: CDN-VT on November 05, 2016, 12:25:16 AM
"Opened the bank to look in and saw 600V or AWM A/B 105C 1000V on the 00 short wires. "

All looks fine with those #'s .
Harvest time quicker than before ? Glad you made the switch/update ?

VT
Title: Re: Converted system to 48V today
Post by: Powerplay on November 05, 2016, 07:18:13 PM
QuoteHarvest time quicker than before ?

The battery does seem to get to float about 15min. faster.  Today, I started the mini-split in heater mode about 1-hour before the sun hits the panels full on, and it drained several percent off the battery bank before the chargers really got going.  But still everything had recovered and charged up by the normal time around noon.

I find it interesting that even though both Classics and I are calculating the same T-comp absorb voltage, the system always seems to charge to a set point about 1/10th Volt lower in both absorb and float.  I don't recall noticing the same in 24V but that could have been a rounding thing that is too big to round now its 48 V.  Any other ideas?

QuoteGlad you made the switch/update ?

Definitely;  about 94% efficient inverter now, about 9 Watts less self-consumption and the same wires can handle 5000W input now so plenty of room for some expansion.  I still have one of the reconfigured panels pointing a little SW from the rest of its string but when I add some panels next spring they might match this odd-ball so it can join the new string without being moved.  The Classic is still able to make a lot of power in the mean time so maybe I'll leave the panel be for now.  I'm getting some MC4 in-line fuse holders to try-out before I add any more strings as the wattages into each combiner will be getting up there by when those are added.  I'm also considering some new applications to connect to the system.
Title: Re: Converted system to 48V today
Post by: CDN-VT on November 05, 2016, 10:20:28 PM
getting some MC4 in-line fuse holders

Plz post the info & why or where your installing & why

VT
Title: Re: Converted system to 48V today
Post by: Powerplay on November 06, 2016, 08:32:06 AM
Quotegetting some MC4 in-line fuse holders

Plz post the info & why or where your installing & why

Not all the 500W series strings of panels can be terminated in the combiner box.  Some will have to be paralleled together before combiner.  Single strings into the combiner can be protected by a 15A or less breaker.  I'm trying out these water tight in-line fuse holders on the strings that will be in parallel with other strings.  Even though the panels only produce about 6A each string once 2 or 3 get out there together in parallel, it would be nice to have a fuse on each series.  I'm trying out the 10A glass audio types (1000V) fuses.  I don't think there will be any nuisance blowing of these fuses but I'm going to try a couple out before going hog wild on them.  Also I'd like to find out how water tight they are & what the quality level is, etc.
Title: Re: Converted system to 48V today
Post by: CDN-VT on November 06, 2016, 08:03:33 PM
Gotcha .
Title: Re: Converted system to 48V today
Post by: Powerplay on November 16, 2016, 04:24:08 PM
Quote"Opened the bank to look in and saw 600V or AWM A/B 105C 1000V on the 00 short wires. "

All looks fine with those #'s .

I did see a cable spec on line that is only rated 60Vdc today:  2/0 GA SAE J1127 Type SGT 105C 60V in fact.

Wouldn't this one be running pretty close to the edge in a 48V or better battery bank?  The banks often exceed 60Vdc (applied) during an equalize phase.  I'm just wondering.  It looks like the marine versions are rated to 600V & these are automotive rated 60V.  I guess some must need 2/0 cable in their truck.
Title: Re: Converted system to 48V today
Post by: Vic on November 17, 2016, 03:49:13 PM
Quote from: Powerplay on November 16, 2016, 04:24:08 PM
Quote"Opened the bank to look in and saw 600V or AWM A/B 105C 1000V on the 00 short wires. "

All looks fine with those #'s .

I did see a cable spec on line that is only rated 60Vdc today:  2/0 GA SAE J1127 Type SGT 105C 60V in fact.

Wouldn't this one be running pretty close to the edge in a 48V or better battery bank?  The banks often exceed 60Vdc (applied) during an equalize phase.  I'm just wondering.  It looks like the marine versions are rated to 600V & these are automotive rated 60V.  I guess some must need 2/0 cable in their truck.

SAE wire gauge specs are different than AWG.   In general,  SAE gauges run a bit smaller (less wire)  than AWG.

In the USA,  for wiring in power systems is all speced in AWG.  Think that SAE SGT 00 cable is about 125,000 Circular Mils (CM),  and AWG is about 133,000  CM.

SAE cable is designed for a different application,  than we generally need on battery- based power systems,   and often runs about 5 - 12 percent smaller than the same number cable in AWG.

You might be Down-under,  where Metric cable dimensions dictate (forget).

Personally,  would avoid using any SAE cable in a stationary power system.  Most SAE cable specs are for cable that is surface-mounted onto metal,  or for "flying leads",  like for starter connections,  etc.

Quite probably the low voltage rating,  is to try to accommodate some abrasion/damage to the cable,   etc.  In the USA,  NEC dictates that insulated cable needs to be protected from damage,  by protecting it in conduit, raceway,  or other enclosures,  in most cases.

Just IMO,   Vic
Title: Re: Converted system to 48V today
Post by: laszlo on November 19, 2016, 01:03:29 AM
Congrats on the upgrade and it 'sounds' like it went well other than the snap. FYI the relevance of conductor voltage rating is for the insulation.  Homepower magazine has a number of Code Corner articles on conductor types, ratings , and insulaiton, and I believe they can be accessed free of charge.
Title: Re: Converted system to 48V today
Post by: Powerplay on November 25, 2016, 05:18:13 PM
QuoteCongrats on the upgrade and it 'sounds' like it went well other than the snap.

No issues at all with the upgrade. All my system cables checked out as the correct gauge & AWM type 105C 1000V wires.  Thanks for suggesting the read over at Homepower.  As I look around at what is available on-line, I see notes about wire X or Y not being suitable for higher voltage solar applications so I'm curious about that.

QuoteFYI the relevance of conductor voltage rating is for the insulation.

Agree, zap.   ;)

I'll try to attach a photo:


Title: Re: Converted system to 48V today
Post by: Powerplay on November 25, 2016, 05:28:19 PM
QuoteQuite probably the low voltage rating,  is to try to accommodate some abrasion/damage to the cable,   etc.  In the USA,  NEC dictates that insulated cable needs to be protected from damage,  by protecting it in conduit, raceway,  or other enclosures,  in most cases.

Practical comment, IMO.  Also, they're getting a 105C rating and at the high temp might change the insulation.  If one's battery bank gets to 105C they've already got some issues.
Title: Re: Converted system to 48V today
Post by: Westbranch on November 25, 2016, 08:06:22 PM
found this...http://standards.sae.org/j1127_201210/


Standard: J1127_201210

Revised: 2012-10-18


    HISTORICAL
    Access the latest revision: J1127_201512

Issuing:

    Cable Standards Committee
    Committee Information

Publisher:
    SAE International

Pages:20
Scope:

This standard covers low voltage battery cable intended for use at a nominal system voltage of 60 V DC (25 V AC) or less in surface vehicle electrical systems. The tests are intended to qualify cables for normal applications with limited exposure to fluids and physical abuse.
Title: Re: Converted system to 48V today
Post by: Vic on November 25, 2016, 10:44:47 PM
Quote from: Powerplay on November 25, 2016, 05:28:19 PM
QuoteQuite probably the low voltage rating,  is to try to accommodate some abrasion/damage to the cable,   etc.  In the USA,  NEC dictates that insulated cable needs to be protected from damage,  by protecting it in conduit, raceway,  or other enclosures,  in most cases.

Practical comment, IMO.  Also, they're getting a 105C rating and at the high temp might change the insulation.  If one's battery bank gets to 105C they've already got some issues.

First,  while it is nice that some cables,  like MTW,  have 105 C temp ratings,  almost all of the terminals to which these cables connect will have a maximum temperature rating of 75 C (terminals as found on breakers,  busbars,  etc).

The photo does show that SAE SGT cable with large lugs installed,  BUT,  sure do hope that those lugs are designed for SAE cable,   because SAE 00 cable is about 6% smaller in diameter than is AWG.   This small diameter difference could be meaningful,  or perhaps not ...

FWIW,   Vic
Title: Re: Converted system to 48V today
Post by: Powerplay on December 02, 2016, 03:50:51 PM
6% less would be roughly 10+ less Amps capacity on 2/0.  But also it depends on how many strands wire, how it is terminated etc.  They should rate the ampacity of the wire rather than the rough diameter of the conductor, IMO.
Title: Re: Converted system to 48V today
Post by: Vic on December 02, 2016, 04:21:30 PM
Hi Powerplay,

Well,  the Ampacity IS rated for SAE and AWG.   In the USA,   NEC Ampacity,  is customarily used.   NEC ratings are fairly conservative.

The reason that I noted the Cross-sectional Area,  was to show the difference in area (and it is the area of the conductor that dictates Ampacity,  all else being equal),   AND to try to show that  the fit of lugs could be compromised,  if one was using Fine Strand AWG lugs on Fine Strand SAE cable.  A smaller cross-sectional area of a cable equates to a lower Ampacity,  while holding other variables constant.  Lug crimps might not be tight enough (and therefore higher resistance)  for poorly crimped lugs when the lugs are not designed for the cable and crimpers being used.

Would seem to me,  that the fit of the lugs would be more important,  when using the SAE cable,  than would be the lower Ampacity of the SAE cable (verses AWG).

Sometimes it is not easy to determine just what type cable lugs are designed for,  as many lugs are not well marked.

Also,  the way that SAE rates Ampacity differs from the way that the NEC rates the same gauge number of cable.

Just my opinions,   FWIW,   Vic
Title: Re: Converted system to 48V today
Post by: CDN-VT on December 02, 2016, 11:20:34 PM
Quote from: Vic on December 02, 2016, 04:21:30 PM


Sometimes it is not easy to determine just what type cable lugs are designed for,  as many lugs are not well marked.

Also,  the way that SAE rates Ampacity differs from the way that the NEC rates the same gauge number of cable.


Quality crimped / swedged , swedged on property & sealed will cause no real problems .
Problem is , Folks can't  READ anymore (over here in AME ) Wire states AWG xxxx Terminal also state's AWG xxxx over here .
Auto  sae is a sloppy joke !

Don't Get Fooled , Ya drive one , as I do also but don't fly that way
VT