Multiple Inverter/Chargers..setup

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rtribble
rtribble Solar Expert Posts: 28 ✭
in Off Grid Solar & Battery Systems #1
I have a 15kw generator, that feeds 4 Trace 5548 inverter chargers. One of the inverter/chargers is wired into the AGS.

What should the parameters be to properly operate ? on each unit ?

Should the AGS control unit (1 of 4) have a lower Bulk Charge Volts, and lower absorb time ?
Should all the others be the standard factory defaults ?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Multiple Inverter/Chargers..setup

    The normal method is that all the inverters draw off one battery bank. As such any one inverter can be used to monitor that bank and judge when to start the generator. If all inverter-chargers are contributing to charge then the one doing the monitoring will still read the battery bank as a whole and judge when to stop the generator. Charging parameters should be the same on all units.

    This is where communication between the inverters helps as it will allow them to be 'in sync' regarding battery Voltage, temperature, charge stage, and set points.
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  • rtribble
    rtribble Solar Expert Posts: 28 ✭
    #3
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    Re: Multiple Inverter/Chargers..setup

    These are sw5548,they are all working off the same battery set, they communicate in pairs for series stacking (i.e. 240 split phase), but no other communication.. there are actual differnces in voltage by tenths, not always the same..
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #4
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    Re: Multiple Inverter/Chargers..setup

    Hi rtribble,

    As Marc has stated, all of the charge settings in the inverters should be nominally the same. There are slight variations in the voltage calibration of each of them. And there are probably small variations in the voltage drops in the busbars and cables connecting the inverters to the battery bank. These variations can be compensated for, to a certain extent by slight changes to the "Bulk" voltage setting in the Charger menu of each inverter/charger.

    Do not know just what the factory defaults are for the SW 5548s, BUT usually, these defaults are very conservative -- set on the low side, so as not to damage the most delicate batteries that might be used in these systems.

    It is very important to set the Bulk voltage (really it is the Absorb voltage, but Trace/Xantrex calls it Bulk voltage) to that recommended by the manufacturer of these batteries. Personally, would guess that the Bulk V should be in the range of 59-ish volts for these Floor Scrubber batteries, in the Winter, when using the generator.

    You will probably want to use a timed Bulk stage, as trying to use End Amps, with multiple chargers each of which believing that it is the ONLY charger will probably work poorly. If you have a shunt in the Negative lead of the battery, you might be able to use a DMM to read the actual battery charge current, and possibly use this to determine just how long an Absorb should be, BUT variations in the DOD of the bank will dictate a variable Absorb time as well.

    Since you seem to have some Hydro, and lots of PV, just getting into the Absorb voltage range with the Generator, and finishing charging with Hydro or PV could work well. When using AGS to run the gneset is a bit of a different strategy.

    Also, if you could do a L-O-N-G Absorb using Hydro, if necessary, this might help you charge some of the possible laggard batteries. Most of us who are off-grid do not have the luxury of doing these long Aborbs, as the solar day is just short. A long absorb gets the batteries that are taking the bulk of the current charged, and this reduces their current share, allowing the lagging batteries to get relatively more of the charge current.

    My opinions, Good Luck! Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • rtribble
    rtribble Solar Expert Posts: 28 ✭
    #5
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    Re: Multiple Inverter/Chargers..setup

    all, good comments, does anyone have a tech support number for the Trace Products, the old number just says mailbox full !!
    the problem is with all the settings the same, the three inverter / chargers that are not the ags unit all drop into float mode long before the ags unit ?? why ??
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
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    Re: Multiple Inverter/Chargers..setup
    rtribble wrote: »
    all, good comments, does anyone have a tech support number for the Trace Products, the old number just says mailbox full !!
    the problem is with all the settings the same, the three inverter / chargers that are not the ags unit all drop into float mode long before the ags unit ?? why ??

    They haven't been Trace for years. Became Xantrex which was bought by Schneider and some of the products are now called Conext. Their customer service has a reputation for being not so good.

    You don't necessarily have a problem. As the four inverters will each read Voltage slightly differently according to the resistance in the wiring and other variations. What you want to know is: does the Absorb stage last long enough with the current dropping off to where the 'control' inverter is not struggling to maintain Absorb once the others have dropped to Float? The other thing you want to know is: are the batteries actually being charged?
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #7
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    Re: Multiple Inverter/Chargers..setup

    Yea, these inverters go back more than ten years, and through two company structures/name changes.

    But, you DO have the manual for these 5548s, RIGHT ??

    Expect that you do not have an issue with some inverters going to Float until the voltage gets near/into the Absorb voltage range. Then, you can sometimes get multiple charge sources to maintain Absorb, by setting the Bulk voltage a bit higher on the ones that try to go to Float -- it is a bit of a balancing act, though.

    Making things a bit more challenging is when there is significant power from the PVs, although, this would not be too common on an AGS start unless there is intermittent sun/clouds.

    As far as I know, these inverters only communicate when Stacked, and then, only as to syncing the sine wave outputs. From there on, each is just doing its own thing.

    And, as also stated by 'coot' Marc, if your massively parallel battery bank is not sharing currents well, not all of the inverter/chargers might be needed when the genset runs.

    THis stuff ain't easy, not Rocket Science, but not that easy.

    I assume that when the AGS is running the genset, that NONE of the inverters are dropping the AC input? This is noted by the AC in relay dropping out (Clunk!!), and the Green AC in LED flashing while the generator AC is being re-qualified. This is a different set of issues.

    Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    #8
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    Re: Multiple Inverter/Chargers..setup

    For old Trace Engineering inverter "service", Craig is the guy you want.

    http://www.phantompowerservices.com/

    boB
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  • rtribble
    rtribble Solar Expert Posts: 28 ✭
    #9
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    Re: Multiple Inverter/Chargers..setup

    No phone on website ?? got one ??
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  • rtribble
    rtribble Solar Expert Posts: 28 ✭
    #10
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    Re: Multiple Inverter/Chargers..setup

    not sharing currents well, not all of the inverter/chargers might be needed when the genset runs.

    How do I determine this ???



    Vic wrote: »
    Yea, these inverters go back more than ten years, and through two company structures/name changes.

    But, you DO have the manual for these 5548s, RIGHT ??

    Expect that you do not have an issue with some inverters going to Float until the voltage gets near/into the Absorb voltage range. Then, you can sometimes get multiple charge sources to maintain Absorb, by setting the Bulk voltage a bit higher on the ones that try to go to Float -- it is a bit of a balancing act, though.

    Making things a bit more challenging is when there is significant power from the PVs, although, this would not be too common on an AGS start unless there is intermittent sun/clouds.

    As far as I know, these inverters only communicate when Stacked, and then, only as to syncing the sine wave outputs. From there on, each is just doing its own thing.

    And, as also stated by 'coot' Marc, if your massively parallel battery bank is not sharing currents well, not all of the inverter/chargers might be needed when the genset runs.

    THis stuff ain't easy, not Rocket Science, but not that easy.

    I assume that when the AGS is running the genset, that NONE of the inverters are dropping the AC input? This is noted by the AC in relay dropping out (Clunk!!), and the Green AC in LED flashing while the generator AC is being re-qualified. This is a different set of issues.

    Good Luck, Vic
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #11
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    Re: Multiple Inverter/Chargers..setup
    rtribble wrote: »
    not sharing currents well, not all of the inverter/chargers might be needed when the genset runs.

    How do I determine this ???


    You WILL need a DC Clamp-On Ammeter. This will allow you to measure the DC current flowing in each string, when they are being Bulk charged at fairly high current. You will also want to use your Digital Multi-Meter to measure the voltage drop (on a low voltage scale, like 200 Millivolts full-scale) to measure the voltage drops on ALL of the DC interconnects for the batteries, again with fairly large and consistent current flowing to/from the inverters.

    DO YOU HAVE THE MANUAL FOR THE SW 5548 INVERTERS ?? ??? ????

    Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,448 admin
    #12
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    Re: Multiple Inverter/Chargers..setup

    If this is your first trip buying/using a DC Current Clamp Meter and don't want to spend too much--This one from Sears for $60 or a bit less is "good enough" for our needs.

    Of course, you can buy a very nice Fluke meter for $400 or so (ouch).

    I recommend you practice using it one your Car (or similar) to see how it all works/make readings. Lights on/off, engine starting/running, etc. Note that a DC current meter can tell the direction of the current +/- (on display)--Unlike AC current meters.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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