Generator sizing & System data logging

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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #32
    Re: Generator sizing & System data logging
    Sun Dog wrote: »
    By the end of the charge cycle the charger is only asking for 13A@29.8V =~400 watts and that isn't particularly healthy for my 10kW diesel either.

    Perhaps you can do that every other day, or once a week. After deeper discharge, batteries will stay at high amps for longer.
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  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    #33
    Re: Generator sizing & System data logging
    Sun Dog wrote: »
    24V. It is getting close to it's limit but only for 30-45 minutes until the charger goes into absorb. Clearly it is a choice that everyone has to make but all generators have a max and lower continuous rating. I am comfortable running close to the limit of the continuous rating for a relatively short time. By the end of the charge cycle the charger is only asking for 13A@29.8V =~400 watts and that isn't particularly healthy for my 10kW diesel either.

    Well like I said, pulling a full "135A" at 24v from a charger on a 5kw generator is likely gonna make it choke. So if you let your batteries get down to needing a full "bulk" charge I would bet you would have an issue. But even so, you must have a very good charger? I wouldn't mind finding a better one myself. What are you using?

    And PS - I love the champion generators. They are a bit "over-rated" in their claimed output (continuous) but you can't beat the price for an engine with a cast iron sleeve and pretty quiet compared to the B&S now-a-days
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
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  • Sun Dog
    Sun Dog Solar Expert Posts: 115 ✭✭
    #34
    Re: Generator sizing & System data logging
    NorthGuy wrote: »
    Perhaps you can do that every other day, or once a week. After deeper discharge, batteries will stay at high amps for longer.

    Yes, the "best" charging strategy is the question. For the first two years I made sure the batteries made it to float every day. Now I hope for float everyday, ensure absorb is reached everyday and don't let them go any longer than two days between float. So worse case would be something like float on Monday, aborb+ on Tues and Wed then ensure they reach float on Thursday again.
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  • Sun Dog
    Sun Dog Solar Expert Posts: 115 ✭✭
    #35
    Re: Generator sizing & System data logging
    jcheil wrote: »
    Well like I said, pulling a full "135A" at 24v from a charger on a 5kw generator is likely gonna make it choke. So if you let your batteries get down to needing a full "bulk" charge I would bet you would have an issue. But even so, you must have a very good charger? I wouldn't mind finding a better one myself. What are you using?

    And PS - I love the champion generators. They are a bit "over-rated" in their claimed output (continuous) but you can't beat the price for an engine with a cast iron sleeve and pretty quiet compared to the B&S now-a-days

    Yes, Champions seem to be a great price/performance product with fantastic customer service. The charger is integrated in my XW4024 inverter/charger.
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  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    #36
    Re: Generator sizing & System data logging
    Sun Dog wrote: »
    The charger is integrated in my XW4024 inverter/charger.

    Ah, that makes sense because the charger won't pull more than the generator is rated for correct?

    Sometimes I wish I went with an inverter/charger - they seem to have "very" good chargers in them; but my unique setup required a rather custom transfer switch that I would not have been able to achieve with a built-in model.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
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  • Sun Dog
    Sun Dog Solar Expert Posts: 115 ✭✭
    #37
    Re: Generator sizing & System data logging
    jcheil wrote: »
    Ah, that makes sense because the charger won't pull more than the generator is rated for correct?

    It is completely adjustable between 3-60A. If set at 60A the max total load (charger and passthru) is 80% so 48A x 240V = 11.5kW

    The charger itself has a max of 150A and 32V.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #38
    Re: Generator sizing & System data logging

    The Magnum inverters seem to be a good value. A number of Magnum users have mentioned that they do not have stellar voltage regulation of the AC output. Some have noted that the Magnum PFC charger is not well PFCed. I have no experience with them.

    BUT, if one was believing that they needed more battery charge current than one 4448 could provide, and therefore stacking a pair of them would be in order, it MIGHT be time to broaden the scope of the Inverter/Chargers under consideration. Perhaps the Schneider XW line could be in order.

    Also some of the higher-end Inverter chargers have two AC inputs available -- Grid and Generator. So one can use a smaller inverter-generator on the AC input, and a larger genset on the Generator input. This is what we do with the pair of Xantrex SW plus Inverters here. This pair can charge at 130 - 150 Amps continuously for hours, especially with some help from PV.

    Generator Support may work for a number of folks, especially those in Northern climes (perhaps), but personally I like SILENCE, so run the genset when it needs to be run, and having one cycle on and off at seemingly random times would probably finish the job of driving me nut-so.

    LARGE battery banks are not always a plus. Batteries need to be cycled for their health -- down to 50-ish% SOC at times. Recharging a bank from this state can take a fairly long genset run time is the charge capability is small. And for Flooded batteries. (really, most LA batteries) each discharge cycle should be to, or balow 90% SOC. Sometimes this can be difficult to manage.

    I know nothing about the Magnum monitoring function that you were asking about, but the XW has good monitoring capabilities. I personally hate Schneider as a company and dislike their "Customer Service", but for off-grid use, think that the XW inverters are very good. There are other manufacturers as well, a number being from Europe. My cents worth. 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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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #39
    Re: Generator sizing & System data logging
    mike95490 wrote: »
    For your loads, what is your monthly electric bill now ? A new, efficient house, should not be worse.

    Well pump considerations.
    a) conventional pump and motors ($400) have a pretty high starting surge requirement, and will need a large inverter to
    start it. Repair parts are common. 3 wire units (starting cap above ground at the pump controller)

    b) there are some soft start pumps, but they cost more, and harder to find repair parts for.

    c) Solar / DC pumps have their own MPPT controller, DC/AC drive controller, and pump & motor. Some models, it's all
    underground in the well. Pretty expensive.

    d) pressure tank (pump cycles on and off as you use water) or gravity feed from a elevated tank. only 1 or 2 pump cycles a day.

    I've got the Xantrex gear, and it took a while to get the Gen support fine tuned, but my 3KW diesel can power everything, and charge a 48V bank at about 30 amps. And if more loads kick in, the inverter dials back the charging, till it actually begins helping the generator. Just remember to allow the generator to cool down when finished, don't just shut it off, or the alternator windings will overheat from residual heat and no cooling fan.

    I was looking at a Grundfos with a pressure tank - (b) above I guess. Not sure what a pump goes for usually but these do not seem extremely expensive unless I don't understand the pricing and everything I'll need...

    EDIT: Sun Dog your inbox is full so I can't reply to your PM's, but thanks for the info!
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