Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

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  • BB.BB. Super Moderators, Administrators Posts: 32,322 admin
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School
    I mentioned our load early on, at least as measured by the controller which shows us using a very steady 9 to 10 amps of power at 12v, from 7am til 11pm, 16 hrs per day. We use no AC except the satellite internet box, run through a small 150watt inverter that is turned off at night. The only other significant draw is our two dual processor mac laptops. Does this mean 160 amp hrs of use a day, or is my math wrong?
    You saw in one of my first posts in this thread how to evaluate your power usage. More or less, for the month of June, you will AVERAGE 140 +/- Amp*Hours per day production and you are using ~160 Amp*Hours per day...

    For the most part, that is really too close... You either need more solar panels (2x as much would not be a waste of money) and/or a backup genset to make up for the lack of panels and sun (in bad weather).

    As per battery bank size... 160 AH at 12 volts and 3 days of no sun and 50% maximum discharge:
    • 160 AH * 3 days * 1/0.50 max discharge = 960 Amp*Hour @ 12 volts
    In any case, if you discharge your bank that deeply--you really need a good backup genset and battery charger to get that bank back up above 80% state of charge (for good battery life). The following are min/max recommendations--not hard limits for recommend charging current:
    • 960 AH * 5% charge rate = 48 Amp charger minimum
    • 960 AH * 13% charge rate = 125 Amp charger maximum
    A Honda eu2000i running a good quality 40-50 amp charger is probably about its limit (somebody here can probably tell you their experience)...

    Iota 45 amp 12 VDC charger
    Xantrex TC2 40 or 60 amp models

    In theory, the Xantex TC2 60 am[p should be able to operate just fine on a Honda eu2000i (1,600 watt) generator--but I would want somebody to confirm that as I cannot.
    Would like to be able to run the above for 3 days of clouds, rare as that is.

    From a load point of view--the Flooded Cell battery bank is a better match for your requirements (storage capacity wise)--And with more panels (another 15 amps) and/or backup genset--would be a good fit (assuming the batteries are still good).

    The AGM's are a bit small--but can also give you at least a couple days...

    In the end, you may end up having to test the battery banks under your operational load and see how each works.
    Plan is to remove the Trojans for now at least, wondering if I should get a larger controller and another panel, and if I should run the panels from lowest output to highest and then to controller?

    In either case, I would get more panels (double what you have would not hurt) and wire them up. See how your existing bank(s) work.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School
    Plan is to remove the Trojans for now at least, wondering if I should get a larger controller and another panel, and if I should run the panels from lowest output to highest and then to controller?

    What is the gauge of wire from panels to controller? You need at least 6 AWG. The problem is low Vmp of your panels. 16.5Vmp * 80% = 13.2V - this is your panel's approximate Vmp after temperature derating. Then, you got 30 feet of wire, lets assume 6 AWG. The Vmp measured at controller is now 13.2V - 0.9V = 12.3V

    This voltage is too low, the Vmp at the controller must be at least 14.9V for your flooded batteries to get full current while near absorption setpoint. This may be the reason why your Trojans are failing to reach full charge.

    Are you able to measure battery voltage and solar panel voltage and current? I need to know your total solar Amps at noon and on hot clear day when battery voltage is below or near 12V while charging. Then measure panel current again when battery voltage is above 13.5 Volts. If solar current is significantly less at 13.5V, then it's a problem.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    i have a suggestion to not throw away the smaller vmp pvs for if you split the batteries into 2 separate banks then those smaller pvs may be able to keep the other battery bank that's not connected on a float charge. or another possibility is to charge one and use the other and while using the other these smaller pvs connected on the battery bank being used may give a slight delay in the discharging of the batteries under load as nearly all of its power will be delivered to the loads that are connected to it at the time. a smaller and cheaper pwm controller can be used for this purpose.
    you still need to get more pvs to properly charge the batteries in any case and another controller to help handle the current for the main battery bank charging.
  • BB.BB. Super Moderators, Administrators Posts: 32,322 admin
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    In typical engineering design terms--Anything that is 10x or greater than something else typically overwhelms the smaller thing... Anything that is within 2x of another "thing" is roughly the same.

    Basically, if somebody was to give you a couple more 10-20 watt panels--it probably would not be worth your time building a mount and connecting them to your 5xx watt array.

    However, if somebody gave you 30x 20 watt modules--then it would double your array size--small or large panels regardless--so it may be worth your time and money to get them mounted and wired in.

    The issue with lots of small panels vs a few big panels:
    1. lots of extra hardware required to mount small panels
    2. the pain of lots of extra wiring connections (that can fail over time)
    3. When buying new panels... Typically panels 100 watts or larger tend to be less expensive than the smaller panels on a $$$/watt basis.
    4. Larger panels tend to be UL/NRTL rated for connection at 600 VAC wiring (same as house wire ratings) for use with large Grid Tied systems--so are "safer" for larger MPPT / higher voltage arrays. The typical smaller panels, if rated at all, are something around 70 volts maximum.
    5. Many of the larger panels are not "standard" Vmp voltages used for battery charging systems (Vmp~17 volts for a 12 volt bank). These non-standard Vmp panels usually work fine with MPPT type controllers but not with PWM type controllers (if Vmp <<>> Vbatt--PWM wastes lots of energy).
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    ah, they already have this system in place as these aren't just new to be installed. it just needs reworked and expanded some.
  • Anima CenterAnima Center Registered Users Posts: 16
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Okay, here's what wife and I think we should do for now, please approve:

    -Split AGM and Flooded battery banks
    -Purchase second Morningstar 30 controller with built in meter
    -Individually test all batteries
    -Upgrade to heavier wire between batteries, and maybe from controller to panels
    -Purchase Iota charger and find used EU series generator hopefully
    -Soon as possible get more panels

    Any tweaking anyone can suggest?

    Will the Honda EU200i run the Iota 55, or should we get the Iota 45 instead?

    You've all been hugely helpful, we were both going crazy before the explanations and advice.

    Stop in and see us sometime, riverside cabin usually available.

    Jesse and Kiva
    Anima Wilderness School
  • BB.BB. Super Moderators, Administrators Posts: 32,322 admin
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    What are your plans to connect the second 30 amp charge controller? In parallel with the existing panels, or getting a whole bunch of new panels?

    Regarding a 55 amp IOTA charger on a Honda eu2000i--The maximum AC current input is listed at 12 amps (108 vac*12amps=1,296VA --Should be OK for the 1,600 Watt / VA rated Honda--but hopefully somebody with more experience with this setup can confirm). You might call the store and/or IOTA Engineering directly and ask (make them earn their money ;)).

    It would be nice to get a Kill-a-Watt meter to monitor your charge controller's power usage--so you can monitor the battery bank as it gets full and the charge controller starts cutting back. Once you get to 1/4 power or so--you can turn off the genset and let the solar finish off the charge). Also, if you are going to use an extension cord between the genset and the charge controller--get a nice 12 or even 10 AWG heavy duty cord (if you can)... And keep it short. Don't get a 100' standard cord--too much voltage drop for the heavy power you want to efficiently move.

    I would also get an inexpensive DMM (Digital Multi-Meter) that has, at least, 3.5 digits of accuracy (1.XXX).

    And before you take things apart, measure the voltage at various points in your system when charging (and/or under heavy load). That will help you find if you need heavier gauge wire or not (for a 12 volt system--you almost surly need heavier gauge wire--but copper cable is not cheap).

    For example. Measure the voltage to the input of your charge controller (should be ~16 volts minimum in full sun to ensure your are moving all of the available current to the battery bank). If you measure less than 15 volts (under full sun with batteries needing charging)--then you absolutely need heavier gauge wiring (and/or have bad connections somewhere).

    The charge controller needs Vbatt+1 or 2 volts higher input voltage to properly charge the battery bank. If the input voltage is too low, then the output voltage will be low too (note: for pwm solar input voltage, if the battery voltage is really low--say 12-13 volts, the solar input voltage will be dragged down too).

    Then measure the output voltage of the charge controller. Hopefully, later in the day you are seeing 14.4 volts or so (with low batteries, you may be seeing less while they charge).

    At the battery bank, ideally, the voltage measured at the charge controller should only be ~0.100 volts higher than your 12 volt battery bank (with 30 amps of charging current). If the voltage difference is ~0.300 volts or more (cable voltage drop)--then the cable is defiantly costing you charging power into your batteries.

    The charge controller needs to measure the exact battery voltage while charging--if there is too much voltage drop--then the controller will think the batteries are more charged than they really are and cut back on charging current.

    If you can figure out the gauge of wire (diameter) and the run length (distance between source and destination)--and how much current is used/needed for each run, we can help you figure out the correct wire gauge.

    And, at the battery bank, each battery should be seeing nearly exactly the voltage at the "common bus connection point" while under load/charging. If not--either the cables are too small and/or you have dirty/loose/corroded electrical connections.

    Another warning--people rarely put fuses/circuit breakers in their battery bank wiring where needed (basically every parallel battery connection should be fused, plus any wiring leaving the bank and going to a load or charge controller)... And for systems with large numbers of parallel battery connections--properly fusing is expensive. So, for now, make sure your battery bank is in a realtively non-flammable area (and not sharing living space with your family, etc.). Battery fires are nasty business.

    -Bill

    PS: You are at a critical point in the design for your off-grid solar system... Your current system needs some work--Do you spend money on getting the system sort of working? Or should you not spend the money on the existing system and instead spend it on a "new system" that meets your needs and will work better in the long term.

    My guess is you are going to patch what you have... It is the cheaper option short term.

    Once you get it working better--When it comes time to replace your battery bank, come back and ask more questions. You will have more Solar RE experience, know your loads/requirements better, and we will be able to help you avoid some of the more common pit falls (like large numbers of paralleled batteries).
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Anima CenterAnima Center Registered Users Posts: 16
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Thanks for the great tips Bill, will do the testing as suggested.

    Getting an electrician friend down here to check on wire gauge, and he'll be here when we test voltage drop later.

    We subsist on student's donations and sales of nature and firearms articles, so no way to replace with all new. Got to make this system work as cheaply as possible, while studying panel options and asking for solar equipt. donations from our supporters.

    Buying battery bank switch and Iota from NAWS this week we think.

    The second controller was so each battery bank can have its own controller and panels, connected only by the switch so I can alter between as needed.

    Planning to buy 2 to 3 120w panels if possible by Fall, to power one bank or the other, run the other bank with the existing panels (minus the 20Watters?), and use genset to keep both banks up for now.

    Hope the 2000w Honda can power a 45 or 55 amp charger (anyone sure about this?), since any other model or any larger model, is reportedly many dbs louder.

    -Jess
  • BB.BB. Super Moderators, Administrators Posts: 32,322 admin
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Jess,

    Ask NAWS about the Iota and eu2000i--they should be able give you the exact answer. By the way, Iota has an IQ-4 option--you don't need that at all--It is for long term float charging of a battery bank with utility power. Does not make any sense to run with a genset (that I can see).

    Regarding the size of the genset--Honda (and others) do make larger and fairly quiet gensets too... Also, see if their is an RV wrecking yard around your area--sometimes nice 3-6kW RV gensets are available for not too much money (and have electric start too--may be a plus if you are not always around to start one).

    Also, look at what makes sense for fuel... Gasoline is the default choice for many--but it is difficult to transport and store (need fuel stabilizer if stored for more than a couple months). If you have propane for other needs around your place (great for storage, clean burning), or diesel (you may be getting tractor fuel without road taxes, less flammable--does need a bio-cide to keep growths out of stored fuel)--a good diesel engine operated correctly will last almost forever. etc...

    In the end, a genset sized to your needs can save you lots of fuel costs. Don't get an 8kW monster because somebody donated it... Those will take somewhere around 1/2 gallon per hour if they are running a 4kW load or a 400 watt load.

    And, sometimes, you get several gensets. A small / quiet one sized to your (smallish) battery charging loads, and a second cheap/larger one to run your shop tools when needed.

    Generators, ideally, should be operate at ~50% of their rated load minimum---They become substantially less fuel efficient as the loads go below that. Diesels, should be operated at 50-60% minimum of rated load or they carbon/"coke" up (with light loads).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 32,322 admin
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Jess,

    By the way, your next controller--you may want to look at the MorningStar MPPT type charge controllers (45 or 60 amp). They are great controllers, can be set for 12/24/48 volt charging. And can take "non-standard" panel Vmp ratings (PWM need to match Array Vmp to Battery Vbatt-charging).

    If you are going to stay at 30 amps and 12 or 24 volt batteries, the Rogue controller is nice too.

    A good MPPT controller will not be a waste of money for the long term.

    Also, with the ability to use "non-standard" voltage panels--you can look at large panels (>>100 watts) which tend to be much less expensive on a $$$/watt basis (always look at the cost per watt of your purchases to see that you are spending your money wisely--however, good quality gear is not cheap--and cheap gear is not cheap either ;)).
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Instead of spending $1000 on EU2000i, better to get much cheaper non-inverter gas generator in 2500 - 3500W max continuous power range. Then spend leftover $500 on Morningstar 60A MPPT controller, then rewire your solar panels in series to double the voltage. You will half your wire loss from panels to controller, will get full PV power up to battery absorption setpoint voltage and equalizing voltage, and will benefit from MPPT additional energy gain, or increase your solar performance by 20 - 30%.

    By buying additional PWM controller and panels and splitting system in two, you are just adding bandaids over the fundamental flaw of your system design.

    The order of steps I would do:
    1. Buy MPPT controller, batt switch, DC energy monitor
    2. Rewire all similar panels in series pairs, to double solar array voltage.
    3. Separate flooded from AGM
    4. Get more panels, look for lowest $ per Watt ratio
    5. If you feel you need it, get regular gas generator + iota charger
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Every time you switch between T-105s and AGMs, you will also have to adjust absorption setpoint voltage on your charge controller. If you forget, you will either undercharge your Trojans, or damage your AGMs. The solution would be to only use one type of batteries. I would get rid of T-105s.
  • BB.BB. Super Moderators, Administrators Posts: 32,322 admin
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    I think it was Jess' intent to use two different Morning Star controllers--one programed for AGM, the other for flooded cell.

    Probably also needs to figure which battery(ies) are good. Bank wise, based on his needs, the larger flooded cell bank is a better fit (if the batteries are still good).

    In any case, balancing charging energy with bank capacity--and getting everything fully charged is important.

    Eventually, a Battery Monitor of some sort (Victron Energy, etc.) will be nice once you have your "final bank"... It will help you immensely in managing your battery bank. It is almost the difference between having a car with or without a gas gauge for the fuel tank. (yes--battery monitors are not perfect either--because what they measure, batteries, are not perfect either).

    The DC Amp*Hour/Watt*Hour meter (DC Energy Monitor) that AntronX recommended is a less sophisticated version of a battery monitor--and well worth having just to monitor your DC loads too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Anima CenterAnima Center Registered Users Posts: 16
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Sounds good.

    The Rogue with its ecological emphasis made me think we should see if they or other companies have donation or discount programs for deserving green projects such as our by-donations school (www.animacenter.org). Do you know if any do?

    We could also offer considerable promotion in return for sponsorship of our upcoming herbal conference (www.traditonsinwesternherbalism.org), reaching thousands of earthy types.

    Will order Iota charger and switch soon as we hear back from our query to NAWS (using the customer service email link), then choose a controller this week week. Came up with a noisy chinese 2000k gen we can use until we can work out the quiet Honda.

    -Jesse and Kiva
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School
    BB. wrote: »
    I think it was Jess' intent to use two different Morning Star controllers--one programed for AGM, the other for flooded cell.

    Bad idea, I think. There in not enough solar power as it is. Splitting this system in two makes things even worse.
  • Anima CenterAnima Center Registered Users Posts: 16
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    I hadn't seen new posts 42-44. Thanks AntronX, I am indeed going to use two separate controllers since I have both AGM and flooded banks, hopefully get an MPPT for the the second bank, putting a load switch between them... of course requiring more panels for the second bank. I was putting charger as #1 to buy since it seems we have been undercharging the flooded ones especially. Sound right to you? I'm used to the readout on the Morningstar Prostar 30, how is the BMV or Doc Wattson R102 different or better?

    Still waiting to hear if 1650 watt gen output will handle the Iota.

    Best, Jess
  • mike95490mike95490 Solar Expert Posts: 9,511 ✭✭✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    If you ask 50 people here, you will get 74 different answers. :-)

    I personally think that splitting the batteries to AGM | Flooded and 2 different charge controllers, is the way to do it.

    Also, any automotive 12V charger will work to bulk charge the batteries, easily get to 30A with many of them. Plug into generator, bulk each bank for an hour or so, and let the sun do the rest.

    Also, there are propane conversion kits for the honda EU gens, so you don't have to stick with gasoline.

    Note about the Iota - it has no meters, power cord or switch on it. You will have to install those yourself, and also need wire for it's output cables, and fuse.

    Maybe another A |off | B switch for the Iota charger, so you can send it to either battery bank without changing cables.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 32,322 admin
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Charge controllers will show their output voltage and current (frequently, the output current is only an estimate with 10-30% error range--frequently estimating high).

    The Doc Watson (more or less a higher power version of the Watts Up) is an inline Amp*Hour/Power Meter... Since it can read both forward and backwards, it can, after a fashion, be used as a battery monitor...

    The difference between a plain old Amp Meter and a Doc Watson or even the Charge Controllers is that they not only tell you a Rate (miles per gallon) they also give you a totalized amount used (Miles * 1/MPG = Gallons used).

    The Charge controller only can measure how many Amp*Hours it has output.

    The Doc Watson, depending on where it is installed, can tell you how much energy (amp*hours or watt*hours) has gone through it... Install between a charge controller and the battery=>energy output from controller/solar panels.

    Put the DW between the load and the battery--it will tell you how much energy the load has consumed.

    But the DW between the battery post and everything else--it will keep track of how much energy is in the battery at that moment (charging, the AH/WH goes up; discharging the AH/WH goes down). You can set up a manual reset switch to "zero the meter" whenever you want (recharge battery to 100% full. Zero meter, as you use loads, meter counts down. Recharge, meter counts back up to zero--full capacity).

    A battery monitor is a more sophisticated version of a Doc Wattson. It has the ability to understand when the battery is full and set itself to 100% state of charge. They also can have other factors to allow for different charge rates and battery inefficiencies, and can give you available capacity in XX% state of charge, Amp*Hours, or whatever.

    The battery monitor current shunt (what measures current) is typically installed between the battery negative terminal and the common ground bus.

    Basically, a "fuel gauge" for your battery. Again--they are not perfect. The do "guess" when the battery is fully charged, and battery capacity estimated on capacity you program into the meter (battery capacity changes over time, usage, temperature, and abuse).

    If you had a standard battery bank (all batteries of same brand/model/age)--you would have seen that you are not recharging the battery bank enough and, hopefully would address (more solar panels, generator, or draw less power) and extend the life of your battery bank (it is pretty easy to reduce a battery bank life by 1/2, or worse, with improper operation).

    In the end, each tool has its purpose--And why service people (mechanics, machinists, etc.) have so many tools. :roll:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Anima CenterAnima Center Registered Users Posts: 16
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    74 answers from 50 people, that's scary when we're trying to get definitive and decisive Mike!

    Cheap car 30 amp car charger will do what Iota will, and with a meter on it???

    Would the pos and neg cables go on opposite ends of a battery string?

    Doing the battery tests next weekend with help, and separating them then. One bank (likely the AGMs) will be left unused until we get a Blue Sky switch. Gen will have to keep both up (noise a real problem in a wildlife refuge) until we can come up with second controller and 3 or more large panels for them.

    Want to end up with remote meters indoors to monitor both systems when they're going, then I'll know when to switch from one to the other, when to equalize etc. What's the best meter/monitor settup for inside?

    thanks!
    Jess
  • Anima CenterAnima Center Registered Users Posts: 16
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Thanks Bill, for the meter info. Still wonder how we can read both systems power in and out, from inside.

    And I hear you about tools for mechanics, but I'm only filling in for the lack of someone who knows what they are doing. I have lots of art and writing tools, the rest is coming harder!

    -Jess
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    do note that a standard car battery charger will not normally be regulated and could easily overcharge the batteries even though it may have meters. they could be used in bulk charging batteries, but need to be watched so that they do not exceed the absorb voltage point of the batteries.
  • mike95490mike95490 Solar Expert Posts: 9,511 ✭✭✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School
    Cheap car 30 amp car charger will do what Iota will, and with a meter on it???

    Would the pos and neg cables go on opposite ends of a battery string?

    Almost. It can provide the bulk charge only, poor at the finishing charge

    After all these messages, I've forgotten, I think you are using a 12v battery system ? Then a auto battery charger may help in the near term, till you get more professional gear.


    As in jump starting a car :
    Positive (red) to positive,
    Negative (black) to negative.

    Connect the wires to the battery bank DIAGONALLY
    http://www.smartgauge.co.uk/batt_con.html

    batt_new.gif
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    A few things to note about the Iotas. They are two-stage converter/chargers without the IQ-4 module. As converters, they are designed to run DC loads while charging - which is (apparently) best done in two-stage mode.

    They come with a plug that when inserted ups the voltage a bit. I believe that without the dingus plugged in, they operate at a good voltage for FLA, and with the dingus plugged in they operate at a good voltage for AGMs.

    Instead of the included dingus, you can get the IQ4 module, which plugs in to the same place as the dingus. The IQ4 module makes them into "3-stage + EQ" chargers. They won't EQ without that module.

    http://www.iotaengineering.com/iq.htm

    HOWEVER - as near as I can tell, the IQ4 is not programmable - and since you don't want to EQ AGMS you would probably need to use the IQ4 when charging the FLAs and unplug it and use the dingus when charging AGMs. And that might not work, since the IQ4 automatically does the EQ every 7 days...but if you unplug it, then it probably resets. So, you might have to leave it plugged in for 7 days for it to actually EQ the FLAs.

    The DLS chargers can be had with the IQ4 built-in, but I think you would probably not want that since you would need to unplug the IQ4 and use the dingus when charging the AGMs.

    I would want to talk to Iota and find out if they think that doing a weekly EQ on AGMs is an okay thing to do. I'm not saying I'd believe them (especially if the battery specs say to NOT EQ), but I'd at least see what they say.


    The specs on the [email protected] version say this:
    Max Inrush Current, Single Cycle 40 Amps

    And the [email protected] says the same. I have noted before that those listed specs seem a bit fishy, since the 30a unit says 27a and the 15a unit says 30a.

    I would also ask Iota what, exactly, do those specs mean?


    As for a generator - I would first ask Iota what generator size their chargers really need. The EU2000i is rated at 1600w continuous and 2000 surge...ask them what is the biggest charger that would run.

    And I don't know that I'd buy an EU2000i just for battery charging. The Iotas don't need pure sine wave. Quiet is nice, and fuel economy is nice...BUT if you could do the job with a generator that costs $400 instead of $1000, then you can (at today's $3/gallon prices) buy an extra 200 gallons of gas for the same price.

    If all I were going to use it for was to charge batteries, then I would probably ask Iota what size gen I need for say the 55a charger, then just buy the smallest "normal" generator I could get to do the job.
  • mike95490mike95490 Solar Expert Posts: 9,511 ✭✭✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School
    dwh wrote: »
    A few things to note about the Iotas. They are two-stage converter/chargers without the IQ-4 module. As converters, they are designed to run DC loads while charging - which is (apparently) best done in two-stage mode.

    They come with a plug that when inserted ups the voltage a bit. I believe that without the dingus plugged in, they operate at a good voltage for FLA, and with the dingus plugged in they operate at a good voltage for AGMs.

    ....................


    The specs on the [email protected] version say this:
    Max Inrush Current, Single Cycle 40 Amps

    And the [email protected] says the same. I have noted before that those listed specs seem a bit fishy, since the 30a unit says 27a and the 15a unit says 30a.

    I would also ask Iota what, exactly, do those specs mean?


    As for a generator - I would first ask Iota what generator size their chargers really need. The EU2000i is rated at 1600w continuous and 2000 surge...ask them what is the biggest charger that would run.

    And I don't know that I'd buy an EU2000i just for battery charging. The Iotas don't need pure sine wave. Quiet is nice, and fuel economy is nice...BUT if you could do the job with a generator that costs $400 instead of $1000, then you can (at today's $3/gallon prices) buy an extra 200 gallons of gas for the same price.

    If all I were going to use it for was to charge batteries, then I would probably ask Iota what size gen I need for say the 55a charger, then just buy the smallest "normal" generator I could get to do the job.

    Since the Iota is only for bulking the batteries, for an hour or two, in the AM, no dongles are needed. The solar PV will take care of topping them off.

    > The specs on the [email protected] version say this:
    > Max Inrush Current, Single Cycle 40 Amps

    Inrush is the AC inrush (from the generator) when you power up the charger, they are switch mode supplies, and have a big honking capacitor to fill up.
    Also means they don't have a real good power factor, since they don't publish it.
    45A @ 12V is 450W, and if the pf is .6, it could try to pull 900W from the generator.
    Nice thing is that after a few minutes, the batteries will not pull full power from the charger, and the load on the genset will taper off. Even an honda EU 1000 should run the 45A Iota.
    Without a amp meter, you could tell by engine noise, as the engines EcoThrottle, throttles back, you can assume the batteries are filling up.

    For a "back to nature retreat", engine noise is a bad thing, so a home depot 3600 RPM screamer is right out.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    I don't think a IOTA 45 will run on a Honda EU 1000.

    Here is the spec 11 amps @ 108 vac = 1188 watts
    The Eu 1000 will run a Xantrex TC 20, but not a TC-40, due to a power factor of ~.7 if memory serves. I suspect the IOTA would have a similar PF.

    I have no idea how long the inrush current lasts, but my guess is that the generator should handle it without a problem.

    Tony
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School
    mike90045 wrote: »
    Since the Iota is only for bulking the batteries, for an hour or two, in the AM, no dongles are needed. The solar PV will take care of topping them off.

    I was operating under the assumption that the gen/charger would be used to EQ the batteries. The FLAs surely need it and the Iota won't do it without the IQ4.

    Also, on days when when there is not enough sun, the gen/charger would need to be used to top off the batteries, so I think that planning on having the ability to do that would be prudent.

    > The specs on the [email protected] version say this:
    > Max Inrush Current, Single Cycle 40 Amps

    Inrush is the AC inrush (from the generator) when you power up the charger, they are switch mode supplies, and have a big honking capacitor to fill up.

    Exactly - the max that it will draw *from the generator* is 40a. Is that not significant considering that the max surge the eu2000i is rated for is 16.7a?

    So, as I said - the thing to do is call Iota and ask.

    For a "back to nature retreat", engine noise is a bad thing, so a home depot 3600 RPM screamer is right out.

    Yes. Supposedly.

    BUT - if cost weren't an issue then they would just buy more panels and not need a gen in the first place. It would of course be up to them how much more they are willing to spend to reduce noise. They could spend 500 (or less) on a gen and have enough left over for another 200w (or more) of PV.

    And a normal type generator doesn't have to be a "home depot screamer" - there are some fairly quiet non-inverter generators out there - not "Super Quiet" (as Honda describes the EU series) but not "screamers" either.
  • BB.BB. Super Moderators, Administrators Posts: 32,322 admin
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    An automotive charger may, or may not, do a good job of bulk charging the batteries. The automotive charger probably won't do a proper equalization.

    The Iota's charge at 14.2 volts when the "jumper" is in. And float at 13.6 when the jumper is removed (PDF manual)... For off-grid applications, there would be no reason to ever "float" the bank at 13.6 unless you run the generator 24x7 (which is not going to happen at your place).

    I still don't thing the IQ-4 module will be of much use for off-grid charging.

    My preference for a charger would be the Xantrex TC2-40 or TC2-60... The original TC family was a nice charger and, I hope, the TC2 family is good too. The TC2 has power factor correction (as well as optional battery temperature sensing). NAWS lists the TC2-20 (too small for this application) and Xantrex has been way late on bringing out this product line and NAWS did not want list something that was back-ordered for 6+ weeks (from what I understood in earlier posts)... Check with NAWS to see if the 40/60 units are available from them.

    But, I have no experience (or have read anything about them)--so I would at least ask NAWS about their opinion regarding the Xantrex TC2.

    About remotes--Many devices have remote "heads" (like MorningStar for there charge controller, Xantrex for their TC2 chargers). Others, like the battery monitors have you install a "shunt" (large precision resistor) at the battery bank, and you run 2 pairs of small wires to carry the voltage information 25+ feet back to the instrument).

    Of course, some of these options are not "cheap". And, since your battery bank is the "heart" of your system--Having the Battery Monitor mounted in a convenient location is probably the #1 priority.

    Note that the suggested use for the Generator battery charging is to start the genset "early" in the morning and get the batteries 80-90% charged (at this point, the AC charger has cut way back on the charging current and the genset is probably beginning to be a waste of fuel)--then turn the genset off and let the solar panels take the batteries up the rest of the way.

    However, if your battery bank is nearly dead (say 20% charged) and you want to get it above 80% state of charge. And you have a 1,000 AH battery bank:
    • (80%-20%)*1,000 AH / 55 amps = 10.9 hours of charging
    So, the first time, it may take 10+ hours to recharge your battery bank to 80% state of charge... And another 3-6 hours to get the last 20% charging (assuming the batteries are still good--not sure at this point).

    Once you have your bank stabilized--then sharing charging with solar panels, you can probably get the generator run time down to a few hours per week (or none during the sunny months of the year).

    You have a very large battery bank and it takes quite a bit of energy and time to get those guys fully charged.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    A honda Eu 2000 can be had for under ~$900. I don't think you are going to get any kind of reasonably quiet Honda (EX series) or the equivalent for $500 less. You might find a good deal on a seldom used ~2kw unit for $400, but more likely, a Home Depot screamer is what you are going to get for $400.

    Another option would be a Onan RV generator. These can be had from RV wreckers, often quite cheap, and often set up to run on LP gas. The are not as quiet as a EU, but pretty quiet.

    Tony
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School
    BB. wrote: »
    ...The Doc Watson (more or less a higher power version of the Watts Up) is an inline Amp*Hour/Power Meter... Since it can read both forward and backwards, it can, after a fashion, be used as a battery monitor...

    Doc Watson meters I have here cannot read current flowing backwards, or from output to input. They just display zeroes. That's why I use two meters.
  • BB.BB. Super Moderators, Administrators Posts: 32,322 admin
    Re: Mixed Panels and Controller Confusion: Advice Needed for Wilderness School

    Well--Darn--you are correct:
    Will a "backwards" or reverse connection damage the "Watt's Up"? E.g. connecting a charger to the LOAD side and a battery to the SOURCE? What will the display read?
    • No. Connecting in this manner causes current to flow in the reverse direction, but will cause no damage up to the rated current of the meter. However, while connected this way, the meter will not indicate the actual current nor any value derived from the current i.e. Watts, Amp hours or Watt hours. E.g. the Amps and Watts will read 0.
    • Any accumulated Ah or Wh displayed will not increase further until power again flows from SOURCE to LOAD, i.e. in the forward direction (meaning current is flowing in the black wires from LOAD to SOURCE).

    I missed that reading through the specs. So, will not work real well as a substitute for a Battery Monitor.

    The Doc Wattson type only accumulate AH/WH in one direction and ignore the other.

    A battery monitor is a true totalizer--adds/subtracts readings based on actual direction of current flow.

    Two Doc W's is not much less than one good quality battery monitor.

    Doc Wattson $60
    Trimetric TM-2025A Battery Monitor System $150

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