Suplimental Solar charging in a mobil appllication

Bunkie314Bunkie314 Registered Users Posts: 11
Well, I have purchased a Magnum Sine wave invter and 3 lifeline 8D AGM batteries (210 Ah). SYstem work extreamly well for a 12 v that I am unfortunately tied to. Now for the questions:

1. I have a cargo trailer that is 8 ft wide and 42 ft long. I could mount 10 of the UniSolar PMV quite easily to the roof. Quesitons I have are what controller to use with the 48 v output of the pannel? Can I only harvest 30% of the second have of the voltage at peak (33 v)?

I have purchased 5 of these pannels and am currently using one to maintain the battery voltage array. Do I need to purchase another 5?

What MPPT system would be needed to pull effective engery from the pannel Vpp.

My hope is to only have to run the generator every couple of days to fully charge the battery.

Thought? Advice? You screwed up? Let me have it, I'm new to this.

Comments

  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication

    welcome. One question, what are your loads?

    Similar to all roads lead to Rome, all good systems are based on their loads
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Bunkie314Bunkie314 Registered Users Posts: 11
    Re: Suplimental Solar charging in a mobil appllication

    Running down one of the calc sheets I came up with about 275 Ah usage on a heavy day (TV, fridge, lights, Microwave, etc)
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication

    Based on the 275 Ah, you will need 275 x 2(50% max usage) = at least a battery capacity of 550 Ah. This is at a rate that will take your battery to the brink of over use and make it unable to be recharged It will also need to be recharged from the grid overnight. So the question i:s just how big a battery reserve do you want?
    Doubling the battery to 1100Ahwill allow you to operate for 2 days before safely depleting your battery.
    So now you have to look at the solar input to replenish the use. A rough rule of thumb taking all system inefficiencies into account, is use 50% of the nameplate rating as what you can get back out of what goes in.
    Now you have to determine the number of watts you will need.

    Multiply the 275 by the system voltage you want ( those panels may just be able to charge a 24 volt battery but it is safer to go 12 v) ,So look at those panels and divide (275 Ah x 12 v) = 3300wh by 4 hours(the average number of sun hours per day) = the daily watts.
    Now divide this by the wattage of one of the panels and it will give you the number of panels you will need.

    think I got this all right...

    there is lots more like inverter and system voltage , but that will come later.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication

    at 210ah x 3 you do have enough capacity to avoid going over 50% dod, but you state they are size 8d lifelines and i believe those are rated at 255ah each.

    i believe westbranch's point is that you want to be sure you will end up with enough in pv to keep those batteries charged every day. at 275ah in loads and if you are lucky enough to get 5hrs of full sun this is 55a being delivered from pv. do not think the stc rating on pvs is the same thing as most pvs won't deliver the stc ratings normally so the stc wattage ratings are derated by about 77%. as such you will need at least 71.5a stc. this is quite a bit in pv for the roof of your trailer.

    it may be easier to run a generator to a 3 stage charger to bring these batteries up and just use the pvs on the roof as a hedge against deeper discharges to the batteries. of course the charger could also get plugged into utility power too when available.

    you state that you are feeding one of those pvs to the batteries with no mention of a controller on it and i must caution you that those batteries are very picky on going too high on their voltage. if allowed to go too high the vents could pop open and cause a loss of electrolyte that you can't replace. this would result in a permanent loss of capacity and could possibly ruin the batteries. nominally this top end voltage would be about 14.4v without temp compensation.

    as to what mppt cc can handle the output from the pvs you propose then please give us the specs on then.
  • Bunkie314Bunkie314 Registered Users Posts: 11
    Re: Suplimental Solar charging in a mobil appllication

    Excuse me, the batteries are 4D not an 8D. (3X @ 210 each = 630)

    That Ah above is based on a calc sheet with my estimates of highest usage. I have taken it (race car trailer is what I have) out to the track a couple of times so far. I only use about 180 Ah over a 24 hr period and then I recharge using a generator of course. I'm not looking to go "Off Grid" or make it my only charging source, just want to reduce the generator charging side and create something unique at the race track (drag racing is my thing). My biggest load is the fridge (1 amp @ 120 VAC) since I spend little time in the trailer except for sleeping, too many other fun activities to get involved in. But those fun activities require opening and closing the fridge a lot.....:roll:

    I have a cheap PWM controller currently, don't remember the brand off hand. I picked the controller up at the RV store because I know better than to just connect the panel to the battery system. I think it was good for up to 30 A charging up to 60 V input. The inverter is a MagnaSine 2012 (up to 100 Amp charge) with the three 4D batteries. I figured this was an overkill, but it might get a new home at some point.

    Biggest question I have is should I spend money on an MPPT charger or purchase more of the flexible panels getting dumped all over right now (I could fit 10 of the 136W panels on the roof). The panels are flat on the roof, but likely everyone understood that. Considerations on what voltage to run from the panels, run to the controller is about 20 ft, 3 ft to the batteries max.

    Thanks for your input!
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication

    Well the best place to start is with your loads and fill in the system from the loads. Watts is the unit that should be used rather than Ah, though it is useful in the design.

    My opinion is an MPPT charge controller is the best way to go if you are going for those flat panels, offers the most flexibility, even if you go for different panels it offers more choices...

    Good inverter, btw do you have times when there are multiple loads occurring simultaneously? this is another issue to factor in between a make do and a Rolls system. what type of gen do you use?
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Suplimental Solar charging in a mobil appllication

    If you look at the specs on those flexible panels you may find you have to buy an MPPT controller because the Voltages on them will be way out of line with what your system requirements are.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication

    with a 48v voc output you will need an mppt controller for sure. odds are you wouldn't be able to utilize an odd number like 5 unless you paralleled them all. at best most mppt ccs have a max at 150v input v so 3 in series would be pushing the envelope and 2 in series can work, but is not divisible by 5. now i'm not sure which model pv you're going for as one is 4.1a imp and the other is 4.36a imp for 136w and 144w respectively.

    now let's do some calcs. 630ah x .05 (min charge rate recommended) is 31.5a. 5 of the 136w pvs parallel is 136w x 5 = 680w (stc). multiply that by .77 for efficiency factors and it's now 523.6w. divide that by the nominal 12v output battery voltage and we'll roughly see 43.63a. now 10 of the pvs would be 2x this or about 87a and is more than enough to do the job in theory. the catch 22 is the pvs will lay flat and won't catch the sun optimally, especially during the winter. at present only 1 controller will handle that much current and that would be the classic 150 lite or full mngp model. you could opt for an 80a fm80, but this will limit the current to 80a and odds are you may only see that around the month of june because of the flatness of the pvs an highest sun angles.

    yes, it will work, but i can't say the batteries will get a full charge in any of the months with around june having the best shot at it. you can opt to use less pvs to allow a lesser charge to resolve yourself into accepting the pvs may not charge the batteries fully and you want to just hedge the usage with just supplemental power. it would be good to monitor your batteries just to be sure you don't drain them too far and do not worry about hitting these batteries with 100a from a magnum inverter as they can take far more. it would be highly recommended to use a remote that would allow tailoring the charger voltage set points to better conform with those of the lifelines.
  • Bunkie314Bunkie314 Registered Users Posts: 11
    Re: Suplimental Solar charging in a mobil appllication

    Great input!

    Most of the info/comments given so far is pushing me toward the Midnite Classic which is what I had been looking at and leaning toward (Classic 150). I know I purchased an odd number of panels, mainly to have 1 to play with and determine what works/what don't. Some folks had very little good to say about these PV's and others like them. I liked the panel mainly due to the "Peel and Stick" feature which works great for my flat roof trailer. I guess I will wind test them myself on the longer road trips at 65 to 75 mph (10 to 12 hr trips). This could be interesting to follow down the freeway with a panel flopping off the back. I am wondering how well the adhesive will work with the harmonics the roof will go through going down the road. I might just mount one and do a road test.

    The inverter/charger has the RC50 remote and the battery monitor (it keeps track of SOC and Ah in/out). I had planned to tie the PV charge side through the inverter shunt to keep the system in the charge loop (Mistake???). The kicker using the generator to fully charge the batteries is the run time. Bulk is done in a short period of time, Absorb takes longer to get back up to full charge. Running the generator for 1 to 2 hrs vs 6+ is maybe a more realistic approach with the PV system.

    I do have multiple loads during the day sometimes. Mainly at night it is the lights and the fridge, possibly a TV (rarely). If I run the microwave or air conditioner, I of course start the generator and switch over to it. The generator is an old Onan 5 kW CCK, which can be a thirsty bugger. This old generator is solid as a rock and it super reliable. I connected the electical system up as 240 and dedicated one leg to the inverter battery charge side.

    Another question on the PV charge system I have is what happens when I switch to the generator and it pours 100 A out to the batteries? Will there be any issue to the PV charger? I'm sure it is designed to handle this, but never hurts to ask. From what I am gathering here it will be a Midnite Classic.

    Any other advice or input?
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication
    Bunkie314 wrote: »
    Another question on the PV charge system I have is what happens when I switch to the generator and it pours 100 A out to the batteries? Will there be any issue to the PV charger? I'm sure it is designed to handle this, but never hurts to ask. From what I am gathering here it will be a Midnite Classic.

    When the generator is on your Magnum inverter/charger will charge the batteries, not the Midnite Classic. The Classic will not be harmed. Which Magnum inverter/charger do you have? You may need to configure it so it doesn't push too many amps into your batteries.

    One problem you might have is with the parallel battery configuration. As a general rule parallel batteries cause trouble. The problems are even more acute with AGM batteries because they have lower internal resistance than flooded batteries. Some folks use a battery selector switch so that they can use just one battery at a time.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication
    vtmaps wrote: »
    When the generator is on your Magnum inverter/charger will charge the batteries, not the Midnite Classic. You may need to configure it so it doesn't push too many amps into your batteries.


    --vtMaps

    this is not necessarily true for the pvs and classic can and will still send power to the batteries while the magnum is charging as these are charging in parallel. you do not have to worry about too much current into those batteries as these are rated at several c and i don't think you will have access to that many amps to over do it. even at c it would be 630a so hit it with whatever you got and no need to worry about 'too many amps'.
  • Bunkie314Bunkie314 Registered Users Posts: 11
    Re: Suplimental Solar charging in a mobil appllication

    So, I bought 5 more of the 136 Watt Unisolar peel and stick panels (10 total now). I've decided on the Midnite 6 circuit combinder panel and likely a classic charge controller. I think I will go 2 in series for 5 strings, which should be good for a classic 150. Question is were to mount the combinder panel. I'm not sure to cut the distance in half between the combinder and classic or to figure out how to mount both in the front cargo bay of my trailer. Suggestions? I will have about a 35 ft run to the compartment from the panels (through the roof, to the outside walls, down through the floor and up to the front cargo area. Info on the panels I should have posted earlier:

    STC
    (Standard Test Conditions)
    (1000 W/m², AM 1.5, 25 °C Cell Temperature)
    Maximum Power (Pmax): 136 W
    Voltage at Pmax (Vmpp): 33.0 V
    Current at Pmax (lmpp): 4.13 A
    Short-circuit Current (Isc): 5.1 A
    Open-circuit Voltage (Voc): 46.2 V
    Maximum Series Fuse Rating: 10 A (UL), 8 A (IEC)

    This is a lot of small wire runs through the trailer or go with a larger gage from a closer located combinder to the classic in the front? Am I making any sense here?

    One more question, is there any reason I can't use the battery monitoring shunt I have with my Magnum Inverter/charger to keep track of SOC, Ah in/out, etc?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication

    the combiner should be rainproof for it to mount outside (which the mnpv6 is) and from the combiner then one pair of larger gauge wires could be run to the inside or run all pv string runs inside and combine inside as this is up to you. if the access is easier to have the connections outside then go that way. where to mount is something you will need to determine for it to be best convenient and out of harms way. the classic is not rainproof and needs protected from moisture and so must be inside.

    not sure what shunt you are referring to, but an appropriate shunt along the negative wire from the battery bank is good for monitoring from an external battery monitor.
    you will find the magnum remote can monitor current in or out from the perspective of the inverter and will not have high accuracy.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication
    Bunkie314 wrote: »
    So, I bought 5 more of the 136 Watt Unisolar peel and stick panels (10 total now). I've decided on the Midnite 6 circuit combiner panel

    I don't know what type of connection the unisolar panels have. If they are MC4, you can special order your midnite combiner with built in MC4 connectors. Just plug & play.
    Question is where to mount the combiner panel.
    I would mount it outside because you need just one hole in the trailer for the combined cable.

    Probably not relevant to you: If you mount a lightning arrester on the combiner box, you want the box to be outside the trailer. A lightning arrester requires a ground rod and is probably not needed on a portable system with frameless panels.

    I presume that you are not going to bond neutral to ground in your trailer. If you do bond to ground, you will have some problems when connecting to the grid.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Bunkie314Bunkie314 Registered Users Posts: 11
    Re: Suplimental Solar charging in a mobil appllication

    The panels are a bottom mount wire, 4 inches long, that will go through the roof below the panel adhesive. All of the PV panel penetrations will be about mid trailer and have to run to the front cargo hold area. I will make parallel connections inside the trailer at the roof for the panels and then run to..... I thought about mounting the combinder on a side wall inside the trailer, closer to the PV panels, then run to the cargo hold in front of the trailer. Everything will be inside, except for the wire run(s) to the front cargo which could be underneath in the frame. I will mount the classic in the cargo hold behind the truck bed out of elements. It seems the single pair of leads from the combinder box, mounted close to the panels, then to the classic would be a cleaner install vs 5 pair of runs. I wanted input on this to see ins or outs or which would be better or what not to do.

    vtMaps,

    I always use a generator and never connect to grid power. I haven't consider a lightning strike.

    Niel,

    The Magnum BMK monitoring kit (shunt) is not that accurate? I've noticed it seems to be kind of out there sometimes..... I thought it was something I didn't have set correctly. I was going to connect the PV charge through the shunt and use the RC50 remote via the BMK to monitor in/out, SOC, etc. Should I rethink this or is this good enough?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Suplimental Solar charging in a mobil appllication

    i was referring to the current readings on the remote itself.
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