Having trouble deciding on a sunsaver or prostar controller

pods8pods8 Registered Users Posts: 16
In my camper I'm running a set of PS-62000 batteries in series. I was thinking of adding a 100watt panel to my rig to supplement usage and also pretty much remove the need to plug in my shore power charger after a trip to condition/maintain the batteries.

Anyways the gen 3 sunsaver looks like it does bulk and float charging with flooded and sealed settings. The sealed bulk setting is a tad lower than I'd want but might just take a bit longer to charge (I don't want to equalize with the flooded setting). Back when it was only a single stage charge I would have leaned towards the prostar but now it doesn't seem like I'd be missing much. Also I can pick a 6 or 10 amp sunsaver which is better suited for the panel rather than a 15amp prostar.

The prostart does come with the option of a meter but for the price I can just add a "Watts Up" meter on my setup for the same upgrade price. The prostar has a temp sensor but I'd me mounting the charger in the same spot as the batteries, does a prob right on the battery make much difference with this sized setup?

So folks with much more knowledge, am I missing anything?

Comments

  • pods8pods8 Registered Users Posts: 16
    Re: Having trouble deciding on a sunsaver or prostar controller

    Anyone have some thoughts? :p Or other suggestions I should consider? As mentioned above leaning towards the Gen 3 sunsaver since it has a bulk and float charge ability now which I want for maintaining my batteries while the rig is parked.
  • mike95490mike95490 Solar Expert Posts: 8,335 ✭✭✭✭✭
    Re: Having trouble deciding on a sunsaver or prostar controller

    Toward the final end of charge, the controller cools down to ambient, and likely does not influence the voltage too much.

    And a 100w panel will just be a "maintain" - it wont bring a big battery up to full from 80%.

    I don't know if you have "tweaked" your alternator to provide a proper charge, or what your shore power charger is. But before you rely on the small 100w panel, the batteries have to be "full".

    you didn't link to the PS-62000 batteries, so I don't know their size, or if they should be EQ'd at all.
    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 ,

  • pods8pods8 Registered Users Posts: 16
    Re: Having trouble deciding on a sunsaver or prostar controller
    mike90045 wrote: »
    Toward the final end of charge, the controller cools down to ambient, and likely does not influence the voltage too much.

    And a 100w panel will just be a "maintain" - it wont bring a big battery up to full from 80%.

    I don't know if you have "tweaked" your alternator to provide a proper charge, or what your shore power charger is. But before you rely on the small 100w panel, the batteries have to be "full".

    you didn't link to the PS-62000 batteries, so I don't know their size, or if they should be EQ'd at all.

    Why would you say a 100watt panel won't fully charge them sitting there day after day assuming it's getting full sun? If the controller is presenting 14.1V (on the sealed setting, a bit lower than ideal though) to the batteries there going to want to let in amps, no? Even if the panel output and controller losses are causing a conservative 50% drop (that is conservative right?) there should be about 2.85amps available during peak sun. Even if my 210ah of battery was at 80% when I got home it should get fully topped off after a couple days and then stay topped off against self discharge. (I would expect them to be that low though after a few hours of driving though, my alt puts out 14.1-14.4V so with proper gauge wire to keep voltage loss to 1-2% I should still get a decent charge) Or what am I missing?

    This panel would actually be for a new camper I'm building that I'd use these batteries in. My current system has a DC-DC stage charger off the alt which does a good job and usually fully charges the batteries after a weekend out on the drive home. If not I have a stage shore charger that finishes the job. On the new camper I wasn't planning to use the DC-DC stage charger and instead just run a decent gauge to get a bulk charge if the batteries are low and then rely on the solar or shore charger to do the final charge/conditioning if needed.

    Here's a link to the data sheet, its a 6V 210ah AGM battery. No equalizing.: http://www.power-sonic.com/images/powersonic/sla_batteries/ps_psg_series/6volt/PS-62000_11_Feb_21.pdf
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Having trouble deciding on a sunsaver or prostar controller

    The problem is that one 100 Watt panel will never produce the optimum current for charging 210 Amp hours of battery. Although this is less of a consideration with AGM (which are more current tolerant and less prone to sulphation) it is still an issue. It is best to recharge a battery as quickly as possible, rather than let it charge slowly over days.

    For a good read you can't beat the battery FAQ's: http://www.windsun.com/Batteries/Battery_FAQ.htm
  • pods8pods8 Registered Users Posts: 16
    Re: Having trouble deciding on a sunsaver or prostar controller
    The problem is that one 100 Watt panel will never produce the optimum current for charging 210 Amp hours of battery. Although this is less of a consideration with AGM (which are more current tolerant and less prone to sulphation) it is still an issue. It is best to recharge a battery as quickly as possible, rather than let it charge slowly over days.

    For a good read you can't beat the battery FAQ's: http://www.windsun.com/Batteries/Battery_FAQ.htm

    I concur about recharging as quickly as possible, I'll still have a shore charger on my rig and if I come back with low batteries I'll plug it in (but that should rarely happen if I add on a panel, see below). The panel would mainly be for supplementing while in the field and keeping the batteries at 100% while sitting (or actively charging them some if I've moved from one spot to another in the field and the truck didn't completely top them off, granted its a slower charge rate but it's better than no charge rate).

    In reality my battery bank is rather large for my more minimalist pop-up truck camper. I probably only use 10-15amps a day, I just wanted to make sure I could boondock for about a week if I wanted while still staying above 50%. So based on that usage a 100watt panel should more or less keep up as long as it's getting some moderate light and I'll hardly be cycling my batteries at all. If it tends to work out that way I may consider smaller bank when these eventually wear out but hopefully I get plenty more out of them. :)

    So based on the above is there some reason a 100w panel isn't going to kick me a few amps per hour during peak light?

    Moving onto the controller issue, for a smaller/basic setup like what I'm going for is there any reason to go for something with more bells whistles when the Gen 3 sunsaver now has bulk and float charging? It would be nice if they have a flooded setting w/o equalizing but I probably don't really need to worry about 3hrs of 14.9V every 28days with my batteries if I set it on that rather than sealed . (Flooded is 14.4 bulk, 13.7V float, and 14.9 eq for 3hrs every 28days. Sealed is 14.1 bulk, 13.7 float, and no EQ).

    I've read that whole link in the past but it's been a while.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Having trouble deciding on a sunsaver or prostar controller

    The 100 Watt panel will probably provide 6, maybe 7 Amps current which is under the 5% minimum recommended charge rate, but is fine for staving off losses and keeping the battery up when not in use. No reason it shouldn't work for your purposes, we just like to make sure people understand this stuff. Expecting it to recharge a seriously depleted battery, even over days, would be unrealistic.

    The lower-end charge controllers like the Sunsaver and the Prostar have got limitations. Specifically the lack of programmable Voltage set points. Your batteries might want Absorb at 14.2 instead of 14.1 for example. In my opinion it isn't worth fretting over a tenth of a Volt as that much difference can be lost in the wiring. You might install a Sunsaver and find you need to switch it to the flooded setting every now and then just to give the batteries a little extra.

    I'm not sure the Sunsaver do the full 3-stage charging, but that also is probably not critical in this application. For choosing between the two I'd look at the possibility of adding more panel: can you/will you/won't you? If it comes up 'no', go with the Sunsaver 6 Amp unit. Chances are that's all there is to be had from 100 Watts.

    If you can add another 100, go for the Prostar 15. 200 Watts of panel might put out 12 to 14 Amps of current and get you right in to that 5% minimum range, meaning the panels might do the whole charging job for you. Wouldn't that be nice? :D
  • pods8pods8 Registered Users Posts: 16
    Re: Having trouble deciding on a sunsaver or prostar controller
    No reason it shouldn't work for your purposes, we just like to make sure people understand this stuff. Expecting it to recharge a seriously depleted battery, even over days, would be unrealistic.

    Understood, probably should have explained better off the bat.
    The lower-end charge controllers like the Sunsaver and the Prostar have got limitations. Specifically the lack of programmable Voltage set points. Your batteries might want Absorb at 14.2 instead of 14.1 for example. In my opinion it isn't worth fretting over a tenth of a Volt as that much difference can be lost in the wiring. You might install a Sunsaver and find you need to switch it to the flooded setting every now and then just to give the batteries a little extra.

    Manufacturer is calling for 14.4-14.7V. The flooded setting does 14.4 but it does do 3hrs of 14.9V during the 3hr EQ phase every 28days. I'm sorta thinking that likely isn't much of an issue as I'm assuming .2V above the recommended charge range for a short period probably isn't going wreak havoc.
    I'm not sure the Sunsaver do the full 3-stage charging, but that also is probably not critical in this application. For choosing between the two I'd look at the possibility of adding more panel: can you/will you/won't you? If it comes up 'no', go with the Sunsaver 6 Amp unit. Chances are that's all there is to be had from 100 Watts.

    If you can add another 100, go for the Prostar 15. 200 Watts of panel might put out 12 to 14 Amps of current and get you right in to that 5% minimum range, meaning the panels might do the whole charging job for you. Wouldn't that be nice? :D

    Here's the manual for the Gen 3 sunsaver, I was surprised to see stage charging in it as well: http://www.morningstarcorp.com/en/support/library/SS3.IOM.Operators_Manual.01.EN.pdf

    Aside from the extra amp capacity are the any other notable differences in the prostar to consider? Yes these are lower end controllers but we're also only talking a small panel.

    Can I add another panel? Sure I could account for space on the roof. Will I? Probably not since 100W would match my usage pretty well and 200W would just be excess amps, panel weight, and cost 99% of the time. I'm running LED lights, low draw fans, 1.8amp draw heater, 12v compressor fridge (which seems to pull about .45ah when averaged out over time in warm weather).

    See any flaws or have suggestions though I'm not committed to anything yet.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Having trouble deciding on a sunsaver or prostar controller

    I'm not keen on running equalization cycles on sealed batteries. Not even half a Volt for three hours every 28 days. You could probably disconnect the power and 'fool the clock'.

    Another thing to do is check the Isc on the panel. If it's over 6 Amps maybe go with the 10 Amp version, just to keep the controller safe. Otherwise I don't see any real problem here.
  • pods8pods8 Registered Users Posts: 16
    Re: Having trouble deciding on a sunsaver or prostar controller
    I'm not keen on running equalization cycles on sealed batteries. Not even half a Volt for three hours every 28 days. You could probably disconnect the power and 'fool the clock'.

    Another thing to do is check the Isc on the panel. If it's over 6 Amps maybe go with the 10 Amp version, just to keep the controller safe. Otherwise I don't see any real problem here.

    I don't like the idea either at .2V over max charge it made me ponder, I'll scour manual to see if there is an override and if not start out on float.

    Isc 6.46, I'm inclined to go towards the 10amp version.

    Thanks for all your thoughts.
  • mike95490mike95490 Solar Expert Posts: 8,335 ✭✭✭✭✭
    Re: Having trouble deciding on a sunsaver or prostar controller
    pods8 wrote: »
    Why would you say a 100watt panel won't fully charge them sitting there day after day assuming it's getting full sun? .....

    100w panel actually puts out 80W, If angled properly. Off axis, I'd expect more like 50W at noon.


    210A battery @ 80% charge, is down 42 AH.

    50W at 15 V = 3.3 A is about 13 hours to replace, or figure 3 good charging hours a day, closer to 5 days, not counting internal battery losses.

    Batteries will be much happier if you top them off before you store, and allow the solar to maintain them.
    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 ,

  • pods8pods8 Registered Users Posts: 16
    Re: Having trouble deciding on a sunsaver or prostar controller
    mike90045 wrote: »
    100w panel actually puts out 80W, If angled properly. Off axis, I'd expect more like 50W at noon.


    210A battery @ 80% charge, is down 42 AH.

    50W at 15 V = 3.3 A is about 13 hours to replace, or figure 3 good charging hours a day, closer to 5 days, not counting internal battery losses.

    Batteries will be much happier if you top them off before you store, and allow the solar to maintain them.

    Thanks for clarifying, we're on the same page about bringing them up the charge quickly when home if needed. I wanted to make sure you weren't saying after 80% charge a 100w panel isn't going to do ANY charging, thus it wouldn't work for maintaining purposes.
  • BB.BB. Super Moderators, Administrators Posts: 29,350 admin
    Re: Having trouble deciding on a sunsaver or prostar controller

    Lead Acid Batteries tend to age quickly/badly when stored for days/weeks/months below 75% state of charge. So, if you have a discharged battery and charge it vary slowly, it will sit for a long period of time below 75% state of charge, it will sulfate and loose capacity fairly quickly.

    Also, batteries have self discharge that can be as high as 1-2% per day (old fork lift batteries). So, if you have an old traction type battery with 1% rate of charge--you are barely keeping up with its self discharge (new flooded cell, and AGM batteries do have a lower rate of self discharge).

    Note that a solar panel only charges for around 5 hours per day, and a battery self discharges 24 hours per day... So a 1% rate of charge will keep even with a battery discharging at 0.2% per day or ~1.4% per week--pretty close to the self discharge rate of a standard deep cycle flooded cell battery.

    In any case, a 1% rate of charge solar panel does not even really need a charge controller--just a blocking diode at most.

    So, for various reasons (self discharge, limiting time below 75% state of charge, many battery mfg. recommending 5% minimum charge rate for equalization/electrolyte mixing, and just to get useful energy from a solar+battery system), we have settled on 5% as being the generic rule of thumb as a minimum recommended rate of charge (regardless of other factors like loads and hours of sun).

    13% is the recommended maximum rate of charge rule of thumb because of other needs/recommendations (batteries may overheat with higher charge rates, battery efficiency goes down, system will not spend long at maximum charge rate so you waste panel power during the day, etc.).

    For AC battery chargers, some people (who know) will say 25% rate of charge is OK--Probably best for generator and mains backup/recharging. Solar panels+charger controllers tend to be very expensive--so their use at 25% rate of charge is costly.

    Again, we start with rules of thumb because they, usually, give conservative results (i.e., systems will work well for most users assuming charge during the day and use power during the night--sort of the worst case set of assumptions).

    If you have other needs/load profiles, then we can discuss where you can shave costs and still have a very useful and reliable system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • pods8pods8 Registered Users Posts: 16
    Re: Having trouble deciding on a sunsaver or prostar controller

    Did you read all the other info I posted? I only use 10-15ah a day while out camping, adding on a panel will make it highly unlikely I'll ever be coming home with much of a discharged battery bank at all. If I was in foul weather and did then I'd plug it in.

    I linked the data sheet for my batteries, they don't discharge at 1-2% per day. Listed shelf life is: 1month = 97%, 3months = 91%, 6months = 83% So looking at about .1% per day. Currently I plug in the camper about every month if it's sitting and not being used, solar would only be an improvement.

    My needs and load profiles were basically stated already. More specifically I'd be running a couple LED lights at .22amps, a 12V compressor fridge that tends to pull .4ah on average, in cold weather the furnace some (1.8amps while running, maybe .6ah on average but wouldn't be used 24/7). Here and there I'd recharge a cell phone or power a portable DVD player or something. This isn't plush RV loads with TVs, microwaves, etc. My bank is quite large for my loads to make sure I can run long without any charge, adding on solar just helps limit losses and keep things topped at 100% while sitting.
  • BB.BB. Super Moderators, Administrators Posts: 29,350 admin
    Re: Having trouble deciding on a sunsaver or prostar controller

    I understood what you posted--I was just trying to answer the question about why we recommend the 5% minimum charge for long term usage.

    Yes, you have an AGM (I guess, I did miss the link to the data sheet) which has much less self discharge, so they can "make use" of a smaller panel and charge (somewhat slowly--but still charge) which don't need the higher current for mixing electrolyte and keeping with higher discharge.

    The only issue about your 80 watt panel are a couple questions I can think of... What is the Vmp? If around 17.5 volts or so, that is fine. If ~15 volts, that is really not intended for use with a charge controller (sometimes these panels were called "self regulating").

    The other is what angle do you mount the panel at and do you do winter vs summer camping. That will affect your over all power harvest too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • pods8pods8 Registered Users Posts: 16
    Re: Having trouble deciding on a sunsaver or prostar controller

    Vmp = 17.2V, Imp = 5.81A

    The panel will either be mounted on the flat top of the roof or a 5deg slope rear portion of the roof. Either way, not really much angle. Camping will be year round, but more in summer.
  • BB.BB. Super Moderators, Administrators Posts: 29,350 admin
    Re: Having trouble deciding on a sunsaver or prostar controller

    Your panel should be fine with a charge controller and a 12 volt battery bank.

    Are you staying in the coastal areas or inland away from the clouds (I assume coastal Washington State)?

    For example, Seattle Wa using PV Watts, A fixed mount, flat to horizontal roof will give you:
    Fixed array, flat, zero degrees, to roof (hours of sun per day) for Everret Washington:
    Month / Average Hours of Sun per day:
    1      0.92     
    2      1.66     
    3      2.89     
    4      4.06     
    5      5.49     
    6      6.06     
    7      6.19     
    8      4.97     
    9      3.84     
    10      2.07     
    11      1.15     
    12      0.75     
    Year      3.34      
    
    Fixed mounted at 47.45 degrees:
    
    1      1.54     
    2      2.50     
    3      3.71     
    4      4.37     
    5      5.31     
    6      5.52     
    7      5.88     
    8      5.17     
    9      4.98     
    10      3.00     
    11      1.76     
    12      1.26     
    Year      3.76      
    
    Fixed mounted at 62 degrees:
    
    1      1.59     
    2      2.51     
    3      3.58     
    4      4.02     
    5      4.72     
    6      4.79     
    7      5.16     
    8      4.70     
    9      4.78     
    10      2.98     
    11      1.78     
    12      1.29     
    Year      3.50
    

    So, at least on the coast, you will not get a lot of energy during winter. To estimate the amount of kWH per day, I would guesstimate:
    • Hours of Sun * 5.81 amps * 0.77 panel derating * 0.90 Battery Losses = AH of 12 volt power per day
    So, flat mounted, you get at least 4 hours of day for almost 6 months of the year:
    • 4 hours sun * 5.81 amps * 0.77 derating * 0.90 batt eff = 16.1 AH or better for ~6 months of the year
    Tilting the panel will give you a bit more energy during winter--But not all that you are looking for.

    You can use PV Watts to estimate different options for other areas you may camp. Note that PV Watts does take take ~20 year average weather patterns into account (clouds, rain, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • pods8pods8 Registered Users Posts: 16
    Re: Having trouble deciding on a sunsaver or prostar controller
    BB. wrote: »
    Are you staying in the coastal areas or inland away from the clouds (I assume coastal Washington State)?

    My truck is parked on the wet side but when I'm out and about I'm all over and often into the sunnier east side. Also might move to CO down the road here so that would help with sun. :D

    Thanks for the link.
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