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  • Solar Pannel Project Help

    Hi I have a project that I am interested in taking on but my knowledge on solar panels, electronics, etc is somewhat limited so I thought I'd ask for some advice. While my project is unconventional, the fundamentals are much the same. What I'm looking to do is add a solar panel to a small electric sprayer that is used for making lawn applications. It currently utilizes a 12v battery. The problem is that I need to use the sprayer for a longer period of time than what the battery is capable of on a single charge. I know solar panels are useful in maintaining batteries that are in things that have prolonged periods of storage or that see minimal use. What I'd like to do mount a small solar panel that would allow some charging or current to be created while using the sprayer that would utilize the power of the sun since obviously I'd be outside while spraying to help extend the time I can run the sprayer. Not to mention the battery could be charging during transport from lawn account to lawn account. Problem/question is I don't know if this can be accomplished using a small solar charger or if it wouldn't be efficient enough to go through the trouble and cost of installing one. It doesn't have to solely power the sprayer just extend the run time. There are so many sizes, types, power ratings, amperages, wattage, calculations, etc when it comes to solar chargers and batteries it's enough to make my head spin. So if this is feasible what solar charger would I be looking for?

    Here are the details:
    12vDC diaphragm pump
    12vDC air purge pump
    System draws about 5.3 amps total
    A ES17-12 12V-18AH/20HR MKBattery Non-Spillable Battery with a standby voltage of 13.5-13.8 and 0.3 capacity & cycle use voltage of 14.4-15.0 and 0.3 capacity
    I'd like to be around a 12"x4" panel size if possible

    Thanks in advance. Questions?

  • #2
    Originally posted by BiggDaddyMJL View Post
    I'd like to be around a 12"x4" panel size if possible
    That is one veeery small solar panel. That is in the region of 5W and less! A 5W panel is not going to work for what you require (except trickle charging the battery....very slowly!). Why do you have such a small space requirement? For what you require, you are going to need more space!...

    The easiest, and perhaps the cheapest solution, would be to increase your battery capacity. Is it not possible for you to rather install/use a higher capacity battery (ie a 30AH instead of the 18AH)?

    Comment


    • #3
      Space restrictions and solar are not compatible. Physical size in area is directly proportional to power. If you only have 1 square foot to work with, you are limited to no more than 5 to 7 watts and that is it.
      MSEE, PE

      Comment


      • #4
        Thanks for the replies guys. Well an 18ah battery is what came with the sprayer system. I do plan on getting a larger battery when it comes time to replace the current one. I have to look at the dimensions, but the battery compartment should be able to hold a 30ah. From my understanding it's a lot harder on these batteries to run them way down and charge them up again so I was hoping I could run a solar charger to help prolong the run time I get now and hopefully not fully drain the battery before I'm done spraying.

        I am limited on the size of the solar panel itself because of the possible mounting locations. The whole unit is about the size of a push mower only it's taller. I also would have to mount it in way that it would be somewhat protected as well due to obstructions (i.e. branches, gates, etc.) It doesn't have to be that exact size, but it's just about where I'd need to be given the circumstances.

        So to get some clarity though and just for curiosity, Watts is the rating I would be most concerned with? About what Watt rating would I actually need then?

        Comment


        • #5
          A 100 watt 12 volt panel is about 26 X 36 inches or so, and should supply about 5 amps or so in bright sun light. You will need a charge controller also.
          John Smith
          Southern California....

          Comment


          • #6
            Ok since you are up for modification and solar is basically impractical given your requirements:

            Replace that standard ups-style 18ah agm, with a tppl (thin plate pure lead) Odyssey PC625 (still 18ah) or perhaps an Odyssey PC925. Typically used on powersports but will work fine for your application.

            Because they are pure-lead, they can withstand HUGE amounts of charging current without going nuts as compared to the lead-calcium ups-style agm's that typically have an inrush of 0.3C. In other words, if you have ac available, and have a big charger like a minimum of 20amps (3-stage QUALITY charger, not auto-parts store speed-chargers) then you'd be down maybe an hour to 90 minutes. Although there is a brand that my Odysseys like that is inexpensive - Stanley BC1509 and 4009 models.

            If your existing battery was not well taken care of in the first place, (often drained till dead, not recharged immediately or not long enough), then perhaps just a quality replacement (make sure it measures at least 12.5v upon receipt, higher is better) that was sitting around in the distribution chain for a few years could make a difference. The easiest mod would be to change from the 18ah to a 22ah which shares nearly the exact same size. I'm assuming these are using the "NB" or nut-n-bolt terminals, and not the "F1/F2" slide-on types.

            How good is the oem charger? Note that for these common ups-style agm's, at 18ah you could charge quickly at around 5 to 6 amps or so - usually spec'ed out on the case, but check otherwise. If the oem charger is a slow overnighter, then maybe just starting out with a good quality replacement, and a decent external charger could improve things quite a bit.

            Comment


            • #7
              Thanks for the replies again.

              The webpage for the sprayer system is http://www.gregsonclark.com/spreadermate.html

              But no, I'm not opposed to modifications, but I sure am disappointed that a solar panel charger isn't more practical. I knew I probably wouldn't be able to run the system on the solar panel alone but I would be lying if I said I didn't think I could install one that would work with the battery to help extend the run time while using the sprayer.

              The website shows some of the "accessories" that are available including spare batteries $85+S&H and $141+S&H for a 33ah. But yes it is a nut and bolt style terminal battery and we are left to our own devices to recharge the battery unless you buy either their version of a truck charger which is nothing more than a fused wire set that hooks up to the vehicle's battery or their wall charger. Both are shown on the site as well. I have been recharging the battery on one of the small Battery Tender brand trickle charger/maintainers overnight as I was always told the slower and fewer amps the better??? I do have a Die Hard and a Schumacher(unsure of model right now) chargers too.

              Comment


              • #8
                Originally posted by BiggDaddyMJL View Post
                Thanks for the replies again.

                The webpage for the sprayer system is http://www.gregsonclark.com/spreadermate.html

                But no, I'm not opposed to modifications, but I sure am disappointed that a solar panel charger isn't more practical. I knew I probably wouldn't be able to run the system on the solar panel alone but I would be lying if I said I didn't think I could install one that would work with the battery to help extend the run time while using the sprayer.

                The website shows some of the "accessories" that are available including spare batteries $85+S&H and $141+S&H for a 33ah. But yes it is a nut and bolt style terminal battery and we are left to our own devices to recharge the battery unless you buy either their version of a truck charger which is nothing more than a fused wire set that hooks up to the vehicle's battery or their wall charger. Both are shown on the site as well. I have been recharging the battery on one of the small Battery Tender brand trickle charger/maintainers overnight as I was always told the slower and fewer amps the better??? I do have a Die Hard and a Schumacher(unsure of model right now) chargers too.
                If all you want is to extend the time to run your sprayer it would be cheaper just to get either a bigger battery or a second battery. The quick disconnect should make it real easy for plug and play. The extra battery would certainly be cheaper than a solar system.

                If you really want to go solar you could build a small solar charge system for the spare battery after it was discharged.

                Comment


                • #9
                  *Just an Update*

                  I took PNJunction's suggestion and ordered an odyssey PC925 battery. The original battery was completely dead when I went to use the sprayer a week ago. A little upset about it really since there was no warning it was going bad and I had it on a "Battery Tender" maintainer all winter like I have in the past. That and I drove several miles all packed up and ready to spray only to find out the battery was shot when I got to the first job site.

                  It's going to be a tight fit but I think I can make it work since it is shorter than the old battery and I can make a spacer under it that will bring it up some and give me the extra room at the base of the battery. It's hard to explain but the battery compartment is tapered and smaller at where the base of the battery would be. That and I heard you can run these batteries on end/side too so that is my fail safe that it should work one way or the other. But wow these batteries are heavy. About 12 pounds heavier than the old one.

                  Have a couple of questions if someone wouldn't mind answering:

                  1. What kind of charger should this battery be charged with? I heard that they don't do well with Battery Tender brand maintainers. My only charger is a Schumacher SE 12-50 Fast Charge Power Booster 10/30/50 AMP. This ok?

                  2. Also what about charging between job sites? Right now I have a big 12v air compressor hard wired in the bed of the truck. It plugs in using anderson connectors and is fused with a 40A maxi blade fuse. I made a set of jumper cable style cables from the left over wire I had that uses an the same size anderson connector so it can plug in where the compressor plugs in and alligator style clamps on the other end. Total there is about 25' (if I count the wire in the truck and the jumper cables I made) of 6 gauge awg excelene welding cable (fine strand copper) that has the 40A inline fuse near the truck battery for the positive and connects to the positive terminal on the truck battery. The negative cable is attached to the truck frame near the back and is about 4-5' long and an additional 8' if you count the length of the cables I made. Same type and gauge wire as the positive cable. So essentially if I were to use the jumper cables I made that plugs into the truck where the air compressor does and connected it to the sprayer battery (odyssey pc925) it would be wired in parallel to the truck battery, I think? So the sprayer battery would be being charged by the truck battery which in turn is charged by the truck's alternator. Would this work well/ok to charge the sprayer battery driving between job sites?

                  Thanks ahead of time for any advice.

                  Comment


                  • #10
                    Bueller? Bueller?

                    Ok so I bit the bullet and just bought one of Odyssey's battery chargers. The OMAX-25A-1B which is a bigger charger then I need for a pc925 battery but I figured if I like these batteries that much that I'll get a charger that would work for bigger batteries in case I want one for say a truck. So that's taken care of. Only thing that sucks is these charges are for Odyssey batteries only. So now I have a $150 charger that I can only use for these batteries. So $300 later I have a battery and charger.

                    So that takes care of recharging the battery in the garage but I still need to know if using my truck to recharge the odyssey battery while I'm on the road is ok as stated in my #2 question in my post above???????

                    Comment


                    • #11
                      You did good! Trust me, being wedded to an Enersys / Odyssey battery and that Odyssey charger is a fine match.

                      I'm really glad you went with that rather than hang on to the generic schumacher. Of course, this Odyssey charger sure looks like a Schumacher right? Different internal programming. Also note that charger will do just fine with Sears Platinum-AGM's, which are rebadged Odysseys.

                      I'd be hesitant to charge directly from the truck, only because in a simplistic setup like this, that is placing two dissimilar batteries together for charging, which you probably want to do quite a bit. The Odyssey can handle the current no problem, I just don't want you killing your starter battery in the process. Then again, you could use the 925 to at least get you back home.

                      For mobile charging, I'd seek more knowledgeable mobile guys out there than me.

                      However, one thing you can do if you are anywhere near an ac outlet is to take the charger with you, and take advantage of "opportunity charging".

                      That is, if you only have 10 to 30 minute break or more, and are near an ac outlet, just put the Omax charger on knowing that you do not need to wait for a full charge. For full charging, wait until you get home let the Omax finish the job. Opportunity charging is a great thing to do during the day - keeps the overall DOD down, which adds to cycle life, and you don't have to wait for it to be nearly discharged to do this. That's the beauty of tppl batteries like these. You can absolutely hammer them with current on the job for opportunity charging. Still, one needs to follow up at the end of the day with a normal charge cycle that finishes the absorb and at least a few hours of float.

                      Note about the battery tender: They, like other similar tenders, are battery-killers for AGM due to operator error believe it or not. A tender should only be used when the battery is *completely* charged. We're talking big batteries here. If the battery is not fully charged, it does not have enough oomph to recharge a battery in TIME to prevent it from sulfating. Oh, you may get a superficial surface charge out of it, and even read somewhat high voltage, but deeper inside, the sulfation is ruining the battery. That is one reason that Enersys and others (and even Schumacher themselves!) warn users not to use tenders as their primary charger! Only after a full charge from another higher-powered charger would this ever be considered.

                      Note 2: Enersys demands that float be from 13.5 to 13.8v. Battery tenders may come close say to 13.4. Not good enough according to Enersys / Odyssey. (see the Enersys white paper for generator-float voltage for the gory details).

                      Comment


                      • #12
                        Originally posted by PNjunction View Post
                        You did good! Trust me, being wedded to an Enersys / Odyssey battery and that Odyssey charger is a fine match.

                        I'm really glad you went with that rather than hang on to the generic schumacher. Of course, this Odyssey charger sure looks like a Schumacher right? Different internal programming. Also note that charger will do just fine with Sears Platinum-AGM's, which are rebadged Odysseys.

                        I'd be hesitant to charge directly from the truck, only because in a simplistic setup like this, that is placing two dissimilar batteries together for charging, which you probably want to do quite a bit. The Odyssey can handle the current no problem, I just don't want you killing your starter battery in the process. Then again, you could use the 925 to at least get you back home.

                        For mobile charging, I'd seek more knowledgeable mobile guys out there than me.

                        However, one thing you can do if you are anywhere near an ac outlet is to take the charger with you, and take advantage of "opportunity charging".

                        That is, if you only have 10 to 30 minute break or more, and are near an ac outlet, just put the Omax charger on knowing that you do not need to wait for a full charge. For full charging, wait until you get home let the Omax finish the job. Opportunity charging is a great thing to do during the day - keeps the overall DOD down, which adds to cycle life, and you don't have to wait for it to be nearly discharged to do this. That's the beauty of tppl batteries like these. You can absolutely hammer them with current on the job for opportunity charging. Still, one needs to follow up at the end of the day with a normal charge cycle that finishes the absorb and at least a few hours of float.

                        Note about the battery tender: They, like other similar tenders, are battery-killers for AGM due to operator error believe it or not. A tender should only be used when the battery is *completely* charged. We're talking big batteries here. If the battery is not fully charged, it does not have enough oomph to recharge a battery in TIME to prevent it from sulfating. Oh, you may get a superficial surface charge out of it, and even read somewhat high voltage, but deeper inside, the sulfation is ruining the battery. That is one reason that Enersys and others (and even Schumacher themselves!) warn users not to use tenders as their primary charger! Only after a full charge from another higher-powered charger would this ever be considered.

                        Note 2: Enersys demands that float be from 13.5 to 13.8v. Battery tenders may come close say to 13.4. Not good enough according to Enersys / Odyssey. (see the Enersys white paper for generator-float voltage for the gory details).

                        PNJunction, Thanks so much for the help and thorough reply!

                        The old Schumacher (and I mean old) was given to me by a neighbor of one of my customers. "Here I thought you might need this." He was moving to a senior condo and said "If I ever have battery trouble again I'm calling AAA". After some deep research on the web I finally found a pdf that listed the Odyssey approved chargers one of which was a Schumacher, just not the one I have. The others were brands I could not find or have never heard of and after being invested this far I figured I might as well just get one of their chargers rather than messing around with one that might work and who knows how the longevity of the Odyssey battery will be affected. Yeah I thought I read that the "Odyssey" chargers were made by Schumacher. Good to know about the Sears AGM batteries too.

                        One thing I found kind of strange was when the PC925 came in, it had 12.6v when I tested it with a volt meter which according to Odyssey is a full charge. However when the charger came in, the battery was only at 2% according to the charger. Same voltage though. So I began charging the battery and at some point the charger stopped charging and was flashing "check" and "18.8" on the display which according to the manual is "Charge Aborted". So I disconnected everything and tried again. It started at 75% and went up to 100% within 15 minutes. It's been in float charge/maintenance since. I left everything hooked up since Odyssey claims it's ok to do so and will act as a battery maintainer.

                        Unfortunately I don't have access to a lot of ac outlets while working. It's usually one account after another. Spray, drive, spray, drive, etc. I was only ever planning on having the PC925 hooked up to the truck while driving between accounts, not while the truck is off, because I was afraid of the same thing. Anywhere from 10-30 minutes of driving between accounts on average. Using the Odyssey charger at the end of the day is not a problem it's just while working that's the problem. That's what got me interested in solar charging but have learned isn't feasible. Any ideas on where to ask for help on this?

                        Good to know about the battery tenders too. I have very limited knowledge when it comes to electronics, electrical, batteries, solar panels, etc. Just enough to understand the basics and maybe get myself into trouble. Thanks for all the help and the recommendation for the Odyssey setup. I hope you are right and it will work out better than before.

                        Comment


                        • #13
                          Originally posted by BiggDaddyMJL View Post
                          After some deep research on the web I finally found a pdf that listed the Odyssey approved chargers one of which was a Schumacher, just not the one I have.
                          Yep, most likely the old 2500 model if I remember correctly. They do have a procedure to help you verify a charger yourself, and unfortunately, all of the generic Schumacher speed-chargers failed my tests. Ruined my perfectly good Deka agm, and boiled a new optima BAD behind my back. I vetted them against what you find in the application manual, and lo and behold, voltages did NOT match the chemistry selections (about 0.7v higher than usual for each chemistry), going into a hard-core EQ of 15.65v or higher where no EQ was needed or requested, all the while showing 14.8v on the display! Even the high-eq which I don't want happening without my permission, did so at the START of the absorb cycle, and not at the end.

                          I'm happy to report that the Sears Platinum-specific charger followed the rules. Stanley and B&D's do ok too, but one should always vet their specifications with their own meters.

                          My Fluke 87V revealed all! So I'm not happy with generic schumacher speed-chargers for NORMAL batteries. Waay to aggressive, which might be ok for totally abused batteries, but in normal use, or once they have been revived - no way. Not at least at my place.

                          I'd be very careful with your generic one for sure. For now, leave that in the corner of the garage. I won't shed a tear.

                          One thing I found kind of strange was when the PC925 came in, it had 12.6v when I tested it with a volt meter which according to Odyssey is a full charge.
                          Not really. Odysseys are rated to be used within a 2 year storage timeframe (at 77F), or 12.4v ocv whichever comes first. Does not mean that is good however, getting them fresher is better. A fully charged Odyssey will read from 12.8v or more. Brand new you may see 13.1v or so.

                          This would be a good SOC test for your new one. Without any load, nor any charge, after 24 hours measure the open circuit voltage. Here's the breakdown:

                          12.8v + 100%
                          12.5v 75%
                          12.18 50%
                          11.88 25%

                          These values do not mean your battery is healthy, or has full capacity. In fact, do not expect full capacity after about 5-10 full cycles. AGM's don't self discharge too much, but don't leave these in a discharged state.

                          I don't know why the charger tripped the first time out, but after a reset, it appears to be operating normally.

                          Regular alternator charging is no problem with the Odyssey, just make sure the voltage is between 14.1 to 14.7v *at the battery terminals* (taking into account voltage drop here in possible long remote cabling) I'm not sure I'd just hang it off your existing battery setup, but perhaps an isolator would be a good idea.

                          It doesn't sound like you got hold of some new-old-stock, but just keep a wary eye on things if this battery discharges too fast.

                          Comment


                          • #14
                            Solar on your PC925

                            IF you have about 4 hours of solar insolation, you can get a 50% DOD 925 charged with a 100w panel and a pwm controller set for 14.7v (temp compensated controller of course).

                            NO, you do NOT need 0.4C minimum current. This is a holdover from the EV days or when anyone contemplates using them from 80-100 DOD! And even then, you'd need to incorporate an IUI algorithm if you wanted a fast 6-8 hour constant cyclic turnaround.

                            So, with 50% DOD as your guideline, this minimum currnent issue is eased greatly, and a 100w panel at 5.7A in about 4-5 hours would be ok - and that includes the required 105-110% recharge figure and pwm inefficiency. BUT, this will only take you to 95-98% SOC. You want 100% if you want the most cycle life, so you are looking at least a few hours of float. One way to accomplish this would be to ensure that your 925 is charged up fully (solar or otherwise), and let it float the whole weekend. Something like that - we have to balance practicality with cycle life. The moral here is that even when a charger says "done" for an agm, they still want to see 6-8 hours in float to um, get into the nooks and crannies.

                            One way to accomplish the needed float after a solar charge, but you've run out of daylight would be to use a small tender. Unfortunately, Battery Tender does not meet Odysseys float voltage requirement. Just short, but not good enough.

                            A VERY good alternative during those dark hours would be a Battery-Minder model 2012-AGM. These guys are nutso over providing the proper voltage, temperature compensation, build quality etc. I personally use a battery minder model 2012-agm for my Optimas and Odysseys, but ONLY if they have had a decent charge to start with. Note that the Omax is not really intended to be a long-term float charger. If that little fan is constantly spinning, it is only a matter of time before the mtbf hours get to it. For long term floating, a fanless battery-minder is the way to go. In your cyclic application however, this may not matter so much.

                            I gotta' stop before I sound like a salesman. It is just after my speedcharger debacles, I really delight when something follows the rules.

                            Comment


                            • #15
                              Oh no not another charger! I actually got another one last Christmas as a gift (sears model of some sort) and took it back since I didn't need another. The Omax charger fan only seemed to run when it was first charging. I haven't heard it run since it's been in float mode when I've checked it. I'll cross my fingers in the mean time and hope the fan keeps working for now. At some point I'm going to inherit 2 more sears battery chargers from my dad too.

                              I just took the Omax charger off the PC925 that has been in float mode for days now so I can test the voltage after 24 hours like you suggested. The display has been fluctuating between 13.6 and 13.7. Within 10 minutes of disconnecting the charger the volts have dropped to 13.2. The date stamp on the battery is Jan or Feb of this year so….?

                              I tested the voltage (Fluke 87 as well) on the truck that will mostly be used for transport of the sprayer:
                              At truck battery terminals: 14.18v
                              At plug where jump leads plug in: 14.12v
                              At alligator clamps: 14.12v

                              I like the idea of the battery isolator. Any recommendations on one for my application? There are different amp ratings, but I would need to go off the truck's alternator amp rating right? The truck has right around a 150 amp alternator. Might be more like 145.

                              Thanks for the help so far! No worries as I'm always up for learning new things. I've had to read and reread you post several times as most of this new to me and might was well be in Japanese. I really appreciate the help and by googling things I'm getting there. So let me see if I follow you.

                              Hypothetically speaking if I did try to build a solar setup. Sunlight is not a problem. The sprayer is either in use in full sun (cloud cover permitting) or in transport in full sun as well. I could pretty much charge the PC925 while I'm working on the road so long as I had a 100w solar panel and a pwm controller set at 14.7v and I finish on the appropriate float charger overnight. However I would want to wait until 50% DOD before letting the solar charger start charging? Again this is all new to me so if it's not too much trouble do you have links or model numbers to the recommended components for this type of setup. I'd like to take a look but I think I need the dots connected for me at this point. I'm assuming this is probably going to take up more space than something I could fabricate to mount on the sprayer itself. More of a unit that would be truck mounted of sorts? That has always been a problem because of everything else that is used and taking up space in transport. Ideally I'd like to have everything contained on the sprayer itself but don't know if it's feasible given the available space. It's already looks like a science project gone wrong with all the gauges, hoses, wires, plumbing, booms, switches, fittings. Not to mention I made a special custom foam kit that drops balls of foam so I can tell where I've sprayed already. I really should patent it. Then I fabricated a custom hitch platform to carry it all on. I think the whole setup is neat, but most don't know what they are looking at when they see it. I "Just do excellent work" "however it works".

                              Thanks again PNJunction for all the help

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