DIY solar setup?

Discussion in 'Prime Plug-in Charging' started by Xeno, Aug 1, 2017.

  1. Piwacet

    Piwacet Junior Member

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    Thanks! Appreciate hearing your ideas and experience. I'd love it if you kept us posted!
     
  2. prime8472

    prime8472 New Member

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    Your welcome.

    I tend to move quickly from studying one thing to another. Life is so fascinating. I will keep you posted but I do think I'm close to having a setup that will meet my needs for mobile power. I am thinking about starting a Youtube channel because I tend to go there to learn and it would be nice to give something back.

    I'd like to re-post my last. I clarified and corrected some of my statements:

    SUCCESS!!!

    I was able to recharge my prime for 43.5 minutes using materials I already had on hand. I also had long periods of full sun today. My prime’s lithium pack was at 75% full and the prime reported it had 1hour 40 minutes to a full charge. I was able to recharge it to 90% from just sunlight.

    I used both battery banks to feed the inverter even though they were dissimilar. I know that this is never done but I think I took enough precautions such as ensuring the amps were running only in the direction I desired. In the future I plan to eliminate this secondary battery assist or use diodes. I made the primary bank the one with the high amperage car batteries (700amps). I used the harbor freight batteries as an assist (35ah). I used two solar arrays which were also dissimilar.

    Bank one has 2 - 100 watt panels with an MPPT charge controller and the supercaps. I expected bank one to do most of the work.

    Bank 2 has my 120 watt folding panels with the 35 ah batteries.

    My inverter constantly shows the battery voltage it is receiving. When I switched the inverter on the voltage dropped almost immediately from 13 something down to about 11.9 then began to go down slowly, 11.8, 11.7 etc. I had the batteries in a vehicle jump configuration. Going right from bank one to bank two. Once I noticed that the secondary batteries weren’t dropping at all, I moved the jumper cables to run from the 35ah batteries/120 watt panel setup to the back of the inverter. The secondary PWM array readout (of the battery voltage) then began to drop in voltage slowly also. The voltage was at 13 point something and began to drop just like the 700 amp battery’s voltage but it didn’t have the initial sudden drop in voltage. What was amazing is that the inverter voltage readout slowed significantly!!! This is what I was hoping for. This simple action caused power to be drawn from both battery banks albeit more from the primary bank which had thicker cables connected. The primary array’s battery would get down to very low voltage and because of the supercaps would recharge quickly. That voltage would go from nine point something to return to about 10 or 11 volts and then decrease slowly again. However, unlike before, no alarms sounded for 43 minutes. I believe this is because the voltage was being kept up by the other power sources and the supercaps reloaded the battery voltage so quickly. I think this quick charging of the batteries may be damaging them by causing sulfation. I don’t think vehicle batteries are meant to be quick charged the way the capacitors are doing it. Even though I’m not seeing any signs of sulfation, this is something I need to research.

    I wanted the secondary array to only have jumper cables for several reasons. 1. This would increase the resistance and not allow current/damage to flow back to my 35aH batteries from the 700amp batteries. 2. This allows for a quicker connect/disconnect of the dissimilar circuits. I will note that the red jumper cable did get hot, which is not good. I know that I still have work to do on this setup but for now I’m happy. When the rest of my supercaps and a few other items arrive I’m sure I can recharge my car for longer than 43 minutes. The recharging is limited by the inverter cutting the power to protect the battery dropping below 9.8 volts. My 35ah batteries never got below 12 point something volts. I think this is a prime spot for diodes, thicker wires and a breaker. I believe it will eliminate the lack of battery draw to the inverter and provide battery protection. When bank two is connected, the inverter must be on to assist in ensuring voltage is only going out to recharge my car and not to battery bank one.

    5:17 p.m. (later the same day 15 Oct 2017) the sun has gone down below the high trees across the street. I noticed that the supercaps have begun to pull power from the batteries (the MPPT must be allowing voltage to come back from load to the battery (which is where my supercaps were connected)) the voltage reads 12.2 and it was 12.34 several minutes ago on the batteries and capacitors. I guess it would need to, in order to read how much power is being used by the load. The capacitors don’t hold a charge as long as batteries and thus became parasitic to the batteries since the sun was no longer supplying power. So I disconnected the supercaps via breaker. I later brought the gear in for the day.

    As I moved my prime to the carport I noticed that the battery was actually at 95% full! I don’t think the short time I had it connected the second time can account for the extra 5%. I think the car’s battery estimating circuitry adjusted its reading maybe? This is something I will have to watch closely, it could be a sign of another issue.

    I will also have to find ways to keep the battery voltage up for longer periods of time. To improve bank one’s configuration, I’m planning on adding more caps and configuring the circuit to allow for different circuit configurations on the fly. Improvements to bank two’s performance will be less complicated. I plan to stop using the jumper cables. Then simply use better wiring, more breakers and add capacitors. For the back of the inverter, I will utilize a bus bar to tie the two banks together. I expect to be able to recharge my car for at least an hour or more. Eventually, I would like to get a 240 volt charger and inverter which would significantly reduce the time needed to recharge.
     
  3. prime8472

    prime8472 New Member

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    1 Nov 1251 pm. I tried another configuration. I decided to let the supercaps run free. I ran the supercaps directly to the inverter and also gave them their own 30 watt solar panel. Each battery bank also ran directly to the back of the inverter with higher AWG cables than before. The 700 CCA batteries/ (with 200 watt solar panels) had 6 gauge which (red cable) seemed to get a little warm. While the 35ah batteries (120 watt solar panels) had 4 AWG. I know I should have it the other way around but the cables were crimped with ends that didn’t fit any other way on my batteries. Next time I’ll crimp them myself so they will be fully sufficient for the job. Or I will add more cables to the connection. But the heat was hardly noticeable. My prime’s batteries was at 80% full. I started at 1135 A.M. and stopped twice, for about a minute to adjust loose cables during the recharge. The CCID didn’t cut out on me until 1228 P.M. and I heard an alarm. I figured I would let the rig recharge again. At 1235 I noticed the batteries and caps were both reading 12 volts I tried to restart the prime recharging but it wouldn’t. That’s because the battery was at 100%!

    The batteries never dropped below 11 volts during the recharging. They kept being recharged by the capacitors. In fact the whole setup was far more stable than I’ve ever seen it before. I would like to attach a 12volt capacitor bank to each of the battery banks which would add to the solar generator’s stability. I do have 400 watts of lightweight foldable solar panels coming in the mail today and plan to see what I can do with them (when I get time). I still haven’t received my additional caps in the mail but they should arrive soon. When I do, I plan to use this configuration to recharge my prime every day. That’s provided I don’t find a better configuration. I think it’s amazing that with just the 3 - 16.2 volt 500 farad capacitors I was able to do so much. Their effective power comes out to be about 14 volts (never had them above 14) and 250 farads (500/6 = 83, then 83.33 x 3=250 farads). Recently, I’ve even used the capacitors to restart my old Toyota Tacoma. The battery is dying in it. I’d like to build Lazersaber’s hand crank capacitor bank and put that in my truck instead of a new battery. In fact when I get time, that’s the plan. I’ve also used the rig to shampoo a rug. The possibilities are endless.

    Right now I’m off to patch a roof.
     
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  4. prime8472

    prime8472 New Member

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    I think the batteries didn't get below 11 volts because I just didn't notice them falling to 9.8 volts, which they must have. The inverter and the capacitor bank both showed voltages that matched the entire setup. I also noticed that after recharging my car, upon recharge attempts the unit wasn't capable of recharging the car as long. probably because the battery voltages needed to be at 12 or 13 volts for a while. it's almost like the voltage was just for the battery electrolyte and not the battery itself, if that makes any sense.

    I have numerous ideas but most of them will have to wait until I get more caps.
     
  5. prime8472

    prime8472 New Member

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    THE CAPS HAVE ARRIVED!

    Unfortunately I worked all day. I keep relearning that I need to slow down and pace myself. I'm not as young as I used to be.

    I will eventually get to putting together my SOLN1 with batteries. As far as my foldable solar panels, the company sent me the wrong one. They said they are sending the correct order and I can keep the 110 watt ones they sent by mistake, which are pretty nice. I have to decide on how i'm going to put this thing together now that I have all of the required parts to make it Laser's way. I really want to leave out the solar charge controller for the caps. I don't know why he had a controller on his because he didn't have batteries to protect from overcharging. The caps have their own protection circuitry which would consume any over voltage past 16.2. I think he was just being cautious, which is never a bad thing when dealing with high power.
     
  6. prime8472

    prime8472 New Member

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    Learning more from failure than success.

    6 November 2017 – I configured a mobile power configuration that I thought would be able to go for longer than 50 minutes providing 1440 watts of A/C power. I first had to put together the new 8 banks of capacitors I recently acquired. So I put them together in a temporary parallel bank utilizing screws and rubber bands which actually worked very well. I also changed the battery configuration. Surprisingly, even with the added capacitors I wasn’t able to break the 50 minute barrier! I then added cables where I noticed they were warm and tried again. Eliminating these power losses didn’t seem to significantly extend its run-time.

    Don’t get me wrong, I was able to recharge my cellphone and lithium batteries for my tools. In fact my solar generator was not only able to supply the 25 or so watts required but the caps/batteries continued to increase is stored power! I ran into problems only when trying to break this previously unknown 50 minute barrier of continuously supplying house power (1440 watts) to my prime. It basically didn’t do any better with additional caps. I have a theory as to why this is so. I will be reconfiguring everything with additional parts and when it’s sunny enough try again. If I added more batteries I would probably be able to go beyond this limit. I don’t want to add weight to the system. It’s still something I may try. I also would like to run the solar generator with just caps for lower wattage or shorter applications that can tolerate many stops and starts, like power tools. In any case, adding or removing a battery should prove or disprove this battery theory. My other theories I will keep under wraps at least until I check them out. I have many possible workarounds I would like to try. I will also probably put the whole thing either on hold for a while or proceed much more slowly. My reasons, include my plan to change my current Information Technology job for something more specialized like Cyber Security. This takes lots of study time and working on my hobbies has to take a back seat to that. Although it is pretty hard to pull myself away from tinkering with electronics.

    I have one big conclusion: There is a lot of unused solar power in what solar generators can collect from the sun. This failure also calls into question how many caps are required to go for 50 minutes with 4 batteries. I can probably use just one 12 volt bank of caps.
     
  7. SR-71

    SR-71 Member

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    I'm in the process of designing a solar system for my home so I may be able to shed a bit of light on this subject. Assuming your Prius Prime's EV battery is fully discharged, during its charging process it draws approximately 1000 or 1500 watts from a 125vac wall outlet (depending if you have your charge rate set at 8amps or max). Now... let's put this into perspective of a solar source. The solar panels I plan to install on my home develop approximately 300 watts (each) in full sunlight. Each one of these panels measures approximately 65 inches by 40 inches, (about the same square footage as a standard home door). The solar wiring itself (wiring between the panels, to the inverter, and to the source) presents some amount of loss so to compensate for wire losses, for a rough estimate let's figure you'll need 4 to 6 of these large solar panels to produce the necessary power (1200 to 1800 watts) to charge your Prius Prime. The other component needed would be an Inverter. An Inverter changes the solar panels DC voltage to AC voltage, and the Inverter would need to be sized to handle current (amperage) of the multiple solar panels.

    So... assuming you have four to six of these large 300 solar panels (they cost is approximately $1 per watt) and you have the properly sized inverter (sine wave type), and assuming you have approximately 5 hours of full sunlight hitting the panels, you should be able to charge your Prius Prime in about 5 hours.
     
  8. prime8472

    prime8472 New Member

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    ///
    SR-71, Thanks for the input, however I've already been there. I've been using solar for some time. I'm actually already successful in charging my car via solar using only 320 watts using supercaps. I just haven't been able to break the one hour barrier, even when adding more supercaps and solar panels. Currently I am: 1. going back to my original setup. 2 Adding an extra power unit consisting of two large 12v supercap banks using an alternating timing circuit to provide extra wattage. I am just waiting on 200 amp relays that I recently ordered. I am also investigating an invention by a group on kickstarter who have a system that I plan to buy.

    See:


    It uses caps with a joule thief circuit and some other interesting devices to do the same thing I'm working on. So you see, this is actually a done deal. I can already recharge my car from 0 volts to 100 volts. it will just take longer than house power, and I don't think it should. Most of the questions I had last time have been answered by my additional reading and research but thanks anyway.
     
  9. Greener1122

    Greener1122 New Member

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    Prime8472 has done some amazing work. I just wonder for those less diy oriented or technically inclined it might make sense to invest $3000 in a Tesla Wall plus solar panels to keep it charged, with solar panels costing about $1 watt. I have about 15 180 watt panels I bought for this price, and if mounted they should provide enough juice within the Wall to charge a Prime in 5-6 hours. Of course, the Wall is connected to the grid so you also have a potential whole house system in an outage or non solar charging. See askaprepper for an article on the Wall plus other articles I have on diy rainwater harvesting and strawbale construction. My site at powerfromsun Is a basic primer on diy solar, but I know the system I designed using deep cycle batteries is not powerful enough to charge a Prime, which we bought a few months ago. Would love to charge the Prime with solar but not there yet. One day maybe.
     
  10. Gen3PP

    Gen3PP New Member

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    I don't know exactly what is going on with the voltages applied to the prime. It appears that the AC to DC converter under the back seat can convert 115vac or 220vac (maybe 240vac 50hz) into the required DC voltages required by the Prime's battery pack (nominal voltage 351.5 V)...from other posts here. The question I have is, could you put direct DC voltage into the Prime from say a Solar array (max solar DC output is less than max rated DC input power into the converter??). One question would be.. is there a rectifier or a transformer in the first input stage of this converter(if Transformer it would burn up for sure). I have heard rumors that there is DC charging available in some countries for the Prime?? (so DC to DC).
    On a different subject, I have a feeling it does not matter if you put clean or dirty sine waves into this circuit since this input is going to get converted to DC anyway.
    FYI, there is also 12volt out of the converter (Weber state Youtube Video on Prime) that powers the batteries computer I believe).

    Don't quote me on any of this!.
     
  11. Salamander_King

    Salamander_King Senior Member

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    Interesting thread resurrected. I must have missed it almost two years ago. OP has been gone over one year... I wonder what happened to his project.:rolleyes:
     
    #31 Salamander_King, May 9, 2019
    Last edited: May 9, 2019
  12. Gen3PP

    Gen3PP New Member

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    He went away fuming. His Prime was turned into a Corolla.
     
  13. Salamander_King

    Salamander_King Senior Member

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    Yeah, "No Plug" is better, according to Toyota. lol :ROFLMAO::ROFLMAO::ROFLMAO:
     
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  14. ETC(SS)

    ETC(SS) The other One Percenter.....

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    Wow....
    I had no idea these Supercaps were this inexpensive now.

    My first impulse when reading this thread was to admonish the OP for not just running a 12/3 cord to wherever his car was parked.
    I recently bought a 100' 12/3, heavy-duty, outdoor rated cord for $40 at a big box store that rhymes with "Jams."

    Since I have 5 acres, 3-1/2 structures and only one power pole, I've become used to burying power lines in conduit....running extension cords.....etc.

    However (comma!!!)
    (1) The OP's zip code in in a large left coast city that makes me think of cement, and they don't even let them pump their own gasoline out there - so 120VAC might really not be an economical solution for them.

    but...

    (b) I'm very intrigued by these super caps!!!
    I'm only using 100w of solar right now for my gate and a security light but I'm thinking that with a bank or two of these caps I might be able to add some solar landscaping as well, and this might add some interesting possibilities to scaling up my solar later on as the prices keep falling. Even at 100w, I'm not using NEARLY what I'm collecting....

    Things that make you go Hmmmmmmm......


    THIS thread is going to cost me some sleep....I can already tell.....:D
     
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