With a good quality battery, you can discharge to 25% SOC hundreds of times. The issue is making sure you charge the battery soon after as it is leaving it in this state that really does the damage.
Solar powered battery chargers???
- Thread starter CaptainpPicardX
- Start date
Help Support Candle Power Flashlight Forum
With a good quality battery, you can discharge to 25% SOC hundreds of times. The issue is making sure you charge the battery soon after as it is leaving it in this state that really does the damage.
independent
Newly Enlightened
- Joined
- Jan 14, 2008
- Messages
- 10
@semiman. from the above statement and your earlier questions it seems you don't fully understand how, what I am describing, works. I am talking about a specific MPP (strictly without the tracking) designed as an LCB. This is not the same as chucking on a USB charging device to a solar panel. Our MPP (without the tracking) LCB is designed with the best components money can buy with big low ESR input and output caps--nice. Solar battery-less USB charging easy ;-) I have tested them with 2x diff expensive N-series microUSB smart phones as well as other devices without problems. Each charging device works differently--but after watching (ie taking note of current flow over different charging scenarios) them react to lesser available current you can see it working well. Also, on our CC licensed circuitboard there are reverse engineered (thanks Lady Ada et al) voltage dividers for 500mA limiting charging currents and a non or higher limited current output. That is 2 different USB outlets with separate voltage dividers on both sets of data pins for the different outputs. Also some of this is academic because much (smaller) cellphone charging is done after the charging regime is into constant voltage mode and the current is tapering down. However, with tablets and big battery cellphones that is another story as they require far higher current capable power supplies.
Last edited:
IonicBond
Enlightened
I couldn't agree more! At that low of an SOC, one has to get it recharged nearly immediately. I regularly reach 50% SOC even though ideally one doesn't want to go lower than 75% for the most cycles. However, one can go overboard if they only draw down to say 75% SOC but only do so a few times a year - the battery will die of old age (4-5 years or so depending) before dying of too many cycles.
It's all about the power budget.Re MPPT controllers - they are great, but if your system is about 200 watts or lower, it may be cheaper and easier to just pick up another panel as long as the PWM controller and battery can handle the additional input.
I have a lot of fun with Odyssey / Hawkers. However the *minimum* charge current is .3C and it's a blast to fast-charge them via solar in an hour if you have enough panel/controller. If one has a panel big enough, the Hawker Monoblocks may be an ideal replacement for small setups when there is very limited solar insolation since you can charge them so fast. I only take the Monoblocks up to 1C, but the big Odysseys can handle a lot more.
Last edited:
independent
Newly Enlightened
- Joined
- Jan 14, 2008
- Messages
- 10
@semiman and others. Apologies. I've been trying to describe a project a friend and I have been working on in our spare time as well as at the same time contribute to this conversation. It's come out a bit muddled (by me) and generally just added confusion to the topic being discussed. My friend and I have built and tested a solid Maximum Power Point (MPP) Linear Current Booster (LCB) circuit. The circuit has been pretty well tested and once the printed PCBs are looking as good we will release the Eaglecad files under some kind of Creative Commons license. Google LM2596 LCB and there is a thread on fieldlines should show some of the preliminary work done..
Last edited:
Not to be antaganostic independent, but I haven't quite understood what you've been talking about all along until I Googled "LM2598 LCB" and saw the thread at Fieldlines.
OK so you guys are having a little fun with a circuit and TI's LM2596 simple switcher buck regulator. Of course any buck regulator would work in this case but you also use a terminology that I've never heard of......(LCB). When I first saw the circuit and only a buck regulator, I knew it couldn't be an MPPT charge controller because there is a lot more to them than just the buck drop down circuit.........such as the smarts that go along with providing the proper 3 or 4 stage charging algorithym. So what is linear current boost?
edit: so reading back on some posts, it sounds like it's a battery-less type of charging that you are doing..........How does it work to keep the charge currents regulated or the charge voltages proper to the device being charged? And how does it know to terminate charge when the device is all charged up?
OK so you guys are having a little fun with a circuit and TI's LM2596 simple switcher buck regulator. Of course any buck regulator would work in this case but you also use a terminology that I've never heard of......(LCB). When I first saw the circuit and only a buck regulator, I knew it couldn't be an MPPT charge controller because there is a lot more to them than just the buck drop down circuit.........such as the smarts that go along with providing the proper 3 or 4 stage charging algorithym. So what is linear current boost?
edit: so reading back on some posts, it sounds like it's a battery-less type of charging that you are doing..........How does it work to keep the charge currents regulated or the charge voltages proper to the device being charged? And how does it know to terminate charge when the device is all charged up?
Last edited:
independent
Newly Enlightened
- Joined
- Jan 14, 2008
- Messages
- 10
@huintahs If you look at the circuit as it is designed on the fieldlines thread there are actually 2x regulators (with big caps on the input and output). For my version there is an LM723 on the front end which is adjustable according to where you decide the MPP of the solar panel to be (from memory operahouse uses zenar diodes for the same function, simpler but lesser granularity). The LM2596 is used for regulation but also in pure LCB mode where voltage is left floating ie the output voltage is not regulated. The capacitors store the energy just long enough so it can be efficiently regulated into a lower voltage. I can't explain here better than what is already in the the thread at fieldlines. But I'll give it a go anyway
If you can get your head around a MPP regulator with a floating regulated output you are more than halfway there.
And that is what this circuit does simply and efficiently. The circuit is adapted from a circuit designed by Chris Graecen of homepower magazine fame.
If you can get your head around a MPP regulator with a floating regulated output you are more than halfway there.
- Consider a solar panel. The voltage when faced with a load, collapses. It is a pure current source output. Great battery chargers but not much good for doing any work.
- Now consider an LCB. When connected to a motor current demand goes up with voltage more or less linearly. More power = more voltage + more current in more-or-less equal amounts. An LCB will attempt to provide for this demand much like a battery would. The circuit we are using will do this when configured with a floating output.
And that is what this circuit does simply and efficiently. The circuit is adapted from a circuit designed by Chris Graecen of homepower magazine fame.
Last edited:
I just wanted to say thanks to everyone again for the informative information. I charged my first set of eneloops on solar. I bought a ammo can to keep everything in. I used deans instead of the mc4 connector and I also ordered a solar breaker switch so I can easily disconnect the battery when not in use. Fuses on the positive side of the battery and the load output from the controller. I was able to find the 3/16 f1 connectors at radio shack for the battery terminals. I pulled the jumper on the 10L so hopefully that is ok for my battery (ub1270). The instructions for the c401fs say it will run from 9-15 volts. I hope that will work ok for the phone charger too.
The only other thing that I'm looking at is fans right now. There is well reviewed 12 v fan called the endless breeze but it eats up 15 watts even on low. I might scavenge some 120 mm pc fans and put a hangar on them or something. It was a very fun project and I picked up all kinds of goodies like a digital volt meter and automatic wire strippers.
The only other thing that I'm looking at is fans right now. There is well reviewed 12 v fan called the endless breeze but it eats up 15 watts even on low. I might scavenge some 120 mm pc fans and put a hangar on them or something. It was a very fun project and I picked up all kinds of goodies like a digital volt meter and automatic wire strippers.
IonicBond
Enlightened
Nice! Just remember to switch on the battery first, and the panel last. Smart controllers need a battery reference voltage first before applying the solar input, otherwise they assume that you have a totally discharged 0V battery, and can prevent charge, or sometimes default to a float trying to protect what it thinks is a dead battery. It is also the reason that trying to check a controller for proper operation without a battery attached first makes some think the controller is bad when it isn't.
What might be interesting is after starting from your fully charged 7ah agm, is to charge the eneloops, and then let the agm rest for 4 hours and take an open-circuit voltage reading and compare it to the values listed earlier to get an idea of how much it has taken out in one charge cycle.
If the endless breeze draws 15 watts on low, then lets see .... 15w / 12v = 1.25a. Yikes - that would mean about 3 hours of operation before reaching the 50% SOC point on the 7ah agm. Keep an eye on that thing!
It is also the reason that trying to check a controller for proper operation without a battery attached first makes some think the controller is bad when it isn't. What might be interesting is after starting from your fully charged 7ah agm, is to charge the eneloops, and then let the agm rest for 4 hours and take an open-circuit voltage reading and compare it to the values listed earlier to get an idea of how much it has taken out in one charge cycle.
If the endless breeze draws 15 watts on low, then lets see .... 15w / 12v = 1.25a. Yikes - that would mean about 3 hours of operation before reaching the 50% SOC point on the 7ah agm. Keep an eye on that thing!
Last edited:
Sub_Umbra
Flashlight Enthusiast
(Spork) Glad you are able to move along.
I have found the teardrop tiny trailers electrical forum to be very informative from my prepper's point of view. Though they are recreational, they are also dealing with the nuts and bolts of tiny systems, which is right where many preppers are at.
Please let us know what you learn about fans.
Many in the teardrop tiny trailers forum have discussed the fan issues you are looking at. Many of them like 12v computer fans.
I have found the teardrop tiny trailers electrical forum to be very informative from my prepper's point of view. Though they are recreational, they are also dealing with the nuts and bolts of tiny systems, which is right where many preppers are at.
Please let us know what you learn about fans.
Last edited:
jamesperner
Newly Enlightened
- Joined
- Dec 19, 2013
- Messages
- 1
You can use solar power to charge your standard rechargeable battery power. This is not only a green practice it can reduce the amount of power you use. Building a solar-powered battery charger needs a screen, a preventing diode and a battery holder.
Sub_Umbra
Flashlight Enthusiast
Emphasis mine.
There is nothing inherently GREEN about power derived from photo-voltaic cells or panels. The entire service life of ANY PV panel will not produce more power than the petroleum required to manufacture it. Thats not to say PV power doesn't have its place...its just not green.
If you want to prove that PV panels are "GREEN" go ahead and lay out a breakdown of just how much energy it takes to create one compared to the energy produced by the panel in question throughout its service life. Without such a breakdown such claims are totally meaningless.
Some facts:
PV panels do not occur spontaneously in our universe.
There are no solar powered earth movers to dig the ore.
There are no solar powered trains to bring the ore to the refiners.
There are no solar powered refineries to process the ore.
There are no solar powered factories to turn the refined materials into PV panels.
There are no solar powered trucks to deliver them to your house.
All of these operations rely on more energy from either petrochemicals or coal and to not figure that into the mix is dissembling at best.
On the other hand, I agree with what you said about the diode.
Last edited:
ChrisGarrett
Flashlight Enthusiast
I went to Walmart and bought an Ozark Trails branded '02 Cool' 10" 12v fan that has a 12v DC input and which runs on 8D batteries.
I used it a lot over the summer, on my patio here in Miami, to beat the heat and humidity while smoking my cigars. You can find them on Amazon for over $20, but I think I paid like $9.99.
I don't expect it to last a lifetime, but the fan blade design is nice and it's got two speeds. Runs on 12v/500mA input, so not a huge drain.
Chris
Sub_Umbra
Flashlight Enthusiast
Lay it out.
Last edited:
Sub_Umbra discuss and respond to the post if you wish, there's no need to make this discussion personal - Norm
Sub_Umbra
Flashlight Enthusiast
Aforementioned post edited
Last edited:
