Batteries power at the field is always an issue

murankar

murankar

Staff member
I have tossed this idea around a while back when I built the firs charge case. The idea of going solar for the field is creeping back in my head. I got a deep cycle battery in my van for the field but no way to charge it if I need more power while at the field. I could run a charge circuit off my main battery. This to me would be a great short term fix to the long term problem.

My deep cycle can handle 10 amps discharge for 10 hours, which to me means 80 AH. I am still not sure how my charge cycles on the packs I would get when adding in the power usage of the PL6 and bump controller. I do know that it will take longer to charge packs since I wont have the full 40 amps the charger can do. I am on a 12v system right now which is fine for now. I dont think taking a deep cycle to 24v will net me the 40 possible amps and I dont think the batteries can handle that for to long if they could do it. So if I can get around 9.9 amps for the packs I can get almost 3C on the 3300 mah packs I have or 9 amps for the 3000 mah packs I have. I charge 1 stick pack for a cycle at a time.

I could also do an inverter at 2000 watts and I should be able to pull my max 3C charge rate for 2 packs. I know I would have losses in there due to the inverter, power supply and the charger.

I found a solar kit on amazon by renogy which is rated at 100W at 5 amps in perfect conditions. My deep cycle should be able to handle 8 amps for max charge. I think this kit would bundle nicely in the van and be able to serve as a dual purpose rig. Not only can I use it for the hobby but when I go camping also. I have no intention on charging while driving due to gas releases from the deep cycle. I real question is could a 100w panel keep me going at the field for the day? Basically leave the house with charged packs and then attempt for 9 total flights which means each stick would need 2 more cycles after getting to the field.

this solution if it works would be cheaper than a generator, cleaner and quieter than a generator. Plus I could use it for other things like camping.
 
D.O.G.

D.O.G.

Goblin 380 Supporter
murankar said:
I have tossed this idea around a while back when I built the firs charge case. The idea of going solar for the field is creeping back in my head. I got a deep cycle battery in my van for the field but no way to charge it if I need more power while at the field. I could run a charge circuit off my main battery. This to me would be a great short term fix to the long term problem.

My deep cycle can handle 10 amps discharge for 10 hours, which to me means 80 AH. I am still not sure how my charge cycles on the packs I would get when adding in the power usage of the PL6 and bump controller. I do know that it will take longer to charge packs since I wont have the full 40 amps the charger can do. I am on a 12v system right now which is fine for now. I dont think taking a deep cycle to 24v will net me the 40 possible amps and I dont think the batteries can handle that for to long if they could do it. So if I can get around 9.9 amps for the packs I can get almost 3C on the 3300 mah packs I have or 9 amps for the 3000 mah packs I have. I charge 1 stick pack for a cycle at a time.

I could also do an inverter at 2000 watts and I should be able to pull my max 3C charge rate for 2 packs. I know I would have losses in there due to the inverter, power supply and the charger.

I found a solar kit on amazon by renogy which is rated at 100W at 5 amps in perfect conditions. My deep cycle should be able to handle 8 amps for max charge. I think this kit would bundle nicely in the van and be able to serve as a dual purpose rig. Not only can I use it for the hobby but when I go camping also. I have no intention on charging while driving due to gas releases from the deep cycle. I real question is could a 100w panel keep me going at the field for the day? Basically leave the house with charged packs and then attempt for 9 total flights which means each stick would need 2 more cycles after getting to the field.

this solution if it works would be cheaper than a generator, cleaner and quieter than a generator. Plus I could use it for other things like camping.
Click to expand...

Here you go URI. Check this out with a marine battery this might work. Solar Panel Kit - Save on this 45 Watt Solar Panel Kit with marine battery
 
murankar

murankar

Staff member
This is why I dont want this kit:

Solar panels for the beginner part 6 Missouri Wind and Solar Harbor Freight - YouTube


Plus I can get this cheaper:

Amazon.com : Renogy 100 Watts 12 Volts Monocrystalline Solar Bundle Kit : Patio, Lawn & Garden

Here is a 50 watt setup that is about what you would get from H.F minus a battery. Since I have the battery already I dont need that and if I need more Amp Hours I'll go and spend the $80 on another battery. Even after a second battery this option is still cheaper than H.F. and higher quality. This would be a one time build project not a buy twice project. That would end up costing way to much.

https://www.amazon.com/dp/B00DCDZOI0/?tag=rch0a-20


All I am concerned about is having enough Solar to replenish the battery. I am not sure how much battery I would need for a full day at the field or camping.
 
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Smoggie

Smoggie

Well-Known Member
I'm quite sceptical about use of solar power for battery charging. Solar has it's uses in fixed installations where the panel has 'all day' to gather charge and where you can cover large areas with panels but for a small portable setup where panel area is limited and you are charging as you fly I'm not sure if the panel would provide enough to be worthwhile in our heavy power demand application.


My reasoning.....
The rating of panels is their maximum output in perfect and ideal conditions; i.e. a cloudless mid summer day at noon with the panel pointed direct at the sun. Having read up a little it seems like the typical average output in summer on a decent day would be about 1/3rd of rated value and in the winter maybe 1/10th. So averaging out over the day and over the seasons you would typically expect very roughly 25W(averaged) from a 100W panel.

Now if you are flying your Goblin 570 with two x 6S 3000mAh batteries then each recharge takes about 150-200 watt hours. So just to provide enough charge for a single cycle of your LiPos and using a big 100W panel would require the solar panel to be working for about 6-7 hours. Sure in the summer on a perfect day and at mid day it would be less, but in the winter it would take even longer. The numbers look far worse for me with my 5000mAh batteries.

For your required 6 battery cycles for your day's flying, assuming your panels are set up at the field for 4 hours then by my calcs you would need about nine 100W panels if you wanted to avoid drawing down on the charge in your deep cycle. If you were willing to draw down on your deep cycle then maybe 4 panels would do it (assume 80-100Ah), but there again if you just doubled up on deep cycles then you wouldn't need any panels!

I guess a lot comes down to where you live and how many hot sunny cloudless days you can realistically expect to get. For me it's a non starter, others in sunnier locations will have it better. For me a generator or simply more/larger deep cycles would be a far more practical approach.

thoughts?


Steve
 
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Tony

Tony

Staff member
One thing to remember is URI will be starting out with a fully charged Deep Cycle battery. Once he starts charging, that is when the solar panel will be connected to the battery via adapters of course to regulate the power. So all he has to do is maintain enough energy in the deep cycle to handle the charge cycles that he is wanting to do at the field. Quite honestly, 9 flights is a lot. I don't think I have ever flown 9 batteries in a day, but if you have a way of doing this, then that is fantastic.

I will just stick with my Genny though...
 
Smoggie

Smoggie

Well-Known Member
Tony,

Yes, I factored the fully charged deep cycle and fully charged LiPos into the calculation. The problem is that these large 12S LiPo packs suck an awful lot out of a deep cycle. You would only get about 3 or 4 recharges from a 12V 100Ah deep cycle. The other problem is according to many who use deep cycles is that these high discharge rates kill them pretty quickly, they aren't really intended for the sort of constant high amp rates that you would pull when charging large LiPos. A 100W solar panel in typical conditions would hardly make a dent in the sort of power requirements we are talking about.

On a good day I burn twelve battery sets (two batteries per set on the big helis).

the genny is the way to go if you want to fly all day IMHO.
 
murankar

murankar

Staff member
Yes that's why I stated I wouldn't be doing much over 3c on charge cycles. This battery is I have is rated at 10AH for 8 hours. So as long as I don't exceed that 10AH rate I should be fine. Now one thing I am finding out with this whole thing is this. I will need more than one battery to satisfy my power needs for field charging. Plus I would need 2 panels at 100w each to keep up. You all saw the videos with my clubs field. I won't have an issue with placing 2 or 3 panels out in the pit area. Once I start adding panels and batteries things get pricey quick. Which for me is not that huge of a deal. I won't be buy the whole system up front.

Why I want solar is simple for me. I can use it for many other things other than the field. Camping would offer a great use for solar. Camp grounds try and keep things quiet. Plus it eliminates the need for a fuel can, very little to no maintenance cost. If the power grid goes down I have energy that can be used. It's not that I am a tree huger it just sounds like it makes sense. I think the benefits out way the negatives.

Right now it's learning the limitations. Would I ever fly nine flights in a day, maybe not. I just wanted to set a number to give us figures to work with. Plus if I get the Gaui X3 going that could give me the extra flights without having to tax the system on 12s packs.
 
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Smoggie

Smoggie

Well-Known Member
murankar said:
Yes that's why I stated I wouldn't be doing much over 3c on charge cycles. This battery is I have is rated at 10AH for 8 hours. So as long as I don't exceed that 10AH rate I should be fine. Now one thing I am finding out with this whole thing is this. I will need more than one battery to satisfy my power needs for field charging. Plus I would need 2 panels at 100w each to keep up. You all saw the videos with my
Click to expand...

Assume you would be parallel charging the two 3000mAh packs together as a pair?

25.2V x 3Ah x 2 packs x 3C charge rate = 454W

Assume charger is 85% efficient and battery delivers 12V:

Amps from deep cycle battery = 454 /(12 x 0.85) = 44.5A


So to charge your two packs at 3C you would have to pull about 44.5A out of the deep cycle, which is over four times its rating and would kill it in short order. To charge within the 10A rating of the deep cycle would mean charging your pair of batteries at around 0.7C, so that would take well over an hour.

Solar is ok for stiff like powering low energy lighting, maybe a small fridge or a small TV and charging your phone (so fine for camping). But for very power hungry applications like large LiPo charging it would need one helluva large array of panels, and a very sunny day! The numbers I quoted in the previous post weren't just made up, they were based on standard solar panel efficiency as per quoted found on many solar power web sites.
 
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murankar

murankar

Staff member
This is info I have been wanting to see. I have seen small lawnmower batteries at the field. Of course those packs being charged were 2200 3s packs.

Here is something else I forgot to mention, because I just remembered. If I happen to be at the field during a "fly in" I won't need to worry. People are kind enough to share generators. I am looking at those times when it's just me. So it looks like if this is to happen I would need a solid flying Gaui X3.
 
murankar

murankar

Staff member
I'll watch it shortly.

I went to a flying field that uses to solar panels and 4 batteries. Now their batteries were bigger. I think there panels are 200watt giving them 400watts total. They have both 12 and 24 volt charging stations. I have the number to the guy who set it up so I'll be calling him to get some input.
 
murankar

murankar

Staff member
Like like my rig of 100w panels could work. More research but it looks like my 4s packs would work just fine. Now to solve the 6s packs.
 
Smoggie

Smoggie

Well-Known Member
Derek said:
I just thought I'd share this as some "food for thought"
Click to expand...

Interesting but you do need to appreciate the difference between charging a 3S 2200mAh at 3A like he was doing in the video and Uri's aim of charging his dual 6S 3000mAh at 3C (18A). The Video guy needed 37 watts, Uri would need 450 Watts... so that would be 12 of the panels shown in the video!.. And even then it would only work on a nice sunny day in summer.
 
murankar

murankar

Staff member
Holly cow old thread batman.

After months of research I found my solution to the power issue. First off the batteries what to get; I finally settled on 2 6 volt golf cart batteries to run in series for 12v. My second phase is buying the panels. I already know what brand and type I am getting. I will have 3 panels the will put out 100w at 18 amps of current in IDEAL conditions and the charge controller will be able to handle the three panels.

I sized the batteries based on the amp hours and amp draw ability. Golf cart batteries are designed for higher amp draws than normal batteries. My total capacity will be 225 amp hours at 2.7 Kw hours. I like those numbers.
 
Tony

Tony

Staff member
Hey URI, I have a question. My eyes are too tired today to read all of this thread, so I thought i would just ask you. Are you ONLY using solar panels and a DC-DC converter to keep the batteries charged, or are you going to be running a power inverter to run 120vAC to power your PSU's to power your charger? Just wondering, I have a couple items on the way from amazon that I'm trying to get a video series setup with.
 
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