Small Solar Proposal

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BlueBell
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Small Solar Proposal

Post by BlueBell » Feb 23, 2018 4:34 pm

Okay, if I configure 126 Turnigy 18650 2000mAh 3.7V Rechargeable Li-Ion Batteries,
in 3s46p for 84Ah at 11.1V,
draw them down at 4 - 5 amps continuously, 24/7,
could I charge them through a
ALLPOWERS 20A Solar Charge Controller Solar Panel Battery Intelligent Regulator with USB Port Display 12V/24V,
and 3 Solar Panel ALLPOWERS 100W 18V 12V Bendable SunPower Solar Panel 5.5A max output, Water/ Shock/ Dust Resistant?

This is for a motorless, racing sailboat.
The race is in June at the 50th parallel north.
New construction and considering to purchase the above arrangement.
Max draw is 10 amps but highly unusual, and at worst, intermittent.
Avg draw 3 - 5 amps, 24/7.

Thanks for any feedback before I go ahead and purchase the above.

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Drunkskunk
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Re: Small Solar Proposal

Post by Drunkskunk » Feb 23, 2018 5:10 pm

Sounds like an awesome project, I'd love to see the progress as you get this built.

If it was me, I'd pick Sanyo or Panasonic cells over Turnagy. More power density meaning fewer cells and lower weight. Also probably higher quality.
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BlueBell
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Re: Small Solar Proposal

Post by BlueBell » Feb 23, 2018 7:23 pm

Okay, thanks DS.
Even at twice the cost?

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Re: Small Solar Proposal

Post by DAND214 » Feb 23, 2018 11:46 pm

BlueBell wrote:
Feb 23, 2018 7:23 pm
Okay, thanks DS.
Even at twice the cost?
I didn't check there cost, so what do they cost?


Dan

John in CR
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Re: Small Solar Proposal

Post by John in CR » Feb 24, 2018 7:54 am

Don't even consider putting craptastic cheap RC lipo batteries in a boat. Use only safe chemistry batteries. A fire that can't be extinguished is a bad thing on a boat, especially a boat that is almost 100% flammable. I assume you aren't racing a shipping container. There are much better and safer battery options for your needs that are less costly too.

Why such a low voltage?

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dogman dan
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Re: Small Solar Proposal

Post by dogman dan » Feb 24, 2018 8:22 am

Starting point on your math is the output of the panels. Potential max output matters not, since it might be cloudy on race day. Even just thin high clouds have a huge impact. So its not 300w x 18 hours.

300w of panel, figure if you are lucky, you get 1500 watt hours per day. Could be less though, or a lot more depending on season and weather. I'm just starting there with 5 hours average daily insolation for a figure.

divide by 24 hours, you get 62 watt hours per hour to work with. Sounds like not enough to me. 5 amps x 12v is 60 watts, so 60 wh per hour. Yes, inside the number, but not much leeway for having cloudy weather even part of the day.

4 panels would do er for sure I think. Or, start with a larger, full battery. You have 1000wh, so 16 hour reserve. That could be plenty if the race is short, like 3 days. If its 15 days, not that big a reserve.

Your calculations mirror what I have thought about solar charging a bike on tour. At some point carrying enough panel just gets impractical, unless you can periodically put more power in. I just watched the show on the solar plane that went round the world. It had to carry really impressive size panels, and enormous battery to get through the night, AND, serious navigation to avoid any clouds at all.

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Re: Small Solar Proposal

Post by BlueBell » Feb 24, 2018 11:42 am

DAND214 wrote:
Feb 23, 2018 11:46 pm
BlueBell wrote:
Feb 23, 2018 7:23 pm
Okay, thanks DS.
Even at twice the cost?
I didn't check there cost, so what do they cost?


Dan
Hi Dan,
Like I said, they cost double.

BlueBell
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Re: Small Solar Proposal

Post by BlueBell » Feb 24, 2018 11:54 am

dogman dan wrote:
Feb 24, 2018 8:22 am
Starting point on your math is the output of the panels. Potential max output matters not, since it might be cloudy on race day. Even just thin high clouds have a huge impact. So its not 300w x 18 hours.
That is correct Dan, thank you. Like I said, the panels are rated (for your reference) at 5.5 max output.
That is in direct sun, mid-day, clear sky, clean panel, and new.


300w of panel, figure if you are lucky, you get 1500 watt hours per day. Could be less though, or a lot more depending on season and weather. I'm just starting there with 5 hours average daily insolation for a figure.
[The season, as I said, is mid June, the latitude ~50 degrees north.
I did the same math but used six hours a day vs your five.
/b]


divide by 24 hours, you get 62 watt hours per hour to work with. Sounds like not enough to me. 5 amps x 12v is 60 watts, so 60 wh per hour. Yes, inside the number, but not much leeway for having cloudy weather even part of the day.
Agreed

4 panels would do er for sure I think.
I simply don't have the space for more than three panels.
This is not a large boat by any means.
Or, start with a larger, full battery. You have 1000wh, so 16 hour reserve. That could be plenty if the race is short, like 3 days. If its 15 days, not that big a reserve.
The race should be 2 - 4 days.

Your calculations mirror what I have thought about solar charging a bike on tour. At some point carrying enough panel just gets impractical, unless you can periodically put more power in.
I cannot.
I just watched the show on the solar plane that went round the world. It had to carry really impressive size panels, and enormous battery to get through the night, AND, serious navigation to avoid any clouds at all.

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Re: Small Solar Proposal

Post by BlueBell » Feb 24, 2018 12:26 pm

John in CR wrote:
Feb 24, 2018 7:54 am
Don't even consider putting craptastic cheap RC lipo batteries in a boat. Use only safe chemistry batteries. A fire that can't be extinguished is a bad thing on a boat, especially a boat that is almost 100% flammable. I assume you aren't racing a shipping container. There are much better and safer battery options for your needs that are less costly too.

Why such a low voltage?
Thanks John.
The voltage is what boat stuff runs on:
Blower, autopilot, nav lights, sat phone, nav equipment, depth sounder, search light, VHF radio, etc.
My draw is low but continuous.
I spent years with the Coast Guard in search and rescue and am more than well aware of the concern of fire at sea, especially in an epoxy/polystyrene boat in one of the most remote, isolated, inhospitably challenging areas of the world, my backyard.
The battery was to be in a sealed, steel cylinder lined with drywall and vented, through a pressure release valve, outside.
This is embedded in a remote, sacrificial area of the boat.
I was considering packing the container with fire suppressant powder but may opt for CO2 instead.
My understanding is that fire is unlikely but catastrophic if it occurs.
The heat produced is the main issue. I believe my plan mitigates that as best as possible.
What battery would you suggest?
Thanks.

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Re: Small Solar Proposal

Post by Drunkskunk » Feb 24, 2018 4:44 pm

BlueBell wrote:
Feb 23, 2018 7:23 pm
Okay, thanks DS.
Even at twice the cost?
If I had to rely on them, then Yes. For puttering around in an RC vehicle, the Turnegy are fine. If my safety was on the line, or if I had invested a lot of money in something like a race boat and planned on winning, and wanted reliable safe equipment, then I would pay for the best I could get.
But it doesn't have to be that much more expensive. Sanyo 2900ma have almost 50% more capacity, so twice the cost more per cell (of the 50% off sale price of those turnegy) only means 50% more cost per equivalent capacity.
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Re: Small Solar Proposal

Post by Punx0r » Feb 24, 2018 5:44 pm

BlueBell wrote:
Feb 24, 2018 12:26 pm
My understanding is that fire is unlikely but catastrophic if it occurs.
Unfortunately for RC lipo packs it is not that unlikely. The quality control on these packs is spotty at best so can suffer internal faults, but they are also have poor mechanical protection, so being tossed around at sea could result in cells chaffing through. Any saltwater ingress would also be wicked straight into the packs and wet the connections between cells where you can't dry it.

Good quality 18650 can cells, like the Sanyos, are similar chemistry to the the RC packs but are much better protected and much, much more reliable, but I'd question whether you really want to build a pack this big. It's a lot of work and the resulting construction can introduce a load of potential failure modes if you're not meticulous.

I'd say check out Nissan Leaf modules as they're OEM quality high capacity cells in a metal can but they're 2S so 7.2V 58Ah so probably no good for your 12V system (unless you'd consider a dc-dc converter [it's another thing to fail though]).

I would consider prismatic LiFePO4 cells. These are lower voltage and less energy dense, but the chemistry is inherently much safer and even a serious fault shouldn't result in a fire and 4S gives a genuine 12V. They come in high capacities in a plastic case with simple stud terminals, very much like a lead-acid battery. You might only need 4S1P with simple wire connections to join them up. You'd need some recommendations for a decent manufacturer though as there are some poor quality ones about.

Your pack construction sounds sensible and well though-out. Possibly overkill if anything if you use LiFePO4. If it can be accommodated in the boat, maybe consider splitting the pack into to physically separated parts? That way if the worst happens and you have a battery fire/internal short/failure you can disconnect that and still power your necessary kit from the remaining half.

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Re: Small Solar Proposal

Post by Hillhater » Feb 24, 2018 7:56 pm

You need to be sure that 3P of those cells will keep your equipment happy.
By the time you have 50% discharge , you will be down to near 9 volts, and running the pack down to low capacity will definitely be in the 8 volts range .
Some of your instruments etc may not work at all, or lose accuracy.
Most 18650 pack fires are from build faults, charging errors, wiring faults, and human error...rather than cell defects. Assembling and completing a safe , secure , well engineererd , reliable , pack is not easy quick or cheap.
Why not go safe, and simple, with something like this 12 v, 100 ah , deep cycle LIFEPO4 , for $1200 ?
http://www.batteriesdirect.com.au/mobil ... 2-100.html
Likely cheaper elsewhere..?
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Re: Small Solar Proposal

Post by John in CR » Feb 24, 2018 10:00 pm

Lifepo4 for a real 12V, which 3s of lipo is not. I'd imagine all those electronics will work on up to 24V, since that's also a common marine voltage. If slightly more than 12V works, then 4s using automotive batteries is the way to go. Get the energy density equivalent to RC lipo, but in a properly engineered pack format with a battery chemistry that won't go into thermal runaway. Then all you have to do is make it waterproof and secure it properly, so that's weight savings over RC lipo in a steel can plan.

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Re: Small Solar Proposal

Post by BlueBell » Feb 24, 2018 10:44 pm

Drunkskunk wrote:
Feb 24, 2018 4:44 pm
BlueBell wrote:
Feb 23, 2018 7:23 pm
Okay, thanks DS.
Even at twice the cost?
If I had to rely on them, then Yes. For puttering around in an RC vehicle, the Turnegy are fine. If my safety was on the line, or if I had invested a lot of money in something like a race boat and planned on winning, and wanted reliable safe equipment, then I would pay for the best I could get.
But it doesn't have to be that much more expensive. Sanyo 2900ma have almost 50% more capacity, so twice the cost more per cell (of the 50% off sale price of those turnegy) only means 50% more cost per equivalent capacity.
Thank you.

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Re: Small Solar Proposal

Post by BlueBell » Feb 24, 2018 11:05 pm

John in CR wrote:
Feb 24, 2018 10:00 pm
Lifepo4 for a real 12V, which 3s of lipo is not. I'd imagine all those electronics will work on up to 24V, since that's also a common marine voltage. If slightly more than 12V works, then 4s using automotive batteries is the way to go. Get the energy density equivalent to RC lipo, but in a properly engineered pack format with a battery chemistry that won't go into thermal runaway. Then all you have to do is make it waterproof and secure it properly, so that's weight savings over RC lipo in a steel can plan.
Thanks John, I like the idea of that.
New?

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Re: Small Solar Proposal

Post by BlueBell » Feb 24, 2018 11:13 pm

Hillhater wrote:
Feb 24, 2018 7:56 pm
You need to be sure that 3P of those cells will keep your equipment happy.
By the time you have 50% discharge , you will be down to near 9 volts, and running the pack down to low capacity will definitely be in the 8 volts range .
Some of your instruments etc may not work at all, or lose accuracy.
Most 18650 pack fires are from build faults, charging errors, wiring faults, and human error...rather than cell defects. Assembling and completing a safe , secure , well engineererd , reliable , pack is not easy quick or cheap.
Why not go safe, and simple, with something like this 12 v, 100 ah , deep cycle LIFEPO4 , for $1200 ?
http://www.batteriesdirect.com.au/mobil ... 2-100.html
Likely cheaper elsewhere..?
Thank you.
Not only double the price, but double the weight, and HUGE.
I understand and appreciate all your points.
I'm trying not to shoot the messenger here.
Perhaps I'll consider a 50 ah to trial.
If need be, I'll get a second one.

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Re: Small Solar Proposal

Post by BlueBell » Feb 24, 2018 11:21 pm

Punx0r wrote:
Feb 24, 2018 5:44 pm
BlueBell wrote:
Feb 24, 2018 12:26 pm
My understanding is that fire is unlikely but catastrophic if it occurs.
Unfortunately for RC lipo packs it is not that unlikely. The quality control on these packs is spotty at best so can suffer internal faults, but they are also have poor mechanical protection, so being tossed around at sea could result in cells chaffing through. Any saltwater ingress would also be wicked straight into the packs and wet the connections between cells where you can't dry it.

Good quality 18650 can cells, like the Sanyos, are similar chemistry to the the RC packs but are much better protected and much, much more reliable, but I'd question whether you really want to build a pack this big. It's a lot of work and the resulting construction can introduce a load of potential failure modes if you're not meticulous.

I'd say check out Nissan Leaf modules as they're OEM quality high capacity cells in a metal can but they're 2S so 7.2V 58Ah so probably no good for your 12V system (unless you'd consider a dc-dc converter [it's another thing to fail though]).

I would consider prismatic LiFePO4 cells. These are lower voltage and less energy dense, but the chemistry is inherently much safer and even a serious fault shouldn't result in a fire and 4S gives a genuine 12V. They come in high capacities in a plastic case with simple stud terminals, very much like a lead-acid battery. You might only need 4S1P with simple wire connections to join them up. You'd need some recommendations for a decent manufacturer though as there are some poor quality ones about.

Your pack construction sounds sensible and well though-out. Possibly overkill if anything if you use LiFePO4. If it can be accommodated in the boat, maybe consider splitting the pack into to physically separated parts? That way if the worst happens and you have a battery fire/internal short/failure you can disconnect that and still power your necessary kit from the remaining half.
Thank you.

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Re: Small Solar Proposal

Post by BlueBell » Feb 24, 2018 11:34 pm

Lifepo4 sounds preferred but the size, weight and cost are crippling.
Double the weight and a big rectangular block to embed in my monocoque skinny boat is challenging.
Perhaps two 1/2 sized would be more doable. I could also wire them separately for redundancy.
During sea-trials I may find my electrical needs are not as high and I can get by with 3 panels and a 50 ah battery.

Any comment on the accessories, charger/controller?

Thanks

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Re: Small Solar Proposal

Post by BlueBell » Feb 25, 2018 2:40 pm

BlueBell wrote:
Feb 23, 2018 4:34 pm
Okay, if I configure 126 Turnigy 18650 2000mAh 3.7V Rechargeable Li-Ion Batteries,
in 3s46p for 84Ah at 11.1V,
draw them down at 4 - 5 amps continuously, 24/7,
could I charge them through a
ALLPOWERS 20A Solar Charge Controller Solar Panel Battery Intelligent Regulator with USB Port Display 12V/24V,
and 3 Solar Panel ALLPOWERS 100W 18V 12V Bendable SunPower Solar Panel 5.5A max output, Water/ Shock/ Dust Resistant?


This is for a motorless, racing sailboat.
The race is in June at the 50th parallel north.
New construction and considering to purchase the above arrangement.
Max draw is 10 amps but highly unusual, and at worst, intermittent.
Avg draw 3 - 5 amps, 24/7.

Thanks for any feedback before I go ahead and purchase the above.
It was this part (in blue) of my original post I was looking for feedback on.
Thanks

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Re: Small Solar Proposal

Post by John in CR » Feb 26, 2018 2:46 am

Back things up a bit. What could be drawing 3 to 5 amps continuously 24/7 on a sailboat? What power hungry electronic equipment is aboard that needs to be on all the time?

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Re: Small Solar Proposal

Post by BlueBell » Feb 26, 2018 1:11 pm

John in CR wrote:
Feb 26, 2018 2:46 am
Back things up a bit. What could be drawing 3 to 5 amps continuously 24/7 on a sailboat? What power hungry electronic equipment is aboard that needs to be on all the time?
Thanks John,

So, this is a race, single-handed, duration 2 - 4 days, in a very small, enclosed, purpose built boat.
Total weight, racing, 500 pounds (225kg).
Think of it as a boat you wear.
The cockpit is similar to a fighter-jet, including five-point seatbelts.
It is a kite boat, very unconventional, so through any stereotypes you may have out the window.
Because it is enclosed, there is a 2 amp blower, on a rheostat, it may be on full time or the forced air intake may suffice.
VHF radio draws 40 mA on stand-by, 1 amp on receive and 5 amps on transmit. Average 0.5 - 1.0 amps.
Auto-pilot 0.5 - 2 amps depending how much work (course corrections) it has to do.
Nav lights 0.3 amps
Nav equipment (small chartplotter) 1 amp
Cabin LED's 0.75 amps on a dimmer
Depth sounder 1 amp but it won't be on all the time
Deck lights 0.5 amp but off most of the time
Sat and cell phone charging 0.5 amps
Search-light 2 amps but off most of the time

So, 3 - 5 amps continuous I figure, 13 amps max.

I did some research and I'm now thinking Lifepo4 12v 75ah
three panels 100w each.

The race is in mid June, around 50 degrees latitude north.

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Re: Small Solar Proposal

Post by BlueBell » Feb 26, 2018 4:21 pm

John, just realized I didn't really answer your question.

Navigation at 1 amp will be on all the time.

The 2 amp blower could be on full time depending.
On a rheostat I could dial it down once the canopy/window fog clears.

If the VHF radio is busy (monitoring 3 - 5 channels) could be up to 1 amp

Based on the above and the prior list, I estimated 3 - 5 amps constant draw as an average.

Not sure why you're asking, I've done my homework.
Any opinion of the panels and charger/controller I'm considering buying?

Thanks

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Re: Small Solar Proposal

Post by Hillhater » Feb 26, 2018 6:16 pm

BlueBell wrote:
Feb 24, 2018 11:34 pm
Lifepo4 sounds preferred but the size, weight and cost are crippling.
Double the weight and a big rectangular block to embed in my monocoque skinny boat is challenging..
Have you actually costed your 18650 pack, (branded cells) with protection, extinguisher, container etc ?
Ditto its weight and size in completed form ?
Have you confirmed that voltage range (9-11v) is acceptable ?
..i suspect you will find the real differences in size , weight and cost , are not as big as you imagine .
Even less so if you actually need 12 v and 100Ah.
This forum owes its existence to Justin of ebikes.ca

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Re: Small Solar Proposal

Post by BlueBell » Feb 26, 2018 11:33 pm

Hillhater wrote:
Feb 26, 2018 6:16 pm
BlueBell wrote:
Feb 24, 2018 11:34 pm
Lifepo4 sounds preferred but the size, weight and cost are crippling.
Double the weight and a big rectangular block to embed in my monocoque skinny boat is challenging..
Have you actually costed your 18650 pack, (branded cells) with protection, extinguisher, container etc ?
Ditto its weight and size in completed form ?
Have you confirmed that voltage range (9-11v) is acceptable ?
..i suspect you will find the real differences in size , weight and cost , are not as big as you imagine .
Even less so if you actually need 12 v and 100Ah.
Costed, you mean I have to pay for them????
Really, complete weight AND size, you're a stickler for detail.
Voltage, really, it matters?
Yes, incredibly I have done all that, and yes, there really are differences, just like I said.
Really.

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Re: Small Solar Proposal

Post by dogman dan » Feb 27, 2018 8:44 am

Somehow, I got the idea this was a remote controlled boat. With a person aboard, if possible go with the safest chemistry you can, lifepo4.

If you do need to go a smaller and lighter chemistry, just get the battery modules from a very high quality source. $$$

It could be possible to get true 12v by doing a 4s pack, then voltage convert to steady 13v. ( like a 12v lead battery full)
The battery can be smaller in AH, not larger in size or weight. Just same size in watt hours.

Example. 10 ah of 4.2v is 42 watt hours. 5 ah of 8.4v is also 42 watt hours. Both could be the same number of 18650 cells.

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