Word to the wise...the battery is being charged all day long, everyday under the hot sun so you can have something for the weekend.
Check under the battery caps to MAKE SURE your not boiling the water away. [ breaking down the H20 with electricity into gases ] This lowers the water level in the cells exposing the plates to air, which must be kept wet. I did this back in 2010. Trashed a good battery by exposing the plates to air. She was making about 8 to 9 volts with what was left of the chemical reaction's ability after being over cooked. The solar cell was making about 18 volts DC and about 300 milliamps. Unregulated.
Note: A battery does not 'Store a Thing', even though some call it a storage battery. It's a instant chemical reaction that occurs when a circuit is completed. And far more energy is needed to replenish the battery than was ever used from the battery. Save every electron you can.
I'm using one 75 amp hour deep cycle battery and monitoring the water on my CP-19 as the solar cell continues to trickle charge and cook my battery.
skip.
We've talked about this before. You need a charge controller to limit damage. Much cheaper than new batteries and a whole lot safer. Do yourself a favor and get one
http://www.emarineinc.com/products/SunGuard-SG4.5--4.5A%7B47%7D12V-charge-controller.html
and even a few dollars less on Amazon. This is for a full PWM controller, not just a diverter.
Shawn
I quit using a solar charger altogether after much web research about the potential damage to batteries. Since I mostly just use my depth sounder, plus GPS occasionally when I'm at the coast, I get many daysails from a full charge on my 225 Ah battery. I've installed a smart on board charger and just plug it into dock power every few weeks. A couple of hours of charging takes care of it.
Wes
A good source for solar panels is wholesalesolar.com. Thats where I got my 135 watt kyocera panel, also genasun.com sells great MPPT charge controllers thats are more efficiant than the competition. Ive got this setup with a victron energy battery monitor so I can see exactly whats getting used. This setup is alot bigger than currently being discused but the rules are still the same. When staying on the boat we have the refrigeration running, 12v box fan to help keep comfortable running all night while sleeping, watching movies on the tv, anchor light and other cabin light usage and will use anywhere from 25 to 35ah through the evening and night. My batteries are usually fully charged by 11am unless there is total cloud cover. Even with cloud cover I dont have to worry a bit about having enough power, during the day in south FL on vacation it was raining every afternoon so when we would leave the boat the only open spot was the companionway. I would leave the box fan running to get that cooler outside air in the boat just in case it rained which it usually did. If we spend a month in the bahamas in a couple years I may put a watermaker on the boat as well and run it during the peak hours of the day when there is more than ample extra power not being used to keep the water tank full and not have to be so anal about water usage. Other than vacations on the boat the club where shes docked the rest of the time doesnt have power so its nice to have cold drinks on the boat at all times and not have to worry. To think how far solar energy has come and its only getting better, and cheaper to.
"A good source for solar panels is wholesalesolar.com. Thats where I got my 135 watt kyocera panel"
Wow, that is a good price on that panel. How do you have the 135 mounted?
I have the Kyocera 40w panel on my companionway hatch with a Sunkeeper charge controller.
Shawn
Its on top of my bimini behind the split backstay to get maximum unshaded sun. I may fabricate some a new davit setup off the stern for the dingy, If I do it I will relocate the panel on top of the davits. Id like them to be a good height but still be under 13.6ft from the road while on the trailer.
So I took some readings after work from the solar cell working on my boat yesterday.
Battery charge was 12.46 to 12.47 volts with solar panel hooked up. Of course I'm reading battery voltage as the solar cell is diode protected. Juice running from solar cell to battery and not from battery to solar cell. The reading was taken down stream of the diode pak.
When disconnected the solar cell was making 15.79 to 15.80 volts D/C.
And the solar cell was making 0.01 amps. Which is a higher amp reading than I expected. [I was looking for 300 miliamps].
The cell mounts on cane tips, for air circulation under it, right over the forward hatch on my CP-19.
I wounder if this is worth it?
skip.
Skip - 300 mA is 0.3 amps. Your actual reading of 0.01 amps is 10 mA, so was much lower than expected. Assume you put the ammeter in series with the battery and charger circuit so current could continue to flow.
Wes
I was surprised to find that my batteries in my last boat would need distilled water every 3 or four weeks. Was not savvy enough to put a controllers on them (two panels). I do now!!! I have a switch where I can switch the panel back and forth from starting to house and they get switched every couple of days. I have one panel for the battery mounted up front on the cabin roof for the windless (isolated from other the other two batteries) and only plug it in for a few days after I use the windless. It is mounted on the starboard side in a battery box under the vburth. One other thing I found noteworthy was the voltage output from the two different brand controllers I use was that they vary on output voltage by up to.4 to .5 volts. One does 12.8 volts and the other one does about 13.2. Don't know why, I switched the panels and got the same numbers so it is not the panel. One came from West Marine (small yellow box) and the other one came from Defender (rectangular blue box). I would have to go put a meter on them to see which one was which. Like the other posts said KEEP THEM FULL OF WATER, I keep a two quart bottle of distilled water (three batteries to monitor) on the boat. I actually disconnected the on board charger when I cleaned up some wiring issues in the engine compartment this season. The panels work out so well I don't need it, I am in a slip but the panels work fine for me.
"One does 12.8 volts and the other one does about 13.2. Don't know why,"
May simply just be where they have their float voltage set to. Can you adjust the controls for the type of chemistry in the battery? That should change the charge and float voltages.
Shawn
There is your problem skip. 15.7 volt output is too much. Amps are fine but volts are too high.
Each type of battery (lead acid, AGM, Lithion Ion, LiFe, etc) all require different charge rates. Thus why the charge controller needs to be either made for the battery type or can sense and adapt to the type of battery installed.
It's likely you need around 13.7 volts for your lead acid battery..and no more than this... as a charging rate. Less..probably 13.1 or so as the battery reaches close to capacity, then about 12.7v or so to float/maintain it. Most modern charges do exactly this. Note these figures are from memory so may be off a bit. Driving a constant (during daylight hours) 15.7 volts is the reason for the battery cooking.
Yep, a charge controller is indeed wise to have if you're charging onboard with solar, drag prop, wind prop, etc.
I just carry my battery home every 2-3 months to charge it. LED nav and cabin lighting, and the occasional cell phone charging just don't draw much power. then it sits on the battery tender all winter long.
Reminds that I need to check the voltage of the battery to make sure I shoulnd't be charging it more frequently.
" It's likely you need around 13.7 volts for your lead acid battery..and no more than this... as a charging rate. Less..probably 13.1 or so as the battery reaches close to capacity, then about 12.7v or so to float/maintain it. Most modern charges do exactly this. Note these figures are from memory so may be off a bit. Driving a constant (during daylight hours) 15.7 volts is the reason for the battery cooking. "
That cooks it! Dab nab it all anyway. No solar cell for me. Off she comes. I ain't got the $20+ bucks to spend controlling the volts on my boat.
skip. And thank you very much again...I'm just dumb as a box of rocks.
Skip--On the contrary my friend...you may not know batteries but your knowledge in other areas more than makes up for it. 8)
Salty and Skip -
Skip reported the 15.7 volt measurement at the output of the solar cell, with no battery connected. This is an open circuit measurement and I would not consider it reliable. All voltage sources will tend to float high when they are unloaded. With the battery load connected, he measured less than 13 volts which seems normal to me.
Wes
Also voltage output has to do with angle of the panel to the sun, the suns strength and any shadows. Panels are usually rated upon a 5 hour day of direct sunlight. Its not uncommon for a panel to put out more than spec voltage at peak times, this is when the better charge controllers come into play. Cheaper controllers may simply bleed off this extra power as heat, where as a more advanced controller will take this extra power at peak time and use it as amps to be more efficiant. Are the two panel voltage readings comeing from identical panels? If not that would be good reason for differant readings as well. Also if there is a shadow from something as this as a stainless shroud it can cut down power output drasically, just because a shadow may cover 2% of panel output may be cut by way more. Reason is many 1.5 volt cells are in series to make up say a max of 15volt output. Remember old Christmas tree light strings that had bulbs in series, one goes out and the whole string of lights goes out, its the same thing with that string of solar cells. so if you cast a shadow and cancel out two out of ten strings of cells that little shadow just coste you 20% of the output. This is why alot of boats have their cells on top of a bimini behind the aft shroud or spanning their davits to be in the least likely getting a shadow. Youll notice some people put their panels on the coachroof under the boom, not a good location.
"Youll notice some people put their panels on the coachroof under the boom, not a good location."
Not optimal for sure, but it can also be the only position for a decent sized panel on a smaller boat. On a 23 you can't do behind the aft stanchions as it would block access to the outboard and interfere with the kick up rudder. No enough clearance under the boom to go above the bimini. Not enough room in front of the mast to go bigger than about a 10 or 15w panel. Putting a 40w panel in a position that will be shaded sometimes is much better than not having the panel IMO.
Shawn
Good point, Im actually not very crazy about on top of the bimini but I dont have davits yet to mount it on yet.
Quote from: Wes on August 01, 2012, 07:17:02 PM
Salty and Skip -
Skip reported the 15.7 volt measurement at the output of the solar cell, with no battery connected. This is an open circuit measurement and I would not consider it reliable. All voltage sources will tend to float high when they are unloaded. With the battery load connected, he measured less than 13 volts which seems normal to me.
Wes
I'll buy the fact that the solar voltage will run high unloaded, but would it drop from 15's to mid 12's with the battery load? No way unless the battery has very high resistance.
A measured 12.46 volts is actually low for a lead acid battery that is supposedly fully charged, indicating roughly 75-77% charged. This is almost certainly caused by internal resistance in the battery..typically sulfation is the culprit (or a bad cell, but voltage would drop considerably less than 12.46). A frequent cause of sulfation is exposure of the internal plates to air (ie lack of water/acid). Add the fact that just after charging, the battery state is "excited" so the voltage runs higher than steady state operation for a short period. A fully charged lead acid battery voltage reading taken just after removing from a charger should be 12.8--12.9 or so..perhaps up to 13.1 depending on the charger output and the battery specs--but the reading should drop after a few minutes continuing over the course of a day or so down to 12.7 or darn close. If it reads anything less than this, it's not fully charged and probably will never be able to gain full charge again (assuming that even with a real charger the reading is the same).
With the solar charger on the battery, one would expect to see more than steady state battery voltage but less than unloaded charger voltage.
Seeing 12.4 volts on a battery with the charger attached tells me it will be lower without the charger (assuming all is working OK). Normal is 12.7 or darn close..anything less and it's not fully charged.
Skip try measuring your voltage after an hour of no solar charging. This will remove the surface charge which is the reading you've collected (artifically high due to surface charge). Betcha voltage drops from 12.46 to, well, somewhere quite a bit lower. If it hits 12.2, you're at 50% charge. 12.0 volts...25% charge. 11.9...it's darn near toast. That means your battery cannot charge beyond that percentage of total capacity-or that simply the battery wasn't fully charged from solar when you disconnected it. I'll guess the former since it's boiled away water due to excess charging voltage in the past. I'm really curious to know what you find out.
The amp reading on the charger is weird. Then again you are in northern WI..the sun angle would be lower. Could have a bad cell too.
Note the voltage figures here are for a lead acid battery. AGM's run higher charging and steady state voltage as a general rule. I'm sure there are exceptions here from one brand/model to the next.
That is odd, do you have another battery that the panel can be hooked up to, so those readings can be compared. Could be a bad cell. Even though there are mathmatics for electricity and DC is pretty easy and straitforward it still does some cooky things.
Interesting discussion, lots of good info. I had to replace both the house and start batteries this year. They both lasted seven years, and I'm told that is pretty good. I've never used solar, have a Guest 5/5 charger and leave the boat plugged in with the charger on when at dock. Batteries have always managed through a 4 day cruise, the longest I've done, by just using the motor when necessary. Replaced maintenance free flooded lead acid with the same. Long discussion on the TSBB some time ago concluded that my use/charge profile indicated that was the best bang for my buck and that AGM would not pay back for the extra cost. I don't know if that is true but it sounded reasonable at the time.
Quote from: Shawn on August 01, 2012, 08:37:20 PM
"Youll notice some people put their panels on the coachroof under the boom, not a good location."
Not optimal for sure, but it can also be the only position for a decent sized panel on a smaller boat. On a 23 you can't do behind the aft stanchions as it would block access to the outboard and interfere with the kick up rudder. No enough clearance under the boom to go above the bimini. Not enough room in front of the mast to go bigger than about a 10 or 15w panel. Putting a 40w panel in a position that will be shaded sometimes is much better than not having the panel IMO.
Shawn
I have a 135 watt Kyocera panel mounted on my stern pulpit on my 23 above the outboard and have never had a problem with access to the outboard or the kickup rudder. I am running two 6 volt Trojan batteries with a charge controller and never run out of power. However this is a little overboard for my setup....all led running and cabin lights, fan, VHF, and a really loud stereo. Bought the big batteries and panel because I plan to put refrigeration on in the future.
Chris
Chris,
"and have never had a problem with access to the outboard or the kickup rudder. "
Do you have the factory rudder or the Ida Sailor Rudder which comes up vertically? Any pictures of your install? When I was planning it out it looked like anything back there would totally block the outboard as I work over the rail to get to the outboard.
Sounds like your setup is much bigger than needed but refrigeration will change that. My 40w panel drives all LED cabin and nav lights, chartplotter, windmeter, VHF and an autopilot fine with just one group 27 battery. I just added a fan but haven't use it much yet.
Shawn
Chris,
Do you have room in the boat for a big cooler? My refrigeration is a Dometic 33qt refrigerated cooler/freezer and it works great. Im my 27 its on the floor lengthwise with the boat against the forward bulkhead where I have a 12v outlet. To keep it from moving I just have a non slip mat under it and it never moved even while in some rather choppy waves i the gulf, lots of other stuff went flying though! I like this and use the ice box as dry storage mostly for canned goods. The cooler is expensive for a cooler but cheaper and much easier than a coldplate in the box. Ive had both and Id call it an even draw between the two setups. On my old boat with a coldplate I had to replace a little circuitboard once and that sucker was almost 500 dollars, ouch!
For batteries I have two optima blue tops only because they came with the boat and are pretty new. A great battery bank for the buck are 6volt golf cart batteries. Sams club has the best price Ive seen so far and they can take a beating. Look at how many people run golf carts untill they havnt anything left. On a previous boat I had a bank of 4 of these. I was living aboard and with the TV, stereo, lights, refrigeration, ect I had power for 8 days untill the volt meter read 12 volts. 4 of these is overkill in most boats but a friend has 2 wired to make 12 volts and does fine. It is good to check their water levels about once every 6 months.
Wow! You skippers have more electricity and ancillary stuff on board than you have 'boat'.
lol skip.