Most interesting to your correspondent is the use of LiFePO4 batteries - this is the first time these have appeared on Small Boat Projects. I think we are seeing the future here.
The biggest project during the winter 2011/spring 2012, and therefore subject to its own entry, was the electrical system upgrade. As indicated by overnight anchorages in 2011, one of the two Optima Yellow Top house batteries had failed. Further, the two, at least 10yr old, 60watt solar panels weren't doing anything.
With any change, one must ask to what end - what is the change to achieve? The goal for the electrical system upgrades was to get at least 4 days on the hook without needing to recharge the batteries via engine or shore power. Why 4 days? 4 days are probably how long Strider's fresh water supply will hold out!
Major Component Overview:4 CALB 180Ah LiFePO4 Batteries with mini BMS
6 Aurinco solar panels: 2x Compact 100; 2x Bluewater 25; 2x Compact 25
2 Genasun GV-10 MPPT controllers
LED Lighting Throughout
MasterVolt ChargeMaster 12-25-3, MasterVolt MasterViewEasyMkII, MasterVolt MasterShunt, MasterVolt MasterDistro 500, MasterVolt MasterBus USB
What is the consumption?To design an electrical system properly, one must first know the consumption, or what one uses. Every electrical item aboard must be taken into account: Refrigerator, lights, radio, pumps (anchor wash down, bilge, galley, shower and head faucets), navigation instruments, hair dryer, fans, stove, windlasses, bow thruster. Everything. When Strider's systems were examined, stem to stern, I erred on the side of caution and rounded everything up, overestimating the consumption: Summer worst case of 40Ah per day. Winter, using the furnace and probably the stove more, would increase consumption.
Second, one has to know how long they want to go between charging. Since 4 days between charging was the goal, 40Ah x 4 days = 160Ah, the working number. Batteries able to handle 160Ah loss need to be purchased.
LiFePO4My mentor Steve, of the Dragonfly 1000 Flexible Flyer, turned me on to LiFePO4 batteries. 'Standard' batteries, gel, AGM, wet and 6volt deep cycle golf cart, had been looked into. All had several drawbacks, weight and discharge capability were foremost. 'Standard' batteries are able to discharge a maximum of 50% without damage for a maximum of 500 cycles. Going by the goal of 4 days on the hook and 160Ah consumed, batteries of at least 320Ah were required.
Looking at the 6volt batteries available, two 370Ah would do the trick. However, while the could fit in the engine bay, they weigh 113lbs and cost $420 each! Alternately, assuming the solar panels could keep up with consumption, the next size down 6volt is 215Ah (107Ah, not 160Ah available), weighs 63.5lbs and costs $238. A little more reasonable, but still heavy.
Gels fitting into the original space under the step are the group 31s. Each has 97Ah, weighs 72lbs and costs $410. Two would be required for just 97Ah usable. To get to the goal's 160Ah, 4 group 31s would be required (3 would fit under the step) or move up to the 4D. The 4D has 183Ah but weighs 130lbs and costs $645. Once again, two would be required and they would have to be fitted into the engine bay.
Then Steve mentioned he was replacing his 6volt golf cart batteries with LiFePO4, a single set for both house and engine start. There are several lithium ion technologies and manufactures, from very expensive, all included, plug and play MasterVolt all the way to less expensive more basic build your own with components. LiFePO4 are stable and a great amount of power available vs cycles: 70% discharge 3000 times or 80% discharge 2000 times! Then there is the size and weight: Small and very light compared to 'standard' batteries.
CALB 180s were selected because they offered a bit more Ah vs size. Though a 400Ah version were available, 4 would not fit into the space under the stair. Further, with the solar panels selected (see below), I began to feel the 160Ah requirement was something to be flexible on. Though rated at 180Ah, they can provide 200Ah (charged above the rated 3.4 volts each). Their rated power (180Ah) available vs cycles: 126Ah @ 70% discharge or 144Ah @ 80% discharge, close to the 160Ah requirement. At 11x7x2.8in and 12.5lbs each, they total 50lbs and fit under the stair! With these, barring something catastrophic, Strider will never see another set of batteries.
BMSA word about the Battery Management System. There are BMSs available which will do everything, protect and keep the batteries balanced. I purchased a 'mini-BMS' which has 5 components, 1 monitor/battery and an overall control board wired to a solid state relay controlling the shore power charger. The BMS does no balancing, this must be done by hand (not difficult). To date, this set up works fine by shunting power across a battery when it is full and prevents the shore power charger from over charging the batteries. I'm not sure it is required for this set up, but it is an insurance policy.
Steve provided a simple circuit to tie the BMS into the refrigerator t-stat so should the BMS cut off the shore power charger, all will be reset when the refrigerator turns on. Now, how to keep them charged?
SolarWind was briefly considered, but dismissed as not practical for a Dragonfly 1000. The solar setup was based on information gleaned through the Cruisers and Sailing Forums. In particular: The rule of thumb for peak solar is 4hrs/day year around in the southern latitudes, 5hrs/day summer-time north and (inferred) 3hrs/day winter-time north.
Again, worst case is winter sunshine is 3hrs/day peak. To keep up with 40Ah/day, with zero loss, the panels needed to provide 13Ah for each of the 3hrs. 13Ah is about 180watts of panels (13Ah x 14volts = 182watts), round up and call it 200watts.
However, this is under ideal conditions: All the panels oriented in the same direction and constantly oriented to the sun. Aboard Strider, there is always shading, from lines, from sails, from the nets. For instance, if under sail and the starboard is in full sun, the port side is shaded by the sail. Further, the panels need to mounted on flat surfaces of the boat and none of them are oriented to the sun. So, while 200watts would suffice in ideal conditions, there are no ideal conditions aboard Strider. What then is required? 300watts? 400?
Aurinco panels were desired because they had a good reputation. They did not need blocking diodes to prevent electrical flow from a producing panel to a shaded panel. They are thin and light with a non-skid surface. And being somewhat flexible, they are able to bend to mount on the boat's surface. Further, they are local (Anacortes, WA).
Aurinco's panel styles helped to decide what and where to be mounted. Strider came with two, 10yr old, 60watt panels and they needed replacing. Aurinco's 100watt panels were the same size! So, two of those, one for each ama. Their location however, is covered when the amas are folded. When the amas are folded, locations left exposed included the tops of the akas and the aft end of the amas. Conveniently, Aurinco has a 25watt panel that would fit on top of the aka and a second 25watt that would fit on the aft end of the ama. With this set up, I'd have 100watts exposed folded (7Ah max ideal) and 300watts extended (21Ah max ideal). Remember: There is no ideal aboard Strider, but I thought all in all, 300watts could cover our consumption.
To date, I've been very happy with the panels. One needed to be replaced as water intruded via the output wires and caused corrosion/delamination. Aurinco was very accommodating. For further discussion, there is a results section below.
Solar Panel Arrangement.The large 100 watt panels on the ama are covered when Strider is folded.
The small panel on the ama sterns are 25 watt.
25 watt panels are on the aft akas.
MPPTA controller is required to regulate the nominal 18-21volt solar panel output to something the batteries can handle. The latest technology is Maximum Power Point Tracking (MPPT), a technology some claim to increase useful solar output 20-30%. Practical experiments at Aurinco showed a more modest 10% increase.
The entire system was split into port and starboard, two systems of 150watts each, for redundancy. A no bells or whistles MPPT by Genasun was selected for each side. Genasun GV-10 can handle 10.5amps and claim a 98.3% efficiency with .9mA night time consumption. Because CALB LiFePO4 batteries had been selected (see above), the GV-10s were programed for a 13.8volt charge to protect the batteries from a potential overcharge. Later, I found out the GV-10 came with a 13.8volt float voltage, this alone woulda/coulda protected the batteries.
Why 13.8volt charge? Though a Battery Management System was purchased with the batteries, I was unsure the BMS did anything except shunt power across a battery once it is charged and shut off a shore power charger to prevent an overcharge. So, 13.8 is derived from the CALB charge chart showing each battery is charged to maximum capacity at 3.4volts. 3.4v/battery x 4 batteries = 13.6volts. .05volts/battery is required to overcome internal resistance. .05 x 4 = .2volts. 13.6 + .2 = 13.8volts. Unknown to me, there was a conversation between my supplier and Genasun at my 'unusual' voltage request of 13.8. According to Genasun, CALB normally requires 14.2volts. Would this have changed anything? Not likely, I wanted to protect the batteries...period. For results, see below.
LED LightingLEDs were not a part of the original consumption calculation, the original halogen and incandescent were. But opportunity presented itself and with the exception of 1 light in a small cupboard, all Strider's lighting was converted to LED, including the navigation lights. As a result, Strider hardly uses any electricity for lighting. Navigation lights are Dr LED via West Marine. Internal lights are Phillips 12volt LED garden lights via Home Depot. The galley overhead light was replaced with a red/white LED light fixture. The white side of the light was wired to the stock overhead light above the cook top, increasing light in the galley. The light in the head was replaced with the same fixture as the galley. The goose neck map light behind the dashboard in the cockpit was replaced with a red/white light also. Now, red light is available from the V-berth all the way to the companionway and into the cockpit making night egress easier without sacrificing night vision.
I have no direct Strider data, but an efficiency example is: Summer 2012, a buddy was having problems with his boat's electrical system and the masthead incandescent alone was using 16Ah per night. An LED was loaned and the consumption went to near zero. This same buddy said Strider's masthead light was very visible (rated at 2nm).
MonitoringStrider came with only a single output, conventional battery charger and a rudimentary monitoring system (volts only). Though there are less expensive components available, MasterVolt was selected because each component is compatible with all the others - they communicate and are programmable.
MasterVolt ChargeMaster 12-25-3. Fully programmable.
MasterVolt MasterViewEasyMkII. Monitors and allows some system programming.
MasterVolt MasterDistro 500 distributes the power to the boat systems and has 4 ports. One is connected to the stock, 65-amp alternator, one to shore charger, one to port solar and one to starboard solar. The type of fuses used in the shunt were readily available for the alternator and charger, but there were none small enough for the solar so I had to create my own.
MasterVolt MasterShunt measures and monitors flow in and out of the batteries.
MasterVolt MasterBus USB connects the system to a small notebook computer carried aboard and via the MasterVolt software, components can be programed.
SettingsThe ChargeMaster is set at 14 volts (could not go lower) and floats at 14. However, it is used only occasionally, mostly during the winter when shore power is connected and an electric heater is running on board. To date, the batteries have had no problem with this setting. When the batteries are down, the stock alternator outputs 45amps @ 14.2 but throttles back to 2amps @ 13.8 as the bank charges. Originally, the GV-10s were set at 13.8 volts (turns out this is also their float voltage). After a summer of use, the GV-10s were sent back to Genesun and reprogrammed to 14.2volts in an attempt to increase charge rate. A neutral result (see below).
ResultsSo, after thousands of dollars and millions of lives, how well does this system work? In a word: Fantastic! Spring, summer and fall, with the amas folded and only 100watts of solar panels showing, the refrigerator on, the batteries are kept charged to 100% during the day, even during overcast days. Winter in this configuration, with thick overcast and rain, the 100watts solar cannot keep up with fridge. So the fridge is shut if off and the batteries stay at 100%.
Once aboard, with amas out, there is excess power and a freezer was added. Once the freezer was dialed in, Strider uses 12-15 Ah between sun charges, including using the diesel cook top and furnace in the morning. Generally, Strider is fully charged around 11am. If there was a water maker, Strider could be on the hook forever.
The worst consumption/charging experience was before the freezer had been dialed in (originally set too cold and running too much) and anchored in a bay surrounded by trees. The panels received the morning sun around 8am but were shaded by 4pm. Additionally, due to angles and shading, the panels were not getting much exposure at all. Further, these days were hot, about 85 degrees interior temperature, so the freezer and fridge were working hard. In these conditions, the system was loosing between 10 and 15Ah per day. Still, after 4 days, Strider was only down about 45Ah. Not bad! Winter, the original worst case scenario, has not yet been fully tested.
Improvements?What would improve the system? Steve's Flexible Flyer has 320 watts solar, 240 Ah LiFePO4 batteries (different brand), super-insulated, water-cooled fridge, a water maker and has enough excess power to heat his hot water to 170 degrees via the inverter. His panels are set up more optimally and Strider will never be able to match his output without the addition of an aft arch (dinghy davit/radar/panel structure) like Flexible Flyer. Still, he has achieved up to 19amps output. The best seen aboard Strider has been 7amps...not even 50% of the solar panel potential. As mentioned the GV-10s were sent back for reprogramming from 13.8volts to 14.2volts. I'd hoped this increased voltage would increase the amp flow, but it doesn't seem to have made a difference. Next step is to move the 100watt panels to a better location, forward on the ama, just behind the hatch and less shaded by the nets. The configuration is working great as is, improving output is just something nagging.
What else? Perhaps add an inverter. But at this point, everything aboard is 12v or hand crank (blender and coffee grinder), which is fine! However, my wife goes without a hair drier (but it would be nice). Doing the hot water system like Steve does would also be nice. We've a 'bucket head' vacuum cleaner for in port, else a small broom and dust pan is used. Another addition would be a watermaker.
But all the additions mentioned are improvements to creature comforts, not system improvements.
ConclusionThe goal was at least 4 days on the hook: Achieved! The worst case to date was in Tenedos Bay in BC's Desolation Sound. Even in these conditions, 4 days was easily achieved and Strider probably could have gone 2 weeks. Anchored in wide open False Creek (Vancouver), Strider was fully charged by 11AM. So: Was consumption grossly overestimated? Perhaps, but the LEDs were not a part of the original calculation and made a huge consumption improvement.
Too much solar? Even with the niggling improvement mentioned above, the solar panels have been great also. Probably could have gone with 200watts in the normal spring/summer/fall conditions. However, the excess does allow for expansion. Winter conditions have yet to be tested.
The LiFePO4 batteries have been a huge success - maintenance and trouble free! The other systems have also been maintenance and trouble free.
Best yet, Strider never hooks up to shore power in marinas spring/summer/fall nor ever run a generator. Quiet!