Help with existing Solar setup on a boat.

Hi, I am new to solar and this forum. I have purchased a boat with solar already installed and I have some questions. After reading through many posts and reviewing my installation, I don’t believe it is setup optimally. I will list my configuration below, and hopefully I can receive some help.

5 group 27 Lifeline AGM batteries (GPL-27T) in 2 house banks (2 batteries each) and 1 starting battery.

Blue Sky 2000e controller

2 Siemens SR100 panels
Max Power - 100W
Rated Current - 5.6A
Rated Voltage - 17.7V
Short Circuit Current - 6.3A
Short Circuit Voltage - 22V

2 Kyocera LA361G51S panels
Max Power - 51W
Rated Current – 3.02A
Rated Voltage – 16.9V
Short Circuit Current – 3.25A
Short Circuit Voltage – 21.2V

The panels appear to be connected in parallel. All panels are mounted on an arch davit on the stern of the boat. There is 14 gauge wires between the panels and 10 gauge wire running to the controller. The distance to the controller from the panels is 20ft - 25ft. With the batteries at 50% discharge I have never seen more than 3 – 4 amps charging.

Bsed on other forum posts I need a different controller, a 3 stage, maybe an Outback MX-60, Blue Sky 6024H, or similar. To eliminate the need to run new wire I would connect the panels in series. Please post your thoughts and advice.

Thanks, Barry

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help with existing Solar setup on a boat.

    You can place identical panels in series. The lowest rated panel will limit the series string to it's own amp limit. So a 3 amp panel would limit a 10 amp panel to only 3 amps. The voltage would still add.

    However, if possible, on a sunny day, disconnect all panels from each other and the charge controller, and measure the amps each panel, by itself, puts out. Each should be about 70-80% of the label rating on each panel. This is the best way to find a bad panel, with a small setup. No lethal voltages involved, and each panels current is likely safely below the 10A limit of most meters.

    Also consider a wireing connection via a switch, some method of charging your starter battery, or starting off one of the aux banks. Maybe think about converting running/anchor lights to LED's that will save a lot of power if you overnight somewhere.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • System2
    System2 Posts: 6,290 admin
    Re: Help with existing Solar setup on a boat.

    Thanks for your reply. If I understand correctly if I wire the panels in series, I would only have 3 amps from all 4 panels. Would a controller, such as the MX-60, then reduce the added voltage and increase the amps?
    mike90045 wrote:

    Also consider a wiring connection via a switch, some method of charging your starter battery, or starting off one of the aux banks. Maybe think about converting running/anchor lights to LED's that will save a lot of power if you overnight somewhere.

    I should have mentioned that I have a Xantrex Pathmaker 100 automatic switch. I should be able to connect the controller to either of my battery banks and charge all batteries. I do plan in installing an LED anchor/tricolor light.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Help with existing Solar setup on a boat.

    Without knowing anything specific about the 2000e, from the data sheet it looks like a good controller for the job. It is an MPPT type controller, it has temperature compensation, equalize charging, you can set the charge voltages, and gauges to read voltage and current. The only major thing missing is a "float" setting--reduces charging voltage (and boiling of battery water) when the batteries are not going to be used for a long time.

    The solar panel wiring, as you describe, seems to be more than adequate for the job at hand. From the voltage drop calculator (Here):

    http://www.wind-sun.com/smf/index.php?topic=1477.0

    20 amps and 50 feet (25 foot run) with 10 awg wire, you should be seeing about a 6-6.8% loss in power due to wiring losses--somewhat over the 3% "rule of thumb" that is recommended by many people here (using larger awg wire is going to cost a bunch of money for very little return in power gain to go way under the 3% level). A second parallel run of 10 awg wire will get you close to the 3% loss level. (by the way, copper resistance rises as the temperature goes up--so in your case, if you are in a marine environment, you may choose a lower temperature (like 20C instead of 50C) to better represent your installation).

    For best operation of the solar charger, try to keep the leads from the solar charger to the batteries as short as possible (and large awg wire--10 awg minimum, with a good size fuse/breaker--like 20-25 amps). If the charger is too far away from the batteries (or there is too much voltage drop between the batteries and the charger), it will read the battery voltage as higher than it really is--and will tend to reduce charge currents too soon (before the batteries are full).

    One last question is how do you charge three (independent?) banks with one solar charger--If all of the banks can be tied together when charging--and the batteries are all pretty much identical in brand/model/age--it will work OK. If you are using diodes to isolate the battery banks from each other, then you will have to account for the voltage drop in the diode (between 0.2 and 1.0 volts, depending on the exact diodes used) to compensate for the controller seeing the wrong battery voltage. If you manual switch the charger between banks, that will work fine too--but it is a bit of a mess to manually manage charging. There are other options out there that might work better--you will have to let us know if you want to discuss that.

    So... Assuming that the installation was done correctly (sounds OK from here), you may have some other problems. One question I have is are the 4 panels all connected in parallel to one Blue Sky Controller (for about 20 amps of current), or are they connected in some other way?

    Like Mike typed below, you will now need to look at each component in the system to see where you may be having problems... Measuring the voltage at each major location (at each panel, at the controller input, controller output, battery harnesses, and battery posts is a good place to start. Next, disconnecting each solar panel and measuring its short circuit current in full sun light will tell you with 90% confidence if the panels are OK. Also, check all of the wiring runs. It is possible that something is not connected like you thought it was, your may have hidden loose/corroded connections/etc. somewhere.

    Got to go now...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help with existing Solar setup on a boat.
    Thanks for your reply. If I understand correctly if I wire the panels in series, I would only have 3 amps from all 4 panels. Would a controller, such as the MX-60, then reduce the added voltage and increase the amps?

    Some more ointment for the fly. If, even a small portion of any panel in series, is shaded, by even a shadow of a stay, it will usually shut down the output of the entire panel, and any others in series with it. unless your panel specificly states in it's paperwork somewhere that it has multiple bypass diodes, this will be the case. Keeping 4 panels 100% un-shaded on a sailboat, with stays and masts, will be difficult. That's likely why they are wired in parallel. Series is nicer because you can raise the volage and skimp on heavy copper wire, but 1 small shadow will shut all panel output off.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help with existing Solar setup on a boat.
    1
    Short Circuit Voltage - 22V

    2
    Short Circuit Voltage – 21.2V

    I'll bet these are actualy OPEN circuit voltages.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • System2
    System2 Posts: 6,290 admin
    Re: Help with existing Solar setup on a boat.
    mike90045 wrote:
    1
    Short Circuit Voltage - 22V

    2
    Short Circuit Voltage – 21.2V

    I'll bet these are actualy OPEN circuit voltages.

    You are correct Open circuit, that was a typo
  • System2
    System2 Posts: 6,290 admin
    Re: Help with existing Solar setup on a boat.

    Thanks BB and Mike,
    it sounds like the system is installed properly and I may have some other problem. I will at first opportunity disconnect all of the panels and test open voltage. I have seen 17V at the the PV input to the controller. My main concern is the system is a proper design. I am concerned about the controller not having float stage with AGM batteries. Based on your replies, it seems that parallel is ok with the wire size and is better because of the possibility of shading.

    BB,
    the leads from the panels run through a circuit breaker before leading to the controller, this allows me to turn off the charging. The legnth of the connection between the controller and the battery is only 10 inches, 10 awg wire. The controller connects to the battery at my battery selection switch. The battery selection is connected to the batteries through fuses. All 3 battery banks are charged by 1 controller by using the Pathmaker automatic battery switch. The pathmaker works by automatically combining multiple batteries while charging them and automatically disconnecting the starting battery from system loads when there is no active charging. All batteries are same manufacturer and age.

    Barry
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Help with existing Solar setup on a boat.

    I would have some questions about the Pathmaker...

    http://www.xantrex.com/web/id/92/docserve.asp

    In general, it sounds like a nice setup--however, each solenoid consumes between 1/2 and 1.0 amps of current... Also, from what I can read, the controller sets when each battery is connected based on the voltage of the battery (bank) that the controller is connected too...

    I would have concerns that the set points are not really based on charge levels and don't appear to be temperature compensated... Also, the unit consumes a ~1/3 amp (assuming 12 volt operation) just being connected.

    All in all, depending on the Pathmaker is setup and how much it is operated during the day--it could end up being a real energy hog (vs the amount of energy you gather with solar power)--when operating from shore or on-board generator(s), the amount of power consumed by the Pathmaker can be ignored.

    If you are using solar charging--the Pathmaker could be consuming upwards of 2 amps (depending on configuration and relays used) and if it is powered 24 hours per day, that would equal 48 amphours... And your solar system is only generating about (just using SWAG estimate) 2-5 hours * 4 amps = 8-20 amp hours per day (currently)--I would seriously study the circuitry, current consumption, and your solar panels/connections/charger to get a better handle on the situation. Admittedly, the 48 amphours per day current consumption of the Pathmaker is a worse case situation--right now, I would be surprised if your solar system was doing much more than just supplying enough power to operate the Pathmaker.

    I don't know where you live (so I don't know how much sun you receive), or if the boat is docked or moored (solar panels face south or swing with the wind) or even if this is a sailboat (lots of lines and masts to block sun). All of this will dramatically effect the amount of power the panels output... But if you have good angle to the sun (high noon, panels facing sun, no shading), you should expect somewhere around 66%-100% of the rated current of the panels (if the panels are in parallel, then the current for each panel should just add).

    17 VDC at the solar controller's input sounds about right (cool day--max rated power voltage was 16.9-17.7 volts @77F from your specs.).

    I would have suggested that the circuit breakers go between the Solar Charge Controller and the battery bank (so you could disconnect the solar controller if anything went wrong--there is very little chance of any current surges from the solar panel wires ever tripping the circuit breakers because the solar panels are already current/power limited and isolated from the batteries by the solar charge controller). But, at this point, I would not change the location of the circuit breaker unless you are already working in the area.

    Also, you cannot place any of these panels in series with the Blue Sky controller--max voltage is only 30 VDC (open circuit)--you would need a different controller (like the Outback MX-60) for that... If you do place the panels in series, you need to make sure that each panel in series is connected to its mate with the same current rating (current will be limited to about the current of the lowest rated panel). When connecting panels in parallel, you will want to make sure that they (or the series strings) have about the same voltage rating (voltage will be about at the lowest rated voltage of the sets).

    Wind-Sun (moderator here) was recommending connecting one set of solar panels to multiple charge controllers (one panel bank connected to the inputs of three charge controllers connected to three battery banks) as a good way to share the solar energy across multiple independent battery banks. This would be a good method to get around your current/power losses introduced by the Pathmaker (I would leave the Pathmaker off unless I was on shore power or using the engine(s) and figure out another method to charge multiple battery banks with solar).

    As always, if you choose to parallel three solar charge controllers with one set of panels, confirm with Wind-Sun that this is appropriate for the model of solar chargers that you would be using (I am not the expert in that--so I cannot safely confirm any particular controller is OK to do that with--although Wind-Sun and said earlier that most controllers are OK to do that with).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Help with existing Solar setup on a boat.

    Bill, again thanks your time.

    I am the 2nd owner of this boat and I am still trying to learn the systems. Everything on this boat was already installed when I bought the boat. I will spend more time on the pathfinder and how it is setup. The boat is currently in N.E. FL. and it spends most of the time at dock, except for some day sails and overnight anchoring. In a few months we will be leaving the docks for good and will only occasionally be connected to shore power. I would like to be able to run a week or 2 off solar (longer would be better) without running the engine to recharge. I know I still have to calculate my daily amphour requirements. Most of the measuring I have done with the solar is the 11 am to the 1 pm time frame and the way my boat is tied to the docks (facing SW) I have no shadowing at that time. Testing at this time, with the outside temp about 70, how low would my battery voltage need to be before I see amp output higher that 4 amps? In the current parallel setup with optimal voltage should I see output as high as 12-15 amps? I am just looking at the LCD screen on the controller for output.

    I am not overly concerned with keeping the starting battery charged by solar, so I could just parallel 2 controllers for the house banks. You have given me some very good information and some good places to start.


    Barry

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Help with existing Solar setup on a boat.

    Good Evening Barry,

    From the 2000E owners manual:

    http://www.blueskyenergyinc.com/pdf/ManualRVPPSB2KErevE.pdf
    Bulk Charge

    Solar Boost 2000E will be in the bulk charge stage when the battery is at a low state of charge, typically less
    than 90% full. Solar Boost 2000E delivers as much charge current as possible during bulk to recharge the battery as
    rapidly as possible. Maximum charge current varies with the number and size of solar panels installed, available
    solar energy, and operation of the proprietary MPPT current boosting system. Battery voltage increases as the
    battery recovers charge in the bulk stage. When the battery recovers sufficient charge for battery voltage to reach the
    charge voltage setpoint, the system switches to the constant voltage stage. During the bulk charge stage, the Charge
    Status LED will be on continuously.

    Constant Voltage Charge

    Once the battery becomes more than approximately 90% charged, the system changes to a constant voltage
    mode and the Charge Status LED blinks. The charge voltage setpoint is factory calibrated to approximately 14.0 volts.
    While charge voltage is held constant, charge current slowly decreases as the last 10% or so of battery capacity is
    restored. If there was no DC load on the system, output current from Solar Boost 2000E would eventually drop to
    approximately the battery amp-hour rating divided by 500, or approximately 0.5 amps for a 230 amp-hour battery.
    The precision PWM voltage control method provided by Solar Boost 2000E prevents over charge while maintaining
    a more fully charged battery.

    So, basically, if the battery voltage reads less than the charge setpoint voltage of 14.38 volts (13.38 volts at 77F is float charging voltage, bulk charge setting is recommended for 1.0 volt more). See this link for battery charts:

    http://www.lifelinebatteries.com/marinegraphs.php

    On page 10 of the 2000E manual, there is a drawing of the charge voltage trimpot showing that it is adjustable from ~13 vdc to 16 vdc (according to the manual, there is a special test fixture used to calibrate the voltage setting)... In any case, look at the back of the 2000E and estimate the battery voltage setting--If the battery is below the setting, the 2000E should be outputting maximum current available from the solar panels to the batteries. Once the battery voltage rises to the set point, the 2000E will only output enough current to keep the batteries at the setpoint voltage.

    This should be pretty obvious from watching the 2000E voltage and current meter... When the batteries are discharged to some degree (somewhere below 13 vdc), as they charge, you should see the voltage on the 2000E rise rise until it stops somewhere around 14 volts and stay there while you have full sun... Watching the current meter, you should see the current dropping even though you have full sun...

    Regarding how much power is required to run a boat--here is a thread about a racing sailboat that tried to use 138 watts of solar panels for all of its electrical needs (SF to Hawaii race):

    http://www.wind-sun.com/smf/index.php?topic=1588.0

    Short answer was that it was not possible. And starting with conservation of electricity (LED marker lights, little extra power for computer/radio, etc.) and more panels/power was required.

    http://www.wind-sun.com/smf/index.php?topic=1588.0

    If you are planning on really being on your own for power--testing before hand and ensuring things work as planned before the big trip is highly recommended.

    There are a lot of numbers and suggestions on the above racing sailboat thread and is probably worth a review. You have about twice the solar power available (and may have better panel placement)--but solar on boats is not the most efficient of installations.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help with existing Solar setup on a boat.
    I would like to be able to run a week or 2 off solar (longer would be better) without running the engine to recharge. I know I still have to calculate my daily amphour requirements.

    Sounds like you need more panels, or new batteries every 6 months. Slowly draining batteries, without recharging in a 24 hr period, will shorten their lifes.
    Lower StateOfCharge = lower battery life. The longer >the< charge is low, the more damage occurs, and the damage is cumulative. Hint, run engine in AM's to deliver a good bulk charge, and run the microwave & toaster oven. Then let the solar top the batteries off with the slow part of the charge for the final 20%

    To quickly test panel output, manually start an EQ cycle for the batteries, that will draw full current from panels.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Help with existing Solar setup on a boat.

    Mike's idea is good... From the 2000E manual, the controller simply takes the setpoint charge voltage (say 14 vdc) and simply adds another 1.2 volts for equalization:
    A proper equalization cycle is a substantial over charging of the battery at relatively high voltages with
    significant battery gassing. Solar Boost 2000E features a manually operated equalization function since an operator
    should always plan and monitor the process. The operator should ensure that equipment connected to the battery can
    tolerate the high equalization voltage which will be applied to the battery, and that the battery attains the proper voltage
    for the desired time period. Battery voltage setpoint during equalization will be the present charge voltage setpoint plus
    1.2 volts or 15.2 volts for the factory calibrated charge voltage setpoint of 14.0 volts. Note that with temperature
    compensation, the equalization voltage can be quite high at cool temperatures.

    Of course, this should only be done as a quick test for AGM (Sealed) batteries--long term usage (over a few tens of minutes? ) will probably overheat and damage the batteries--So turn it off when you are done testing/measuring/diagnosing.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Help with existing Solar setup on a boat.
    mike90045 wrote:
    To quickly test panel output, manually start an EQ cycle for the batteries, that will draw full current from panels.

    Mike, gave it a try, still only 4 amps. I had PV 15.6 V at the controller from 10:30 am to 1:30 pm today max of 4 amps (both EQ mode on and off).

    Over the next couple of weeks I am going to test everything, starting at the PV panels and work my way to the controller. I will post my results.

    Barry
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Help with existing Solar setup on a boat.

    What was the voltage on the battery side of the controller, and at the batteries during the 4 amp charge?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Help with existing Solar setup on a boat.
    BB wrote:
    What was the voltage on the battery side of the controller, and at the batteries during the 4 amp charge?

    -Bill

    12.6V-12.7V I keep a load on the batteries with lights and refrigeration.

    Barry
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Help with existing Solar setup on a boat.

    Yep, I would guess that you should see the "full current" available from your solar arrays (whatever that may be)...

    You can double check the voltage right at the solar controller's charge output terminals and confirm that they are within a few tenths of a volt of the batteries (no corrosion or poor connections).

    By the way, if you are going to use refrigeration while off-shore--I don't think solar will even supply much more that a fraction of the energy you will need.

    I would humbly suggest looking at a propane fridge (if legal/safe for marine installations) or possibly even a small electric ice chest modified to operate as fridge.

    Check your fridge's (and other systems) power requirements--it will be quickly obvious if solar by itself would be capable of suppling the bulk of your power in good weather.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Help with existing Solar setup on a boat.

    Bill,

    I checked the voltage at the output of the controller, at the batteries, and at the Link 20 monitor installed.

    My intentions are to use solar and wind to assist in keeping the batteries charged while sailing and at anchor. Even though I have a sailboat, much of my travels will require motoring, which will keep the batteries full. I will also carry a small Honda generator and use it for charging when needed. Without any charging at all and being conservative, I can go 3 days before I need to charge.

    My goal here is, first, make sure all of my systems are working correctly. Next I will replace as much of my lighting as possible with LED. I am also replacing the fridge with a more efficient unit. I thought about propane, but decided on a 12V/110V fridge. If it makes economical sense I will replace PV panels with larger ones. Adding more panels is not an option.

    I believe that the 300 watts of panel I have will keep up on good days, just not everyday.

    Barry
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help with existing Solar setup on a boat.

    300W of PV panels will not run much of a fridge. I think a propane fridge will be a better option, but then you have to worry about bilge gas (propane is heavier than air)
    Sorry.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,