conflicting information about solar install?

Sumner · Apr 10, 2016

centerline said:
I would agree not many probably would try it... but Walt did, and gave us some surprising numbers... but in series, I think there would be a problem....

Agreed that it wouldn't be good in series, but personally I'd never run panels in series on a boat anyway. I don't see any real gain in doing so other than some savings on wiring but possibly large losses if any shading occurs. On a house installation it can have benefits.

I started with a 40 watt panel and then added a 60 and then a 100 watt panel, all going to a MPPT Blue Sky 2512ix and it has worked fine. Maybe not optimum but I believe close to optimum. To do this they recommend panels that work at the same voltage and of the same cell type and all 3 panels meet those criteria.

I've since added six 60 watt panels and I did make sure all of these were the same and even bought an extra one in case one broke in the future. I have 4 of them wired in 2 pairs that are in series all the time that run to an MPPT controller putting out the correct voltage to charge a pair of 12 volt batteries in series (24 volt bank) for a trolling motor. The other 2 60 watt panels can be switched to parallel and connected to the 2512ix which is connected to the house bank or switched to series and their output sent to the trolling motor controller and its 24 volt battery bank.

If needed the 24 volt bank can be switched to a 12 volt bank and used at night as a house bank also.

http://purplesagetradingpost.com/sumner/endeavour-electrical/electrical-index.html

On the Endeavour I sourced all the panels as 80 watt panels and again bought a spare as at times they change the dimensions of the panels and I wanted to make sure I would have one that would fit the array if one was damaged,

Sumner
========================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...
Mac Trips to Utah, Idaho, Canada, Florida, Bahamas

walt · Apr 10, 2016

I tried the 20 watt plus the 10 watt simply because I have the two panels. For a few years I have had the 10 watt panel permanently mounted on the boat with a removable 40 watt panel. I had the sailboat in a slip for four months last winter and mostly get by with just the 10 watt panel but twice I put the 40 watt panel on for a few days as I run a little "deficit" using only the 10 watt panel. Im not fond of the size of the 40 watt panel (just a personal preference). Just recently I changed the permanent 10 watt to a 20 watt and Im fairly certain this will be all I ever need. It will more than enough for the marina sailing I do and for week long trips, I have two golf cart batteries and no problem to end the trip with a deficit. But.. now the old 10 watt panel that came off is my "just in case" extra panel - mostly if I were to take a trip where I used the computer more than I do now. I was expecting to lose about 10% of the MPPT gain of the 10 watt panel (which I would have been just fine with) so was also surprised when I did not. I cant think of anything wrong with how I measured things..

Also.. for parallel, you are forcing the voltage of both panels to be the same so its the maximum power point Voltage you must worry about matching. Current matching does not matter in the slightest so as long as Vmax tracks over temperature, two panels can be of different watt ratings and work fine. For series connection, it is now the current that you are forcing to be the same so now panel power (and specifically current) should be closely matched. Matching Vmax no longer matters for serial.

Another aspect for MPPT controllers to worry about. With my 20 watt panel, I have watched the panel voltage that the Genasun MPPT controller thinks is Vmax over the day. Early in the day when it has been cool, the Vmax has been just under 19 volts (and I saw a 40% boost over what a PWM would do). However, near the end of the day, the panel was fairly hot and the Vmax was now as low as 14.4 volts (boost is way down).

I cant find this spec for the Genasun GV5 but the Victron Blue controller spec (MPPT 150/70) says this controller has a panel input turn on voltage of Vbatt + 7 volts and an operating panel input voltage of Vbat +2 volts.

So.. if you had the panel I have that runs at 14.4 volts when hot (and its only April here - gets WAY hotter in the summer), the MPPT controller referenced above wont even run if the battery voltage is above 12.4 volts. If its a hot day and you want either an absorption voltage of 14.2 or even a float voltage of 13.8, it just isn't going to happen. The panel voltage is too low and the controller needs a panel voltage 2 volts above the battery voltage to even run. On a hot morning, where panel voltage was low enough that the 7 volt start up condition was not met, the controller might not even turn on - at all. The only good thing is that battery voltage also goes down with higher temp so might slightly compensate for this issue.

I cant find this spec for the Genasun GV5 anywhere (or for the MorningStar) but its "kind of" an important number to know. Its especially important for me since Im going to leave the sailboat for the summer in one of the hottest places on the planet (Lake Havasu) and would really like to come back and find the batteries charged. I am guessing I will not have a problem as I think the Genasun just connects the panel to the battery similar to PWM for low panel voltage or low current. I think.. that it senses when the current in the "PWM" mode exceeds some level such as 0.3 amps, it turns the MPPT on. Anyhow. I will find out..

walt · Apr 10, 2016

Another somewhat interesting thing from the Genasun web site (and was in the manual for my controller ) http://genasun.com/support/faq/ under "do I need blocking diodes"

With multiple panels in parallel running through one controller, blocking diodes are generally recommended to prevent panel damage, unless the panel manufacturer recommends otherwise.

I dont know of anyone who adds blocking diodes for multiple panels. I watched for any problems with my two panel experiment - did not see any. This may be an issue with a certain type of panel architecture.. but I dont know. Adding the diode of course drops the voltage the MPPT controller sees with a resulting loss in conversion gain..

Ron20324 · Apr 10, 2016

Okay, here's the scoop from my panels just minutes ago. 2, 40-watt Solar Blvd( Sumner suggested) panels wired separately to switches to change from series to parallel wired... then to controller, then thru a ckt breaker to disc to the batteries. Panels are not pointed at the sun. The batteries are 100 percent charge state according to Victron 600.

In Series: at first was 42.09 v. Settled down to 31.58 (as read off remote display 6 inches from controller).
1st panel only, second off line :at first was 15.86 v, settled into 17.38 constant.
2nd 17.38 v constant.
2 panels in parallel, 20.45 v.
With the controller output to the batteries switched open , but the panels connected to the contoller/display the, the display volts was 43.

walt · Apr 10, 2016

Annapolis MD temp right now = 45F - ie, cool = higher panel Vmax temps. Very odd that the MPPT controller finds the Vmax of each panel indivually at 17.38 volts but 20.45 in parallel. If both panels are the same, you should see the same Vmax when run one at a time or in parallel. The batteries being at 100% (no voltage given) might influence what you see since the controller is likely limiting what it is taking out of the panels and putting into the battery.

Sumner · Apr 10, 2016

Ron20324 said:
Okay, here's the scoop from my panels just minutes ago. 2, 40-watt Solar Blvd( Sumner suggested) panels wired separately to switches to change from series to parallel wired... then to controller, then thru a ckt breaker to disc to the batteries. Panels are not pointed at the sun. The batteries are 100 percent charge state according to Victron 600.

In Series: at first was 42.09 v. Settled down to 31.58 (as read off remote display 6 inches from controller).
1st panel only, second off line :at first was 15.86 v, settled into 17.38 constant.
2nd 17.38 v constant.
2 panels in parallel, 20.45 v.
With the controller output to the batteries switched open , but the panels connected to the contoller/display the, the display volts was 43.

In reference to your statement ...... "With the controller output to the batteries switched open" .... were all of the readings taken with the panels not connected to the batteries ?
I could see the higher voltages if the controller wasn't connected to the batteries considering the panel's specs are as follows:

Open Circuit Voltage (Voc): 21.6V (2 X 21.6 = 43.2 -- close to your 43 v reading)
Maximum Power Voltage (Vmp): 17.2V
( https://www.solarblvd.com/product_info.php?cPath=1_269&products_id=2664 )

I also find the 20.45 reading strange unless again they weren't connected to the batteries at the time and it was reading the open circuit voltage,

Sumner

P.S. My philosophy has been add panels until they meet my needs

.
=====================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...
Mac Trips to Utah, Idaho, Canada, Florida, Bahamas

Ron20324 · Apr 10, 2016

...were all of the readings taken with the panels not connected to the batteries ? I could see the higher voltages if the controller wasn't connected to the batteries considering the panel's specs are as follows:
Open Circuit Voltage (Voc): 21.6V (2 X 21.6 = 43.2 -- close to your 43 v reading)
Maximum Power Voltage (Vmp): 17.2V
( https://www.solarblvd.com/product_info.php?cPath=1_269&products_id=2664 )

I also find the 20.45 reading strange unless again they weren't connected to the batteries at the time and it was reading the open circuit voltage,

Ron :Only the last line as noted being open between controller and battery. All other had battery on line for stability/consistance conditions.

Sumner · Apr 11, 2016

centerline said:
....will the IPN pro remote work with the 2512iX controller?...

Yes the 2512iX will according to the manual ...

"Additional features included in the Solar Boost 2512iX version of the product include a battery temperature sensor input, equalization capability, full IPN Network interface...."

.... the 2512i does not have full IPN Network interface capabilities ( I don't think you can manage the set-points with the 2512i.

centerline said:
.... and do I need a shunt when used on (4) T-125 batts?

You will need at least one depending on how you wire your house bank. You can order it with one or order separately. Are you going to wire the 4 batteries as one large house bank? That is what I'm doing on the Endeavour.

Also I wouldn't consider wiring panels in series with the 2512ix as their recommended max voltage is 28.0 volts ( Maximum PV VOC @ STC is 28.0V) although further in the manual they say ....

"PV Input Voltage 35VDC absolute maximum (Recommend maximum VOC at STC ≤ 28VDC)"

Since two 12 volt panels in series can have outputs of 35 volts or higher I wouldn't do series. I have the 2512iX on the Mac and all panels are in parallel. On the Endeavour I'm using the 3024iL and I'm still running the panels in parallel but it does have the option of input voltages up to 45.6V.

I'm not running the IPN-ProRemote on either boat at this time and probably won't in the future either,

Sumner
===============================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...http://purplesagetradingpost.com/sumner/endeavour-main/endeavour-index.html
Mac Trips to Utah, Idaho, Canada, Florida, Bahamas

Sumner · Apr 11, 2016

centerline said:
.... and I can slip the IPN pro remote in at any time after the install.... at $200....

I found it for $206 plus $17 shipping at one place with the required shunt. Have you found it with the shunt for $200 any place? I might still consider one for the Endeavour.

Thanks,

Sumner
===============================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...http://purplesagetradingpost.com/sumner/endeavour-main/endeavour-index.html
Mac Trips to Utah, Idaho, Canada, Florida, Bahamas

Deleted member 117556 · Apr 11, 2016

I have the IPNpro remote and it is excellent. But I do not know what I should set the acceptance and float voltages at? They are still at default settings. Can Maine or anyone else help? Batteries are 4d interstate.
Thanks
bob

walt · Apr 12, 2016

Another slightly interesting thing.. I have a 20 watt panel / Genasun GV5 / two golf cart batteries. The Genasun spec lists the Absorption voltage as 14.2 volts for 2 hours. The thing I was just watching is what happens on a day to day basis if the batteries are not being used. It looks to me that the batteries get that 14.2 volt Absorption voltage on a daily basis. Each night the panel shuts down and the next day, the cycle of bringing up the voltage to Absorption for 2 hours then going into float repeats. You might consider this daily cycle if you are trying to increase the absorption time and the batteries get operated for long periods of time this way. Or.. maybe not.. but at least interesting that the controller software will repeat the cycle each day.

Maine Sail · Apr 12, 2016

Guys,

The IPN-Pro is really the only way to get into the software and change your absorption and float values as well as absorption time etc... The Ah counter is about like the others, pretty tough to keep accurate.

Some of the newer controllers, such as the new Victron's, have a BlueTooth dongle so you can program from your phone and some others have built in programability without dongles, remotes or expensive comms cables. The Victron BT dongle is about $200.00 less than the Blue Sky UCM.. The value in any controller is in the ability to actually "control" or order it set up for your batteries.

A

14.2V Absorb
13.2V Float
2 Hour Absorption Limit

Is ridiculous and the only good use for it is a "one size fits all controller". Each battery maker has charge voltage guidance. If they don't call and ask what the settings should be for your expected use. If you plan to PSOC the batteries quite a bit, and use solar as a main source, tell them that and the voltage suggestions will likely be higher. If you spend most of the time at a dock the standard factory voltages can work well.

Absorption voltage, absorption time and float voltage are critical because the Blue Sky factory defaults are not well suited to all batteries or use scenarios. In fact I don't know of too many batteries other than the Firefly AGM that would do well on those and even then 2 hours is far too short an absorption.

For example I would set a Trojan flooded battery to 14.8V absorption and a 4 hour minimum absorption time but could be longer depending upon PV size and expected use. If the owners are full time cruisers then I would set absorption to 6 hours and float to 13.6V. If the boat is on a mooring, and on float quite a bit, I might program it for 13.4V..

For a boat out cruising you simply don't have enough solar hours in a day to get back to 100% SOC so absorption can easily be set to 6 to 8+ hours.

conflicting information about solar install?

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Deleted member 117556

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