Battery / Solar controller / High Voltage ?

[xeitosaphil]

I have a Morningstar Pro Star 15 Solar controller which has been controlling my 100w panel all summer. The combo has been keeping up with the Fridge Freezer discharge for the last 5 months admirably. Now having turned the F/F off for the winter, the panel is producing more power than needed to keep the batteries at 100% on sunny days.
I found yesterday that the Smart Gauge High Voltage Alarm cut in a couple of times, and it would appear quickly reading in the instructions for the Prostar that the High Voltage disconnect voltage is 15.2v.

Is the voltage of 15.2v going to damage the batteries? 15.2v is also above the 14.4v gassing level?

Why would a company set this sort of level if it was going to damage the battery or cause excessive gassing?

If it will damage the batteries and excess gassing, is there any electronic gismo I can introduce into the circuit to limit maximum battery voltage?

I have yet to test the controller for a problem as suggested in the manual for “ High Battery voltages “ due to limited time onboard yesterday, so I actually turned the solar panel off as batteries were already at 14.56v when I left the boat. Controller set for sealed battery type.

If it is not a problem I could always set the SG alarm threshold higher, but wondered if I am shortening the battery life by doing so?

User manual can be found here - http://www.morningstarcorp.com/en/support/library/PS2.IOM.English.EN.021.pdf

Any input would be welcome - Philip

 

[parbuckle]

If it will damage the batteries and excess gassing, is there any electronic gismo I can introduce into the circuit to limit maximum battery voltage?

Yes another controller/regulator sounds like its time to get on the phone.

 

[vyv_cox]

I disconnect my 125 watt solar panels when the fridge goes off and substitute a 38 watt one. This is almost certainly too big just to keep the batteries up to scratch but it seems to have worked well for the past ten years or so. Maybe you could substitute a small cheap panel, perhaps a 10 watt one?

 

[Tony Cross]

I've just had a quick look at the manual you linked to and there are two things mentioned in there...

1. The controller has an automatic and periodic battery equalise function that increases the charging voltage to 15.1v for a time dependant on the state of the batteries. Could this be what's tripping your Smart Gauge?

2. In the "Protections" section it talks about high battery voltage. In this case it says that first the solar array is disconnected and then the load (if any) is disconnected, it also says it auto-resets. This should protect your batteries against over voltage from the panels.

If the controller is working properly it should not be possible for the panel to overcharge the battery, if the batteries require less power than the panel is producing the controller should shunt it away (as heat probably).

It's important to ensure you have the elector switch set to the correct battery type.

 

[vyv_cox]

, if the batteries require less power than the panel is producing the controller should shunt it away (as heat probably).

In June/July at around mid-day our batteries are fully charged by the panels. In dumping the excess power as heat the controller gets quite hot, so much so that the panel display disappears. Power at this stage is probably about 8 amps, just approaching the maximum the controller can handle. I am thinking of improving the airflow, maybe with a fan, OK when we are on board but not otherwise. If I was installing the controller again I would site it somewhere rather better from that point of view.

 

[xeitosaphil]

I've just had a quick look at the manual you linked to and there are two things mentioned in there...

1. The controller has an automatic and periodic battery equalise function that increases the charging voltage to 15.1v for a time dependant on the state of the batteries. Could this be what's tripping your Smart Gauge?

2. In the "Protections" section it talks about high battery voltage. In this case it says that first the solar array is disconnected and then the load (if any) is disconnected, it also says it auto-resets. This should protect your batteries against over voltage from the panels.

If the controller is working properly it should not be possible for the panel to overcharge the battery, if the batteries require less power than the panel is producing the controller should shunt it away (as heat probably).

It's important to ensure you have the elector switch set to the correct battery type.

Parbuckle/ Viv /Tony

Thanks for your reply's,

Parbuckle --- The controller was purchased new in the spring of this year so is well within the warrantee period

Viv – Smaller panel may be an option as a last resort, but the controller should cope with the panel output and I could always turn it on and off to suit, althought it would be a pain in proverbial to continually monitor - but why would they set the HV disconnect so high 15.2v?

Tony --- The controller battery setting is set to Sealed lead acid so the equalising voltage specified in manual says it equalises at 14.35v. The controller does say it won’t allow overcharging and dissipates heat with the shunt but it still allows the battery to attain 15.2v before the High voltage disconnect comes into play, this is what is worrying me at the moment.

Next time I go to the boat I will have to try the high voltage test suggested by the manual, just in case there is a problem with it, but the manual seems to suggest they are bullet proof?

I did wondered in the mean time if it’s over charge to 15.2v will be a problem and also if anyone had any experience of this controller.

Still looking for reassurance that putting the battery to 15.2v isn’t going to cause lasting problems or produce significant amounts of gas and dry batteries.

 

[parbuckle]

I thought that pv panel controllers had no heat sink they just short out the supply when up to voltage my controller is completely encased and waterproof but I know there ara dual purpose types that regulate wind generators.

 

[RAI]

Why should the PV controller not open the circuit to protect the batteries rather than shunt to power?

How about partially covering the solar panel when you leave the boat? Even a little coverage usually drops the output wattage considerably.

 

[xeitosaphil]

Why should the PV controller not open the circuit to protect the batteries rather than shunt to power?

How about partially covering the solar panel when you leave the boat? Even a little coverage usually drops the output wattage considerably.

Panel output is not an issue because I can always turn the panel off at the controller, a partially shaded panel will still allow the battery to charge up to the disconnect voltage.

The worry is that the controller allows the battery to attain 15.2v with the associated issues, before it disconnects!

 

[VicS]

Panel output is not an issue because I can always turn the panel off at the controller, a partially shaded panel will still allow the battery to charge up to the disconnect voltage.

The worry is that the controller allows the battery to attain 15.2v with the associated issues, before it disconnects!

It is a PWM controller so is not dumping the excess power to shunt, it is controlling it by pulse width modulation
It should not need any additional cooling if installed as specified in the instructions

If it is set up correctly and working correctly it should, for a sealed battery, control the voltage to 14.15 during the PWM stage with an equalization stage of 14.35 and a float at 13.7 .

Normally the high voltage disconnects should not come into operation.

As you say it should control the charging without the need to change panel sizes or any other such faffing about.

It might be worth going through the installation and setting up again from scratch, just in case something has upset its little brain.


Do you use the "load" terminals. If so what for? The F/F?

 

[Tony Cross]

Tony --- The controller battery setting is set to Sealed lead acid so the equalising voltage specified in manual says it equalises at 14.35v. The controller does say it won’t allow overcharging and dissipates heat with the shunt but it still allows the battery to attain 15.2v before the High voltage disconnect comes into play, this is what is worrying me at the moment.

In that case I would contact Morningstar for a clarification, that doesn't sound right to me.

 

[xeitosaphil]

It is a PWM controller so is not dumping the excess power to shunt, it is controlling it by pulse width modulation
It should not need any additional cooling if installed as specified in the instructions

If it is set up correctly and working correctly it should, for a sealed battery, control the voltage to 14.15 during the PWM stage with an equalization stage of 14.35 and a float at 13.7 .

Normally the high voltage disconnects should not come into operation.

As you say it should control the charging without the need to change panel sizes or any other such faffing about.

It might be worth going through the installation and setting up again from scratch, just in case something has upset its little brain.


Do you use the "load" terminals. If so what for? The F/F?

Vic,

When installed I was sure I had done it correctly and I was particular to keep panel covered while installation was taking place, and all has been well over the summer months while the F/F was in use?

For whatever reason the installation instructions and also in the user instructions do say;

Mount the ProStar to a vertical surface (4 stainless steel #8 self-tapping screws are included). Tighten the mounting screws using care not to crack the plastic case. Do not install directly over an easily combustible surface since the heat sink may get hot under certain operating conditions

I have sent Morning Star Corp an email enquiry asking for clarification with regards to the heatsink use and PWM, and will post findings.

I will go over tomorrow and do the re - installation check, which also involves the Over Voltage Check.

The answer to your question re the load- I don't have a load connected, so the load option is turned off. ( not really sure what I would use it for? )

I do however have a Vetus Gas Monitor supply cable connected to the same permanent fused electric supply from the battery in the form of a six way fused Dis Brd with neons, which the solar panel / controller return charge to the battery cable is fixed too. I am using this fused supply cable, to input the solar charge return from the controller to the battery.

Is there any way that when the gas monitor is in intermittent mode, the power to the monitor could be intermit and possibly create pulse which could confuse the controller?
I assumed that the power feed to the gas monitor would be constant and any intermitant monitoring would be regulated by the monitor electronics or am I wrong.

 

[VicS]

Yes I read the bit about the heat sink getting hot. That's why I said, "as specified in the instructions" It'll be interesting if Morning star clarify when/why the heat sink does get so hot.

I think you can use the "load" terminals for something that is normally on all the time but which you would want to turn off automatically if the battery voltage falls and not turn on again until recharged. A fridge is a typical example.
The table of figures in the tech specs gives the disconnect and reconnect voltages as 11.4 and 12.6 volts respectively for a sealed battery

I'd not like to say if the gas monitor is affecting it but I'd not think it would unless there is a bad connection somewhere. I would, however, have made a direct and dedicated connection from regulator to battery.

 

[xeitosaphil]

Yes I read the bit about the heat sink getting hot. That's why I said, "as specified in the instructions" It'll be interesting if Morning star clarify when/why the heat sink does get so hot.

I think you can use the "load" terminals for something that is normally on all the time but which you would want to turn off automatically if the battery voltage falls and not turn on again until recharged. A fridge is a typical example.
The table of figures in the tech specs gives the disconnect and reconnect voltages as 11.4 and 12.6 volts respectively for a sealed battery

I'd not like to say if the gas monitor is affecting it but I'd not think it would unless there is a bad connection somewhere. I would, however, have made a direct and dedicated connection from regulator to battery.

Prostar 15 Solar Charger Update.


Having done the checks today as per the trouble shooting suggested checks in the operators user manual, and completely installing it again from a fresh start, I can say that the controller is installed correctly as per the user manual instructions.

Having also done the High Voltage trouble shooting check I can also confirm that there doesn’t seem to be a problem with the controller re malfunction ( according to the manual?)

I'm not 100% sure there isn't a problem with the controller yet, as the batteries are up to 95% SOC @ 12.86v but without any sun today can't check what the high voltage disconnect will be until the voltage gets above 14.4v.


My original question though, has still not been answered - will raising the battery voltage up to 15.2v which is over and above the 14.4v gassing level before the solar panel disconnects, cause any long term damage to the battery life and deplete the battery of acid as it is sealed?

If it does, is there any way around the problem without buying another controller with different lower disconect levels?

I have taken your advise Vic, and have taken the solar charge from controller via a dedicated inline fuse direct to the battery.

 

[VicS]

I am assuming that the 15.2v high voltage disconnect is some form of emergency/safety cut out because normally if its all working correctly it should control to a maximum of 14.15, or 14.35 during equalisation.

You say you've had high voltage alarms on the Smartgauge. Do the instructions indicate what voltage triggers that or give any indication what might cause it.

 

[xeitosaphil]

I am assuming that the 15.2v high voltage disconnect is some form of emergency/safety cut out because normally if its all working correctly it should control to a maximum of 14.15, or 14.35 during equalisation.

You say you've had high voltage alarms on the Smartgauge. Do the instructions indicate what voltage triggers that or give any indication what might cause it.

This is the point I was trying to make, in the normal charging sequence it should be regulated to 14.15 or 14.35 both under the 14.4 gassing level.

If it is passing this level for what ever reason, and allowed to regularly reach 15.2 before the HV Disconnect comes into play, will it effect the long term life and fluid levels in the battery?

If this is going to be a problem then I need to sort it quickly and return the controller under the warrantee as it must be defective?

Would it be safe to assume that because the batteries are sealed lead acid, that they would except a short term period of 15.2v overcharge ( maybe hours not days ) without any detriment, assuming the gassing if any is not an issue?

Smart Gauge alarms, some are factory defaults, some are user programmable pre-set functions, and quite involved to set up. I have not programmed any in yet but when an alarm notification came on screen, I was a bit worried. I should have taken more notice of what it said, but my first reaction was to turn the solar panel off and sort it out when I had more time, as it was only a quick visit to the boat between Swimbo’s shop dodging

 

[vyv_cox]

I have no idea whether a solar regulator works in the same way as an alternator regulator but my Sterling shut down a few times on a similar high voltage. I rang Sterling, who advised that the cause was probably a poor earth connection somewhere. I checked everything I could find and the problem persisted, only occasionally but annoying when it did. Much later I found a poor connection at the alternator earth to the engine. Since fixing it the problem has never recurred.

 

[VicS]

I have no idea whether a solar regulator works in the same way as an alternator regulator but my Sterling shut down a few times on a similar high voltage. I rang Sterling, who advised that the cause was probably a poor earth connection somewhere. I checked everything I could find and the problem persisted, only occasionally but annoying when it did. Much later I found a poor connection at the alternator earth to the engine. Since fixing it the problem has never recurred.

No it does not work in the same way at all

An alternator regulator works by controlling the field current. With no field to control the solar panel regulator cannot do the same thing.

Similarly generators, such as wind gens, which have permanent magnet fields cannot be controlled in the same way.

Wind gens are usually controlled by dumping the excess into a shunt.

The simplest method of controlling a solar panel is to disconnect it at a set voltage, reconnecting it when the battery volts falls to some set lower value.
PWM regulators break the charging into a series of pulses of decreasing length as the battery becomes charged.

 

[VicS]

This is the point I was trying to make, in the normal charging sequence it should be regulated to 14.15 or 14.35 both under the 14.4 gassing level.

If it is passing this level for what ever reason, and allowed to regularly reach 15.2 before the HV Disconnect comes into play, will it effect the long term life and fluid levels in the battery?

If this is going to be a problem then I need to sort it quickly and return the controller under the warrantee as it must be defective?

Would it be safe to assume that because the batteries are sealed lead acid, that they would except a short term period of 15.2v overcharge ( maybe hours not days ) without any detriment, assuming the gassing if any is not an issue?

Smart Gauge alarms, some are factory defaults, some are user programmable pre-set functions, and quite involved to set up. I have not programmed any in yet but when an alarm notification came on screen, I was a bit worried. I should have taken more notice of what it said, but my first reaction was to turn the solar panel off and sort it out when I had more time, as it was only a quick visit to the boat between Swimbo’s shop dodging

There is not a lot to suggest that the solar regulator is faulty. The alarm could be some quirk of the Smartgauge.

The way forward I think is to monitor the output volts from the Morningstar. Perhaps a multimeter which records the maximum reading will do the trick.
Maybe do sme checks now and more when we get some more sunshine.

 

[xeitosaphil]

There is not a lot to suggest that the solar regulator is faulty. The alarm could be some quirk of the Smartgauge.

The way forward I think is to monitor the output volts from the Morningstar. Perhaps a multimeter which records the maximum reading will do the trick.
Maybe do sme checks now and more when we get some more sunshine.

Are these type of recording multimeters available without spending hundreds of pounds?