4 Solar Controllers in Parallel?

[Sumner]

Originally Posted by Captain Bill

.... I once wrote to Bluesky and suggested that they make regulators and battery chargers that plug into their communications circuit so that all the charging sources on the boat could work together, but got no response.

I can see where that is a problem since it can't momentarily shut the alternator down like it can the slave controllers. Probably something could be done by them, but it would be complicated considering all of the possible combinations of what people might have. I would think this might be a problem with any controller that has to read the battery voltage.

How long do you run with the alternator up? Once it is off does the controller then kick back in?

We at times run a gen-set for 15-30 minutes and what you are describing is probably happening at that time. If we do run the gen-set it is during the morning or evening when sun angles are low anyway, so doubt it makes that much difference in our case.

I guess the solution is that you need to add more panels so you run the motor less ,

Sum

[Captain Bill]

Originally Posted by noelex 77

The Blue sky self consumption is reasonably low (if their figures are to be believed its a bit less than 1.5AHrs a day), but their MPPT implementation is not really state of the art.

I can't say if their MPPT implementation is state of the are or not, but their charging algorithm is terrible. The biggest problem is that it goes into float mode prematurely. I have a 420 ah agm batery bank which is supposed to be held at acceptance voltage (about 14.4 depending on the temperature) until the charge current drops to .5a/100ah or a little over 2 amps in my case. This all works well until a cloud passes overhead and the output drops in which case it immediately reads this as batteries are fully charged and drops to float voltage. It won't go back into acceptance until it goes into bulk mode and it won't go into bulk mode until the voltage drops significantly which usually does not happen while the sun is still high enough to produce useful power. I thought the unit was broken and called tech support. They told me that it was working as designed. I guess there were no clouds in the lab where they designed it. The tech support guy even had me check the version of firmware I had just to make sure I had the latest and greatest.

When I had my Xantrex PWM controller I got to full charge quite often as they had a pretty good charging alorithm. I have also never gotten as many amps out of the Bluesky as I did out of the Xantrex. Can you tell me where you got your information on the power point tracking technology?

[Captain Bill]

Originally Posted by Sumner

I can see where that is a problem since it can't momentarily shut the alternator down like it can the slave controllers. Probably something could be done by them, but it would be complicated considering all of the possible combinations of what people might have. I would think this might be a problem with any controller that has to read the battery voltage.

How long do you run with the alternator up? Once it is off does the controller then kick back in?

We at times run a gen-set for 15-30 minutes and what you are describing is probably happening at that time. If we do run the gen-set it is during the morning or evening when sun angles are low anyway, so doubt it makes that much difference in our case.

I guess the solution is that you need to add more panels so you run the motor less ,

Sum

If Bluesky made an external controller for alternators they could shut down the field coil and turn off the alternator output. The big problem with alternators is when you remove the load without shutting down the field coil first such as turning a battery switch to off while the engine is running. I would think that they have the basic regulator technology available and just need to change the interface to the unit to control an alternator. They would also need an output module capable of handling the power from various size alternators.

With regards to how long I run my genset it is for a couple of hours/day. I'm currently having problems with my fridge and it's drawing about twice what it used to draw. I need to replace it but I have to liquidate some assets first. So at the current time my daily load is about twice what it should be. The alternator is on all the time the genset is running, but because it reading the alternator voltage as battery voltage the charger itself both throttles back prematurely and shuts down prematurely.

The charging algorithm in my solar charger appears to have been designed by an engineer who was reality challenged, so I never know what my real state of charge is (see my last post). The unit determines it as 100% charge by when it switches to float voltage. If it's at float it must be at 100% right? Except that it goes into float prematurely so it's not really at 100%, but somewhere in the low 90s and then it stops charging. The solar panels essentially cannot get my batteries to 100% because of the idiotic charging algorithm. Since I have AGMs it is really bad that they never get a true 100% charge. They are only 3 months old and I'm starting to see indications of capacity issues.

I have no more room for additional solar panels which aren't really the problem anyway. The problem is a fridge that needs replaced and a lousy charging algorithm in my solar controller. When I had the pwm controller and a fridge that was working properly I often got to a real 100% charge by 12-1:00 anytime between the first of April and the end of september with no getset at all, at least on sunny days.

[noelex 77]

Originally Posted by Captain Bill

Can you tell me where you got your information on the power point tracking technology?

Mostly from observing the performance of input and output parameters. There are many ways to implement MPPT technology and some will track the MPP much better than others. On a boat this quite critical as the MPP fluctuates quite rapidly as shadows come and go as the boat swings.

There is also some discussion on solar forums such as these:

Solar Electric Power Discussion Forum by Northern Arizona Wind & Sun

But you have to wade through a lot of discussion. These was about 30 pages just discussing one of my favourite controlers (the Rogue).
Some of the dislike for blue sky products on these forums stems from the fact that they will only accept quite low input voltages. This is a big drawback for domestic systems, but less of problem for boat systems. Nevertheless competing products are generally regarded as better for MPPT tracking, as well as durability and battery charging parameters.

[Sumner]

Originally Posted by Captain Bill

..... Since I have AGMs it is really bad that they never get a true 100% charge. They are only 3 months old and I'm starting to see indications of capacity issues...

I was joking about the 'add panels' as I figured that you had things covered there.

I wonder if the controller has a problem with the AGM's vs. the flooded lead acid that we are using and I haven't seen the problems you are having. It looks like the default settings are for 'flooded' and it looks like you need the 'remote' to change those. I've never changed any settings on ours (also don't have the remote).

Which controller do you have and do you have the remote?

Hope you can get the fridge squared away soon,

Sum

[Captain Bill]

[QUOTE=Sumner;1069751]I was joking about the 'add panels' as I figured that you had things covered there.

I wonder if the controller has a problem with the AGM's vs. the flooded lead acid that we are using and I haven't seen the problems you are having. It looks like the default settings are for 'flooded' and it looks like you need the 'remote' to change those. I've never changed any settings on ours (also don't have the remote).

Which controller do you have and do you have the remote?

Hope you can get the fridge squared away soon,

Sum
/QUOTE]

I do have the remote and I have it all set up properly. I've reviewed each setting with the tech support guy on the phone to make sure I had not screwed something up. He tells me It's working the way it's supposed to. I don't believe him but the only way to get it checked out is to take it out and send it back to the factory(at my expense). They don't provide a lender unit in the meantime, so I have to get another controller to use while they work on it (three week turn around). By the time I get it fixed I'll have spent almost as much as I did for the controller, not including the remote of course. Since several other bluesky woners have said theirs does not act this way I'm pretty convinced mine is not working properly despite what tech support says.

[Sumner]

Originally Posted by Captain Bill

.... He tells me It's working the way it's supposed to. I don't believe him but the only way to get it checked out is to take it out and send it back to the factory(at my expense). They don't provide a lender unit in the meantime, so I have to get another controller to use while they work on it (three week turn around). By the time I get it fixed I'll have spent almost as much as I did for the controller, not including the remote of course. Since several other bluesky woners have said theirs does not act this way I'm pretty convinced mine is not working properly despite what tech support says.

I think I'll make a phone call Monday. Not saying that it will do any good, but who knows.

We are in Utah with the boat/controller in FL. The controller is only hooked to one panel at the moment keeping the start battery up that the bilge pump (for any rain water) is connected to. If I was close to the boat I'd pull it out and loan it to you.

Did you get the controller from a dealer that is local that might have something you could borrow or can you put the PWM back in?

Good luck,

Sum

[Captain Bill]

Originally Posted by Sumner

I think I'll make a phone call Monday. Not saying that it will do any good, but who knows.

We are in Utah with the boat/controller in FL. The controller is only hooked to one panel at the moment keeping the start battery up that the bilge pump (for any rain water) is connected to. If I was close to the boat I'd pull it out and loan it to you.

Did you get the controller from a dealer that is local that might have something you could borrow or can you put the PWM back in?

Good luck,

Sum

Unfortunately I bought it on the internet. I got the MPPT only because the PWM unit died. It was 10 years old. I'll see if I can pick up a cheap PWM unit to hold me until I can get this one checked out. At least at this time of year I don't need to worry about getting one that will take the full theoretical output of the panels.

[sailinglegend]

Originally Posted by Captain Bill

........The charging algorithm in my solar charger appears to have been designed by an engineer who was reality challenged, so I never know what my real state of charge is (see my last post). The unit determines it as 100% charge by when it switches to float voltage. If it's at float it must be at 100% right? Except that it goes into float prematurely so it's not really at 100%, but somewhere in the low 90s and then it stops charging. The solar panels essentially cannot get my batteries to 100% because of the idiotic charging algorithm...........

This is a problem with all charging regulators, including alternator and shorepower regulators. They don't know what capacity your batteries are and they can't measure the current going into the battery. Your house systems might be taking much of the current the charging source might be delivering. Regulators switch down to float to save your batteries from overcharging, but this will be after some combination of time/voltage/current so may be well before the batteries are back to 100%. Bill, you know what is going on, but most of those solar power users who say their batteries are 100% charged by midday are fooling themselves.

As you say batteries are charged to 100% when the charge current is down to 0.5% of the battery capacity @ the absorption voltage. The trouble is you will never see this voltage and current unless you turn the regulators on and off to get them back to boost/absorption mode. It may be quite normal to find that in float mode you may have 1 amp going in - switch back to boost/absorption mode and the current may go up to 15 amps - and stay there. In this case the batteries are not 100 % charged. You may have to keep repeating this all day as the regulator keeps falling back to float after a "timed period", which has nothing to do with the batteries being 100% charged.

[noelex 77]

Originally Posted by sailinglegend

This is a problem with all charging regulators, including alternator and shorepower regulators. They don't know what capacity your batteries are and they can't measure the current going into the battery.

Some of the better solar controllers will do this.

It does help get the charging correct.

If your system will not do this its worth adjusting the absorption time so that on average it's ending as the battery return amps reach the desired level.
0.5% is a big aggressive for most batteries. 2% is a commonly recommended point to terminate the absorption voltage.
Mine is set for 1.5%.

[sailinglegend]

Originally Posted by noelex 77

Some of the better solar controllers will do this......

I don't understand what you mean by this. Do you mean they measure the charge current into the battery - NO controllers can do this, that would need a shunt - correctly installed!

Originally Posted by noelex 77

.....its worth adjusting the absorption time so that on average it's ending as the battery return amps reach the desired level.
0.5% is a big aggressive for most batteries. 2% is a commonly recommended point to terminate the absorption voltage.
Mine is set for 1.5%.

How do you set this - are you just talking about setting the Battery Monitor to reset your AH count at 1.5 % of charge current - but at what voltage? You can't set this to the absorption voltage because the controller will have dropped to float mode well before this. Lifeline recommend 0.5% at 14.2 volts. 2% is often used by Battery Monitor makers because they know that otherwise the Ah will never be reset as batteries will seldom get back to 100%. Its better for your Ah to be reset early than never at all. Another reason why Battery Monitors are so inaccurate.

[noelex 77]

Originally Posted by sailinglegend

I don't understand what you mean by this. Do you mean they measure the charge current into the battery - NO controllers can do this, that would need a shunt - correctly installed!
.

Yes you need a shunt. The difficult part is not the shunt but the controller needs to process the information from the shunt, to use this to terminate the charge.

The better controllers will do this although generally it needs some optional extras.

Originally Posted by sailinglegend

How do you set this - are you just talking about setting the Battery Monitor to reset your AH count at 1.5 % of charge current - but at what voltage? You can't set this to the absorption voltage because the controller will have dropped to float mode well before this. Lifeline recommend 0.5% at 14.2 volts. 2% is often used by Battery Monitor makers because they know that otherwise the Ah will never be reset as batteries will seldom get back to 100%. Its better for you Ah to be reset early than never at all. Another reason why Battery Monitors are so inaccurate.

You can set the parameters to whatever you like.
Mine is set to 5.0A for 5 mins at 0.2v less than the absorption voltage. When these parameters are met the solar controler will drop out of absorption and go to float.

[sailinglegend]

Originally Posted by noelex 77

Yes you need a shunt........The better controllers will do this although generally it needs some optional extras.

I'm still confused? I do not know of any controller that can measure the current actually going into the battery. Would be very interested in brands that do this.

Originally Posted by noelex 77

...Mine is set to 5.0A for 5 mins at 0.2v less than the absorption voltage. When these parameters are met the solar controler will drop out of absorption and go to float.

Are you talking about a Battery Monitor or your solar controller. If its your solar controller then how does your solar controller know what is actually going into the battery. If its your Battery Monitor how does it turn off the solar controller?

[noelex 77]

Originally Posted by sailinglegend

I'm still confused? I do not know of any controller that can measure the current actually going into the battery. Would be very interested in brands that do this.

Mine is an outback FX 60
With the outback system you need a flexnet DC and mate to enable the battery return amps feature.

[sailinglegend]

Originally Posted by noelex 77

Mine is an outback FX 60
With the outback system you need a flexnet DC and mate to enable the battery return amps feature.

Many thanks for that - if only this would also "talk" to your alternator and your shorepower charger.

Come on all other manufacturers make some system that will do the charging job properly.