Windgen, 2 Outputs, 1x LiFePo4, 1x Leadacid, Voltage increase?

[Franziska]

Hi,



We have a Rutland 1200 Windgen which is working fine but turns off to early. More on this below.



Background, the Rutland/Marlec manual says the first outlet needs to be connected to a Lead Acid battery to prevent the Windgen controller from ever being suddenly without power should the LiFePo4 ever be shut down by the BMS.


Our gel type lead acid starter battery is connected to outlet one of the Marlec controller.

The LiFePo4 is connected to the second output of the Marlec controller.



I noticed that the Windgen goes into float charge mode at 12.7V, likely when the starter battery is full and keeps breaking then despite there still being ample wind which we could feed into the 840Ah 12V LiFePo4.

So, I'm wondering if I could raise the voltage at which the Windgen switches to float. By this we could use that windpower to continue charging our LiFePo4 bank longer.



Now the question is, will this kill higher float value our starter battery in the medium term?


Here is the interface cable manual:
https://www.marlec.co.uk/wp-content/uploads/2021/06/SM-482A.pdf



Thanks for your input.

[newhaul]

Originally Posted by Franziska

Hi,



We have a Rutland 1200 Windgen which is working fine but turns off to early. More on this below.



Background, the Rutland/Marlec manual says the first outlet needs to be connected to a Lead Acid battery to prevent the Windgen controller from ever being suddenly without power should the LiFePo4 ever be shut down by the BMS.


Our gel type lead acid starter battery is connected to outlet one of the Marlec controller.

The LiFePo4 is connected to the second output of the Marlec controller.



I noticed that the Windgen goes into float charge mode at 12.7V, likely when the starter battery is full and keeps breaking then despite there still being ample wind which we could feed into the 840Ah 12V LiFePo4.

So, I'm wondering if I could raise the voltage at which the Windgen switches to float. By this we could use that windpower to continue charging our LiFePo4 bank longer.



Now the question is, will this kill higher float value our starter battery in the medium term?


Here is the interface cable manual:
https://www.marlec.co.uk/wp-content/...06/SM-482A.pdf



Thanks for your input.

Ok why not just put the lifepo4 on the primary and skip the fla for the wind generator?
Just set to stop charging at 13.8v to the primary lifepo4 bank. ( well below the HVD point for lifepo4) Put a 50 watt solar panel with cheap pwm to keep start lead topped up during off season .

Why complicate things

[Franziska]

Originally Posted by newhaul

Ok why not just put the lifepo4 on the primary and skip the fla for the wind generator?
Just set to stop charging at 13.8v to the primary lifepo4 bank. ( well below the HVD point for lifepo4) Put a 50 watt solar panel with cheap pwm to keep start lead topped up during off season .

Why complicate things

Thank you.



Marlec wants a lead acid on output 1 to prevent the controller to be damaged should the BMS shutting off the LiFePo4 and the turbine be in operation.


Apparently a running turbine would damage an unpowered controller.



Isn't that a risk?



If we were to follow your thoughts we could indeed just put the LiFePo4 on 1 and maybe just use a small DC to DC charger to keep the starter battery topped up.

[newhaul]

Originally Posted by Franziska

Thank you.



Marlec wants a lead acid on output 1 to prevent the controller to be damaged should the BMS shutting off the LiFePo4 and the turbine be in operation.


Apparently a running turbine would damage an unpowered controller.



Isn't that a risk?



If we were to follow your thoughts we could indeed just put the LiFePo4 on 1 and maybe just use a small DC to DC charger to keep the starter battery topped up.

It's all dependent on your settings to stop charging. Set same as your solar controller.
That's what I do with my airx 400.

[Franziska]

Originally Posted by newhaul

It's all dependent on your settings to stop charging. Set same as your solar controller.
That's what I do with my airx 400.

Thanks.


But what happens if the turbine is running and the LiFePo4 goes flat due to the BMS shutting it down.


Then the wind controller has no power but wind input. Marlec says that damages the controller. Is that not the case?

[newhaul]

Originally Posted by Franziska

Thanks.


But what happens if the turbine is running and the LiFePo4 goes flat due to the BMS shutting it down.


Then the wind controller has no power but wind input. Marlec says that damages the controller. Is that not the case?

if you have your controller properly set the bms won't shut off the power .

[Franziska]

Originally Posted by newhaul

if you have your controller properly set the bms won't shut off the power .

Sorry, but I don't get it this time around might be because I'm blonde :-)



Let's say few days without sun and we are on a passage.



We only have the LiFePo4 attached to the terminal 1 of the windgen controller. A DC-DC charger keeps the starter battery topped up.



The LiFePo4 empties due to house loads and at the cut off point the BMS shuts it off (remember we have a "dumb" Daly BMS which is said to be ok for LiFePo4 but we can not adjust any settings on it.).
The windgen still runs, but has all over sudden no voltage supply on terminal one.
Will that not kill the controller (Marlec seems to think it gets fried then)?


How do I avoid this?



I can only adjust the solar MPPT and the Windgen controller.
As you suggest both set to the same float and bulk voltages.

[newhaul]

Originally Posted by Franziska

Sorry, but I don't get it this time around might be because I'm blonde :-)



Let's say few days without sun and we are on a passage.



We only have the LiFePo4 attached to the terminal 1 of the windgen controller. A DC-DC charger keeps the starter battery topped up.



The LiFePo4 empties due to house loads and at the cut off point the BMS shuts it off (remember we have a "dumb" Daly BMS which is said to be ok for LiFePo4 but we can not adjust any settings on it.).
The windgen still runs, but has all over sudden no voltage supply on terminal one.
Will that not kill the controller (Marlec seems to think it gets fried then)?


How do I avoid this?



I can only adjust the solar MPPT and the Windgen controller.
As you suggest both set to the same float and bulk voltages.

Ok I guess I'm missing something .
Your wind generator doesn't charge the battery on terminal 1 then?
Just the one on terminal 2?

[Franziska]

Originally Posted by newhaul

Ok I guess I'm missing something .
Your wind generator doesn't charge the battery on terminal 1 then?
Just the one on terminal 2?

It charges on both. Terminal 1 the Lead Acid.
Terminal 2 the LiFePo4.

As it seems I can not set different parameters on the two terminals.



Currently it cuts bulk charging at 12.7V because the Lead Acid is then deemed full.
I'd love to continue bulk charging to pump into the LiFePo4, but I'm afraid it would kill the lead acid.

[newhaul]

Originally Posted by Franziska

It charges on both. Terminal 1 the Lead Acid.
Terminal 2 the LiFePo4.

As it seems I can not set different parameters on the two terminals.



Currently it cuts bulk charging at 12.7V because the Lead Acid is then deemed full.
I'd love to continue bulk charging to pump into the LiFePo4, but I'm afraid it would kill the lead acid.

Ever see what your battery in your car is sitting at when the engine is running?
At idle the alternator is putting out anywhere from 13.5v to 14.5v
Set the wind generator to charge to 13.6 and let solar top it off.
If your really worried then put a small u1 battery on terminal1 and a small dc2dc from LiFePo4 to your start bank.
A u1 is a lawnmower battery and can be had for under $50 USD.
just for your peace of mind wrt your start bank.

[Franziska]

Originally Posted by newhaul

Ever see what your battery in your car is sitting at when the engine is running?
At idle the alternator is putting out anywhere from 13.5v to 14.5v
Set the wind generator to charge to 13.6 and let solar top it off.
If your really worried then put a small u1 battery on terminal1 and a small dc2dc from LiFePo4 to your start bank.
A u1 is a lawnmower battery and can be had for under $50 USD.
just for your peace of mind wrt your start bank.

But that lawnmower battery is also a lead acid, no, so it would be the same what we have.



Do I understand you right, it's not really a problem, I could just increase the bulk on the windgen to 13.6V (instead of the 12.7V) and leave everything as it is with this (sounds like it in your car engine example).

[newhaul]

Originally Posted by Franziska

But that lawnmower battery is also a lead acid, no, so it would be the same what we have.



Do I understand you right, it's not really a problem, I could just increase the bulk on the windgen to 13.6V (instead of the 12.7V) and leave everything as it is with this (sounds like it in your car engine example).

Exactly .
Now as the u1 battery it could be a sacrificial if your worried about the 13.6v

[Franziska]

Originally Posted by newhaul

Exactly .
Now as the u1 battery it could be a sacrificial if your worried about the 13.6v

Great. So we'll keep things as us and ump it up to 13.6V on the wind controller.
Saves us buying a DC-DC charger. We only have a small cheap starter battery anyway, as it just needs to start the two Yamaha 9.9.

Have a great day, we are sailing over to Malta in a few hours.

Btw. what you said about the car alternator providing a range of voltages to the car battery, is there no charge controller involved?

[barnakiel]

Our regulator is 13.8 float (acid battery).


Given some loss, I will estimate 13.7 at the battery (lead acid plain car grade starter battery).


I have not noticed any battery deterioration. Hence my assumption is float at 13.8 is perfectly fine for a plain lead acid battery.


Float 12.7 sounds very 70'ies - like an old style alternator regulator in my granpa's Ford T.


I would turn it up while monitoring acid battery temps. All the way to 13.8. And beyond - if it is cold and not bubbling.



b.

[newhaul]

Originally Posted by Franziska

Great. So we'll keep things as us and ump it up to 13.6V on the wind controller.
Saves us buying a DC-DC charger. We only have a small cheap starter battery anyway, as it just needs to start the two Yamaha 9.9.

Have a great day, we are sailing over to Malta in a few hours.

Btw. what you said about the car alternator providing a range of voltages to the car battery, is there no charge controller involved?

There is a voltage regulator. As to the amperage output that is the lead battery and the peukert effect and internal resistance they have . The closer to full the more resistance.
Just set your wind generator to 13.6 or 13.8 and call it a win