Midnite 150 classic not reading more than 70 watts

[Jrm2288]

Hello,

I have the following:
MidNite classic 150 sl
2 - 12 volt AGM batteries
4 - 340 watts 46.60 voc 9 amps Seraphim PVs

These panels are parallel connected.
It seems that I can not get more than 70 watts when all connected in parallel when full sun.

What do I need to change in order to get more watts?

Thanks,
Javier

[mike90045]

What voltage is your battery system, 12V or 24V ?   A 24V system needs up to 32V for charging, and the controller should have 130% of that voltage [ 42V ]

[ClassicCrazy]

In addition to Mike's questions would also be good to know what settings for Absorb and Float and what status the charge controller says when you think it should be putting more power out. Once the batteries are full then no more power will go into them , but if you turn on big loads  you should see more power if available from PV at the time.

But like Mike says - if you have 24v system then you probably need to series two of of your PV to get the voltage up high enough for controller to work properly .

Larry

[boB]

When you DO see around 70 watts output, what is the PV INPUT voltage on the Classic showing 

as well as the charge stage (Bulk MPPT, Absorb, Float, etc) ??

[Vic]

Hello Javier,

Using the Classic String Sizing Tool,   will help you design the best configuration of your PVs.   Be certain to pay attention to what is said in Note 2,   regarding having a minimum Vmp  of 130% of the highest battery voltage,   etc,   as has been alluded to earlier:

http://midnitesolar.com/sizingTool/displaySizing.php

FWIW,   Vic

[Jrm2288]

Thank you all.
I changed the Absorb volt option in the controller to 42v. When I did this it started reading 500 watts - 73 volts - Bulk MPPT mode. Looks like it is working now.

Best,
Javier

[ClassicCrazy]

Thank you all.
I changed the Absorb volt option in the controller to 42v. When I did this it started reading 500 watts - 73 volts - Bulk MPPT mode. Looks like it is working now.

Best,
Javier

If you have two 12v batteries in parallel then you have 12v battery
If you have two 12v batteries in series then you have 24v battery

Setting your Absorb voltage so high you are going to cook and ruin your batteries.

Larry

[ClassicCrazy]

As Vic suggested above use the Midnite calculator tool and put in the info from your system.
Then post a screenshot of the results for us to see and we can give you better information about your system and settings
We do not know the size of your batteries ( in amp hour capacity) or if you have them wired for 12v or 24v .
If you use the wrong settings you will destroy your batteries. So it is very important to look up the battery manufacturer and see what they recommend.
We can help you on here but need more info

http://midnitesolar.com/sizingTool/displaySizing.php

Larry

[boB]

Warning Will Robinson !

If you are charging a 12V or 24V battery system at 36V to 42V, your batteries are most likely dead now. Especially AGMs as they will be "plump" and can be VERY dangerous !    At this high voltage, AGM batteries will usually also be VERY HOT.

If the batteries were only accepting 70 watts before, then they were probably already charged and would not take any more power at that point !

Please check your system.

boB

[Jrm2288]

Sorry for the confusion. Absorbe was at 32 v and I changed it back to 28 v when I ear batteries making noise.
Like bob says, controller is not reading more than 70 watts, because batteries may be almost charge.

See attachment for sizing tool and let me know with any advices.

Thanks again.
Javier

[Vic]

Hi Javier,   thanks for the added info.

Even with AGM batteries,   your system would most probably produce more reliable power production,   by wiring your PVs as Two strings of Two PVs in series.

If you are in the Tropics,   with attendant higher average temperatures,  you might be able to do OK (generally),   with all PVs in parallel.

Make certain that you use the Battery Temperature Sensor (BTS),   attached to one of the batteries,   about half-way down the battery case.

When AGM batteries make any Venting noises,   this is NOT GOOD.

EDIT:  OH !!   FWIW,  you should change the number of Strings in that Sizer output from one,   to four.  This is your current configuration.

AND,   did you enter your expected ambient temperatures before you ran the Sizer?   Those do look like the Defauts.

Also,  the Power that you need to enter at the top of the Sizer chart,   is the power of each PV.   Changing this to 340,   and to four strings of one should help the Sizer output be more meaningful (sometimes) ...<

FWIW,   Good Luck,   Vic

[boB]

Javier, even 32 volts may be too high for AGM batteries.  Look at the specifications to make sure.

Also, you should use a volt-meter to check voltage across each 12V battery to make sure they are similar voltage.
I have seen too many AGM batteries get "off" and then one battery gets hot and bulges out because it got hot while charging.

If there is a difference, you might also check the temperature difference between the two batteries to make sure they are similar in that way too.  If they aren't being charged at the time you check, they may be cool then so you might check when they are charging.

Just to make sure things are OK....

What kind of loads do you have ?  Have you loaded them down to make sure the batteries are delivering power ?

boB