Author Topic: showing 25 volts in no amps or watts ???  (Read 2266 times)

alehowe

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showing 25 volts in no amps or watts ???
« on: October 19, 2015, 04:18:21 PM »
I have 750 watts of solar panels on my roof (all new) showing 25 volts in on my MidNite charge controller. But I am not showing any watts or amps in?  ??? :o

Westbranch

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Re: showing 25 volts in no amps or watts ???
« Reply #1 on: October 19, 2015, 06:24:03 PM »
Got the specs for those panels?
What time of the day did you get the reading ?
Is the classic connected to your batteries?
Did you take any other readings somwhere on your wiring system?

cheers
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Halfcrazy

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Re: showing 25 volts in no amps or watts ???
« Reply #2 on: October 19, 2015, 07:27:23 PM »
What is the battery voltage?
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alehowe

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Re: showing 25 volts in no amps or watts ???
« Reply #3 on: October 19, 2015, 08:34:08 PM »
3 Renogy 250 watt EA. (750WATTS TOTAL) solar panels put on roof at 2pm today full sun, wired to MidNite Combiner with a 30amp fuse for the input of the solar panels. The volts in are 25. the MidNite Classic is wired with a 150amp fuse to a 24 volt battery bank ( 8, 6 volt 215amp gulf cart batteries in (SERIES) Help please, Thank You

alehowe

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Re: showing 25 volts in no amps or watts ???
« Reply #4 on: October 19, 2015, 08:39:31 PM »
The battery voltage is 23.1

Westbranch

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Re: showing 25 volts in no amps or watts ???
« Reply #5 on: October 19, 2015, 08:44:55 PM »
That is not good (23.1V) that battery is close to death if this continues...

What loads do you have ?
How old are the batteries?

If they are FLA batteries, what are the specific gravity readings for all the cells?...
there may well be a couple of bad cells.

also measure the volts of each of the 6V batteries.

hth

ADD:  the panels specs are 30.1Vmp, 37.5Voc, 8.32A Imp, 8.81A Isc
« Last Edit: October 19, 2015, 08:47:15 PM by Westbranch »
KID FW1811 560W >C&D 24V 900Ah AGM
CL150 29032 FW V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
2 Cisco WRT54GL i/c DD-WRT Rtr, NetGr DS104Hub
Cotek ST1500 Inv  want a 24V  ROSIE Inverter
OmniCharge3024  Eu1/2/3000iGens
West Chilcotin 1680+W to come

alehowe

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Re: showing 25 volts in no amps or watts ???
« Reply #6 on: October 19, 2015, 08:59:13 PM »
The batteries are a year old, I got them new and stored them in a room in my house. I have not put any loads on yet. Ea. battery is about 5.6 volts

Westbranch

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Re: showing 25 volts in no amps or watts ???
« Reply #7 on: October 19, 2015, 09:05:08 PM »
get a charger hooked up asap and bring them up to ~ 13.2V per 12V pair of batteries if you do not have a 24V charger.  Even a basic car charger is better than nothing...

they have just degraded themselves while siting... and are possibly suphated too...  we will see as you geet them charged up...
KID FW1811 560W >C&D 24V 900Ah AGM
CL150 29032 FW V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
2 Cisco WRT54GL i/c DD-WRT Rtr, NetGr DS104Hub
Cotek ST1500 Inv  want a 24V  ROSIE Inverter
OmniCharge3024  Eu1/2/3000iGens
West Chilcotin 1680+W to come

dgd

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Re: showing 25 volts in no amps or watts ???
« Reply #8 on: October 19, 2015, 09:10:32 PM »
It appears you have the three panels wired in parallel and the output voltage of 25 is not high enough to allow the Classic to charge the 24v battery bank.
Disconnect one of the panels and wire the remaining two in series so you see about a 50volt output from them. This will be good for the Classic to start charging the bank.
Get a 4th identical  panel and make another series pair that can be wired in parallel to the first pair so you still get near 50v at about 16 amps in good bright sunlight.

Do this ASAP as these batteries are getting closer to death.

dgd
Classic 250, 150,  20 140w, 6 250w PVs, 2Kw turbine, MN ac Clipper, Epanel/MNdc, Trace SW3024E (1997), Century 1050Ah 24V FLA (1999). Arduino power monitoring and web server.  Off grid since 4/2000
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Vic

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Re: showing 25 volts in no amps or watts ???
« Reply #9 on: October 19, 2015, 09:12:05 PM »
The batteries are a year old, I got them new and stored them in a room in my house. I have not put any loads on yet. Ea. battery is about 5.6 volts
Hi alehowe,



Several things;

It is generally a very bad idea to let batteries sit,  without some charging every month or so.  NiCd  batteries and NiMh batteries are possible exceptions.

You say that ea battery is about 5.6 V.   Assume that  these batteries 6 V ea,  and there are four in series for a 24 V bank.

This is a fairly low voltage.

AND,  an Input voltage of about 25 Volts is not enough for any MPPT CC to work,  on a 24 V bank.

Most 250-ish Watt PVs are 60 cells.  This equates to a Vmp of about 30-ish volts at STC.  With the PVs warm or hot,  this will not be enough voltage to allow most  MPPT Charge Controller (CC) to work well.

Assume that you have wired all three PVs in parallel.  On a 24 V battery bank,  and with three PVs,  you may not have much choice,  but to wire all three PVs in series.   This will give about 90,  or so volts input to the CC.  This configuration of three PVs in series,  should help the  CC to charge those batteries.

We all are making a lot of assumptions,  because there is not much information on the details of your system.

Guessing done,  for now,   Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

Halfcrazy

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Re: showing 25 volts in no amps or watts ???
« Reply #10 on: October 20, 2015, 06:50:48 AM »
As DGD pointed out the issue here is the PV for some reason, Are all 3 Modules wired in Parallel?

If I am reading the specs properly these are at 37VOC so you could put all 3 in series and then the Classic will work. (PLEASE VERIFY I am correct on the specs so you do not go over the 150v limit)
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