Cobra CPI 1575 inverter squeeling OCP code

[Ozark Mountain Gal]

We have a small system that gives power to our dock. It operates a few lights, our boat lift, occasionally a small vacuum etc. It was installed by a certified electrician, who is no longer in the area, just over 4 years ago. It consists of two deep cycle marine batteries, a Cobra CPI 1575 inverter, a Morning star ProStar-15 PS-15M Solar Charge controller and a solar panel. It has run without a hitch until last week we cut a 2x6 with a circular saw. First time fine. Second time, saw would not work just squealed. Or maybe the inverter squealed. The lights will come on but nothing else will work. Not the blower for the boat lift, the saw, the vacuum etc. We disconnected the batteries. One connection looked iffy so we replaced the connecter. We tried testing everything but we don't know, or understand what we are looking at. We purchased a new inverter but when we hooked it up it did the exact same thing and gives us an OCP code like the old one. Per the inverter manual OCP means Over temperature protection Hard to understand as we don't understand how it could be over temperature when it has just been turned on. I am sending the new inverter back on the off chance it's bad. There isn't a electrician within two hours of here. We are trying to educate ourselves but really don't know what to check next. I scanned through some of the posts on this forum to see if I could find an answer, but my head hurts from reading stuff I just don't understand. Its like trying to understand a foreign language... If someone could point us in the right direction it would be so appreciated...

[Mike90250]

Welcome

I suspect the batteries are getting old and soft, and cannot meet the heavier loads anymore. Not having the code book, I suspect the alarm you hear is the low battery alarm.

4 years is a good life for marine batteries, since a replacement inverter has the same symptoms.

When you replace them, use a pair of 6v 200ah golf cart batteries wired in series, they handle loads better.

[inetdog]

Welcome

I suspect the batteries are getting old and soft, and cannot meet the heavier loads anymore. Not having the code book, I suspect the alarm you hear is the low battery alarm.

4 years is a good life for marine batteries, since a replacement inverter has the same symptoms.

When you replace them, use a pair of 6v 200ah golf cart batteries wired in series, they handle loads better.

The manual is pretty clear that OCP is the over temperature alarm. It also has this comment:

Power Output
The inverter can deliver1500 watts for about 60 minutes.
The inverter must cool for 15 minutes before it can
resume operation at 1500 watts. Note: The wattage
rating applies to resistive loads.

So it would not be surprising for the first inverter to not turn back on immediately, but I have no explanation for the error on the new one, first time the load was connected.

I suppose it is possible that the programmer made a mistake and the OCP code is also shown for some other obscure error condition. But overcurrent and low battery are definitely different codes.

See https://www.cobra.com/sites/default/...ls/CPI1575.pdf for more information.

[Ozark Mountain Gal]

Welcome


When you replace them, use a pair of 6v 200ah golf cart batteries wired in series, they handle loads better.

Thank you for the response Mike. I hope I did the the quote thing right. So this is going to indicate how much we don't know.... Confirm wire them in Series because I'm thinking we are currently wired in parallel and we really have no clue what the difference is. We normally don't need much power. And am I correct in thinking that the sudden request for power with the circular saw might have been what caused this fiasco?

[Ozark Mountain Gal]

The manual is pretty clear that OCP is the over temperature alarm. It also has this comment:


So it would not be surprising for the first inverter to not turn back on immediately, but I have no explanation for the error on the new one, first time the load was connected.

I suppose it is possible that the programmer made a mistake and the OCP code is also shown for some other obscure error condition. But overcurrent and low battery are definitely different codes.
.

Ah. Hmm.. when I read the manual (which I didn't understand) I missed the part about waiting 15 min. Thank You. We are going to go back down tomorrow and hook the old one back up. It has now been off for a week. When it was on the digital reading says 14 which we take to mean that's what the batteries are at. and the controller says the batteries are charged. But is it possible that they have gone bad? We aren't sure how to check them. My thought was that maybe there is enough power for the lights but not enough for a heavier draw like the blower for the boat lift? Does that make any sense? As far as the new inverter giving the same code I am hoping that It's my "luck" that the new one is bad. We have a Snap on EEDM503D Digital Multimeter that we are trying to learn how to use. Anything in particular that we should test? Thank you so much for your help.

[Mike90250]

..... We have a Snap on EEDM503D Digital Multimeter that we are trying to learn how to use. Anything in particular that we should test? Thank you so much for your help.

1) I suggested 2 six volt golf cart batteries in series (produces 12V) if you put 2 - 12V in series, you get 24V and lots of smoke and flames.

2) and I'll suggest you stop messing with batteries and such, until you get a bit of electrical knowledge under your belt. Even using a quality meter in the wrong way (left in AMPS setting and attempting to measure Voltage) can cause a big fireball in your face.

There may be some good places to learn basic electricity and how to work safely with it, we have no tutorials for that here.

Go slow and be safe.

[Ozark Mountain Gal]

1) I suggested 2 six volt golf cart batteries in series (produces 12V) if you put 2 - 12V in series, you get 24V and lots of smoke and flames.
.

Thank You. I read Sunking's tutorial on batteries and have a better understanding. Doesn't solve our problem but I am slowly building a foundation. Every little bit helps.

[Sunking]

Ozark two things are biting you in the butt.

1. To small of a battery for the inverter. You can get away with with it when the battery is fully charged, run the inverter near full power for a short amount of time, and the sun is out shinning to supplement the battery.

2. Running a Inverter at full power for extended period of time on small cables.

The two will compound and cause exactly what you are seeing. Ideally you want to size the Inverter so it is only loaded to no more than 75% maximum load. For extended run times closer to 50%.

If you need to run a small battery which it sounds like that is the case for your intermittent use, you need to consider using AGM batteries and be very selective which manufacture and size you use. Example lets say the inverter needs to run a 1000 watt load at 12 volts for 15 minutes. You are going to want to use at least a 1500 watt Inverter which is really large for 12 volts but let's run with it. A 1500 wat Inverter requires 140 amps @12 volts. Really good AGM batteries can candle a C/3 load current. That means you are looking for a 3 x 140 amps = 420 AH AGM battery. You are looking at something like using a pair of Concorde PVX-4050HT L16 6 volt batteries. Don't have a heart attack when you click the link. In addition you wil need a set of 1/0 Extra-Flex copper cable to connect the batteries to the inverter.

The Concorde 4050HT has an internal resistance of .002 Ohms with two in series. At 100 amps the voltage will only sag to 100 x .002 = .2 volts or less than 2% at 12 volts. A pair of FLA at 400 AH batteries will sag up to 2 volts or 20% which means inverter shuts off.

[Ozark Mountain Gal]

Ozark two things are biting you in the butt.

Thank you for the info Sunking. Yesterday I stumbled on sticky posts written by you that were tutorials. One was about batteries. Today I can't seem to find them. Never mind just found it. I stumbled on it again. I really appreciate the time you took with your suggestions... We purchased a battery tester and found that Mike was correct. Under a load, our batteries pegged dead. I have done further research and found that we cannot change the components of our existing system without an additional inspection from the corps of engineers. The dock is on the lake and under their jurisdiction. Also changes, installation, must be done by a certified electrician. We are stuck with maintaining the existing system that was installed 4 1/2 years ago by the corps inspector. Unfortunately he has left the area. I am hoping that Inetdog was also correct and that the high temp code was actually a program error and should have been a low battery code. We will see once we find new batteries and hook everything back up today. Mike I did note your suggestions re generator... went that route. Generators are a favorite of local sticky fingers. And not possible to cart it back and forth as we have to hike to the dock. Solar components don't seem to be on their Christmas list.

[Mike90250]

Well, you got 4 years, which is good, just get 2 more of the same, and wire as before, and repeat in 4 more years

[Ozark Mountain Gal]

Well, you got 4 years, which is good, just get 2 more of the same, and wire as before, and repeat in 4 more years

Fingers crossed.