So I think my ZAMP controller is trying to tell me something (but I don't understand)

[Vic]

(Disclaimer - I'm OK with a wrench but not so sharp on electrical, so don't assume I know anything. I'm putting down all of the clues I have collected)

Took a 4 day trip to Yosemite last weekend...and ended up with dead house batteries. Noticed it when we went to lower the lid and the motor wouldn't turn. I have a suspicion that something is going on that I don't understand and hoping you can help me diagnose.

The clues:

1 - truck was plugged in up until the day of the trip, and then drove 4 hours to get to Yosemite. I assumed that I would start the trip with a full charge. Did run the fridge the whole way. Usual way I depart for a trip.

2 - Fridge is a Novakool 4500 with 2.4 amp draw on 12v. Didn't run the furnace this trip and only other known draws were detectors/some lights and water pump. Compared to my last big trip in March - a 9 day trip to Arches where we ran the furnace quite a bit too in addition to the fridge and more lights, this was a very light usage trip. And a lot more sun this trip.

3. ZAMP is mounted in kind of an awkward place for me to see so I don't check it enough, but on evening of day 3 I noticed that the low batt light was on, but fridge was still running and we were leaving the next day so I turned the fridge warmer to minimize draw and turned in for the night.

4. Late morning headed back and there wasn't enough power to lower the lid, so I fired up the truck and everything was fine, and headed back to home (another 4 hour drive)

5. Got home - and this one really surprised me - and the house batteries were still too low to run the lid or barely even the LED lights. I didn't get much charge in 4 hours of driving.

I should mention that I have 2 6 volts as the house batteries.


so today I finally had a chance to gather more info. I had everything turned off except the monitors for the first 4 hours. Here are my stats:

7:00 am 12.8v .5a .47ah
8:15 am 12.9v 1.2a 1.51ah
9:15 am 12.9v 0.0a 2.70ah
11:15 am 12.8v 0.0a 4.0ah
1:00 PM 12.8v --- 4.72 ah
1:05 PM 12.5 1.3a 4.74ah <---turned on fridge and fantastic fan
2:00 PM 12.4 1.4a 5.94ah fridge still on and cooling down

 

[Vic]

so I went to the ZAMP instructions. It says the controller has 4 readouts to toggle through

Battery Voltage
Charging Current
Charged Capacity (Amp Hour)
and Battery Temp (which isn't hooked up)

So here are my first 2 questions.

First - In my 3rd and 4th readings of the day, I got a 0.0 charging current. Does that mean the Solar Panels were in a coma or that the controller shut them off because it was charged at that point from sitting in the sun with basically no draw?

Second - What really does Charged Capacity mean? Clearly not the total capacity of the batteries? Is it just what the panels have put back into the system that day?

Bonus question - the 1.2-1.4 output that I'm getting seems on the very low side for 2 100w panels on a sunny day, yes? If the fridge is 2.4, and I'm only getting 1.4 max, don't see how they would ever keep up with the fridge.

I'm going to stop there and see if I'm on the right path, and keep collecting data this afternoon.

Thanks in advance!

 

[craig333]

You should be getting a lot more amperage than that. I'd start by making sure all the connections are good.

 

[Vic]

so here is my other dilemma - I seem to be having trouble charging from both the truck and solar. Related or 2 separate problems?

 

[JaSAn]

Here are my stats:

7:00 am 12.8v .5a .47ah
8:15 am 12.9v 1.2a 1.51ah
9:15 am 12.9v 0.0a 2.70ah
11:15 am 12.8v 0.0a 4.0ah
1:00 PM 12.8v --- 4.72 ah
1:05 PM 12.5 1.3a 4.74ah <---turned on fridge and fantastic fan
2:00 PM 12.4 1.4a 5.94ah fridge still on and cooling down

First - In my 3rd and 4th readings of the day, I got a 0.0 charging current. Does that mean the Solar Panels were in a coma or that the controller shut them off because it was charged at that point from sitting in the sun with basically no draw?

It means that your batteries are getting very little. The 'charged capacity' is increasing so your batteries are getting a little charge (~ 1a per hour)

Second - What really does Charged Capacity mean? Clearly not the total capacity of the batteries? Is it just what the panels have put back into the system that day?

Looks like it is adding up amphours put into the battery in some period of time (it probably resets to 0 overnight).

Bonus question - the 1.2-1.4 output that I'm getting seems on the very low side for 2 100w panels on a sunny day, yes? If the fridge is 2.4, and I'm only getting 1.4 max, don't see how they would ever keep up with the fridge.

Unless your frig runs constantly it only draws 2.4 amps for a part of an hour. At 30% duty cycle = 0.72 amphours per hour; so it is barely keeping up during the day and the frig runs at night too.

Your voltages look low. I'm getting 14.6 volts in absorption and 13.5 volts in float from my system which is similar to yours. If your batteries are discharged you should be getting up to 12 amps from 200 W solar from full sun in bulk.

Here is where I would start:

Check the batteries. Charge them. If FLA, measure specific gravity. If AGM, you need to let them rest for 12 - 24 hours (nothing in or out to let surface charge dissipate), then check voltage. 6 volt batteries should be ~ 6.6 volts fully charged. If your system has worked well before it could be that one of your batteries has a bad cell. You could also take them in to have them tested.

If batteries OK start at one end and check voltages at all connections. Your panels should be generating ~17 volts in full sun so you should be getting 15+ volts at the charge controller and 14+ volts at the battery terminals in absorption (look at Zamp documentation for absorption and float voltage settings).

jim

 

[Squatch]

That's a pretty deep discharge and you may have damaged the batteries. Also some AGM will kind of lock up if discharged too low. They can still be good but won't take a charge. They need a kick in the pants to wake them up. This can be done by hooking one to a good charged battery and then trying to charge. Optima used to have a video on this.

Also sometimes a battery can have great voltage but falls on it's face when a load is applied. As in no amperage available. I ran an Optima blue top in my 4x4 for several years as my battery. It was working fine. I drove 8 hrs home from a vacation and the next day the truck wouldn't start. It had 12.8 volts. Took it to a battery place for load testing and there was nobody home. No amperage at all. It was also 7 years old.

 

[PaulT]

+1 on what JaSAn said.
Check fuses in solar panel wires going into Zamp solar input. Check fuse in Zamp output line going into battery.

Determine what your battery type is for your two 6 volt batteries. The Zamp shows the battery profile it is following. Be sure it matches your battery type.

12.9 is a good voltage for a battery that is fully charged with no solar input. The charger should show about 14.5 volts in good sun while charging a battery that is discharged considerably. When the battery is fully charged and the Zamp is in float mode, you should be seeing about 13.5-13.6 volts in good sun.

The Amps display shows the current the Zamp is putting out to the load which includes battery charging plus the fridge, lights, furnace etc.
To truly know the battery SOC (State of Charge), you need a battery monitor like the TriMetric.

If you plug into shore power, the Zamp will show 14+ volts as the inverter is charging the battery. Ignore the aH reading for now as it shows the charge that the Zamp has put into the battery and not from the truck or shore power. It does not show what has been pulled from the battery. The TriMetric would do that.

Congratulations. You are in the steep learning portion of understanding how your battery storage/charging system works. This, too, shall pass. Hang in there.

Paul

 

[Vic]

Thanks all for the responses. I've got my checklist for today's project. Time to dig out the old multi-meter.

 

[Vic]

Ok - need to put my thoughts in order here and figure out what I have:

After I verified the controller was set to the right battery type, I started this morning with 2 saddle blankets on the roof. I covered both panels and had my wife check the monitor as I uncovered 1 at a time. Covering/uncovering the right panel didn't seem to change the readings so I began to suspect a bad panel.

I pulled the master solar fuse, covered both panels, and unplugged them (the big warning labels everywhere about not disconnecting when under a load got my attention). With both panels isolated, I tried the volt meter on each:

Left Panel - ~18 volts
Right Panel - 0.0 volts

Next step was figuring out the amp meter part of my multi-meter. After a bit of reading, I went back up top and did the same thing with amps:

Left Panel - 3.99 Amp
Right Panel - still dead

So then I get the interesting idea to reattach everything EXCEPT the dead panel. Now I'm getting 3 Amps at the controller - more than double what I was getting with both panels attached.

Is it possible that a dead panel was doing something negative with the good panel and removing it from the circuit helped?

Also, I'm a little surprised I lost a full amp from the panel to the controller - its about ~6 feet of wiring - is that excessive?

So...next step is replacing the dead panel for sure.

 

[smlobx]

Vic- what year is your Everest?
Also, do you have two 6 volt batteries like I do?

 

[CALIcamperdad]

Check polarity i found the wiring on my two panels were reversed regarding marked wires


The panel will have a small diode in the small box on the back of the panel. I've heard in many cases you can just replace that and be back up running again.
My little 10watt Renogy panels 2 tied into a single feed to a basic $30 20amp controller will max out around 21 volts at prime June cool sunny days pushing about 3amps max. Typical output is about 13-16volts at 2 amps. My charger goes to float at 13.4. My little 28amp hr lead acid battery is pushing yr three and so far is pretty happy with the setup. No issues.

 

[wuck]

Panels usually have at least one bypass diode in them, my ancient Kyoceras have 4 diodes wired in the junction box on the rear of the panel. When I purchased my camper, I had one panel only putting out half of the rated voltage. Opening the junction box, I found the diodes blown up, with some of them shorting out half the panel:

Those blown diodes, along with two blown ASC controllers, no fuses in the solar circuitry, and new flooring underneath the 140-something pound battery led me to believe the previous owner had connected the battery backwards after installing the new floor. But, the panel survived. New diodes did the trick.

You can certainly "Lose an Amp" after connecting the system back up. Some basic DC theory: Power, in Watts = Volts x Amps. When measuring the open circuit voltage on a panel, there is no current flowing (A voltmeter is an open circuit for all practical purposes), so 18 volts x 0 amps = 0 watts. Similarly, when you measure the short circuit current, there is no voltage present (the ammeter shorts out the panel) 4 amps x 0 volts = 0 watts. With the system connected and a non-MPPT controller, the voltage adjusts to whatever the battery level is, so let's say 12 volts x 3 amps = 36 watts. Ah, real power at last! A Max Power Point Tracking (MPPT) converter will adjust the loading the panel sees in order to maximize the power output, so the panel voltage will be somewhere 14-18 volts while peaking the current.