Questions regarding decoding my codes

Re: Questions regarding decoding my codes

Welcome to the forum Jason.

First, do you have a DMM (voltmeter) that you can use to start independently measuring voltages? If not, I would highly suggest you get this (or similar) AC/DC current clamp DMM (digital multi-meter) which is "good enough" for our needs.

Next, you need to get a hydrometer and measure/log the temperature corrected specific gravity for each cell in every battery.

From your readings:

One thing that I an confused by is the volts reading : 4.98min, 12.32 max, currently reading 11.76 volts (this reading changes when I turn stuff on)

Your batteries have probably been taken DEAD (10.5 volts resting or less, is a dead battery and probably not long for this world even if recharged).

Measuring battery voltage is a tough thing to do and get accurate/interpretable results. Batteries are State of Charge, temperature, and current flow sensitive.

For example, a good battery that has rested for ~3+ hour with no load at room temperature:

• ~12.7 volts is full charge
• ~12.0 volts is ~50% charge
• ~10.5 volts is "dead"

When running larger loads (more than 1 amp or so), you probably do not want to see the battery bank operating below ~11.5 volts for very long--That is ~50% state of charge and should be recharged pretty soon (starting in hours or next day).

When charging a battery--You want to see the battery voltage >~12.7 volts minimum. And at least ~13.8 to 14.5 volts when charging well (lots of current, no loads). And you want to see the battery with >14.5 volt held for ~2-6 hours (longer time if the battery is well discharged).

In some cases, you may want to see ~15.0 volts (or more) when equalizing/trying to recover a battery that has been severely discharged/abused.

You don't want to ever expose the battery plates to air--That will ruin the exposed portions very quickly.

So--If your system voltages are correct (11.5 volts when charging)--It is very probably that your batteries are now "toast".

-Bill

Re: Questions regarding decoding my codes

So, you have several steps to take.

Measure the SG of your batteries.
Get the batteries on an AC battery charger (generator/utility power?) and get them >75% charged right now (keep batteries from further sulfating)
Determine if your solar charging system is working (measure charging current/voltage under full sun--A DC Current Clamp Meter is very handy for that).
Fix/upgrade the solar power system (review battery bank size, loads, charging system parameters).
Replace batteries (probably)
Monitor battery bank state of charge with S.G. readings, monitor loads, voltages, charging current--A Battery Monitor (like Tri-Metric) is a very nice to have (but not cheap).

Here is some information about batteries:

http://www.windsun.com/Batteries/Battery_FAQ.htm
http://www.batteryfaq.org/
http://batteryuniversity.com/

=Bill

Re: Questions regarding decoding my codes

Things to check include making sure the solar charge controller is close to the battery bank with fairly heavy copper wiring (i.e., 15' of 14 AWG wiring would be legal with one solar panel, but can severely restrict charging current (i.e., battery bank is at 11.8 volts but charge controller is "seeing" 14.5 volts because of excessive voltage drop).

-Bill

Re: Questions regarding decoding my codes

Assuming you are in the southern US, your sun is around 31 degrees this time of year. Flat panels would have a derating of:

• 7.95 amps * Cos (90-31 degrees) = 4.1 amps assuming everything else is "ideal"

So--4 amps around 11am-12pm is pretty much "dead on" for flat mounted panel around solar noon at this time of year into a battery that the charge controller "believes" needs full charging current.

If you tilted the panel to approximately 60 degrees from horizontal, you would get almost 2x more solar power during the middle of the day. ~45 degrees would be a good compromise for this time of year (assuming you are around 30 Degrees Latitude).

At this point you either assume that everything is working OK and you simply have too much load and/or not enough solar power.

If you wish, we can go through the setup you have right now and figure out if everything is actually working OK. Here is what I would do. First using PV Watts for near where you are at (I pick Los Angeles for now--Move to your true location if different). Fixed array at 0 degree tilt:

Month    Solar Radiation (kWh/m 2/day)
1      2.88     
2      3.87     
3      4.77     
4      5.76     
5      6.57     
6      6.79     
7      7.00     
8      6.60     
9      5.13     
10      4.15     
11      3.21     
12      2.72     
Year      4.96

Pick ~2.8 of sun at this time of year and I would guess the total amount of AH available per day would average around:

• 140 Watts * 0.52 system eff * 2.8 hours of sun = 204 WH of AC power per day (on average)
• 7.95 Amps (full sun) * 0.80 Battery Eff * 2.8 hours of sun per day = 17.8 AH per day (of 12 volt power)

If you system performs as above--You can pretty much stop there for now and figure out what to do next (more panels, less loads, more generator use, etc.).

You can also look at the present system design and make sure that everything is OK. Roughly what I would do is get a deceint DMM (or AC/DC Current Clamp DMM) and do some measurements and document your system setup (to review). And give us the results of each step (take voltage/current measurements in the middle of the day with a "discharged" battery bank and/or turn on some battery loads in your RV).

1. In full sun, measure battery voltage and charging current. If battery is under 12.7 volts, continue below
2. Measure the voltage on the Battery Out of the Charge controller
3. Measure the voltage on the Solar Panel In of the Charge controller
4. Tell us what brand/model of charge controller
5. How long and what gauge is the wiring between the charge controller and the battery bank (i.e., 4 feet of 14 AWG cable).
6. How long and what gauge is the wiring between the charge controller and the solar panel/array.

Ideally, I would recommend that you only see a 0.05 to 0.10 volt drop in the wiring from the charge controller to the battery bank (under full charging current). Too much voltage drop will cause the charge controller to think the battery is at a higher state of charge than it really is.

For voltage drop between the array and the charge controller, upwards of 0.5 volt is OK, better would be 0.1-0.2 volts.

With a PWM charge controller under full charging current, the Vpanel input will be 0.1 to 2.0 volts higher than Vbatt-charging.

With a MPPT charge controller under full charging current, the Vpanel input will be around Vmp-array (something like 17.5 to 18.6 volts or a bit less).

And, get a decent glass hydrometer and tells us the specific gravity of each cell in the battery bank.

Your choice how far you want to go--But a "small array" and mounted flat to roof is going to put your charging current/total harvest way down during the winter time. During summer, you will get 2+ times more energy harvest and the "flat mounted" panel(s) is less of an issue.

-Bill