Poor-fair-good-charge

[SmokeyBear]

1997 Eagle.

These are the lights that light up for the chassis battery when I hit the test switch.

Everybody please note it is a 1997 therefore no panel, membrane buttons, digital, display nor any other of that modern crap.

All the lights are fairly obvious to me except the CHARGE light. When this (green) light is on, does that mean the battery is fully charged or does it mean it is being charged?

Thank You

[norty1]

It's a pretty meaningless indicator that is supposed to tell you the current state of the batteries charge.

Not to be confused with a real voltmeter.

[Grumpy]

Originally Posted by SmokeyBear

1997 Eagle.

These are the lights that light up for the chassis battery when I hit the test switch.

Everybody please note it is a 1997 therefore no panel, membrane buttons, digital, display nor any other of that modern crap.

All the lights are fairly obvious to me except the CHARGE light. When this (green) light is on, does that mean the battery is fully charged or does it mean it is being charged?

Thank You

If you're plugged into shore power it will always show full charge. You need to unplug and then it will give you a better indication regarding your battery condition.

[dvspl]

Here's the description of the four lights from my Jayco manual:
C= Charge at 12.7 volts
G = Good at 12.1 volts
F = Fair at 11.6 volts
L = Low at 6.0 volts

In practice, this means that the C light will come on when plugged in and may flash on and off for a little while after unplugging. The G light will be illuminated most of the time (for LAF batteries) if they're in good condition and charged. F will not come on until the battery is almost completely discharged (~20% SOC) and L will only illuminate when the battery is completely dead. This makes the 4 light unit virtually useless, in my opinion. Much better to use a real voltmeter or get a shunt-based battery gauge.

[SmokeyBear]

dvspl and norty1

Why do you consider these lights useless and meaningless. Please enlighten me.

Granted, they may not be completely accurate but at least a reasonable indicator. If the test FAIR light is on, then I know it's time to do something - generator, engine, or shore power - to charge the battery.

With my unit, in order to get the accurate volt-meter readings you suggest, I have to

1. Unlock and open the battery compartment door.
2. Remove the lock bolts that hold the battery in place.
3. Slide the battery out of the compartment.
4. Take the reading.
5. Slide the battery back in.
6. Replace the lock bolts.
7. Close and lock the battery compartment door.

Sure, I'll get a more accurate reading, but it seems a less-than-accurate reading will suffice.

[dvspl]

Originally Posted by SmokeyBear

Why do you consider these lights useless and meaningless.

Well, others may have a different opinion and it's been frequently debated on this forum. But I think that 11.6 volts is too far to routinely run down a flooded lead acid battery. I have lithium batteries, but if I were using lead acid I would try to limit my use to stay above 50% SOC (~12.1V). So I think the lights are worthless since there is virtually no way to tell the difference between 80% SOC and 20% SOC.

If it's difficult to get to your batteries to read the voltage, you can hard wire a voltage gauge to it. Many people have also used a 12V digital readout that will plug into a 12V (cigarette lighter type) outlet. Many older coaches had those located somewhere in the coach. Make sure it connects to your coach battery, not your chassis battery.

[SmokeyBear]

Originally Posted by dvspl

Well, others may have a different opinion and it's been frequently debated on this forum. But I think that 11.6 volts is too far to routinely run down a flooded lead acid battery. I have lithium batteries, but if I were using lead acid I would try to limit my use to stay above 50% SOC (~12.1V). So I think the lights are worthless since there is virtually no way to tell the difference between 80% SOC and 20% SOC.

If it's difficult to get to your batteries to read the voltage, you can hard wire a voltage gauge to it. Many people have also used a 12V digital readout that will plug into a 12V (cigarette lighter type) outlet. Many older coaches had those located somewhere in the coach. Make sure it connects to your coach battery, not your chassis battery.

Thanks. A much more definitive and objective answer than a subjective "I don't trust them."

No cigarette lighter type outlet powered by house battery, only chassis battery.

As an aside, what does SOC mean?
50% SOC= ~12.1V? Is 100% SOC ~24.2V?
50% SOC= ~6V?
80%= ~9.6V?
20%= ~2.4V?

Hint: Not good to use abbreviations for someone who is obviously unfamiliar.

[JFlightRisk]

SOC is State Of Charge.

[dvspl]

Sorry about the abbreviation. It wasn't clear to me from your question that you are "obviously unfamiliar" with batteries. Here's one chart that shows the relationship between voltage and SOC for flooded lead acid 12V batteries. As I said, there is much debate about the use of battery capacity below 50% SOC and the effect on battery longevity. You can find plenty of threads on this site using the search function.

[pconroy]

Originally Posted by SmokeyBear

Thanks. A much more definitive and objective answer than a subjective "I don't trust them."

I don't trust them either. Our old RV had 'em. The newer 2016 does not. The inverter has a numeric display.


You're also trying to measure a tenth of a volt to make some decisions. The accuracy and precision of the monitor is unknown. Use the panel to yield only the most broad guidance.

I agree with the others - what Jayco calls "Fair", I'd call discharged (if measured at rest).

When I started having problems with my lead acid battery, I bought an inexpensive volt meter, measured it's accuracy against my better meter, and then mounted it right next to the battery.


The insider meter registers about 0.1V off.

[craigav]

I trust the panel for what it is worth, which is very little, but it can still be of some value for a quick check. If you want to increase the value and accuracy of the monitor it is important to turn off all of the 12v lights and fans that you have on in the RV and not be connected to shore power (charging).

On mine for example, the battery level monitor can indicate one or two lights lower (good to poor) by simply turning on the lights in the RV. The reason is that the monitor doesn't have a direct connection to the battery and instead is measuring the voltage on a circuit that is subject to a voltage drop due to whatever is turned on in that circuit.

Similar thought is that if a person wanted to install a digital battery level voltage meter in their RV, it would be best to run the wires from the meter directly to the battery(s) as if you wired it to the same wires that the 4-light monitor uses, then you would see a similar voltage drop whenever 12v lights and fans were in use due to line loss, which you would not see the same drop in voltage at the battery (assuming a good battery that is charged). ~CA

[SmokeyBear]

Thanks everybody.

I think my next step is to get a digital battery level voltage meter, wire it directly to the house battery, and find a convenient location inside the rig where I can easily monitor it.

Any recommendations? I did a Bing search and found about 50, priced anywhere from a no-name for $7.68 to Auto Meter for $157.99.

[JFlightRisk]

It doesn't need to be super fancy, unless you have a preference to a particular model. Just one that shows the actual battery voltage on a digital display. I see a lot with a red/green bar scale, and those don't tell you much. Others look like they show a charge percentage. Better, but I like to see XX.X numbers that I can relate to.

[pconroy]

Originally Posted by JFlightRisk

It doesn't need to be super fancy, unless you have a preference to a particular model. Just one that shows the actual battery voltage on a digital display.

Agreed.
I've bought these style meters (from AliExpress) by the bucket-load:

digital voltmeter

[salukee]

I love the Victron Energy SmartShunt:

(https://www.amazon.com/dp/B0856PHNLX...t_details&th=1)

You can learn a lot about your 12v system with this unit. It is a bit pricey, but the info is worth it to me. Also, no drilling in the coach is required and I can also monitor the chassis battery.

I have read some negative reviews about the bluetooth and trending capabilities. My experience with both is positive. I can read the data from my phone from outside my enclosed pole barn and my RV doors shut. My batteries are located below the entry steps, just inside of door. Also, trending is really cool and informative. My only complaint about the trending is that you can only trend one parameter at a time.

[SmokeyBear]

Originally Posted by salukee

I love the Victron Energy SmartShunt:

(https://www.amazon.com/dp/B0856PHNLX...t_details&th=1)

You can learn a lot about your 12v system with this unit. It is a bit pricey, but the info is worth it to me. Also, no drilling in the coach is required and I can also monitor the chassis battery.

I have read some negative reviews about the bluetooth and trending capabilities. My experience with both is positive. I can read the data from my phone from outside my enclosed pole barn and my RV doors shut. My batteries are located below the entry steps, just inside of door. Also, trending is really cool and informative. My only complaint about the trending is that you can only trend one parameter at a time.

Interesting. Something I will look into. I like being able to see the info on my phone although it looks a bit more complicated than my feeble mind and abilities. I also like it is transportable if I should ever sell my rig. But, with today's technologies, it may be obsolete by then.