LiTime 500A Battery Monitor Problem

Ricardo99

New Member
I have converted my 2013 EZGO RXV to a LiTime 48V 60Ah LiFePO4 lithium battery, and it is working real good. The battery has a BMS that constantly checks the status of the battery and checks for dangerous situations and shuts-off when it detects such problems. I am now trying to install the battery monitor that is recommended by LiTime for it. It uses a shunt. The monitor is installed but is not showing valid information, and it flashes constantly when turned on. The install instructions shows 6 parameters that are stored, but only says to enter the "Ah Capacity" which is 060.0 Ah, the "resting voltage" value when fully charged which was 56.8 V, and the "Zero Capacity" voltage value which I entered 000.0 because I didn't know what to enter. The other three parameters that are stored are "PowOff" voltage, the "Alarm Ah" Amp hours to warn when the charge is getting somewhat low, and the "Atten %" which is the battery attenuation ratio. But the instructions do not say anything about loading these values and what the values might be. Presumably if the right values are entered into the monitor, it will display valid battery status information.

The information the LCD is supposed to display is: (1) current Capacity Percentage; (2) Present Capacity in Ahs; (3) Charge/Discharge status (arrows up/down; (4) Remaining Charge/Discharge Time in hours&minutes; (5) Present Voltage; (6) Present Current in amps + or -; (7) Present Power Consumption in Kws.

The Capacity Percentage has always stayed at 100% thru 3 rounds of golf. The Present Capacity in Ahs has always stayed at 60 Ah thru 3 rounds of golf. The Charge/Discharge arrows are showing charging. The Remaining Charge/Discharge Time has always stayed at 00:00 hr/mn. Present voltage has declined from 54.x to 50.x.
The Present Current keeps changing rapidly. The Present Power Consumption keeps changing rapidly.

Can anyone help with what the 6 parameter values loaded in the monitor should be? The first 2 I believe are correct. I think the Zero Capacity Voltage needs to be a value other than 000.0V. The battery shut down when the voltage was above 48 V. I am guessing the PowOff voltage should be set at about 48.0 V. The Alarm parameter default is 40.0 Ah now, but should probably be at about 20.0. I have no idea what the Battery Attenuation ratio should be.

Can anyone help me with getting my battery monitor working properly?
 

Ricardo99

New Member
Hi Pat11. Below is link to a picture of the wiring on my EZGO RXV cart with the new LiTime lithium battery and their battery monitor and a narrative about the wiring.

Picture: New item by Dick Johnson
a. there is only one cable on the battery Negative post and it goes to B- post on the shunt. It is the original negative cable.

b. there are 5 wires/cables connected to the battery's Positive post:
1. Main (original) power cable
2. Wire to LiTime charger Anderson connector positive terminal (red)
3. Wire to prior charging receptacle (no longer being used)
4. Wire to DC/DC Converter (I believe) on driver side under the seat.
5. The special red, pinned-tip wire for the Battery Monitor to the B+ terminal of the shunt.

c, On the shunt, in addition to the cables/wires already mentioned above, there are the additional cables/wires detailed below:
1. From the shunt's B- terminal, a black wire to the Charger's Anderson connector used when charging the battery.
2. From the shunt's B+ terminal (in center of shunt) a shielded wire with a connector that came with the monitor to the monitor screen that is mounted in the dashboard of the cart where the old battery gage had been.
3. From the shunt's P- terminal there are four wires that used to be on the old battery's Positive terminal that were moved to the shunt's P- terminal. One goes to the old charging receptacle, one seems to go to the Reverse Warning buzzer alarm, and I don't know where the other two go.

I hope this gives you enough info to solve my problem.
 

Pat911

Cartaholic
According to the description above, it is wired incorrectly.

ALL positive cables should go to the battery positive terminal, not the shunt. This includes power for the shunt which is the B+ you mentioned above. You seem to have connected them to the shunts P-, that is incorrect.

The ONLY connection to the shunt B- is to the battery negative. Nothing else to either of those two connections, just a thick, high current cable connecting them.

Shunt P- has all the negative cables that would otherwise have been connected to the battery negative, so...... charger, thick main cart negative, DC-DC converter negative etc.....ALL negatives.

As for the original charging port, leave all cables disconnected except the one thin one which should be connected to battery positive.

Lastly, have you bolted the shunt to a metal frame? It looks like you may have. Make sure you're not shorting the B- and P- bolts via the frame.

Your shunt seems to be a repackaged Renogy 500A. There are operating and installation instructions for that on the 'net.
 

Ricardo99

New Member
Pat911: I made some mistakes where I described the wiring details.

a. should have added that the negative wire for the LiTime Charger's Anderson connection was also connected to the battery's negative post. I changed it to be connected to the shunt's P- post as you recommended.

b. this point concerned all the wires connected to the battery's positive post. This was correct as stated.

c. sub-point 1 should have been the P- post, not the B-.
sub-point 2 was correct as stated.
sub-point 3 was incorrect concerning where the wires had been connected. It should have said "from the old battery's Negative terminal" not the Positive terminal.

So now Pat, I checked the actual wiring and I believe everything is as you said it should be.

Regarding the wires of the old charging receptacle: I removed the positive and negative cables and the cart would not run. No juice. So I reattached the wires and it runs OK now.

Regarding whether the shunt is attached to metal and shorting out between the B- and P- posts: The shunt has a thick plastic piece thru which my installer (I didn't do the install of the monitor. I used the same guy who installed the battery and did that wiring) used sheet metal screws to attach the shunt to the body where the plastic body joins the metal flange along the back of the seat area, So the plastic part of the shunt abuts the metal flange, and the metal flange abuts the plastic flange which is on top of it. Study the picture. What I figured is that the plastic insulates the shunt from shorting. Howevcer, in examing it more closely, I found that the posts are metal and the upper end of each bolt could be touching the metal flange that runs past each post. So I was able to overcome this (I think) by wedging double-thickness of cardboard between each post head and the metal flange that was common to each post.

Regarding instructions for the install and operation: my installer used the manual for the Battery monitor to do the install, but as I found out he made a couple of errors that I uncovered and I believe I have fixed them. He didn't do the final part of the install where you enter values into the monitor and discharge the battery until it shuts-down to set the Zero Capacity voltage and the other values I had to get from you and from LiTime Support. I did that part. I guess my installer didn't know that was part of the install.

Concerning why I started a new thread: I thought focusing a thread on the fact that the Capacity Percentage staying at 100% might ring a bell with more reviewers. I can probably delete it if this creates a problem.

So at this point the cart runs and charges OK but the monitor is still giving me false information, and is always flashing when I have it lit. So to be safe, I am having to charge it after the equivalent use of 2 rounds of golf, where I believe I could get 3.5 rounds if I had info I could rely on from the monitor.
 

Pat911

Cartaholic
In regard to the other thread, you already had our attention, a new title hasn't made a difference.

A flashing display indicates charging, well on the equivalent Renogy anyhow. That would be why your SOC meter is constantly showing 100%. Are you certain you haven't got the shunt reversed. With the shunt reversed, and the charger connected to the wrong point as it was, it would always read 100% as charging current wasn't counted and discharge current is being treated as charge current. If you now have the charger connected correctly, but still have the shunt reversed, it should count down while charging and up while discharging. Opposite to what it should be doing. Is this now the case? I cannot study the picture as it is not clear or close enough. Can you post a closer picture of the shunt and its associated wiring please.
 

Pat911

Cartaholic
Adding to that, does your display show amps when using the cart or is it zero? Same when charging, does the display show the amps? See the image. It should be positive when charging and negative when discharging.500A.jpg
 

Ricardo99

New Member
The monitor seems to be displaying what might be reasonable info now after I just charged it up all the way. When I turn the key to Neutral, the monitor comes lit and it ISN"T flashing. It is showing 100% and the battery image shows full. The Present Capacity shows 60 Ah. The arrows show it is discharging. The remaining charge time now shows 43.xx hours and changes slightly. The present voltage shows 53.2 V and doesn't change. The Present Current shows -(minus) 1.xx Amps and changes slightly. And the present Power shows 75.xx watts and changes slightly. When I turn the key back to off, the monitor dims to off after a couple seconds.

The shunt is installed correctly as far as not being reversed. There is a label on the left side that shows B- and one on the right side that says P-.

It is 11:30pm (late)...I will send a photo of the shunt tomorrow afternoon. Thanks, I think we have made progress. I am anxious to see what is displayed while using the cart.
 

Ricardo99

New Member
Took the cart out for a spin to see if The Capacity Percentage, Present Capacity and Present Voltage decreased as they should when used. I drove the cart for 31 minutes for 7.75 miles at an average speed of 15mph, max speed of 24mph. The driving was on paved streets which were very level.

The Capacity Percentage went down to 79% from 100%, the Present Capacity went down to 46 Ah from 59 Ah, the Present Voltage to 52.8 from 53.2 V. The remaining time (not stopped) was 67 hours, but this value changes frequently and by quite a bit depending on speed and other conditions while driving.

So it looks like the monitor is working. I am anxious to see if the alarms come on at the values that have been entered into the monitor.

Thanks Pat911 for all your help. I really appreciate it. The secret was to get all the wiring connections right as detailed in the manual, as Pat911 detailed above.
 

Pat911

Cartaholic
The remaining time (not stopped) was 67 hours, but this value changes frequently and by quite a bit depending on speed and other conditions while driving.

Great to hear it's working.

The remaining time is highly dependant upon the current your drawing and will only be accurate if the current is constant. This is never the case on a cart. I would disregard that metric. Even the battery voltage is mostly irrelevant with LiFePO4 due to the very flat discharge curve. With voltage, just remember that when you hit 50v, you've got very little run time left, so get to a charger ASAP. If you get down to 48v, prepare for the battery to shut down on you.

The main thing you should look at is percentage. If it's accurate, try to keep it above 20%.
 
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