Installing a battery level meter

[jlpmedia]

I just bought a 48v golf cart battery level gauge, it has a positive, negative, and signal terminal. To get this to work properly would I need to wire in the signal? where does this signal come from? the controller?
I dismantled my thumb throttle that had a simple full, half, and empty charge indicator and found that it only had 2 wires. pos/neg. is this all i need for my new meter?

 

[amberwolf]

YOu'll need to check it's directions, but if it has all three wires then + and - probably go to a separate battery to run it, while signal goes to your main battery + and - to your main battery -.

 

[jlpmedia]

It didnt come with directions and I'm 94% confident that golf carts have only 1 power source. (many batteries in parallel/series)
Even though you said it needs a separate battery Im thinking what you wrote after that is correct:

battery + to meter +
battery + to meter signal
battery - to meter -

where the battery + to meter + will be wired through the main power switch as to prevent battery drain.
I'm just afraid of doing damage to the meter..at $25 it's not exactly cheap

 

[Takemehome]

Amberwolf gave you the right answer.

 

[amberwolf]

There are some battery meters taht themselves need something like a little 9V battery to run them, instead of being powered by pack voltage, becuse they can't run on the higher voltages of the pack. I don't know anything about that one, though.

It is quite possible that your assumption about switching the meter off is correct, but it's much simpler to use two wires for the meter and just have it on the controller side of the keyswitch instead of battery, so it only displays when the keyswitch is in the "on" or "accessory" positions (assuming the golf cart(s) have such a switch). So it would make no sense to me for htem to have three wires for it just for that purpose. Doesnt' mean they didn't do it anyway.

 

[aroundqube]

I don't know,but I am trying to help. On youtube " how to install a golf cart battery meter" the Tech is connecting the signal terminal to the key switch,and that turns on the display. Pos and Neg go to the main battery. Have a look, is that your 48v meter?

 

[jlpmedia]

although similar, it's not my meter. mine is rectangular in shape with 2 triangular flanges on either side. I suppose I'll just hook it up as Amberwolf and the youtube video suggested and hope for the best.

thanks guys

 

[jlpmedia]

It turns out all i need to do is plug in the positive and negative leads. who knows why the signal wire is there.

 

[dnmun]

why did you call it a signal wire? is there voltage on that wire when you wire up the other terminals to the battery? is there a light in the meter?

 

[circuit]

There are many meters with such contacts. Usually these are 12V. Battery full is shown when signal is shorted to ground and battery empty is when signal is left unconnected. This kind of meters goes into most older cars, scooters, etc. The signal must come from analogue fuel debacle or some sort of electronics (usually a smart BMS in EVs).
Don't know about your exact model though. But be warned that connecting it directly to 48V could be not the smartest move.

 

[jlpmedia]

why do i call it a signal wire? because that is what it is labeled on the back of the meter. it has the following on each corner:
+
-
Signal
the forth corner has a metallic contact but no male prong/terminal

My meter was designed for 48v golf carts. so im not worried about over volting it with my 53v fully charged battery.

I took it out for a 6 hour drive and on the return trip home the meters power just dropped 7 out of 10 notches in the last 30-40 minutes. so i imagine it is using overall voltage as its way to gauge capacity...so me trying to figure out that signal wire should help. im thinking if i hook up 1 3.2v? battery cell to the signal wire it will solve this. if it breaks it...whatever. ill use what the original 3-stage(100%,50%,0%) battery meter