LED Charge Indicator, how many bars?

dogdad11 · 10-12-2014, 11:53 AM

I have another thread about my project CarryAll II questions in general, but figured I'd narrow down specific questions.

I've been scratching my head as to why the Charge Indicator (little rectangular meter, with a row of LED's) will only show one bar all the way to the right, even when hooked up to 4 good 12v batteries. Based on the printed icon on the meter, it looks like full-charge would be all the way to the right and complete discharge all the way to the left.

So, should I have just the one LED lit at a time and then it move across the face of the meter during discharge, or should a group of them light to indicate state (ie, kinda like reception-bars on a cell-phone)?

Thanks!

kernal · 10-12-2014, 12:34 PM

If it is like the one on my cart, it operates thusly: Full charge is a lit bar at the far right or top if a vertical meter. As the charge is depleted that bar will go dark and the next bar to the left will illuminate. When you get to the next to last bar on the left you are at 70% discharge. After that the 2 farthest left bars start to flash indicating 80% discharge (theoretically). You should have gone back to the barn and the charger long before this.

The display doesn't operate like a cell phone.

dogdad11 · 10-12-2014, 01:18 PM

AH HA!!!! Ok, many thanks on that explanation, really appreciate it kernal. And I kinda feel like your dog's picture in your avatar.

Been chasing my tail trying get the display to show what I thought was a full-charge (lotsa bars). I realize the display doesn't do anything except tell you charge-state, but I'd convinced myself that having just that one bar meant I had other severe problems somewhere upstream of the display, causing it to show very low voltage.

Hey, on the bright side I can now say I have one thing that works! Looks like I'm back to the drawing-board with the rest of it, tho.

10-12-2014, 01:28 PM

for accurate reading you need a digital volt meter (mini)

dogdad11 · 10-12-2014, 01:43 PM

Right you are, CTD. I even have my trusty Fluke DVM in hand, but was so bogged-down in convincing myself that what I saw was wrong that I couldn't/wouldn't accept it. Shoulda trusted Occam's Razor (again).

Thanks.

RPatten · 10-12-2014, 06:16 PM

Quote:

Originally Posted by crash test dummy

for accurate reading you need a digital volt meter (mini)

I have never seen one that high. Are your batteries nuclear?

10-12-2014, 09:00 PM

Quote:

Originally Posted by RPatten

I have never seen one that high. Are your batteries nuclear?

a 48v cart will charge that high or higher before charger shuts off

Quote:

Originally Posted by rib33024

Welcome to BGW

What you said about - some people have said 62 volts is a full charge, the problem I have with this is my new 48 volt axe controller has a high voltage limit and can't be set any higher than 60 volts,--- this is true, but when the pack gets above 60v it will be on the charger and you will not be driving the cart, so there is nothing to worry about, when the charger turn off the pack will be below the 60v mark, here's some info

60 - 65 volts", is correct.
In fact, the charger may have to take a 48V battery pack up to 67V, or above, to fully charge it.
On the other hand, 59V may fully charge a 48V battery pack.
The voltage it takes to fully charge a 48V battery pack depends on who manufactured the batteries in the pack as well as their age and condition.

By definition, a lead-acid wet cell is fully charged when the specific gravity of the electrolyte ceases to increase while a charging current is passing through it. Since open-circuit voltage increases/decreases as the electrolyte's specific gravity increases/decreases, open-circuit voltage is an indirect or secondary means of monitoring the electrolyte's specific gravity and is often used to do so.

An ideal charger would monitor pack voltage and when it ceased to rise over a predetermined period of time, it would stop the regular charging mode and go into a float charge mode, however few, if any, chargers typically used by golf cart owners are ideal. Most of them simply shut off at a predetermined voltage that is high enough to almost fully charge most battery packs without being so high that repeated use would significantly harm battery packs that are fully charged at the lower end of the typical voltage spectrum needed to fully charge a battery as determined by empirical data.

Here is Trojan's recommended charge curve for a single (2V) deep cycle wet cell. There are 24 cells in a 48V battery pack, so do the math and you get 58.80V to 66.96V. However, Trojan uses an electrolyte that is 27.7% sulfuric acid by weight (SG = 1.277) and other battery manufacturers use different concentrations, so the on-charge voltage that is typically reached when their batteries are fully charged, will be higher or lower.

10-12-2014, 11:53 AM	#1
dogdad11 Not Yet Wild Join Date: Nov 2013 Posts: 29	LED Charge Indicator, how many bars? I have another thread about my project CarryAll II questions in general, but figured I'd narrow down specific questions. I've been scratching my head as to why the Charge Indicator (little rectangular meter, with a row of LED's) will only show one bar all the way to the right, even when hooked up to 4 good 12v batteries. Based on the printed icon on the meter, it looks like full-charge would be all the way to the right and complete discharge all the way to the left. So, should I have just the one LED lit at a time and then it move across the face of the meter during discharge, or should a group of them light to indicate state (ie, kinda like reception-bars on a cell-phone)? Thanks!
dogdad11 Not Yet Wild Join Date: Nov 2013 Posts: 29

10-12-2014, 12:34 PM	#2
kernal Gone Wild Join Date: Jul 2010 Location: Peachtree City, Ga. Posts: 2,759	Re: LED Charge Indicator, how many bars? If it is like the one on my cart, it operates thusly: Full charge is a lit bar at the far right or top if a vertical meter. As the charge is depleted that bar will go dark and the next bar to the left will illuminate. When you get to the next to last bar on the left you are at 70% discharge. After that the 2 farthest left bars start to flash indicating 80% discharge (theoretically). You should have gone back to the barn and the charger long before this. The display doesn't operate like a cell phone.

10-12-2014, 01:18 PM	#3
dogdad11 Not Yet Wild Join Date: Nov 2013 Posts: 29	Re: LED Charge Indicator, how many bars? AH HA!!!! Ok, many thanks on that explanation, really appreciate it kernal. And I kinda feel like your dog's picture in your avatar. Been chasing my tail trying get the display to show what I thought was a full-charge (lotsa bars). I realize the display doesn't do anything except tell you charge-state, but I'd convinced myself that having just that one bar meant I had other severe problems somewhere upstream of the display, causing it to show very low voltage. Hey, on the bright side I can now say I have one thing that works! Looks like I'm back to the drawing-board with the rest of it, tho.
dogdad11 Not Yet Wild Join Date: Nov 2013 Posts: 29

10-12-2014, 01:28 PM	#4
crash test dummy Guest Posts: n/a	Re: LED Charge Indicator, how many bars? for accurate reading you need a digital volt meter (mini)
crash test dummy Guest Posts: n/a

10-12-2014, 01:43 PM	#5
dogdad11 Not Yet Wild Join Date: Nov 2013 Posts: 29	Re: LED Charge Indicator, how many bars? Right you are, CTD. I even have my trusty Fluke DVM in hand, but was so bogged-down in convincing myself that what I saw was wrong that I couldn't/wouldn't accept it. Shoulda trusted Occam's Razor (again). Thanks.
dogdad11 Not Yet Wild Join Date: Nov 2013 Posts: 29

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