lifted club cars - lifted ezgo
Home FAQDonate Who's Online
Go Back   Buggies Gone Wild Golf Cart Forum > Golf Cart Repair and Troubleshooting > Electric EZGO
Electric EZGO Electric EZ GO Marathon, Medalist, TXT and RXV.



Post New Thread  Reply
 
Thread Tools Display Modes
Old 11-30-2014, 10:56 AM   #1
bigstik40
Gone Wild
 
bigstik40's Avatar
Yamaha
 
Join Date: Sep 2010
Location: Erie, Pennsylvania
Posts: 989
Default Total Charge III shuts off early.

I have a Total Charge III charger that works perfectly except the on charge shut-off voltage is too low. The relay picks up, the charger comes on then goes to 19 or 20 Amps initially. It charges for a while, then shuts off at 41.8 volts. Charge current is still quite high (15-16 amps) at this point, and I don't think the batteries are fully charged. I have inserted four 1N4001 rectifiers in series with the red sensing lead to the control board. The charger still works normally with the rectifiers and the "at battery" shut-off voltage has increased to 45.8 volts. I think that I might remove one rectifier to make the shut-off a little lower at around 45.2 volts.

Was just wondering if there is any downside to this "fix", other than the rectifiers should be removed if the control board is ever replaced. I noticed a trimpot on the circuit board and wonder if this is for voltage adjust? Thanks for any advice/suggestions on this. - Ray
bigstik40 is offline   Reply With Quote
Alt Today
BGW

Golf car forum Sponsored Links

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum
   
Old 11-30-2014, 01:09 PM   #2
JohnnieB
Techno-Nerd
 
JohnnieB's Avatar
E-Z-GO
 
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
Default Re: Total Charge III shuts off early.

Sounds like your "fix" is working pretty good.

I'm a bit confused about the voltage drop you are getting across each 1N4001 Diode.
You said it shut off at 41.8V, you added 4 diodes to the red wire and it now shuts off at 45.8V. That's a 4.0V increase or 1.0V per diode.
Later you said you were thinking about removing one diode to decrease the 45.8V shutoff down to 45.2V, which is a 0.6V drop. (I've always used 0.6V as the forward biased voltage drop on a silicon diode.)

Personally, I'd leave all 4 diodes in, since 45.8 is within the 44V to 46V nominal shutoff range.

I was thinking about adding some diodes to the battery sense line in my PW-II to kick the shutoff voltage up into the "Equalize" range and a switch to bypass them for the regular shutoff voltage, but I bought a DPI instead.

-------------

I'm pretty sure the pot is fine tuning for the shutoff voltage but I've never tried adjusting it. The control board in my PW II is potted, so I can't get to it.

------------

The amps only dropping to 15-16 at 41.8V sounds about right. Attached is a the charge curve the TC-III is based on and the dotted line labeled 2.35VPC works out to 42.3V for a 36V pack, so the amps haven't tapered off all that much where the lines intersect.

My guess is that the amps are down to less than 3 when it shuts off now.

------------
BTW: Everything related to charging the battery is in the transformer and capacitor and the two high current rectifiers.
All the control board does is turn the charger on and off.
Attached Images
File Type: jpg Charge curve.JPG (33.2 KB, 0 views)
JohnnieB is offline   Reply With Quote
Old 11-30-2014, 02:31 PM   #3
bigstik40
Gone Wild
 
bigstik40's Avatar
Yamaha
 
Join Date: Sep 2010
Location: Erie, Pennsylvania
Posts: 989
Default Re: Total Charge III shuts off early.

Johnnieb - I've also always used .6 v. as the forward drop for a rectifier and was also a bit confused by what I got. I don't think my reading/measurement of 41.8 v was all that accurate for the original shutoff voltage. I think I walked away for a bit while watching the SOC meter and took the last reading from memory.. It must have been higher! Anyway, I took a WAG at 4 diodes and ended up with the 45.8 V. I may take a look at the drop across the rectifiers, just out of curiosity. If it's 1 v. per rectifier I'll let you know. I'll take your recommendation for now and leave it alone. I'll probably check it a few more times, just to be sure. The ammeter was under 5 (probably 3 or 4 ) when shutoff occurred. Pretty hard to read and really not that accurate (just a good indication).

Thanks for the response, you are the best ! Ray
bigstik40 is offline   Reply With Quote
Old 11-30-2014, 04:28 PM   #4
bigstik40
Gone Wild
 
bigstik40's Avatar
Yamaha
 
Join Date: Sep 2010
Location: Erie, Pennsylvania
Posts: 989
Default Re: Total Charge III shuts off early.

FWIW - I couldn't let it pass and I had to measure the rectifier voltage!! They weren't at 1 volt each but they were higher than I would have thought. The voltage I measured across all four of the 1N4001's was 3.15 volts. That works out to .787 volts per diode at 80-85 ma. Couldn't get any closer on current as I could only use the 10 A. range on my Harbor Freight DVM. - Ray
bigstik40 is offline   Reply With Quote
Old 12-01-2014, 07:45 AM   #5
JohnnieB
Techno-Nerd
 
JohnnieB's Avatar
E-Z-GO
 
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
Default Re: Total Charge III shuts off early.

That is odd. I've seen them vary by a few millivolts, but not 187.

I've had to use a burden resistor in some applications to increase current flow into the nominal operating range, but 80-85 ma should have them fully forward biased. Maybe one is "shorted" and acting like a resistor. (I've seen that happen before, but not with a 1N4001)

Try measuring them individually.
(Also might be the HF DVM. )
JohnnieB is offline   Reply With Quote
Old 12-01-2014, 01:17 PM   #6
bigstik40
Gone Wild
 
bigstik40's Avatar
Yamaha
 
Join Date: Sep 2010
Location: Erie, Pennsylvania
Posts: 989
Default Re: Total Charge III shuts off early.

I was hoping that I wouldn't have to undo my heat shrink job, but you have me wondering now what's going on. The rectifiers were not new and from my junk box so maybe there's a bad one. The H.F. meter has always seemed ok, but who knows. I'm gonna dig a little deeper. Thanks - Ray
bigstik40 is offline   Reply With Quote
Old 12-01-2014, 02:02 PM   #7
bigstik40
Gone Wild
 
bigstik40's Avatar
Yamaha
 
Join Date: Sep 2010
Location: Erie, Pennsylvania
Posts: 989
Default Re: Total Charge III shuts off early.

Well, I dug a little deeper and here are the results. I didn't take my rectifier string apart, but I did find the 5th & last 1n4001 from the same batch in my junk box. I ran 50 ma through it and it measures .76 volts on two meters (both H.F.). Ran diode test and it has excellent diode result (no leaky). I also ran same test with two 1n5401 rectifiers (same vintage - scrounged at the same time as 1n4001's). I got .56 volts on one and .68 volts on the other (two meters). These are older rectifiers scrounged from the same circuit. Maybe the fwd drop increases as they age. Maybe my H.F meters lie. I did check a couple fresh AA batteries with them and both meters show 1.62 volts. I,ve gone about as far as I can go with my limited test facilities. If I get some time I may borrow another meter to check out my H.F. meters but am pretty much done for now. Thanks again for all your help. Ray
bigstik40 is offline   Reply With Quote
Old 12-01-2014, 03:21 PM   #8
JohnnieB
Techno-Nerd
 
JohnnieB's Avatar
E-Z-GO
 
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
Default Re: Total Charge III shuts off early.

The important part is that they upped the shutoff voltage.

I've got some New-old-stock 1N4004 diodes around here someplace, I'll have to check a few out if I can find them, but I know they used to be 0.6V. Or at least the ones I've used as low voltage zener substitutes were.

If I remember my PN junction theory correctly, the forward voltage drop depends on the amount of doping and the material used, so it is entirely possible the construction of the diodes is different now than what it was a few years ago.

When I was learning how LED's work, a blue LED was said to be a physical impossibility, but we see them almost every day now, so there have been some changes in the diode world.
JohnnieB is offline   Reply With Quote
Old 12-01-2014, 07:50 PM   #9
bigstik40
Gone Wild
 
bigstik40's Avatar
Yamaha
 
Join Date: Sep 2010
Location: Erie, Pennsylvania
Posts: 989
Default Re: Total Charge III shuts off early.

Ok, here's the spec. sheet on 1N4000 series rectifiers and it looks like the typical forward drop starts at .6 volt and 10 ma. The curve shows that .75 volt is possible at 100 ma., so I think these are in the ballpark. - Ray
Attached Files
File Type: pdf 1N4000 series specs..pdf (49.4 KB, 0 views)

Last edited by bigstik40; 12-01-2014 at 07:52 PM.. Reason: attach file
bigstik40 is offline   Reply With Quote
Old 12-02-2014, 08:20 AM   #10
JohnnieB
Techno-Nerd
 
JohnnieB's Avatar
E-Z-GO
 
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
Default Re: Total Charge III shuts off early.

Wow!!! Things have changed.

The first attachment is the classic voltage vs current curve for a generic PN junction (diode).
It shows the voltage remaining constant over a range of current flow.

The second attachment is the chart from the 1N4000 series spec sheet.
It shows the voltage continuously increasing as current increases.

Some days I learn stuff I didn't know, other days I learn the stuff I already knew, has changed.
Attached Images
File Type: jpg Diode curve-1.jpg (9.6 KB, 0 views)
File Type: jpg Diode curve-2.jpg (63.9 KB, 0 views)
JohnnieB is offline   Reply With Quote
Reply
Go Back   Buggies Gone Wild Golf Cart Forum > Golf Cart Repair and Troubleshooting > Electric EZGO


Thread Tools
Display Modes


Similar Threads
Thread Forum
ezgo total charge shutting off early Electric EZGO
EZ-GO Total Charge 2 Electric EZGO
Powerwise shuts off early Electric EZGO
powerwise shuts off early Electric EZGO
Looking for Total Charge III Golf Carts and Parts


All times are GMT -5. The time now is 11:16 PM.


Club Car Electric | EZGO Electric | Lifted Golf Carts | Gas EZGO | Used Golf Carts and Parts

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
This Website and forum is the property of Buggiesgonewild.com. No material may be taken or duplicated in part or full without prior written consent of the owners of buggiesgonewild.com. © 2006-2017 Buggiesgonewild.com. All rights reserved.