Battery charger question for johnnieb...

[bigstik40]

I rewired the Powerwise charger we have been discussing on another thread. The relay picks up after a 4 or 5 second delay and applies power to the transformer (as it should, I believe). That's the good news !!! The bad news is, it seems that the sensing circuit does not drop the relay out when voltage is reached. I'm reading 5 amps and 44.9 volts (at the transformer & rectifier heat sink). Is that a high enough voltage to drop out the relay, or is there also some elapsed time at voltage that must be met before dropout??
(The manual is not very clear on this). I'm thinking that maybe I need a voltage control card,Or is there any troubleshooting one can do on the old card? Thanks - RAY

[bigstik40]

Bump - Johnnieb ?? anyone ??

[dougmcp]

If this is a 36v cart, your voltage could be as high as 46.8v before it drops out.
44.9v on a 36v pack is only 2.49v per cell and chargers regularly go to 2.5v-2.7v per cell before they shut down.

[TDAWG]

Originally Posted by dougmcp

If this is a 36v cart, your voltage could be as high as 46.8v before it drops out.
44.9v on a 36v pack is only 2.49v per cell and chargers regularly go to 2.5v-2.7v per cell before they shut down.

Also Bigstik40 you are correct about there being a time factor at a certain voltage involved. Not necessarly a particular shut-off voltage, but a certain amount of time has to elaspe while charging without the total voltage of the battery pack changing before the charger will shut off. Alot of people dont understand that part. Let your charger finish.

[bigstik40]

I borrowed a friend's charger before mine was repaired to top off my batteries. His was a powerwise II and his charger did shut off at the end of charge on my pack. Maybe my charger is a little short on total voltage. Maybe I'll borrow his again and check the finishing voltage of his. I'll try again tomorrow. Thanks - RAY

[simple man]

" TDAWG " is right on with his statement! I have a Lestronic II and when I charge my cart ( older batteries ) the terminal voltage is 44.6V. I let my friend use this charger ( while his was being repaired ) and his newer batteries let the terminal voltage go up to 45.8V. The voltage reached is also dependent on your batteries.

[JohnnieB]

Originally Posted by bigstik40

I borrowed a friend's charger before mine was repaired to top off my batteries. His was a powerwise II and his charger did shut off at the end of charge on my pack. Maybe my charger is a little short on total voltage. Maybe I'll borrow his again and check the finishing voltage of his. I'll try again tomorrow. Thanks - RAY

Sorry Ray - I somehow missed this one.
Must be old eyes and rusty braincells.

Like the others said, 44.9V might not be high enough to shut off charger. Just let it run longer.
Your batteries can take 5A for a long time without hurting them, but if voltage doesn't get any higher than 44.9V after 6-8 hours, the Capacitor in the charger might be bad.
(FWIW - The typical voltage increase on a T-105 in the gassing phase is only about 0.012V per hour, so it takes time to see a change)

Since you've already done some measuring inside the charger with the power on and haven't electrocuted yourself, you could check the open circuit AC voltage across the two transformer secondaries that are tied together the make a center-tap. Clip the test leads to the Anodes of the diodes and bypass the relay. You should get about 100VAC.
Much less than that, the capacitor (or transformer) is bad.

Without the Capacitor disconnected, you should get about 80VAC if the transformer is good.
(The secondary going to the Capacitor will be about 480VAC)

Be careful, the capacitor can have a 650VDC charge on it.

[bigstik40]

Hi Johnnieb: Thanks for responding. Do you know what the value of the capacitor should be?? The cap. in this charger has been replaced and I don't know if the value is correct. I think the original cap. is round, but this one is oval. I have the charger buttoned up for now, but will make those voltage measurements later. At least the charger is working to some degree and I no longer have to use jumper cables to charge (I installed the cord from the "QE" into this one). Oh, and by the way, this "QE" cord has a third wire, which I taped off and marked as "extra wire". I believe this may have been used as a "sense" wire in the "QE" to eliminate the voltage drop in the charging wire. Is this extra wire of any use in my application?? Thanks, you've been a great help - RAY

[JohnnieB]

Originally Posted by bigstik40

.................
1. Do you know what the value of the capacitor should be?? The cap. in this charger has been replaced and I don't know if the value is correct

2.Oh, and by the way, this "QE" cord has a third wire, which I taped off and marked as "extra wire". I believe this may have been used as a "sense" wire in the "QE" to eliminate the voltage drop in the charging wire. Is this extra wire of any use in my application??
............

1. Don't know for sure, but I think it's 20mfd. Probably better check with EZGO and get a Part# used in your specific charger. Have charger serial# handy when you call.

2. Sounds like you've got the "Third" wire figured out.
Tape it up good, it connects to B- via the Auxiliary contact in the plug.

If you want to connect it:
There are two wires going to control board from output circuit.
One connects to the heat sink (B+). Leave that one as is.
The other connects to B-, either at the ammeter or center-tap of transformer. Disconnect it and splice to Third wire in output cable.

Here is a quick and dirty test to see if your charger will turn off if the battery voltage gets high enough.
Simply pull the plug out of the cart while charging. It should turn off (Transformer stop Humming) almost instantly.
It won't tell you if it is good, but it will tell you if the control board is bad.

[bigstik40]

Well, this afternoon I connected the charger and decided I would stop "watching" it. I actually forgot about it as I became involved in another project. When I returned home, lo and behold, the charger was off. I tried it again after supper and once again, it turned off. It looks like it is probably going to be ok. I'm going to make sure that third wire is safely taped up and I'll take those voltage measurements and check the capacitor for reference. I don't plan to use the
3rd wire at this time (if it aint broke - don't fix it). Again, thanks everyone for all the help - RAY