2009 Ezgo 36V Motor & Controller Upgrade disappointment

[bbsb1712]

ScottyB, I have a simple full to empty dash meter but are you talking about one of the ones with actual numbers? You have a good one you'd suggest?

As for the batteries, is this a sign of bad pack, bad charger, or maybe a combination of both?

[scottyb]

Yes the meter you have is not accurate and can actually lead to battery abuse because it resets to full each time the charger is plugged in regardless of the end result.
We sell an inexpensive waterproof, reverse polarity proof, bomb proof meter on my website which I am warranting for 12 mos.
By watching the pack voltage under load you can see a load test anytime it comes to a hill or you can see exactly when it need a recharge. A good meter is cheap insurance on expensive batteries.

We include this battery use chart along with the installation instructions

[bbsb1712]

Thanks ScottyB. Just placed an order on your site. Actually got the 3 hole trim piece. I love that.

Now just need to know whether I should be investing in batteries or what? Should I even be thinking of going to 48 volt?

[JohnnieB]

I noticed the battery voltage dropped to 27.5V with 344.2A being drawn from the battery pack at 12:54:52, but only dropped to 28.2V with 427.0A being drawn at 12:53:02, about two minutes and three accelerations earlier.

That makes me think the batteries have a diminished storage capacity, which is logical since they have been chronically undercharged. Attached is a Technical Service Bulletin addressing the undercharging issue, or at least it does when you read between the lines, which appear to have been written by bean counters rather than engineers.

In a nut shell, the older technology chargers, like the PW 28115, shut off at a predetermined voltage and about half of the PW 28115 chargers will not fully charge US Battery brand batteries. Modern chargers using dV/dT (change in Voltage over change in Time) to terminal charge allows the voltage to rise until it stops rising, so they tend to fully charge US Battery brand products much better and many of the modern charges have user selectable charge profiles so one specifically for US Battery products can be selected.

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The good news is your batteries might recover some if you charge the daylights out of them.

Bypass the relay in the PW 28115 as mentioned earlier and charge the batteries every night for about 12 hours whither cart was used during the day or not.

Keep an eye on the electrolyte level because the batteries are going to gas a lot. The electrolyte expands during charging, so add distilled water after charging. If the plate are exposed prior to being put on charge, add just enough distilled water to cover plates plus about 1/4", then fill to proper level after charge.

[bbsb1712]

Thanks JohnnieB. What charger would you suggest for me to buy?

Also, given my current setup, how far away am I from converting to 48 volts. Batteries, charger, and what else? I think the motor, controller, and solenoid I just put on will all operate at 48 volts. Is the difference in voltage worth the performance gain I would get?

Thanks again.

[JohnnieB]

IF you have a MZJ400-48V solenoid, you're good to go except for batteries and charger.

Going from 36V to 48V ups both torque and speed by about 33%

If/when I go 48V from my current 42V, I'm going with the Lester Summit II (650W version) that Scotty sells. (Unless something better comes along before I make the jump)

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I believe it might be best to try and get the cart running as good as possible and practical on 36V with existing batteries and charger. That way if there are any problems after you go to 48V, there is only one set of variables to troubleshoot.

In Post#19, you said it took off like a rocket. I suspect that was when the batteries had a halfway decent charge and very few amps had been drawn from them.

[bbsb1712]

I think i just stumbled upon something. Been charging the batteries as suggested. I've continued to have sporadic cases of the cart not moving. Was tightening something on the controller the other day when it wasn't running and suddenly the controller kicked back on and began working. Only to stop running later.

Today I was tracing wires and began probing for voltages. As I was checking the white wire from the ITS, i noticed the error code blinking on the controller had stopped. I pushed the accelerator and it moved. I went through several steps which included unhooking the voltmeter all together and just pushed on the white wire with my probe and i could literally make the error codes start and stop. SO, i'm assuming i have a bad connection with the white wire.

I've unplugged, cleaned, plugged back in and the problem still persists. Can I replace a Molex? What should I do?

[JohnnieB]

You can replace the bad pin in the molex plug. In fact, the existing pin might not be fully seated and might be okay if seated properly.

They are inserted from the backside of the plug, so try pushing the wire forward until it stops moving.

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I'd don't know the part numbers for the plugs and pins, but several people on this form do. Hopefully one will be along soon, If not start a new thread asking for the part numbers in the title. I'd try the General B.S. forum also.

[bbsb1712]

Thanks. I just tried pushing it in but it didn't seem to take.

[JohnnieB]

If it is not seated, pulling gently on the wire will pull it out of the plug.

To do the job right you need the right tools. The pin extractors are inexpensive, but the crimpers are a bit more expensive. The trick is finding out what size pins.