Only 36.4 volts on each charge?

[azTony]

Does any one have any idea why my batteries (36 volt) only charge to 36.4 volts when I charge them?

96 EZ-Go Series, Powerwise charger

Each battery is within less than a volt of one another.

[dmi518]

i have a powerwise that does that, i noticed the ammeter is only climbing to ten amps at start. all my others climb up to 20+.
i still have to open it up to see where the problem lies.

[rib33024]

How old are they? what make? did it ever charge all the way to 38.2 full charge? did it just start doing this? tell us more

[azTony]

It just started, always fully charged since I have had it. I had already replaced the control board a few months ago because it would shut off.

Batteries are about 15 months old.

[rib33024]

when the charger is charging do you know what the volts go up to ? or does it never get past 36.4? do you have another charger you can use to see if it charges ok, to rule out the charger, or try your charger on another cart?

[JohnnieB]

Check what the voltage is at the battery pack main terminals are when charger shuts off.
(Should be about 45V)

[azTony]

36.4, I have checked them each individually and as a pack. I know what it used to be now suddenly this started. After replacing the control board in the charger I am not sure what else is involved with the voltage monitoring during charge...

[JohnnieB]

Originally Posted by azTony

36.4, I have checked them each individually and as a pack. I know what it used to be now suddenly this started. After replacing the control board in the charger I am not sure what else is involved with the voltage monitoring during charge...

The Powerwise charger (pictured below) has two circuits that are entirely separate with one subtle exception.

1. Battery charging circuit, consisting of a ferroresonant transformer, a matching capacitor and two diodes, plus an ammeter and possibly a fuse or circuit breaker and some wires connecting it to the battery pack. When AC power is applied to the transformer, the charging circuit will charge the battery pack with a high initial charging current that tapers off as pack voltage rises.

2. Control board. All the control board controls is a relay, which in turn connects or disconnects AC power to the transformer according to the following conditions:

a. The voltage between the Black and Red wires on the control board (Battery sense) has to be high enough to energize the relay initially. The cart's battery pack closes the relay initially, so charger does not have to be plugged into AC power for relay to close. For a 36V system, the pack voltage need to be above about 30V to close the relay.

b. Once the relay is closed and the battery charging circuit is powered up, the relay is held close by the battery charging circuit output voltage until the on-charge voltage reaches about 45V. At that point the control board opens the relay, shutting down the battery charging circuit.

c. If the on-charge voltage does not reach the predetermined voltage (about 45V) in a predetermined length of time (about 16 hours) a back-up timer causes the relay to de-energize.

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At 36.4V, the plates in your batteries are sulfating as we speak, so get them charged post haste.
You can do it by charging them in pairs with a 12V car battery charger or by bypassing the relay in the 36V charge so it stays on all the time.

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If the on-charge voltage is only 36.4V as measured on the Red and Black wires on the chargers control board (See attached schematic), there is a problem with the charger's battery charging circuit.

If the on-charge voltage as measured on the Red and Black wires on the chargers control board is reaching about 45V before charger shuts off, the problem is in the battery voltage sense circuit.

If the cart is running fairly normally (and none of the interconnecting cables on the battery pack are getting hot) the problem is excessive resistance between the wires highlighted in blue and red on schematic and the wires from the cart's charge receptacle attaches to the main + & - terminals on the battery pack.

[azTony]

Sorry JonnieB, I do not see a pic attached

Originally Posted by azTony

Sorry JonnieB, I do not see a pic attached