Anyone have this charger

[LukeL]

https://rover.ebay.com/rover/0/0/0?m...2F184022875504

[noserider]

Originally Posted by LukeL

https://rover.ebay.com/rover/0/0/0?m...2F184022875504

Hey good find. Thank you! The specs look pretty good.

[JohnnieB]

Originally Posted by noserider

The charger has been on now for about 13 hours. The pack is showing 43.4. I am curious to see if this charger will shut off at a certain pack volt (it should) or if not has an internal timer to keep the batteries from boiling. Before I cleaned the batteries and cables it would charge for a few hours and shut off. The pack was getting to 44 more quickly before I cleaned everything. Not sure why except maybe not taking a deep charge. Maybe it's doing it's thing now that everything is clean. I'll manually disconnect at the 24 hour mark if it does not shut off.

I'm not familiar with this charger at all, but I am familiar with most types of chargers used to charge EZGO battery packs and they fall into two categories, those that cutoff at a predetermined voltage and those that use dV/dT (change in Voltage over change in time) technology.
In Post#1 you said it cut off at 44.5V, which indicates the former type. (Cut off range of 44V to 46V for 36V battery packs)

This type would also explain why it shut off sooner when the cables connections were corroded. The added resistance of the poor connections developed a voltage when the charging current (18A?) was passing through them, so the cutoff voltage was reached before 45V +/-1V was felt by the batteries themselves.

After the charger shuts off, restart it. Repeat several times and keep an eye on the fluid levels, they are going to gas a lot.
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Check the charging voltage applied to the individual batteries. If the voltage applied to the 36V pack is 44V, each of the six 6V batteries ought to have about 7.3V applied and there shouldn't be more than about 0.2V variance between the on-charge voltage of all the batteries.

[noserider]

Originally Posted by JohnnieB

I'm not familiar with this charger at all, but I am familiar with most types of chargers used to charge EZGO battery packs and they fall into two categories, those that cutoff at a predetermined voltage and those that use dV/dT (change in Voltage over change in time) technology.
In Post#1 you said it cut off at 44.5V, which indicates the former type. (Cut off range of 44V to 46V for 36V battery packs)

This type would also explain why it shut off sooner when the cables connections were corroded. The added resistance of the poor connections developed a voltage when the charging current (18A?) was passing through them, so the cutoff voltage was reached before 45V +/-1V was felt by the batteries themselves.

After the charger shuts off, restart it. Repeat several times and keep an eye on the fluid levels, they are going to gas a lot.
--------------

Check the charging voltage applied to the individual batteries. If the voltage applied to the 36V pack is 44V, each of the six 6V batteries ought to have about 7.3V applied and there shouldn't be more than about 0.21V variance between the on-charge voltage of all the batteries.

Great info and advise. Thanks!

[noserider]

The battery charger has been on now for 17 hours. It's still charging. The pack voltage has been stuck on 44.3 now for 6 hours. I'm not sure exactly what voltage is required to trigger it off. I'm thinking the batteries may not be able to charge higher. Do you think it's best to shut it off, wash the tops clean, remove the caps and refill/check the level and put back on the charger?? The readings with the charger on are 4 at 7.4, one at 7.3 and one at 7.2. I know that does not equal 44.3 but it's close.

[JohnnieB]

Originally Posted by noserider

The battery charger has been on now for 17 hours. It's still charging. The pack voltage has been stuck on 44.3 now for 6 hours. I'm not sure exactly what voltage is required to trigger it off. I'm thinking the batteries may not be able to charge higher. Do you think it's best to shut it off, wash the tops clean, remove the caps and refill/check the level and put back on the charger??

Sounds like a good plan.

Typical cutoff is 45V +/- 1V or from about 44V to about 46V for the preset cutoff voltage type and may go a bit higher for the dV/dT types, which don't shut off until the on-charge voltage stops increasing. (or at least reduces to a rate specified by manufacturer. For US Battery brand batteries it is 0.004V per cell per hour)

[noserider]

Originally Posted by JohnnieB

Sounds like a good plan.

Typical cutoff is 45V +/- 1V or from about 44V to about 46V for the preset cutoff voltage type and may go a bit higher for the dV/dT types, which don't shut off until the on-charge voltage stops increasing. (or at least reduces to a rate specified by manufacturer. For US Battery brand batteries it is 0.004V per cell per hour)

Ok checked cells for water and all good. It's back on the charger. I'm going to let it run overnight and see if it can charge enough to shut off. I'm fairly certain the batteries are toast but it's worth a shot to see if another 6 months can be squeezed out of them. I'll take it for a test drive in the morning and see if the run time is getting longer from the charging. I'm hoping the plates might improve with some charging cycles.

[noserider]

This morning I checked the status of the charger and it finally shut off. It doesn't actually shut off but goes into float charge mode. The pack voltage is currently at 41.5 but I'm hoping that's just a residual charge and it will continue to drop to slightly above 38.2 and stay there. I am a little concerned the charger's float charge might be set to high and might keep the batteries overcharged and gassing. I think I will not test drive it today and let it stay on the charger and see what the pack settles to overnight in float charge mode. I want to be able to return the cart back to the owner with some good data on how to use this charger and whether is possible to keep the batteries a little longer. I'm hoping I can say your batteries need replacing ASAP but in the mean time use the cart and just know your distance is shorten with bad batteries but it's safe to just keep the charger plugged in all the time when not in use.

[noserider]

Originally Posted by noserider

This morning I checked the status of the charger and it finally shut off. It doesn't actually shut off but goes into float charge mode. The pack voltage is currently at 41.5 but I'm hoping that's just a residual charge and it will continue to drop to slightly above 38.2 and stay there. I am a little concerned the charger's float charge might be set to high and might keep the batteries overcharged and gassing. I think I will not test drive it today and let it stay on the charger and see what the pack settles to overnight in float charge mode. I want to be able to return the cart back to the owner with some good data on how to use this charger and whether is possible to keep the batteries a little longer. I'm hoping I can say your batteries need replacing ASAP but in the mean time use the cart and just know your distance is shorten with bad batteries but it's safe to just keep the charger plugged in all the time when not in use.

I just check pack voltage. It has not moved and is still 41.5 on the float charge. This does not seem right to me. I would have thought that after 4 or 5 hours in float mode it would have started to move toward 38.2. Thoughts??

[JohnnieB]

Float charge is a constant voltage charge mode whose regulated voltage is above the At-Rest voltage (38.2V) and below the gassing voltage (about 43V), so 41.5V does meet that criteria, but is a bit on the high side.

Trojan recommends 40.5V and US battery is about 40.0V.

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The way float charge works, the charger varies the amp flow through the battery pack to compensate for self-discharge and other drains on the battery pack to maintain the float voltage. The cutoff voltage for the normal charge cycle is above the float voltage, so no amps are flowing to the battery until the pack voltage decreases to the float voltage value. Maybe the voltage will drop some more in time, but as long as the batteries are not gassing, 41.5V ought to be okay.

Also, the charger might act different attached to a set of batteries that are in good health.