Strange voltage reading and no movement

[2K6TBSS]

So I had my cart on the charger for a few days and unplugged it to take my kids to a friends house and something very strange happened.

Details on cart:
2003 EZGO TXT (Series), 48v, Alltrax 48500 controller, 400 solenoid, SocttyB digital battery meter, Lester Summit 2 charger

I unplugged the charger and my battery meter showed 54.4 volts (1st time I have ever seen this), I turned the cart on put it in reverse heard the buzz, got the solenoid click, but no movement. Same thing when I put the cart in forward (solenoid click, no movement). After letting the cart sit and the voltage drop to 51.4 volts the cart worked fine.

As I said, this is the first time I have experienced this issue and wondering if there is some sort of voltage regulator in the controller that won't engage the motor (or controller) if the voltage isn't within a certain range?

[PingEye3]

There is a voltage setting in the Alltrax Toolkit for that max voltage adjustment. I run lithium so I am set at max 62V. Set yours between 55-62 and you will be ok.

[2K6TBSS]

Originally Posted by PingEye3

There is a voltage setting in the Alltrax Toolkit for that max voltage adjustment. I run lithium so I am set at max 62V. Set yours between 55-62 and you will be ok.

Thanks. I will look into it.

Is it normal for the voltage to get that high? Typically I only see the voltage get between 50.8 and 51.4 (mostly closer to 50..

[Sergio]

That is the "float voltage" level but since the Summit II does not provide "float" for Lead Acid profiles, You better double check with the ChargeConnect app that You do not have an AGM profile loaded.

[JohnnieB]

If the peak on-charge voltage is higher than normal, clean all the connections in the cart's charging loop.

The Summit-II uses dV/dT (change in Voltage over change in Time) technology to determine when pack is fully charged, so the on-charge voltage will climb until the rate of increase meets the cut off criteria. (US Battery recommends 0.004V per cell per hour - don't know what it is for other brands) So any excessive resistance in the charging loop will cause the pack's on-charge voltage to get higher before the cut-off criteria is reached.

FWIW: I've always set the over voltage to max (62V) in my Alltrax controllers, even when running a 36V pack. But, I run a sepex system and regen braking raises pack voltage during operation.

[Sergio]

JohnnieB, he said the cart was connected to the charger for a few days so there is no way it was still charging and lead acid cells cannot hold that high voltage for long.

It has to be a float profile (about 2.25vpc) which the summit does not have for lead acid batteries.

I ran lithium now so my Alltrax over voltage is just below the pack max allowed voltage to protect the batteries (and/or not trigger a BMS shutdown) during Regen brake.

[JohnnieB]

Originally Posted by Sergio

JohnnieB, he said the cart was connected to the charger for a few days so there is no way it was still charging and lead acid cells cannot hold that high voltage for long.

It has to be a float profile (about 2.25vpc) which the summit does not have for lead acid batteries.

I ran lithium now so my Alltrax over voltage is just below the pack max allowed voltage to protect the batteries (and/or not trigger a BMS shutdown) during Regen brake.

AGM and Gel are lead-Acid batteries also and do have float charge in their Summit-II profiles. Just the Wet-Cell profiles don't have float charge.

He never said what type battery was in cart or the charge profile selected.

Since 54.4V / 24 = 2.2666...V, the charger might be set to an AGM profile (2.27VPC float voltage).

If the Green LED blinks slowly instead of staying steady green, it is in float charge.

Could be someone changed the charge profile.

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Yep, I overlooked the connected to charger for several days part on post#1.

[2K6TBSS]

Originally Posted by JohnnieB

AGM and Gel are lead-Acid batteries also and do have float charge in their Summit-II profiles. Just the Wet-Cell profiles don't have float charge.

He never said what type battery was in cart or the charge profile selected.

Since 54.4V / 24 = 2.2666...V, the charger might be set to an AGM profile (2.27VPC float voltage).

If the Green LED blinks slowly instead of staying steady green, it is in float charge.

Could be someone changed the charge profile.

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Yep, I overlooked the connected to charger for several days part on post#1.

I have Trojan T-875 batteries (installed 3/2020), Battery Profile is 22251, System profile is 29142

[JohnnieB]

Not sure how the battery pack could be at 54.4V if the charger had completed its charge cycle several days earlier and the charger wasn't float charging.