New batteries 3 miles

[chriskent85]

So i had a customer that had old worn out batteries in his PDS and the controller was overheating because of the Larger tires. We installed a new 400amp alltrax with new 48v batteries and a new charger, after i installed it i took it for a trip about 2 miles. voltage would drop from over 48 to under 48v when i had the throttle down, is this normal. let the customer take it home last Monday and got a call this morning saying that he took it off charger yesterday mormning and his wife took it about 3 miles and it dropped below 20v and shut off, I know i have the low voltage cut off set at 20v. Only thing I didn't change was the stock 36v solenoid. didn't have a 48V high amp solenoid yet, Do you think that the old solenoid overheated causing the cart to stop or does it sound like something is draining the batteries to fast. He is dropping the cart off with me tomorrow so i can run some test on it.

[branson]

why did you set the low voltage cut off so low? it should be around 42 volts for a 48 volt pack. I don't know if the solenoid could have welded closed causing a continious load on the batteries. as far as I know that only happens on resistor carts. when is the last time they charged it.? the correct answer is last night.

[JohnnieB]

Originally Posted by chriskent85

So i had a customer that had old worn out batteries in his PDS and the controller was overheating because of the Larger tires. We installed a new 400amp alltrax with new 48v batteries and a new charger, after i installed it i took it for a trip about 2 miles. voltage would drop from over 48 to under 48v when i had the throttle down, is this normal. let the customer take it home last Monday and got a call this morning saying that he took it off charger yesterday mormning and his wife took it about 3 miles and it dropped below 20v and shut off, I know i have the low voltage cut off set at 20v. Only thing I didn't change was the stock 36v solenoid. didn't have a 48V high amp solenoid yet, Do you think that the old solenoid overheated causing the cart to stop or does it sound like something is draining the batteries to fast. He is dropping the cart off with me tomorrow so i can run some test on it.

Hopefully the batteries were fully charged prior to first use, but the red highlighted statement leads me to believe they weren't, since 48V is only 50% charged for a 48V pack.

Running a 36V solenoid on 48V is very likely to burn out the coil, however feeding a 400A controller through a stock solenoid (85A rated) is likely to weld the contacts closed.

Low voltage cutoff at 20VC is mighty low, but 42V (1.75VPC) might be a bit high since the cart has tall tires. The minimum is about 1.5VPC, or 36V for a 48V pack.

The first thing I'd do is measure the pack voltage and individual battery voltages. Then put them on charge if they read less than 50.9V.

[chriskent85]

batteries were fully chargered and Im pretty sure that the cut off waqs set at 20 from factory, it was on the last 400amp pds i did. If it shouldnt be that low i will change that setting. i will do some voltage measuring when he drops it off

[JohnnieB]

Originally Posted by chriskent85

batteries were fully chargered and Im pretty sure that the cut off waqs set at 20 from factory, it was on the last 400amp pds i did. If it shouldnt be that low i will change that setting. i will do some voltage measuring when he drops it off

The words I'd like to hear are: "I fully charged the right after I installed them." -or- " I fully charged them before I installed them."

I'm probably preaching to the choir, but no matter what the battery dealer says, charge the batteries when you get them. It's okay to make sure the cart runs forward and reverse, but only for a few feet before the new batteries are fully charged.

Battery manufacturers only take their products down to 1.75VPC when they do non-destructive testing and warn that irreversible physical damage can occur if they are taken below 1.5VPC. That would be 42V and 36V respectively for a 48V pack.

The DCX400 can tolerate voltages down to about 16V, but the batteries cannot, so the low voltage slider has to be adjust according to the pack voltage being used, AH capacity of batteries, ampacity of controller, motor used and tire height.

FWIW: I run mine slightly over 1.5VPC since I'm running a 500A controller and a high performance aftermarket motor and can take a 42V-245AH pack below 1.75VPC when the pack is fully charged.

[scottyb]

What battery did you install? How many times have they been cycled?

[chriskent85]

He got powertron and after I charged the batteries the first time I'm not sure how many times he has charged it since then.

[chriskent85]

So I got the cart yesterday and I put the cart on charge over night, took it off charge when i got here at 8:30. Installed the new solenoid and took it on a 4 mile trip and the batteries got down to 48v. I started with 51v. Sometimes while driving it would get down to under 40v when i had my foot in it on flat ground, but then when i would let off the throttle it would come back up to a little over 48v. What is the actual mileage I should be getting out of these.

[chriskent85]

I thought the Batteries were powertron but the are US Battery. AH-170 RC-337

[chriskent85]

Just drove it for another 2 mile and batteries are down to 46.3. The motor was pretty hot, too hot to keep your hand on it. There is also a whining noise that comes from the rear end area since ive had it. Doesnt feel like it has any drag, Cart has plenty of get up. What could be causing it to be getting such low mileage.