Battery Trouble???

[tcascario]

I have a 99 ezgo dcs 36v limo with an alltrax 400 controller. I bought new batteries from costco when I got it 5 months ago. Everyhting was fine with good distance and speed. Now I can only travel about half as far as before and my soc meter drops to half the first time pedal is pressed after a full charge. After letting batteries sit 12 hrs after charging the pack reads 38.6v and each individual reads 6.6 to 6.7v under load pack drops to 34.2 and stays there and each battery drops to 5.7v and stays. Are my batteries dead?

[tcascario]

I was also wondering if there was anything that could cause this or if I got a bad lot of batteries?

[JohnnieB]

I suspect the batteries from Costco where in the 180AH range and the standard AH rating for a regular cart is 225AH.
For a Limo, it probably should be higher.

Battery life depends, among other things, on the average State of Charge they are maintained at, and with a 400A controller, they were very likely being hit hard as well as being about 20% underrated, so they may very well be reaching the end of their useful life.

However, 5 months does seem awfully short, even if they are too small for the application. Do they have a warranty?

Also, check for mechanical drag. You should be able to push cart easily by hand, once it is moving.

FWIW: If you are discharging batteries below about 70% SoC, or so, with your routine usage, your batteries aren't big enough.

[scottyb]

Agree on the amp hour thing.
Isn't the costco warranty 6 mos?
Better grab your receipt and run back before they expire.

[tcascario]

I was thinking of going to 48volts if I am going to return the batteries anyway. Would i be looking for the same ah rating or is it different. Just confirming I would need new batteries a charger and a 48volt solenoid to convert to 48v correct?

[rib33024]

you want the highest ah rating you can get, and you need, 2 or 4ga cables, 48v controller, and HD f/r switch . You can find some packages here

http://www.cartsunlimited.net/Custom_Options.html

Originally Posted by tcascario

I was thinking of going to 48volts if I am going to return the batteries anyway. Would i be looking for the same ah rating or is it different. Just confirming I would need new batteries a charger and a 48volt solenoid to convert to 48v correct?

[scottyb]

Make sure your controller is programmed for 48v. 8v batteries hold less amperage than 6v (220ah - 225ah).
So the AH ratings are lower. a good one is 165ah and a better 8v is 195ah.
The longest run times comes from 8/6v batteries

[tcascario]

So I will lose run time by going to 6 8v in a 48v setup compared to running my 36v setup now with 6 6v batteries?

[JohnnieB]

Originally Posted by tcascario

So I will lose run time by going to 6 8v in a 48v setup compared to running my 36v setup now with 6 6v batteries?

There are a myriad of variables, but if you went from the standard 6V (T-105 - 225AH) to a premium 8V (T-890 - 190AH) you might stay about the same.

Theoretically, a 225AH 36V battery pack stores about 9.0kWh of energy, while a 190AH 48V battery pack stores roughly 10.14kWh, but you'll have better acceleration and torque and due to human mature, you'll be using it, so you'll be drawing Watts from the 48V 190AH battery pack at a higher rate than you would be from a 36V 225AH battery pack, so Peukert's law kicks in and you won't be able to get all of the 10.14 kWh stored.

On the other hand, a 8x6V battery pack (48V 225AH) would store 12kWh and even with a heavy foot, you would still have a longer run-time than with a 36V 225AH battery pack.