Cart charge and discharge

[sophiecat3]

I have a 2001 electric 48v Club car.

I wish to take advantage of the off prime time power company rates. these can b significant. In my area normal rates are .33 cents per KW.. Off prime rates are .11 cents per KW. Off prime time is 10 pm to 6 am.

To do this I put a timer on the ac plug on the charger set to go on at 10pm.

I plug the charger into the cart at any time convenient for me. Sometimes everything is ok. The batteries (new) are recharged the next morning and away I go.
However, sometimes when I go to the cart in the morning the discharge light is on and the cart won't go. Batteries seem to b charged because when I turn on the charger manually the charge rate is very low. Also the lights are bright. Can anyone help me with this ?

[scottyb]

The battery light will come on if the charge cycle is interrupted. Maybe you are loosing power at night? I'm gonna suggest you get a digital volt meter so you can get some real information on this problem. Note pack voltage before charge and in the AM when it's okay and when it won't run? This will give us a starting point.

[joesam]

Even though you would think logically that it would; and assuming your cart and charger are stock - an A/C timer won't turn your charger on for you. Only pulling the big rubber DC plug and plugging it back in, will do that.

If you REALLY want to save power, you'll have to open and modify your charger with an A/C relay. That relay would "simulate" pulling the big rubber charger plug out and plugging it in.

Exactly how to wire it in, has been described (by Sergio I think) "somewhere" in this forum. It wouldn't be expensive - but depends on how determined you are to do it.

[Volt_Ampere]

At least on my Yamaha cart, I would have to interrupt the connection to the cart and not the AC connection to do this. That can be done but you would have to interrupt the wiring somewhere - either in the charger, lead to cart, or on the cart. Don't do this if you don't know what you are doing. It could get expensive!

[Sergio]

The correct way of doing it is to wire a 120vAC continuous duty relay directly to the mains inside the charger.

You would then run the sense wire inside the charger through the Normally Open contacts of the relay.

The idea is that when there is no power to the charger, the Relay contacts are open and it simulates the DC cord being unplug from the cart.

Of course don't do it unless this makes perfect sense to you.

The blinking pattern You are getting may just indicate that the charging cycle was not completed when the Timer when off.

I would suggest setting the Timer from 10PM to 2PM, since the maximum charge cycle would be 16hours at the most.

The charger will not consume any power if the OBC has cycled the charger OFF, so there is no downside to this method.

[Sergio]

I plug the charger into the cart at any time convenient for me

One more thought, if You plug the charger at 10am without AC power (timer is off), the OBC will start the charge cycle and fail the pre-charge test.

The OBC will continue to try to start the charge cycle for 7 days, I don't know the frequency it retries.

If it succeeds at 11PM, that is already 13 hours into the "charge cycle", even if the charging works fine for 4 hours, the entire time would be 17 hours.

The blinking light may just reflect that entire time.

Do You recall if the times the light was blinking were days that You plugged the charger to the cart in the morning?

[tag50]

In a thread titled "Battery maintainers" by pat5000, he determined that for his cart 1Kw was used and replaced for a 2 mile test run. I am assuming the energy replacement would be the same for the bulk charge, and savings by shifting to a lower Kwh rate is not worth the effort.


.

[Sergio]

I remember that very non-scientific thread, I think he actually interrupted the charging and started it again later assuming some kind of linear relationship between discharge and charge....

Anyway, saving about 50 cents a day will pay for a new pack by the time you need to replace the batteries.

[tag50]

Great, I save more than that walking past Starbucks.


.


.

[beau]

You may be able to get an even better rate if your utility has an EV rate during those hours. It is my understanding that utility companies are trying to encourage the use of EVs. There is more and more wind power coming online everyday, a very high percent of this energy is produced in the non-prime hours. Any abundance must be sold and transmitted elsewhere as utility companies typically don't/can't store.
Add 100,000 electric cars to the local grid every night and you have an effective external storage system with all of the costs to maintain it externalized!