How To Decrease Self Discharge When Not In Use

Rickochet

I have an '07 TXT PDS 36v that I bought in '12 and it came with a new set of trojans. During the summer I leave the cart at the lake in the marina parking lot with about 40 other carts. There is no electricity in the parking area. I charge the cart the night before I leave and drive it 1/4 mile to the lot. I have often left it for 3 weeks with no issues and when I arrive back at the lake I have plenty of power to get me to my boat. The last time there when I arrived after 4 weeks it barely had enough power to get me to my boat. This is the first time it has done this.

I keep the water checked and try to never let it go below 80%. Perhaps at 4 years the batts aren't as strong as they once were. I also set the run/tow switch to tow and there are no accessories to get left on.

I was wondering if there is anything I can do to keep the charge up on the pack while parked for extended periods. I have found some 36v solar chargers but they are pretty expensive and I am afraid it would get stolen. I also wondered that if I get to the cart and voltage is way down could I use an additional 12v batt jumper cabled to the pack to boost voltage to get me the 1/4 mile to the boat or would this fry the controller? Would doing a 48v conversion help my situation?

Any other suggestions other than get a gas cart would be appreciated.

BGW

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crash test dummy

only a solar charger would work in your usage
they do bolt to roof
adding a 12v jumper box would work short term , if put in parallel with 2 of your batteries , but i would not do it

Rickochet

I keep a driving enclosure on the cart. I would have to bolt the charger down through the enclosure or alter the enclosure.

Volt_Ampere

Solar charger might work for you if it's outside.

JohnnieB

The self-discharge rate of batteries is about 1% of the SoC per day, so for 225AH batteries it is about 2.3AH per day, or a flow rate of about 0.1A. So a 36V solar charger that puts out 100 Milli-amps or more, ought to keep them charged.

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Putting the Run/Tow switch in Tow doesn't completely turn off a PDS controller and keeping the filter capacitors charged in any type controller draws current for the battery pack.

Disconnecting the any of the high current cable connecting the batteries in series will reduce the parasitic drain on the battery pack. The batteries, in and of themselves, will still self-discharge, but the overall discharge rate of the pack will be less. (Be aware that you'll get an arc when you reconnect the cable.)


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Going to a 48V system might help since you are starting with a higher voltage. Also the cart's performance will be better.

MattFX4

1% per day. That's nuts. My neighbor leaves his cart unplugged a week or two between charges all while using during this time and it makes me cringe. He also relies on the ezgo battery meter and recharges when it reads dead. My cart remains on my dpi charger 24/7 unless I'm using the cart, or letting it sit out in front of my house for a few hours on the weekends. I like to think that my batteries will outlast his given no defects in the batteries themselves.

JohnnieB

Last winter, I lost power at my place for a week after an ice storm and the opportunity to measure the daily discharge rate of my battery pack was forced upon me.

I disconnected my DPI charger after the power was off for a couple days (Strange what you think of doing when there is nothing much to do. ) and measured the battery voltages right before I plugged it back into the cart after the power was restored. I seem to have misplaced the spreadsheet I used, but IIRC, I lost a bit over 1% per day with batteries connected, but Run/Tow in Tow. (DCX500 controller at the time)

The 1% discharge rate is a general rule of thumb and is the basis for the recommendation that carts be charged at least once a month while in storage. Some cart setups discharge more while others discharge less.

I suspect your battery's life span will be greater than what your neighbor will get, but even if it isn't, you will be starting each trip with full charged batteries and enjoy better performance on the trip.

kgsc

If you have 39 other carts there, you could think about putting in a power pole and split the costs... You would need a bunch of outlets though..

crash test dummy

there are some sacrifice's you have to make

Rickochet

The parking area in question floods about once per year so it is unlikely that we could get permission to run a line and outlets and might be too expensive anywho.