Does Onboard charger drain the batteries?

[tmcdon]

Changed my 96 Medalist to 48V (8-6V), Alltrax controller, solenoid F&R, and Lester Charger on board. I programmed it as onboard, but seems like it drains the batteries when I don't have it plugged in. Do I need to put a switch in the cable to the battery or does it need to be plugged all the time when not in use? I'm losing about .5V per day.

[2K6TBSS]

I haven't had any problems with my Lester on-board charger consuming power. It usually takes about a week to lose .5V on mine.

[JohnnieB]

Originally Posted by tmcdon

Changed my 96 Medalist to 48V (8-6V), Alltrax controller, solenoid F&R, and Lester Charger on board. I programmed it as onboard, but seems like it drains the batteries when I don't have it plugged in. Do I need to put a switch in the cable to the battery or does it need to be plugged all the time when not in use? I'm losing about .5V per day.

Normal self discharge is in the neighborhood of 1% SoC per day and 0.5V per day is about 10% SoC per day, so there is a significant drain of some kind or another.

If an on-board charge had a shorted diode or SCR in the output circuit, it could put a drain on the pack, but if the charger had a bad device in the output, I doubt if it would be charging the batteries.

What make/model 8V batteries?

What make/model charger?

What make/model of DC voltage reducer? (If you don't have one, how do you power the cart's 12V accessories?)

[Cobra,1]

Had similar problem. Found my 48 to 12 volt reducer was always on even when tow switch in tow position.
Wired it to only Tuen on when in run helped stop parasitic battery drain.
I used an inductive amp meter to check that reducer was causing drain. Either that or unplug 48volt wire going to reducer when not in use to see if it is problem.
As Johnie mentioned, battery condition will also play a factor.

[tmcdon]

My batteries are 6 black box Trojans, 2 napa, no voltage reducer, only accessories is a small light bar wired from 2 batteries. i have a battery meter that is powered thru the key switch and the f&r powered from the solenoid. It is a New Lester Summit 2 650w. It shows no faults with batteries.

[JohnnieB]

Originally Posted by tmcdon

1. My batteries are 6 black box Trojans, 2 napa,

2. no voltage reducer, only accessories is a small light bar wired from 2 batteries.

3. i have a battery meter that is powered thru the key switch and

4. the f&r powered from the solenoid.

5. It is a New Lester Summit 2 650w. It shows no faults with batteries.

1. Sounds like you added two 6V batteries to the existing 6 X 6V 36V pack to get 48V. That means six of the batteries have some years on them and it may mean they have different AH ratings, so they may not be being charged properly since the charger charges them in series and only sees the pack's average. Measure the individual battery's voltage while on charge. They should all be within 0.1V of the others.

2. Tapping the 48V for 12V imbalances the pack no matter how small the 12V accessories are. Measure the individual battery's voltages after they have sit for 12 hours after being charged. All should be within 0.1V of each other. Should have either a voltage reducer to drain all 8 batteries equally, or a separate 12V accessory battery.

3. Shouldn't be an issue. Battery meters only draw a few milliamps. My battery meter is connected straight to the pack and runs all the time. But try disconnecting on of the battery leads from meter to check if it is the culprit.

4. With the key turned OFF and the pedal not pushed, can you hear the solenoids on the reversing contactor click when the F/R switch is moved from F to R. If so, an energized coil on the reversing contactor may be the source of the abnormal battery drainage and you'll have to rewire the reversing contactor coil circuit so it is only powered when key is on. or remember to tut F/R in neutral when you park the cart.

5. The Summit II not having any battery fault errors only means there was nothing found that would prevent it from trying to charge the batteries. That doesn't mean the batteries will take enough charge to power a cart, or if they will hold a charge.

[DaveTM]

If easy.....why not disconnect the OBC after a charge and see if the batteries still "drain" the same amount.

If it slows, the OBC is a culprit. If its the same......maybe not the OBC?

[tmcdon]

I'll check that this weekend. If it warms up enuf to get into the shop!

[tmcdon]

Every time I disconnect the charger it sparks the terminal. Is that normal?

[JohnnieB]

Originally Posted by tmcdon

Every time I disconnect the charger it sparks the terminal. Is that normal?

I'm pretty sure the charge output cable shouldn't spark, unless the charger is plugged into AC at the time.