Voltage reducer – battery drain?

[cobolnofun]

Ehhh i don't know about improvements. It is still slowly draining the battery. I unhooked the converter for a few days and the batteries stayed up around 38.5. Put the reducer back on and it has dropped to around 37.5 over a week.

The weird thing about this all is, it works correctly. No 12 volt power with the keyswitch off. With the key switch on, everything works just fine.

I think i am going to put a Battery Disconnect Isolator on the positive between the battery and the voltage reducer. That way i can just flip the switch and turn off the reducer completely when sitting for awhile.

as far as where i installed mine: i added an aluminum piece and mounted it in the seat/motor area. See attached pic.

[Sergio]

Next time you let the cart stay idle for a week and the voltage reads 37.5v, turn the cart ON and drive 10 yards or so, park again and check the voltage after a few minutes.

I am wondering if You are seeing a "surface charge" and not the true SOC of the batteries.

[cobolnofun]

well that could be. I have some time this weekend i will check the specific gravity of the batteries.

I am also wondering though if i could use a multimeter and see if i can find any current in various parts of the system when off to see if it is leaking somewhere.

[Sergio]

Even if the electrolyte is at the correct specific gravity, the "surface charge" on the plates may not reflect the true SOC of the battery due to the small discharge rate and the speed of the battery chemical reactions.

This is the same issue why your battery may show 46v under load and then go back to 51v after you stop.

The battery was never at 46v and somehow got recharged, that was just the "surface charge" reading and the true voltage will stabilize after the slow chemical reactions finish and the surface of the plates reflect the true SOC.

Just speculation since I don't really see that happen on my Precedent which also has a "trigger" type voltage converter.

[tellico416]

Well, I"ll call it a success. Followed your lead and got the reducer installed and decided to just use a banana connection in the middle of the power lead (yellow wires on top of middle battery) to disconnect/reconnect power for the dc reducer for storage. Everything works as it should.

Glad I read about the nasty spark when connecting up the negative terminal as I would have otherwise swore I had a dead short somewhere. After doing a recheck and making sure ignition was off and in tow mode did the re-connection and got the same spark but no residual heat or melting of wires....so hopefully just confirmation of the reducer's capacitor charging/discharging. Cart drives fine and not worried about using lights now.

[jazzyjohnny]

I mounted mine (same reducer) in the same location. I ran the yellow 48+ wire thru a 30amp toggle switch that is mounted beside the tow/run switch. Every time I put the cart in tow for charging I flip off the toggle for the reducer so it is no longer receiving power from the pack. That has keep me from having to deal with the sparking every time the reduce is hooked back to the pack.

[Sergio]

There is no need to flip to Tow to charge, but no harm either.

Even Though You can no longer see the "spark", there is still damage being done to the filter capacitors as the charging current is uncontrolled.

There are many different voltage converter designs so it is hard to tell how quick that will cause damage, but unless the converter is specifically designed as a "no spark", I would prefer to leave it connected all the time and just turn the load ON/OFF (the way it is designed to work).

[jazzyjohnny]

[QUOTE=Sergio;1495193]There is no need to flip to Tow to charge, but no harm either.

Even Though You can no longer see the "spark", there is still damage being done to the filter capacitors as the charging current is uncontrolled.


I agree normally I leave this on over the weekend while at campground but when I leave sometimes for 2-3 weeks at a time I feel better knowing all power has been disconnected. Rather slowly kill the reducer than to find a black spot where my cart or camper used to sit.

[tellico416]

Good comment Sergio....connecting/reconnecting will probably do more harm over the short term as you surmise rather than just let it function as designed.

Is there any better way to disconnect this converter for those of us that use lights as their only 12v load and foresee using them once in a blue moon? I envision just leaving my converter disconnected for the majority of my operating time rather than connected. Why leave something that is drawing current with no functional use.....until needed? I may use the cart 5 times a week and the lights once every 2-3 months for 20 minutes of use or less.

Perhaps what I am really asking is did I install a converter too large for my initial application that now feel apprehensive about leaving on all the time. My neighbor has a similar application (but has LED vs my halogen lights) and is operating fine on a little 10 amp converter.

[Sergio]

Unfortunately it is our current reality with electronics, pretty much any electronic device in your house or cart is never totally OFF.

Most converters when no load is present have a very small quiescent current that keeps the filter capacitors charged, most of its internal electronics like oscillators are idle since there is no need for them to be working.

It is also better for electrolytic capacitors to remain charged all the time.

The amount of current used by those devices in this state is much less than the self-discharge current of your batteries or Controller, OBC, etc.

If your cart is OFF for weeks at the time, it should be either on a charger or you should disconnect the pack anyway.

I just don't see the need to worry about such a small current drain, but since the converters are cheap, there is also no point in worrying about your cart when you are away.

In this case I would agree with You that if makes you feel better, just add a switch to the converter input.