Eliminating Equalizer Idle Battery Drain - Just disconnect ground or?

[Brian Diehl]

I'd like to be able to eliminate the equalizer drain on my start batteries when doing extended boon-docking.  To "turn off" the equalizer do I just need to disconnect the ground?  I'm thinking I need to disconnect the ground and then disconnect the 24v lead as well. 

After boon-docking I would turn "on" the equalizer when driving down the road to re-equalize the batteries.

The equalizer seems to have a fairly high idle drain on the batteries and I want to be able to eliminate the drain when parked with no engine 12v loads present.  All my household 12v needs are met by a 24v->12v DC converter not associated with the start batteries.  Only engine/transmission 12v needs are met by the equalizer.

[gumpy]

I believe the label on the vanners says to disconnect ground first and connect ground last.

You probably need to disconnect one of the hot wires, too. I'm pretty sure when I hook mine up after being disconnected for awhile, I get a spark on connecting
the second hot wire, before connecting the ground. That means something in there is drawing current.

BTW, you may need a disconnect on your 12v supply, too. I found I had a leak in the 12v tap somewhere that was draining one battery even when the 24v was
disconnected. I put a switch on it and solved the problem. Never did figure out what was drawing current. Didn't have a radio at the time.

[Cary and Don]

We have the same drain on the 12 volt side on the Neoplan. It seems that the ecm for the transmission is 12 volt. If we leave it sit we disconnect the batteries. Wing nuts on the two positive posts works great. Takes less than three minutes to reconnect. No more killing that 12 volt battery.

Don and Cary

[Jim Eh.]

What about running this ( http://www.partdeal.com/cole-hersee-battery-selector-master-disconnect-switch-afd-with-keys-m-753.html?zmam=74973193&zmas=1&zmac=98&zmap=77171883&gclid=CjwKEAjw0KK4BRDCiKHD5Ny8pHESJACLE620hlKwqZbYIc0PdeZDRaFRGFEYUdGUKygvTBj_48TvdBoC5SDw_wcB  )(both sides, 1 & 2) on the ground wire. I believe it is rated for 300 amps continuous and 500 intermittent. I can't see the reason or need to disconnect the negative then the positive and reverse when reconnecting. If the vanner is turned off when disconnecting what should it matter? Whenever I have dealt with batteries it has always been ground first/ground last but only because if you happen to contact a body panel or something metal you don't weld your wrench to it.

[Brian Diehl]

Disconnecting the ground appears to disable the Equalizer based upon testing I did yesterday.  So - there is the answer to that question.

However, in the testing I found what I think is the real problem.  Both batteries appear to be not holding a charge.  With ignition on and engine off the voltage of the batteries drops precipitously.  I'm bringing them in tomorrow to be load tested to validate.  If they are bad I'll replace with Group 31 batteries.  These are Group 31 and have worked great for the past 8 years.

Thanks for everyone's input.

[bevans6]

A simple description of an equalizer is that it's a switching power supply that runs from 24 volts and puts out a 12 volt supply that is exactly half of the 24 volt source.  Disconnecting the negative turns the switching power supply off. If the battery voltage at the 12 volt output is equal to the output voltage, no current flows.  If the "lower" battery is discharging, current flows to bring the battery voltage up to half the input voltage, up to the current capacity of the equalizer (or the fuse, I suppose).  Failing batteries tend to really screw this whole deal up.

[luvrbus]

What draws off the Vanner ?,I recall Cummins updated the wiring harness on the 1998 to 2003 I engines to stop the phantom draw on the 12v trucks between the ECM and starter something was killing the ECM.I'll check and see if I can find the S/B in all this paper mess I have .
My MCI will kill 1 of the 8-D batteries when shut off and the jumper cable between the 2 -12v  batteries disconnected the only way I can stop it is disconnect everything hooked to batteries   

[sledhead]

I use a latching solenoid's ( 2 x ) one for the 12 volt + and one for the 24 volt + switched inside above the drivers seat
no more battery problems

dave