Terminal arcing when connecting battery

[soccerdad]

On my 96 GSX, I get a small arc when I hook up the battery cable. It has been happening since day one and still happens after I replace the MPEM for a starting problem. I never get this when I connect the battery on the 96 GTX. This happens with and without the VTS cables connected. Is this normal? Not sure what would be drawing any power to make it arc. Note that this is a late year 96 GSX and uses a 97 MPEM (combined CDI)

 

[68ragtop]

there are electronics (capacitors, etc) in the MPEM that hold voltage & drain over time. When you first hook up the battery & re energize things, that can create a very small spark, almost not noticeable. If you disconnect the battery & hook it back up there will normally be no spark at all. If your battery is not draining I wouldn't be concerned, unless its more than just a little spark?

 

[soccerdad]

Just a little spark. Battery seems to be doing fine. Just checking.

 

[Minnetonka4me]

Well...it could be nothing, but usually it means theres something wrong with the electronics somewhere. I had a customer bring a 97 GSX in for other repairs and I noticed his do it. When it sits take note of how many days it sat and how dead the battery is. He didnt want me to try to find it so I cant tell you what to look for, but it could be any component. Prob not the MPEM b/c you replaced it.

You know...it could be the LCD gauge. Unhook the connectors for the LCD from the MPEM and reconnect the battery.

 

[Sportster-2001-951C-Stock]

That spark may be normal for this ski as mentioned a slight current surge may flow briefly while system capacitors are charging to the battery output voltage, however, to test for parasitic power consumption you need to use an ammeter capable of measuring down to less than 10 milliamps and as high as up to 10 amps, disconnect one battery terminal and place the meter leads in series with the battery and electrical system, begin testing with the meter set on the 10 amp scale and work your way down until the meter reads near half scale and stop there, this is your parasitic power consumption x hours = amp hours.

From this current measurement you can calculate approximately how much time it will take to discharge the battery based on the Amp-hour capacity of the battery.

A typical current draw of around 10 milliamps or less is normal to keep most electronic devices from losing their memory settings, the smaller this parasitic current the longer it takes to run the battery flat (a healthy battery at rest for 12 hours or more after charging should measure at least 12.5 volts if fully charged).

 

[soccerdad]

Well...it could be nothing, but usually it means theres something wrong with the electronics somewhere. I had a customer bring a 97 GSX in for other repairs and I noticed his do it. When it sits take note of how many days it sat and how dead the battery is. He didnt want me to try to find it so I cant tell you what to look for, but it could be any component. Prob not the MPEM b/c you replaced it.

You know...it could be the LCD gauge. Unhook the connectors for the LCD from the MPEM and reconnect the battery.

It is interesting that it was a 97 GSX since that is basically what I have as far as the MPEM goes. The 96 GTX does not do it but it is the other style MPEM.

Anyway, the ski has been sitting for two weeks and I tested the battery today. It is sitting at 12.7VDC so it does not appear to have been drained much if any. IIRC, it does not do it if I disconnect the cables and them hook them back up quickly. This probebly indicates that the caps are just charging. I will keep an eye on it.

 

[68ragtop]

On a side note: when my 96 GSX & 97 XP sit for several weeks they will be a little discharged. I keep all my toys on maintainers now.

 

[Sportster-2001-951C-Stock]

12.7 after two weeks sounds pretty reasonable to me, if there was an appreciable draw voltage would be much less by now. Sounds like you've got a good battery as well, some batteries don't seem to hold a charge very well while others can hold a charge for months on end. Absent any actual proof concerning wet cell construction methods, I attribute an ability to hold a charge well primarily to good electrolyte isolation between cells.

What I'm actually saying is I believe avoiding over-watering a battery may help extend it's ability to maintain charge, the water should only just cover the tops of the plates and not be allowed to drop below that level but it's really easy to over-water so go very slowly when adding and stop when the top of the plates are covered.

EDIT - Oh, I forgot to mention I've also seen my fair share of cooked batteries from back in the days we didn't have the nice automatic trickle charger setups we have now but despite that I still remove the charger or at least put it on a timer so it only is powered 30 minutes each day.