Cranking battery drawing down electrical short 07 ZX 225

2007 ZX225, 225 HPDI

First let me apologize as this is going to be a long winded one...

I've got a draw on my cranking battery that first shuts off my Lowrance electronics and then won't crank the motor later in the day. Started happening when I was using a Interstate Deep Cycle/cranking battery (27M)-one year old and then I purchased an Optima blue top 31M in June of 2010. Didn't really happen again all summer (with the Optima) but this fall (Nov 2010) when it was cold it started to happen again. This is also when I wasn't running any fill/recirc/bilge pumps. Just fishing with graphs on only and didn't start the engine much or run very long (a minute or so).

A week ago, went walleye fishing and it was cold!!!. Cranked the motor right up idled a few hundred yards and fished. The only thing on was my Lowrance 520c and Lowrance 28cHD, hooked to NMEA network/bus running a LGC-4000 GPS puck.
Side Note: The entire bus and GPS puck is switched through the "power button" on the panel at the driver console, which is how Skeeter wired the NMEA bus. the 520c is wired directly to the cranking battery (not a panel) and the 28C is using a power from the console/panel on the drivers side, also how skeeter wired the Lowrance graph it came with.

to continue with the saga....I pumped one livewell full, shut that pump off, then ran recirc pump (only) on timer/low setting the rest of the day. about noon (3.5 hours into the day) cranked the big motor and graphs shut off. At the end of the day (4 hours later) wouldn't crank the big motor and my voltage gauge read 9ish. Couldn't see the voltage on my Lowrance, they shut off...

I have a 4 bank Minn Kota battery charger as I'm running a 4 battery setup (36 for TM) and cranking/accessories. The charger looks to be functioning normal and everything is green. In fact, when I pull it off the charger and leave it for a few days/a week and plug it back in, the cranking battery pops back to green about 5-10 seconds after the TM batteries do. I'm assuming that is normal at least that has been my experience on my other boats.

I've checked all the connections to all pumps, auto bilge float, oxygenators, lights etc and they look good/solid with no corrosion. I had an electrician friend come over (I'm "challenged" when it comes to electrical) and we pulled all power leads off the cranking battery and started testing voltage and resistance. We originally saw 12 volts off the power cable that runs just about all accessories (pumps, panel/switches at driver console, oxygenators, lights etc) and a 10 mA reading. We started checking pump wires, checking resistance (infinity on all, which I understand is good) and when we pulled the wires apart for the autobilge and float, the 10 mA on the power wire back at the battery disappeared. We reconnected the wires and could not duplicate the 10 mA draw. It was gone for good.

so having said all of that, with everything off/disconnected, when you rub this same wire across the threads to the power terminal there is a very small spark. So something on the accessories power is drawing. Right?? Is there anything that should be drawing?? Remember, everything was off.

It doesn't appear to be drawing down/shorting while the boat sits with nothing on. Just when the power panel at the driver console is on. Do you think it could be in the wiring to the switches/gauges at the panel/console?? We haven't gone through the wiring to the panel or gauges yet. Probably this weekend. I'm also going to charge the Optima and have it load tested just to make sure. But seeing that it has happened for two new/newer batteries, I don't think its a battery issue.

Any help, hints or thoughts?? Anyone else have these issues or something similar?

Bob

wow..talk about mad typin skills http://www.bassboatcentral.com/smileys/eek.gif ..i dont think it should spark ..have you checked the cranking battery with another charger..maybee your onboard is lying to you and you might have a short with it..im no mechanic, but thats were i would start

I've got a stand alone charger that i was planning on charging it up with and taking to Autozone for a load test. I still don't think it's the battery. Otherwise, I've got the worst luck in the world and have two bad ones in a row...

Thanks for the response Doc.

I had a float switch go bad and the pump wouldnt shut off. Maybe a short in the float switch or wire going to it?

This is a new float switch (installed 2010) and we checked it pretty good. pulled the entire switch, cords good, float operating/not stuck, checked resistance (good), even the manual over-ride (little lever on the side) worked as it should. That was good suggestion though, as I had to replace the last float/switch. The housing/anchors broke and it would get stuck on (like yours the bilge would run forever) and you would have to jiggle the housing to get it to stop.

Thanks keep them coming.....

Anybody had any issues with oxygenators?? I really didn't test those, just looked at the splices, which were good..

I had the same issue on my '7 zx225 and my '08 zx225. It was the auto bilge on both. I unhooked it from the battery and never had it happen again. I have a Perko battery switch so it wasn't that big of a deal just annoying.

So did you unhook the auto bilge float/switch or was it the pump itself? I think the bilge pump is a rule 1500 but it also operates manually from the panel as well. How did you hook up the perko battery switch? was yours drawing down while in storage or just on the water when panel was powered??

Sorry about all the ??? just trying to not lose my mind chasing this...

and thanks for the help

Mine was only going dead when on the water. I keep it hooked to the charger at all times when in the garage. The perko switch is easy to install and is a life saver if your battery dies in a tournament. You simply turn the switch to the trolling batteries and start the engines.

Thanks for the responses. Was your float the "Rule A Matic Plus" on each boat ?http://www.westmarine.com/1/1/12274-...at-switch.html

This is to ZXskeeterB. If you run your motor with 36 volts instead of twelve won't you hurt the alternator or something else on your motor?