Axis Wakeboard Boat Forum

Put in a 2nd Optima Blue this Spring. I occasionally have a "No ECM Data" error message. Talked to the tech at my dealer, who said it was one of two things. One, a CAN cable that he'd have to order. Second, he knew I put in a dual battery myself, so he said that if I didn't have good voltage to all of the ancilaries, I may have the problem right there. If the ECM, dash gauges, etc. are all running off of hte alternator, rather than a battery, it may casue the problem.

When I installed the second batter, I took the two cables from the boat, bolted them together, and then sent a 0GA cable up to my switch (installed it close to the door for easier access). This is an intermittent problem, not a constant one. Which lends credence to his theory.

Those of you with dual batteries, how is that second smaller cable wired? Is it to the common switch, or is it directly to one of the batteries? I'd put it on my #1 battery, but if it feeds stuff like lights, I don't want to drain the battery if am anchored at night, running off of #2 for the stereo, etc.

I left the accessory connected to the common on the switch. So no matter what battery you use your accessories have power. If I am reading yours right all is connected to battery 1 and if you drain it you will have to switch it to battery 2 and your emc will have no power.

Where is your stereo wired to?

From what I gather most everyone connects their stereo to a battery or a bank along with led's that are more than stock. the accessory goes to the common. On both batteries the pos goes to the switch and the neg is connected to both terminals and then one will have the boat ground too.

Hope that helps

No, mine is connected to the common on the switch, too. Was wondering if I need to consider moving it. I thought I hooked up my amps to the switch, too, but the more I think about it, maybe I did hook them up to battery 2. Need to go check, but I keep my boat at a marina, so I can't verify right away.

I moved my amps to the second battery, all accessories stayed on the common terminal of the switch.

I've got engine, stereo power, and accessory to common. #2 for stereo batteries and #1 for starter.