Engine Battery - parasitic drains?

[Nancy]

We are new R29 owners and we spent our first night mooring. In the morning we experienced no battery power to start the engine. We switched to parallel and the engine started easily.

Here is a list of the possible things we may have done wrong in retrospect.
1. hit the stop/start button to shut the engine off but left the engine switch on the Power Panel overnight.
2. left the garmin plus radar on (but doesn't that draw from house batteries)? The house batteries were obviously okay.

Any comments? Are there parasitic drains on the engine batteries? What is the minimum voltage the engine needs to start?

Many thanks
Nancy

 

[LADYBUG TOO]

I would suggest borrowing an amp meter. Hang the meter across the start battery cable and it should show any current being drawn by a "parasitic" load. Based on a chart I have from the 12 Volt Bible, 12.6+ volts indicates that the battery is fully charged. At 11.9 volts, the battery is 40 percent charged and I am not sure that that would be enough to crank the engine but it could be. At 12.06 volts the chart says 50 percent and my engine has cranked when the Blue Sea meter read barely 12 volts. The real key is cranking amps available. Our R-29 came with a 1000 cold crank amp XXHD Group 27 flooded cell battery.

Pat
Ladybug, Too

 

[knotflying]

Did you accidentally leave the engine key on? I have done that before when I wanted to check my engine hours after we stopped. Leaving that key on will definitely drain the engine battery and it will do it with the engine battery switch off.

 

[Nancy]

Yes, I believe we did leave on the ignition. Somehow in our training, the fact of turning the ignition on and off was lost. Perhaps we were told but with everything else, it was lost. So we have been locking the system with the key fob and the system goes off. Then it comes back on when we unlock with the key fob. We would just push start/stop. When we were at anchor, we didn't bother to lock the system. Reading today, I think the ignition was left on (we certainly didn't turn it off) - your post has convinced me that this was the reason the engine battery was gone. Thanks!

Thanks too for the reference to the 12 volt battery book for boats - that is on my 'buy' list!

Some one told me it would take 12 months to learn the nuances of the boat - I believe them. So far though, it has all been part of the fun.

Nancy

 

[knotflying]

Mistakes are the best learned lessons!