Electrical Drain Issue

[HiltonHeadFun]

Newbie here. Thanks in advance for any input!

• Scenario: We had three 4 to 5 hour trouble free trips until we made it back to the boat ramp on each occasion. The boat would just not start. It would turn over then eventually make a beeping, drained battery type sound.
• 2 Brand new batteries (27) and a charged spare. Perko 1,2, and All type switch. Garmin GPSECHO.
• Had Perko switch on the deep cycle battery most of the day. (I think) Tried starting with 1, 2, and ALL when arriving back to the ramp from the outing with no luck.
• GPS and all lights on console worked, horn sounded weak.Tested the batteries and both were at 12.6V.
• Previously tested the batteries with engine running and they were charging from 12.6 up to 13 or 14V. So, appared that motor/alternator was charging the batteries?
• Cleaned the contacts on the wires to batteries. Tried jumping the battery.

Thanks again for any input!--

 

[Faztbullet]

Check connections on Perko switch

 

[Chris1956]

If I understand your post, a series 27 battery was drained in one day. That is a large short. I would expect you would hear or see sparks when connecting the battery, with the switch on.

You will need an ammeter to fix the short. You would connect the ammeter from battery positive post to boat positive battery wire. Read the current of the drain and then do some educated guessing of what is causing it,

There are not many items that could draw that kind of current. The alternator and starter are two of those. if you have a water heater or winch or some heavy pumps, they could be culprits. Warm or hot wires would indicate a short, as well.

 

[dingbat]

2 Brand new batteries (27) and a charged spare.

Where the brand new batteries fully charged when installed?
How old is the spare?
How was it fully charged?

Perko 1,2, and All type switch.

• Had Perko switch on the deep cycle battery most of the day. (I think)

You think?
Can’t sort this out w/o specifics

• Tried starting with 1, 2, and ALL when arriving back to the ramp from the outing with no luck.

The Perko switch only supports 2 batteries.
How is the third battery connected to the switch?
You understand the two batteries attached batteries equalize when switch is set to ALL, right?

Combine a 12.6v battery with a 10.5 volt battery and you end up with two 11.5v batteries which are technically dead. Certainly will not start a motor

How is the third battery being charged?

• with engine running and they were charging from 12.6 up to 13 or 14V.

Again…specifics.
Battery should read close to 14+ volts with engine running. 13 volts doesn’t cut it.

 

[HiltonHeadFun]

Check connections on Perko switch

Will do that next and thank you!

 

[HiltonHeadFun]

If I understand your post, a series 27 battery was drained in one day. That is a large short. I would expect you would hear or see sparks when connecting the battery, with the switch on.

You will need an ammeter to fix the short. You would connect the ammeter from battery positive post to boat positive battery wire. Read the current of the drain and then do some educated guessing of what is causing it,

There are not many items that could draw that kind of current. The alternator and starter are two of those. if you have a water heater or winch or some heavy pumps, they could be culprits. Warm or hot wires would indicate a short, as well.

Thanks Chris, I will try this.