When my trolling motor died and I was troubleshooting why, I tested the plug with a multimeter and it read 34.5v's. This is strange because I only have a 24v system. My first thought was the previous owner may have tied in the cranking battery. I completely unhooked the cranking battery and for some weird reason other then today is a solar eclipse I still was reading almost 36v at my TM plug. How is this possible? I admit I am not great on this subject so I asked to make sure I was using the multimeter right and I was. And no there isn't a 3rd battery I'm unaware of or it's invisible So any help would be greatly appreciated. 

Do you have a pic of the battery wiring?  If you have a 24v system, then you should have three batteries: two deep cycle, and one cranking.

1 minute ago, J Francho said:

Do you have a pic of the battery wiring?  If you have a 24v system, then you should have three batteries: two deep cycle, and one cranking.

 

Correct. 1 crank and 2 deep cycle. Tried posting but said file was too big. I'll try again. 

https://postimages.org/

9 minutes ago, J Francho said:

https://postimages.org/

 

https://postimg.org/gallery/po11ep5c/

 

thank you 

Hmmm.  Can you disconnect all the 3-bank charger wires, and take a reading?  I wonder if that's where it got screwed up.

The straight up answer is you CAN NOT get 36 volts from two 12v batteries.

 

Did you disconnect both cables from the crank battery? If so, try un-plugging the battery charger and see what it reads.

 

4 minutes ago, J Francho said:

Hmmm.  Can you disconnect all the 3-bank charger wires, and take a reading?  I wonder if that's where it got screwed up.

It's only a 2 bank charger 

2 minutes ago, eddallen said:

The straight up answer is you CAN NOT get 36 volts from two 12v batteries.

 

Exactly.  This is weird. I don't really know what's going on here.

7 minutes ago, eddallen said:

The straight up answer is you CAN NOT get 36 volts from two 12v batteries.

 

Did you disconnect both cables from the crank battery? If so, try in-plugging the battery charger and see what it reads.

 

I did completely unplug cranking battery and made sure it wasn't  touching either post. Did you mean unplug the charger? If so I didn't have charger connected during test. 

1 minute ago, releget said:

I did completely unplug cranking battery and made sure it was touching either post. 

 

OK sometimes if the charger is ON, when you disconnect one of two batteries the charging channel for that battery can remain open (supplying voltage). If you unplug the charger it will close that channel. Which two batteries is the 2-bank charger feeding? What all is on your boat? Might there be a house battery for your electronics?

Here is a labeled picture of what is on the 2 deep cells 

https://s3.postimg.org/oka5zswer/IMG_7693.jpg

2 minutes ago, eddallen said:

 

OK sometimes if the charger is ON, when you disconnect one of two batteries the charging channel for that battery can remain open (supplying voltage). If you unplug the charger it will close that channel. Which two batteries is the 2-bank charger feeding? What all is on your boat? Might there be a house battery for your electronics?

If there is it's very well hidden. The 2 bank is charging the 2 deep cells. I have a 2004 Nitro nx882 with 3 electronic units, motorguide TM, an annoying anchor buddy, couple lights, normal dash etc. 

Haha before you tear the boat apart looking for a battery, remove the pos from both deep cycle bats and the crank bat, then see if electronics will turn ON.

 

4 hours ago, J Francho said:

https://postimages.org/

Thanks for that - I've been looking for somthng since Photobucket piddled all over their customers and their own bed...

Why is it always the most simplest thing. I decided to start from the beginning and unhook everything to the bats and test them 1 by one. When I put my multimeter on it read 18-20v. Now I know something is wrong with my multimeter. Go buy another one. Also reads 18-20. Frustrated as hell I search car forums for odd multimeter readings and found out it was as simple as the 9v battery in he multimeter is dead enough to cause miss readings. I used the same battery in both multimeters so when I purchased a new battery and checked. Perfect. Hooked it all up and had my 24v at plug. So this was all due to a miss read and dead 9v battery. Why do I always learn the hard way. I really appreciate you guys working though this with me but consider this case closed. 

10 hours ago, releget said:

Why is it always the most simplest thing. I decided to start from the beginning and unhook everything to the bats and test them 1 by one. When I put my multimeter on it read 18-20v. Now I know something is wrong with my multimeter. Go buy another one. Also reads 18-20. Frustrated as hell I search car forums for odd multimeter readings and found out it was as simple as the 9v battery in he multimeter is dead enough to cause miss readings. I used the same battery in both multimeters so when I purchased a new battery and checked. Perfect. Hooked it all up and had my 24v at plug. So this was all due to a miss read and dead 9v battery. Why do I always learn the hard way. I really appreciate you guys working though this with me but consider this case closed. 

 

We ALL continually learn, if our minds are open to the task. Glad all is well.

Man, I'm glad you figured it out!

Well I think we've all learnt something there. Thanks for finishing the story. 

On 8/22/2017 at 8:28 AM, releget said:

Why is it always the most simplest thing. I decided to start from the beginning and unhook everything to the bats and test them 1 by one. When I put my multimeter on it read 18-20v. Now I know something is wrong with my multimeter. Go buy another one. Also reads 18-20. Frustrated as hell I search car forums for odd multimeter readings and found out it was as simple as the 9v battery in he multimeter is dead enough to cause miss readings. I used the same battery in both multimeters so when I purchased a new battery and checked. Perfect. Hooked it all up and had my 24v at plug. So this was all due to a miss read and dead 9v battery. Why do I always learn the hard way. I really appreciate you guys working though this with me but consider this case closed. 

OK, I'm gonna put that one in the memory banks...never woulda thought about that.

Never seen that solution coming .....