12 V92 Ta's and DDEC, no throttle in gear on one engine..

I see a couple resistors but no diodes. hmmmm

Hi,

I have followed this thread with interest.

Given the state of the electrical connections in the photos how far does this type of mess extend through the rest if the boat and engine controls?

With rusty and corroded connections in the circuit you will be fighting an uphill battle to identify and repair the culprit.

Something as simple as a loose connection could be causing your charger to go berserk by it being unable to sense what is actually happening to the batteries and just doing what it was designed and built to do - provide a charge current to a demand for it.

I agree with K1W1 on this. Any one of the crimped wires could have resistance on it from corrosion. This in itself could be messing up this system. It will be interesting to see how this is resolved.

rust

How long was the boat under water for.

I have seen less corrosion on a boat being sold from a certain marina up the New River that reportedly had a little water in it but had sand and crabs inside the tower station.

Try cleaning the things that matter and stop polishing the bilges.

Hi,

The blue and white wire looks like it could be attached to a diode, better view of the end of it in the first photo in the lower right hand corner.

This could be the diode....

I agree, get a new battery charger or a new owner. I've thrown away working battery chargers that were 20 years old that looked much much better than that thing.......Put your foot down and tell the owner "we NEED a new battery charger" It sounds to me like you fried a DDEC circuit board as well......

And your engines were marinized by Stewart and Stevens which you rarely see in the DD world. I've seen 1 set marinized by them in my life.....also ddec's but 8v92's......you can tell by the Westerbeke red paint color they used.......

Trust me on this......just get the proper charger.......spend the money and don't get some old used Constavolt of unknown origion on Craigs list......either that......or install 2 chargers and have one do the engine bank and the other the house depending on what loads you are seeing......such as the 60amp for the house and a 30 amp for the engine bank, depending on how your battery banks are allocated.....etc etc...........You're running a yacht and sometimes you just have to spend the money to repair things that are broken.

2 8D's are borderline for starting 16v92's when you look at the cranking power you need to start them. However, if the only thing the 24 volt Constavolt is charging are 2 banks of 2 8D's, I don't see why you cannot install a 60amp charger to charge them. Especially if you have a battery parallel. The only time you'd have an issue is if they will not start and you have to attempt to start them multiple times. However, a 75amp charger is not going to recover them that much faster than a 60amp in the real thick of things.

Are you certain your 12v supply to the DDEC comes off your house batteries? On my 12v92 DDECs I have 24v starting batteries and alternators and the DDECs get 12v by pulling off of one of the 8d batteries tht are in series for starting. The problem with this set up is it draws one battery down and overcharges the other. I get voltage spikes of over 32 volts when this happens due to unbalanced batteries and weird loads on the alternators. In my system I sometimes get a low voltage alarm on my DDEC and put a meter on the two 8ds and find one at 11v and the other at 16v.
I'm in the process of installing dedicated 12v batteries for the DDECs to get them off the 24v bank. I've ordered a 24 input, 12v output battery to battery charger so I can stil charge all the batteries from my 24v alternators. This will allow my 24v banks to stay balanced and equalized.
Your problem sounds similiar to what I've experienced. And if you are getting your 12v supply from the house bank I would change that. The DDEcs use a lot of power as the injectors are 12v. My 12v92s use upwards of 35 amps, so your 16s are gonna use even more.