[Steve]

Had a new alternator installed the old one burnt out and when starting the port engines the gauge drops from 13.5 to 11, the battery seems to be charging underway so is there a electrical diagram of how these two battery banks work or any suggestions on trouble shooting it. Not sure if i buy new battery's the issue will be solved. 1st year with this boat battery's were marked 8/15 as new?

[Russf]

I suggest that you re read your email and be clear about the symptoms. Your post says the new alternator burned out. Is that correct? You also talk about port engines! Also you might report on what the starboard engine volts are. On my boat the port engine charges the house bank. Also what do the panel voltage gauges show? Put a matter on each battery and see if the voltages agree with the meters. I have been through some alternator issues and know how important it is to assemble as much troubleshooting data as possible. With the limited and ambiguous information you provided I doubt that you will get any good feedback.

[Uhehner]

Yep, I agree, that's why I did not attempt to answer his question. 

Steve, there should be a DC schematic in your owners manual or you can have one e-mailed from Tiara.  I would expect the gauge reading to drop when you put a heavy load on the battery while starting.  Both engines should be the same. Do you keep the battery selector switch in the BOTH position?  I never do. When in the BOTH position, if you have one dead / bad battery you will now have two dead batteries. I only use the BOTH position for starting if one battery won't do it. Most Tiaras have a parallel switch.

More information concerning the BOTH position: If you always keep the switch in the BOTH position so that your electronics do not drop off line when starting I have a fix for that using  two diodes and a spring loaded switch or a battery combiner ( not a battery isolator ). I install it on all my fishing friends boats and it works great. Contact me for the schematic diagram.

Capt.  George

[Russf]

Yep, I agree, that's why I did not attempt to answer his question. 

Steve, there should be a DC schematic in your owners manual or you can have one e-mailed from Tiara.  I would expect the gauge reading to drop when you put a heavy load on the battery while starting.  Both engines should be the same. Do you keep the battery selector switch in the BOTH position?  I never do. When in the BOTH position, if you have one dead / bad battery you will now have two dead batteries. I only use the BOTH position for starting if one battery won't do it. Most Tiaras have a parallel switch.

More information concerning the BOTH position: If you always keep the switch in the BOTH position so that your electronics do not drop off line when starting I have a fix for that using  two diodes and a spring loaded switch or a battery combiner ( not a battery isolator ). I install it on all my fishing friends boats and it works great. Contact me for the schematic diagram.

Capt.  George

Captain. I have a 2005 Tiara 2900 but do  not know where the battery selector switch is. There are three battery on off switches under a stair and a round orange battery against the firewall in the engine room. Is it one of those?

Thanks

[Uhehner]

I'm not familiar with the 2900. Look in your owners manual or scan your DC schematic and email it to me.

Perhaps Cris B. can answer your question.

Capt. George

[Ernesto]

I have a 2006 Tiara 3600 Open and had a similar issue this weekend. This boat is one month old for me and have a similar problem to the one posted.

I will try to be as specific as possible to see if I can get a better idea where to start off with my problem.

I went away for the weekend and docked my boat at a friends home who is remodeling his back yard dock and had no shoreline at the moment, during my 3 day stay I planned to turn on the engines every 8-12 hrs. for recharge after the second night my batteries drained as I had left the refrigerator on. I tried starting the boat but the batteries did not have enough juice to crank the engines, unfortunately my Westerbeke gen set is not generating and is scheduled for overhaul next week, so I went to the switch panel and turned the "Emergency Battery Bank Interconnect" switch which as I turned it fell apart in my hand, now the parallel mode was not working as the bronce bridge on the back of the switch was not making contac. Now the boat volt gauges dropped off and the only way to crank it was by pressing the parallel button between both ignition key switches. I connected an external battery charger to both battery banks, I have 3 on stbd. and 2 on port but after an overnight slow charge for both banks the next day I still had to use the booster mode to start the engines. So here I am guessing one or more batteries went bad (I later learned from the previous owner that the AC Delcos where 3 yrs old) After starting the engines and keeping them charging for an hour or so I turned off the Port engine and both shut off, I re started both and now turned off the stbd. engine, Port stays on. I asked the previous owner if he had any alternator issues and said no, he also said he had always ran the boat with the parallel switch on the "on" position. My mechanic said if the switch is on the "on" position and both gauges read a voltage measure you are transferring power from one engine to the other, that will eventually  burn one of the alternators. I am assuming that I need an alternator, Batteries and the switch
I just want to make sure and not buy unnecessary parts.

1. Does anyone know what brand and model the emergency switch is?
2. Should I go with AGM batteries?
3. Alternator part number for Cummins 380QSB 12V

[Uhehner]

Rule number ONE : Never leave the boat with "anything" ON unless you are connected to shore power and your battery charger works.

Never anchor out with anything ON except the anchor light.

Have a GOOD mechanic check that each engine will supply about 13.8 volts to its battery with the battery charger OFF.
Next stop the engines and check that the battery charger supplies 13,8 volts to ALL batteries with the battery switches OFF.
Avoid putting port and starboard  batteries in parallel.  If one is bad they will all be dead.

Why did you need an external battery charger? Is the one on board also bad?

Your report says to me that the starboard alternator is not putting out and its engine only runs because the battery switch is paralleling the P&S.

If you install AGM batteries, make sure your battery charger can handle them.

With a new boat and 3 year old batteries it's time for a full replacement. 

As a starting point contact Tiara for any boat parts you need and Cummins for an alternator.

Welcome to the world of boating.

Capt. George

[Ernesto]

Capt. George, Thank you for your quick reply.

First rule, learned the hard way!

I had to use an external battery charger because the boat had no power batteries/shore/gen. Mine works but not without shore power.

I just purchased all 5 Deka AGM batteries and will switch my battery charger to AGM charge mode. I have a CHARLES INDUSTRIES MARINE BATTERY CHARGER 50A 12V 5000SP which as per the mfg. is the only charger that has a selector between lead/acid, AGM or Gel batteries. I will also replace the damaged Emergency battery selector BEP brand model 701

My mechanic worked for the Cummins dealer and has contacts in the parts dept. so he will get me the alternator part number if I need it.

Thanks again!