Changing Battery Location on my tomcat 255

thataway · Posted: Sun Aug 25, 2019 1:25 pm Post subject:

It is obvious that the PO put in first class gear, and did his research. Are your sure about the model number of the Master Volt inverter? I don't find that listed in the current catalog. My best guess is that is a 12 volt DC, 2000 watt/120 Volts AC--not 200 watt pure sine wave inverter. That makes a lot more sense. Many of these also come with an 80 to 100 amp battery charger as part of the Inverter/charger. (For example I use a Vectron 2000 watt PSW inverter, with an 85 amp 12 volt charger.). It is very possible that he installed just the inverter.

Now consider that at full 2000 watt output the inverter is pulling a little over 200 amps an hour out of your battery bank--and that is why he has the 4 golf carts. Probably your Honda's alternators each put out in the 50 amp 12 volt category, at max output. There is some utilization for the operation of engine, and boat's systems, such as electronics, lights, pumps etc. Figure that max charge is going to be in the 30 to 40 amp range. (I have limited my Honda 150's charging to my Li ion batteries to 30 amps max, thru a "Battery to battery charger"..

The MasterLink Charger / inverter controller, should show you amp hours consumed by the battery and state of charge of the battery bank. It also measures voltage (only) of the start battery (which is all you need).

So the PO had a reason for the big golf cart bank. Is it necessary? No, the two golf charts would be fine. But you have a rather expensive setup and it is logical to make full use of it.

Yes, you can use the existing cable--but we don't know the size--if it is 2/0, that is way overkill (it would be good for 100 amps/12 V DC. For 50 amps, you want 2 gauge wire (figuring 40 foot and 50 amps).

The next question is where does your windlass draw its power from? You want to have the outboard running, and charging that battery. I power mine off the engine start battery--but others use the house battery. So you want to check out that circuit. (Great that the PO provided a circuit diagram--I sure wish I had one, I periodically find unlabeled wires--and don 't know if they are to code or where they originate and terminate.). This why I label wires when I pull new ones, at Origen and termination. For example today, I found two #10 green, with black stripe, and one black wire, in a bundle--orignional factory wiring, which terminates under the hanging locker--with about 10' of wire in a loom. Green with stripe, is trim / tilt; up / down, but I have those functions in another set of wires...

I would keep the two engine start batteries--Are you sure about the model number--I cannot find it in the Lifeline catalog--but I may be missing something--the weight of 62 lbs suggests it is a group 27 battery. (Lifeline group 24's tend to be in the mid to low 50# category. In any case these are high end batteries, and well worth keeping!!!

If you were to go down to one engine start, then I would run the 2/0 cable to the house bank from the engine combine switch.

Randall · Posted: Mon Aug 26, 2019 10:27 am Post subject:

Just to throw in a data marker....this boat was originally "Knoty Lady" and the operator was somewhat active on this site. I recall seeing discussions of the electrics when new. And this boat does, indeed have the fresh water tank on the port side ahead of the refrigerator.

Randall

Foggy · Posted: Mon Aug 26, 2019 10:41 am Post subject:

I agree on two start batteries for two engines
(per Honda Rep).

Also minimize distance from start batterys to engines;
bad for weight distribution often but good for engines
and batteries.

Aye.

ChapaRRal Cock · Posted: Mon Aug 26, 2019 10:21 pm Post subject:

Amazing Info, I love all of the participation. I do plan on keeping and utilizing all existing batteries. I went through and labeled all wires and confirmed via the wiring diagram. I have a new layout started. I will be shortening so many wires! The only wire that I will be adding will be for the motors, and I will go with a large 2/0 ground and positive cable to feed the motors. I am excited to see how this turns out. I will contact the moderator to get permissions so that I can post pictures.

pcg · Posted: Mon Aug 26, 2019 10:26 pm Post subject:

ChapaRRal Cock · Posted: Mon Aug 26, 2019 10:40 pm Post subject:

The windlass is powered off of the house batteries. The ACR's are wired so that if the engines are running all the batteries are being charged if required. I have learned a lot reading owners manuals and following along on the wiring diagrams, and then putting my hands on the wires themselves. I am considering adding a small storage area behind the fridge that is located on the Port side directly across from the captain's helm. Any thoughts?

Foggy · Posted: Tue Aug 27, 2019 7:03 am Post subject:

thataway · Posted: Tue Aug 27, 2019 9:47 pm Post subject:

Ref putting storage behind the refrigerator which is on the port side under passenger seat. There should be no problem, as long as there is good ventillation. I recently had to replace the Engle Chest refrigerator (similar to the Norcold I had in Thataway, the TC 255, which was in this location. I could not get the same Engle currently so I put in a slightly larger Norcold 12 volt only. The space under the forward dinette seat is about the same size in the Tom cat and the fiberglass interior 25. There should be some room there. I did put in a small (with you muffin computer fan. It draws about 0.1 amp, so I am going to leave it running all of the time. I left the circuit, so I could easily install a "snap disc" thermostat which is set at 104* F--which I will have aboard, and can add if necessary. The fan will help dissipate heat from the refer.

ChapaRRal Cock · Posted: Thu Aug 29, 2019 4:07 pm Post subject:

Any reason you replaced with a D.C. unit only? There is plenty of space I was thinking of adding drawers accessible from the berth. I saw that someone else also utilized a computer fan to create circulation. I was actually thinking of building a small bank that I could put in the front window to create air circulation with minimal draw. I am still working on the project. Work and family the boat is a diversion Very Happy

ChapaRRal Cock · Posted: Thu Aug 29, 2019 5:20 pm Post subject:

Randal Thank you for keeping me honest. I am not sure What the name of the boat will end up. I just kept going with what I thought was correct.

thataway · Posted: Thu Aug 29, 2019 9:02 pm Post subject:

ChapaRRal Cock · Posted: Sun Sep 01, 2019 12:51 am Post subject:

So I actually have it all back together and so far it seems as if everything works! I have A lot of clean up and zip ties to install. I think I removed 5lbs of wire because of shortening things up. I will get pictures up soon.

ChapaRRal Cock · Posted: Fri Jan 10, 2020 5:30 pm Post subject: Pictures of Battery Relocate

So I have posted a few pictures, I need to complete the Pictures, But would appreciate any feedback

Foggy · Posted: Fri Jan 10, 2020 5:44 pm Post subject:

Wanna change a couple heavy load (batteries, water tanks, fuel tanks)
positions on your boat?

Why not take a couple people , approximating the weight change you
anticipate, and place them (politely) in areas you'e considering the new
heavy loads and see how your boat handles - dead slow, getting on plane,
at your cruising speed.

Take them for a nice ride. Change positions of the friendly ballast as
required to give you a clue on how to progress.

Aye.

westward · Posted: Fri Jan 10, 2020 8:41 pm Post subject:

An unfortunate design aspect of that particular boat is the lack of adequate sponson height (and thusly freeboard/tunnel clearance). If the sponsons were made 6-8" taller I'd be a TC 255 owner.