53MY, auxiliary 12volt system

my 1970 53MY has an auxiliary 12 volt system, like most I guess, for electronics. of course in 30 years, there has been some creative wiring along the way and each boat is now very different but ...

- I didn't see any reference to the 32v system in the hatteras manual and plans, am I right to assume that it is an add on ?
- what else besides modern electronic woudl be 12volts? I haven't checked yet, but I hope / pray that the bilge pumps were not replaced at some point with some 12v units... I will discon the 12v tonight to see what doesn't work...
- cigarette lighter plug at lower helm looks failry original, if it is how was that originally powered ?

the 12 volt battery is in the stbd engine room (2 6 volt batteries actually), needless to say, it gets real hot in there underway. is it worth relocating it to the generator room for longer life?

I'm also considering running the 12volt circuits off the generator battery (12volts, new Norpro genset). if only the electronics are connected, I'm not adding any significant loads since i run the boat at least once a week and I could connect the charger on a timer to come on jsut a couple of hours a day. I don't like connecting anything to the genset battery but if just the electronics, why not... of course having an extra 12v battery on board is nice in case the genset batery fails....

any suggestions and how it's done on your boat welcome!

pascal
Miami, FL
1970 53 MY

Pascal,

My 1978 53MY has only the original 32v system. All 12v newer electronics are run from 2 32v to 12v transformers. No 12v batteries. Even original Onan genny starts with 32v starting motor. No cig. lighter socket on the helm.

I have original Hatteras bluebrints for wiring and shows only 220, 110 and 32v systems. Hatteras can get you your own boat's original build sheet bluepriiint schematics based on your hull number if you want.

Doug

Pascal,

My '72 vintage 53' MY is set-up the same as Doug's. 220v,110v,32v inc. the gen, and 12v step down transformers off of the stbd 32v batteries. No 12v is shown an any of my schemtics, and I have all of the factory originals that came with the boat. Mike, MV "Finally"

The 1974 53 MY I didn't buy...I was so positive I was buying it that I purchased the original owners manual from Hatteras...did not have any 12V circuits on the boat or shown in the electrical schematics.

That being said, many, if not all modern electronic marine devices (GPS, Radar, etc,) are designed to operate properly on from 11-35 Volts. So there may be no need for 12v circuits; higher voltage circuits are more efficient anyway. If you are planning to put in new electronics, check the specs of the systems you are planning to install; odds are that if it is for MARINE use, it will work fine with the 32v.

When I got my 56my it had 32 to 12 transformers for the nav gear. (probably not original) When I put modern electronics in I was concerned that the fail mode of the step down trans would be 32volts straight thru and maybe damage to the new stuff.(DC converters are also hi tech to repair, especially in the boonies.) So I added a 12V 8d battery with a dedicated 60 amp charger and rewired the pilothouse panel to 12v. I went with the 8d because Ive got a SSB that pulls a lot of juice in transmit mode.Every other dc circuit on the boat including bilge pumps is original 32v off the main batteries and I wont be changing that. I like having a segregated supply for radios in an emergency and the gensets (both new) also have 12v batteries,alts and charger for mutual support.

thks for the feedback.

I checked, indeed some electronics are 12-32v but isn't t that because a 24v charging system will deliver as much as (guess) 28 to 29v.

I do not think they are meant to be connected to a 32v system which will usually have 35 to 37v while charging.

I checked the manuals and blueprint for my boat... no 12v so I know it's an add on. since I already have the charger and battery in place, I'm jsut going to change the battery and maybe just move the battery to the gen room, on the other side of the bulkead because of the heat build up. the 2 year old Norpro gen set is 12v and has it's own starting battery but I'd prefer to keep it dedicated.

Pascal,

The systems that accept, for example, 11-35v are designed to operate on any voltage within that range. As an example, Garmin's current marine electronics are all specifically designed this way so they can be fitted to virtually any boat. They do not make a "12v version", a "24v version", etc. I have a GPS 232 on my current 12v system, the boat next to me at the marina has the same unit on his 24 volt system, and a friend with a HAT 58LRC has the same unit as a back-up connected to the the 32v HAT DC system.

It really is "Plug-and-play!"