36 Tri cabin Battery Charger

[tpd777]

BigD

Thanks for taking the time to provide such a complete education on this subject.

Tom

[P-Dogg]

I don't see any reason why not

Me neither, for reasons Big D has expounded on above. When I added my smart charger, I connected the generator battery to it. No problem. Why didn't Trojan do that? I dunno. But I dunno why they didn't bother to seal the limber holes that they cut in the wood stringers either.....

I would add that adding a smart charger and ditching the OEM battery charger is one of the few improvements that that you can perform that actually makes your boat lighter.

[P-Dogg]

BigD

Thanks for taking the time to provide such a complete education on this subject.

Tom

It's what we do here! Just try to avoid asking a question that the "search" feature can help you with. Some folks get tired of answering "how do I bed hardware?" over and over again. Can't help but notice your fine taste in boats.......

[prowlersfish]

Where We Go,

I have to assume that I know much less about this topic than I thought I did. So I'm feeling pretty humble.

Big D knows what he's talking about and after reading his post I do have a couple of additional questions that I may ask him.

In every generator equipped boat I've ever owned, past and present - the shore power and the generator were/are both connected directly to my main panel.

There has always been a rotary switch on the panel with three possible positions.... SHORE - OFF - GENERATOR

When out on anchor and in need of AC power, I turn the switch to GENERATOR. When returning to the dock, I usually connect the shore power chord and turn the switch to SHORE.

So I assumed by moving the switch to SHORE I was also shutting down the Generator side and vice versa. I assumed that each "side" powered the Main Panel independently of the other.

Maybe I should just leave quietly......

Rick

Correct on all points , and nothing wrong with questions

Let me add I run my gen set under way no issues as does everyone I run with . I also run it at the dock with shore power hooked up . The switch separates the power .

[larryeddington]

Mine was not hooked to genny either, the charger was colored blue and only had two circuits. I have changed for a genius charger and now keeps all batteries up.

[Big D]

.....In every generator equipped boat I've ever owned, past and present - the shore power and the generator were/are both connected directly to my main panel.....

Correct

.......There has always been a rotary switch on the panel with three possible positions.... SHORE - OFF - GENERATOR......

Correct, or same thing accomplished with source selection breakers instead of rotary switch.

......When out on anchor and in need of AC power, I turn the switch to GENERATOR. When returning to the dock, I usually connect the shore power chord and turn the switch to SHORE.......

Correct

.....So I assumed by moving the switch to SHORE I was also shutting down the Generator side and vice versa. I assumed that each "side" powered the Main Panel independently of the other......

Correct. Looks like we're all on the same page

......Why would anyone try to charge their generator battery while the generator was running??

This would be the case where the charger is hooked up to the generator battery. It would charge the generator battery while on shore power and would also be used to charge the generator battery while the generator is running at anchor for instance. Not needed IMO and is part of the reason OEMs for the most part don't bother hooking them up that way. The other reason of course is production costs which they would have to pass along to the end consumer. Price point is everything in a competitive market. Another example is an engine sharing the same bank as house loads. Not a good design but it cuts costs and you'd be amazed to find just how many brands and models are wired that way. It's a more common setup than all separate banks.

You are correct in that most chargers are not wired to generator batteries but some are and it's pretty common for owners to do it after replacing original chargers. The third bank would be best used though for isolating each load; one battery per engine, and the house bank, that makes three banks. Heck, some higher end electronics installations are now requiring their own isolated bank for sensitive electronics.

So let me throw another wrench into the mix here; if it's not necessary to hook up a charger to the generator battery because the generator's charging system is quite capable of maintaining and topping up its own battery, why do we bother hooking up a charger to the engine batteries? I mean the engines have alternators that put out way more than you'd need to top off what the engines draw during operation. I can see a charger for the house bank but we don't hook up external chargers to our cars all the time so why the charger for boat engine batteries? Just putting it out there!

[WayWeGo]

......Why would anyone try to charge their generator battery while the generator was running??

This would be the case where the charger is hooked up to the generator battery. It would charge the generator battery while on shore power and would also be used to charge the generator battery while the generator is running at anchor for instance. Not needed IMO and is part of the reason OEMs for the most part don't bother hooking them up that way. The other reason of course is production costs which they would have to pass along to the end consumer. Price point is everything in a competitive market. Another example is an engine sharing the same bank as house loads. Not a good design but it cuts costs and you'd be amazed to find just how many brands and models are wired that way. It's a more common setup than all separate banks.

One reason I hooked the charger to my generator battery is that I have an AGM battery for the generator and I wanted a more sophisticated charge controller that was designed for an AGM battery. I could have added a separate controller for the generator battery, but I was in a bind and working with what was immediately available at the local West Marine. I am not sure if the additional cost would be worth it to me. After this conversation, I am thinking it might be a good idea to disable the generator charge circuit since the battery charger will charge the battery faster and better whenever the generator is running. The downside is that I am drawing off more of the generator's capacity to charge batteries if I want to run the AC or stove/oven.

So let me throw another wrench into the mix here; if it's not necessary to hook up a charger to the generator battery because the generator's charging system is quite capable of maintaining and topping up its own battery, why do we bother hooking up a charger to the engine batteries? I mean the engines have alternators that put out way more than you'd need to top off what the engines draw during operation. I can see a charger for the house bank but we don't hook up external chargers to our cars all the time so why the charger for boat engine batteries? Just putting it out there!

With some of the dock queens at many marinas, they are not getting used enough to keep up with normal parasitic discharge rates, so if they ever wanted to leave the dock, there would be little chance of the engines turning over.

[kallen]

If the engine batteries are not maintained by the charger when docked how long would the batteries last if the bilge pumps were running due to a leak and no one notices the bilge pumps running. So I have the charger charging the engine batteries when on shore power.

[rickalan35]

Hi Kallen,

I think Big D was probably assuming the house bank would be running the bilge pumps which in turn would be maintained by the shorepower charger, but that's just an assumption on my part.

Are you still running the F32? I seem to remember you mentioning it in the past. I keep my boat in Portland on Big Rideau Lake not far from you. We usually cruise down your way every second summer and stay in Kingston a few days, then up to Ganonogue and finally Pecks. You and I are both pretty fortunate to have these cruising grounds.

All the best

Rick

[Big D]

If the engine batteries are not maintained by the charger when docked how long would the batteries last if the bilge pumps were running due to a leak and no one notices the bilge pumps running. So I have the charger charging the engine batteries when on shore power.

LOL, just giving you something to ponder. But my question was why do we need a charger hooked up to the engine batteries, I wasn't questioning the need for maintaining the house bank. Like Rick said, the pumps should be running off that. In a perfect world, each engine would have its own battery and the house loads off a separate bank also. Realistically the engine batteries should hold their own without an external charge except for the alternators when running the engines. Batteries do naturally discharge a bit on their own and more so in hotter temps but a good battery would have to be unattended for months to get low enough that they wouldn't start an engine. As for the dock queens, well, there's no hope for them, in truth I've seen some never leave the dock or run their engines except to winterize and commission. I was a member at a marina for a number of years where we suspected one guy still had leaded fuel in his tanks

[mikeandanne]

A question. If an old dumb charger that was 30amps had its three legs connected, would the charge be portioned out as 10/10/10 no matter what.I do realize that you would never get all 30 but for the sake of example, Then if there were only two legs connected, would that be 15/15 and so on.Now if that is true, then that would seem to me to be the reason to connect as few legs as possible to get the max charge where needed.
Now if you have one of the new smart chargers , then a different story.

[prowlersfish]

That can vary from charger to charger

[kallen]

How did Trojan originally configure the batteries. I have seen 2 starting batteries and 1 house battery. Was a house battery original equipment or a option. If the boat didn't have a genny was the house off of the starting batteries. Did the genny have a battery or was it tied in to the starting bank.

[Big D]

A question. If an old dumb charger that was 30amps had its three legs connected, would the charge be portioned out as 10/10/10 no matter what.I do realize that you would never get all 30 but for the sake of example, Then if there were only two legs connected, would that be 15/15 and so on.Now if that is true, then that would seem to me to be the reason to connect as few legs as possible to get the max charge where needed.
Now if you have one of the new smart chargers , then a different story.

Like Paul said, it depends on the charger. Now-a-days it's usually the cheaper chargers for small vessels that divide the total output per bank and you can only get up to that mount of output max in a given bank such as 10/10/10 (3 bank 30 amp) or 5/10/5 (3 bank 20 amp). In the latter, you want to make sure the 10 bank is hooked up to the house bank, the engine banks typically require very little. Better chargers can deliver their full output capability to any one of the banks. In a low house bank, you could have 59 amps of a 60 amp charger going to that bank. For that reason, the wiring to each bank needs to be able to handle full output.

[Big D]

How did Trojan originally configure the batteries. I have seen 2 starting batteries and 1 house battery. Was a house battery original equipment or a option. If the boat didn't have a genny was the house off of the starting batteries. Did the genny have a battery or was it tied in to the starting bank.

In my experience, for the most part, and it's pretty typical for other brands even today to have two banks; one for one of the engines, and the other bank for the house and other engine. Circuitry will vary such as combining all banks automatically when starting an engine but in general it's two bank circuit. Not the best setup for sure but it's less expensive in production for number of reasons.