Need a few electrical/genset questions answered quickly!

GonzoF1 wrote:
So we are getting ready to head out to Lookout tomorrow. We anchored on Saturday night and I have taken a few looks at the battery/charging system. Ineed a few questions answered before we leave. My boat electrical system book is at home... dammit!

Is the alternator supposed to charge BOTH battery banks?* It depends on how your system is configured.* A single alternator to multiple battery banks usually has some sort of* echo charger/solenoid connection that permits the alternator to charge but not discharge multiple banks. *Mine appears to only charge the starter battery via the positive lug on the starter. That means that running the engine, should the house batteries get low, does nothing.* There must be a charging connection to the house battery bank, unless the system is set up only to be charged via shore power/generator.

Should the need arise, can I swap the leads from the starter battery to the house bank as a temp work-around? What about jumper cables? Too ghetto?* If departure is imminent, jumper cables can be a functional alternative.* They may be good to have onboard in an emergency anyway.* Just remember to remove the connection after engine charging has stopped.

What should the voltage read off the house batteries sitting idle? They are at 12.88 without the charger on and 12.92-ish with. However, I did not disconnect the loads when I read that.* Battery voltage is generally not meaningful unless all loads have been removed, there is no charging going on, and the battery bank has been left in this condition for 24 hours.* This is where a good battery system monitor can help.* Wet cell batteries can be tested with a specific gravity measurement, but this also requires the battery to be at rest.

The genset has a small water leak in the raw water inpeller pump but still moves water thru to the exhaust. I have to run the genset to run the charger to charge the house bank. Any danger if there is still water moving thru it?* Not sure I understand your question here, but you will need to watch the water leak closely, and assuming it isn't too large, watch your exhaust line temps as one of the primary purposes of the raw water cooling system*is to cool the exhaust line.* Lack of cooling water can destroy the generator/exhaust system and cause a fire.* Don't wait too long to repair the water leak.

One other issue is that it appears that the PO has bypasses the over-temp sensor (bad I know), but is there a way for me to monitor the temp should I need to run it to charge the house bank this week? It's a Next Generation genset. There is the small coolant tank on the top (with the radiator cap on it) that gets to be about 160 degree when I run it. I assume that's normal, but thought I would ask anyway.* As you know, an overheat sensor on a generator that produces a lot of heat is a critical part of the system.* Use a hand-held heat gun for a temporary solution.* You should have one of these onboard anyway.* Not familiar with the Next Gen product, but most small generators will run up to a thermostat rated around 180 degrees F.* If the water tem of the coolant gets up towards 200 degrees F, you will need to shut it down and allow it to cool, and get motivated to replace/repair the raw water pump.

I am wondering if I have overheated it a few weeks ago when I ran it and the main engine for a few hours coming home from Carolina Beach. However, I really have no proof of that except that the whole unit was about too hot to touch when we got to the marina. What would be the symptoms or signs that a Kobota had been overheated?* There may be a number of reasons that the generator could have overheated, including the raw water pump leak mentioned above.* Other reasons can include lack of raw water supply when the boat is cruising.* If the PO disconnected the overheat sensor in response to this siutation, maybe it's a raw water cooling system design flaw (cupped thru-hull strainer facing the wrong way, for instance).* Maybe there is an air supply issue when the main engine is operatiing.*

Any help I could get to make me feel better about being on the hook for a day or two would be GREAT!

Tom, it's great that you can get out boating, and I think you can get by for a couple of days.* BUT - You need to have a long-term plan to identify your system components and how they function and are connected.* It may be that your desire to anchor out is not consistent with how your system is designed to operate.* You need to develop some wiring schematics (if you don't already have that in your book at home), and decide on the size/type of battery banks, charging systems and reserves depending on how you intend to use the boat.* A great starting point is Calder's book.***

Bon Voyage!

Thanks y'all!

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GonzoF1 wrote:
My genset doesn't have its own alternator and I don't see a way to add one. It's just a little Next Generation 3.5k.

Sorry about the crude drawing. I just bodged it together quickly in MSWord. I'll get it up to your standards for you when I have a few spare hours (just kidding). The only fuse in the rig currently ( <- PUN ) is on the windlass.

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GonzoF1 wrote:
My genset doesn't have its own alternator and I don't see a way to add one. It's just a little Next Generation 3.5k. Sorry about the crude drawing. I just bodged it together quickly in MSWord. I'll get it up to your standards for you when I have a few spare hours (just kidding). The only fuse in the rig currently ( <- PUN ) is on the windlass.



-- Edited by GonzoF1 on Friday 15th of July 2011 03:43:36 PM

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