moonrakercat
Cadet
- Joined
- May 11, 2012
- Messages
- 26
Hi - This is a bit of a long read - but I'm posting the entire story here so anyone who can help me out understands what I'm trying to do.
I changed marinas this year - previously docked my Magnum 230 thundercraft at a marina that had shore power - it was nice as 5 or 6 times during the summer my small family would sleep on the boat (at the dock with shore power) - and cook breakfast, make coffee in the morning - and my 2 boat batteries would be all charged up overnight.
My new marina does not have shore power - to compensate I added a 3rd battery to my boat - I put on a new battery switch and in effect all the batteries are wired in parallel. I also installed a 1000w Pure sine wave inverter to allow us to charge our phones & computers, but as well - make coffee with a small 700w single cup coffee maker, and use our 850w toaster to make toast in the morning. I have the battey switches set up so I have all batteries in parallel as this works for the inverter - if I separated the batteries into 1 for starting the boat and then 2 for house batteries - I wouldn't be able to run the inverter for near as long. I do have a propane camp stove that I use for making eggs etc. I also have a coolatron cooler that draws 5A from the batteries to keep our food cold.
My original alternator is an old motorla/mando ? 37A 3 wire unit. It charged the 2 batteries on the boat ok - never really had a problem - even with the cooler onboard during the day. But I had shore power at night to top the batteries up.
I was hoping that a new upgraded 3 wire 68A alternator would keep me charged up at my new marina - I ran an extra wire with a 50 A circuit breaker from the alternator directly to the batteries to compensate for the extra current I expected to be drawing to charge up the batteries.
With the 3 batteries onboard all charged up - I can easily make 4 or 5 cups of coffee, as well as lots of toast for the kids. I tested the setup when at home with the boat on the trailer. I had a 30A dewalt house charger that I hooked up to the 3 batteries (all in parallel) - and it started at about 22A and took 2 hours to charge up all 3 batteries.
I had some issues with my new alternator - when I closed the circut breaker on the direct wire from the alternator to the batteries (I still had previous wiring hooked up - the main alternator wire, voltage sensor wire and exciter wire) - the engine slowed and the alternator began putting out its max power to the batteries - this is not good - it did charge the batteries very fast - but the alternator ended up getting very hot ....too hot - (ie smokin hot) - so I disconnected this direct line.
I'm not sure why this happened - I have what I believe is the engine wiring schematic that was given to me by another member here (have included it - he said it was from Mercruiser genuine factory service manual #3) and it shows in effect that the original wiring is connected directly from the alternator to the batteries - my new extra wiring should make no difference - but it does.
My boat has a voltmeter at the dash - not an ammeter - and the alternator wiring does have a 50A breaker on the engine.
With the extra wire disconnected - and the batteries somewhat drained after our morning coffee, toast and having the cooler plugged in all night - I checked and the alternator is charging the batteries at approx 3-4.5 A each battery - I thought it would be a significantly higher charge rate. At this charge rate it will take me 10-12 hours of boating to completely recharge the batteries -not an option unfortunately.
My boat is too small for a generator - and my marina won't allow one at the dock I'm sure. I know I can make coffee & breakfast completely with a propane stove - but I'd like an alternator system that charges my 3 batteries back up in 2 or 3 hours of boating - and hoping for some suggestions as to what I can do.
I do have some understanding of 3 wire alternators,
I know Blamar makes specific charging systems/ charge controllers / alternators for boats - so I'm considering calling them.
I'm also considering speaking with my local starter/alternator shop in town to see what they say I'm doing wrong.
I'm hoping someone can point me toward the charging system specifics for my engine type so I can better understand how the system works and why my alternator is only putting out a few amps to each battery(even when they are low) and why the system is so affected by my extra wire /circut breaker. Is the above Mercruiser genuine factory service manual #3 available online as a pdf somewhere ? or do I have to buy it ?
I really don't want to spend thousands for a simple system on a small boat - so I'm hoping you guys can help me with some suggestions.
Thanks in Advance - Matt.
I changed marinas this year - previously docked my Magnum 230 thundercraft at a marina that had shore power - it was nice as 5 or 6 times during the summer my small family would sleep on the boat (at the dock with shore power) - and cook breakfast, make coffee in the morning - and my 2 boat batteries would be all charged up overnight.
My new marina does not have shore power - to compensate I added a 3rd battery to my boat - I put on a new battery switch and in effect all the batteries are wired in parallel. I also installed a 1000w Pure sine wave inverter to allow us to charge our phones & computers, but as well - make coffee with a small 700w single cup coffee maker, and use our 850w toaster to make toast in the morning. I have the battey switches set up so I have all batteries in parallel as this works for the inverter - if I separated the batteries into 1 for starting the boat and then 2 for house batteries - I wouldn't be able to run the inverter for near as long. I do have a propane camp stove that I use for making eggs etc. I also have a coolatron cooler that draws 5A from the batteries to keep our food cold.
My original alternator is an old motorla/mando ? 37A 3 wire unit. It charged the 2 batteries on the boat ok - never really had a problem - even with the cooler onboard during the day. But I had shore power at night to top the batteries up.
I was hoping that a new upgraded 3 wire 68A alternator would keep me charged up at my new marina - I ran an extra wire with a 50 A circuit breaker from the alternator directly to the batteries to compensate for the extra current I expected to be drawing to charge up the batteries.
With the 3 batteries onboard all charged up - I can easily make 4 or 5 cups of coffee, as well as lots of toast for the kids. I tested the setup when at home with the boat on the trailer. I had a 30A dewalt house charger that I hooked up to the 3 batteries (all in parallel) - and it started at about 22A and took 2 hours to charge up all 3 batteries.
I had some issues with my new alternator - when I closed the circut breaker on the direct wire from the alternator to the batteries (I still had previous wiring hooked up - the main alternator wire, voltage sensor wire and exciter wire) - the engine slowed and the alternator began putting out its max power to the batteries - this is not good - it did charge the batteries very fast - but the alternator ended up getting very hot ....too hot - (ie smokin hot) - so I disconnected this direct line.
I'm not sure why this happened - I have what I believe is the engine wiring schematic that was given to me by another member here (have included it - he said it was from Mercruiser genuine factory service manual #3) and it shows in effect that the original wiring is connected directly from the alternator to the batteries - my new extra wiring should make no difference - but it does.
My boat has a voltmeter at the dash - not an ammeter - and the alternator wiring does have a 50A breaker on the engine.
With the extra wire disconnected - and the batteries somewhat drained after our morning coffee, toast and having the cooler plugged in all night - I checked and the alternator is charging the batteries at approx 3-4.5 A each battery - I thought it would be a significantly higher charge rate. At this charge rate it will take me 10-12 hours of boating to completely recharge the batteries -not an option unfortunately.
My boat is too small for a generator - and my marina won't allow one at the dock I'm sure. I know I can make coffee & breakfast completely with a propane stove - but I'd like an alternator system that charges my 3 batteries back up in 2 or 3 hours of boating - and hoping for some suggestions as to what I can do.
I do have some understanding of 3 wire alternators,
I know Blamar makes specific charging systems/ charge controllers / alternators for boats - so I'm considering calling them.
I'm also considering speaking with my local starter/alternator shop in town to see what they say I'm doing wrong.
I'm hoping someone can point me toward the charging system specifics for my engine type so I can better understand how the system works and why my alternator is only putting out a few amps to each battery(even when they are low) and why the system is so affected by my extra wire /circut breaker. Is the above Mercruiser genuine factory service manual #3 available online as a pdf somewhere ? or do I have to buy it ?
I really don't want to spend thousands for a simple system on a small boat - so I'm hoping you guys can help me with some suggestions.
Thanks in Advance - Matt.
