High Output Alternators

[sailinglegend]

Originally Posted by Bambolera

.... I have trouble starting the engine due to the load created by the alternator. .....
Somewhere in this thread, I read that a delay can be rigged. Can someone please tell me how this is done and/or discuss other options for engaging the alternator manually.

With a good external regulator like the Balmar there is an automatic built in delay of 45 seconds before the field voltage is connected. This allows the engine oil to circulate and gives maximum power to the engine. Every cruising boat should have one as there are many other advantages.

It is often too easy for the alternator to get too hot when motoring. A good regulator will accept sensors to measure both the alternator and the battery temperatures and control the charge rate. An alternator could be providing maybe 15 amps to the boat systems, another 25 amps to say a watermaker or an inverter, and then a heavily discharged bank may be demanding 50 or 60 amps. In this situation the batteries won’t get charged and the alternator will burn out if not protected by a temperature sensor. Battery temperature will also rise with a heavy charge current so the charge voltage must be reduced as the temperature rises. At 25 C batteries start to gas at 14.4v, at 40C they gas at 14 volts so the external regulator will reduce the charging voltage automatically to compensate for this. If batteries are fitted in an engine compartment it is very easy for them to get even hotter than this and lose water. This is fatal for sealed batteries.

[Bambolera]

In my experience, high-tec, external regulators are temperamental. It's just another piece of complicated electronics, which doesn't belong in a humid, salty, environment (i.e, boat). I've seen my share of charging problems and they are often caused by these complex regulators.

I'm a simple guy with a simple boat and I just want a simple switch that can be manually operated. I appreciate all the helpful advice, but as I have already stated: I have never had a charging problem with my current set-up in 11 years of continuous use.

I'm inclined to just put a switch in the field wire, but I don't know enough about this stuff to feel comfortable with this decision. I was hoping that someone with more experience than me could make a recommendation.

Thanks

[DeepFrz]

Bambolera, Blue Stocking answered your question long ago.

[Albro359]

You can put a switch in the field wire, no problem....
No field current means no alternator output...the alternator is not turned on.
Flick the switch to on and you have the same setup as you have now.
If you forget to switch it on, your batteries wont be charged, that's all.

External regulators are not that complex and in my experience are very reliable. A 3 stage reg provides the best way of charging and maintaining your batteries.
An alternator with an internal fixed automotive type regulator is not the best way to charge and maintain deep cycle batteries that are, by automotive standards, regularly heavily discharged.

[sailinglegend]

Originally Posted by Bambolera

In my experience, high-tec, external regulators are temperamental........

It's a great pity many old sailors just can't move with the times. Modern external regulators like Balmar are totally sealed and encased in resin so no salty sea-air can get anywhere near the sensitive electronics. They either work or they don't, they are never temperamental!!!

The only potential problem is people don't read the instructions and put them in the engine compartment. Electronics don't like heat and vibration - it says so on the tin.

[Bambolera]

Originally Posted by Albro359

You can put a switch in the field wire, no problem....
No field current means no alternator output...the alternator is not turned on.
Flick the switch to on and you have the same setup as you have now.
If you forget to switch it on, your batteries wont be charged, that's all.

This is the exact answer I was looking for. Thank you.

[bmm32005]

I contacted Electromaxx for a pulley kit for my Westerbeke 38B4, sent them pictures and measurements as requested and then never heard back from them.

I'm polite, professional and shower daily, I dont get it.

LUNA
Tartan 3800