Sterling advanced regulator

[Sarnia]

Whilst this is true, it's important to note that the Sterling add-on regulator which the OP first mentioned cannot drop the voltage to float level unless the alternator's internal regulator is removed or disabled. This of course negates the fail-safe mode, and it might not be wise to do this with a Sterling device. To achieve what you have suggested would involve the OP spending more to get a decent external regulator such as the Balmar you mentioned.

I have read with great interest the sailinglegend420 informative post, it doesn't appear he missed anything! although I am at a loss how the alternator can think the batteries are close to it by ambient temperature, even if the batteries are well removed from the engine (mine are in my engine compartment in a wooden compartment against the hull below water level and two feet away from any heat ) I would welcome further enlightenment.
Your reply is as equally informative regarding possible complications of disabling the internal regulator, why would one want to do that, is the fail-safe mode a part of the alternator or the Balmar? it does not sound a good idea if using a Sterling device, therefore does employing a Balmar (which is a name I am not familiar with) regulator mean that the internal regulator works with it and can drop to float voltage without adjustment.

 

[pvb]

...does employing a Balmar (which is a name I am not familiar with) regulator mean that the internal regulator works with it and can drop to float voltage without adjustment.

No, you have to remove or disable the internal regulator.

 

[Birdseye]

Boats with a more modern 14.2-14.4 volt alternator with a built-in regulator will also have a simple temperature sensor which will soon drop the output voltage down well below the 14.4v gassing voltage of the batteries - it thinks the battery is close to it in the engine compartment. This shouldn't happen on a boat - batteries should be well away from the engine compartment, so they will see a lower voltage than they need once the alternator has warmed up, and so may be undercharged.

There are many other very good reasons why you should fit an external regulator:

1. A good external regulator will be a multi-stage device that can raise the alternator output voltage even higher and charge the battery faster, and reduce the output to a Float voltage when the battery is fully charged to prolong the battery life.


2. It should have settings for different battery types, but it should also be programmable to match the alternator and battery bank sizes. Balmar's regulators allow many parameters to be changed, for example they may set the Boost voltage to 14.6, hold that for 45 minutes and then reduce it to 14.4 for the duration of the absorption stage. They can be programmed to stay longer in the absorption stage without dropping down to float too early.


It is worth noting that with sealed batteries most battery manufacturers recommend that you use a multi-stage regulator to drop the charge down to float mode at 13.2-13.8 volts to avoid gassing and overcharging. This is a condition of the warranty on some batteries.


3. It will delay the charge current for about a minute at start up until the engine oil is well distributed. A 100 amp alternator draws 4 HP which is a heavy load on an engine when starting with a weak battery.


4. It will also accept a sensor to measure the alternator temperature and control the charge rate. Even a 100 amp alternator could be providing 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 may not get charged and the alternator will burn out from continually trying to deliver its maximum output if not protected by a temperature sensor. It is often too easy for the alternator on a boat to get too hot if used for long periods.


5. It will also accept a sensor to measure the battery temperature which will rise with a heavy charge current. At 25ºC batteries start to gas at 14.4v, at 40ºC they gas at 14v 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 too hot and lose water. This is fatal for sealed batteries. Sailing in high temperature regions may mean the batteries are already at 35C before charging starts.


6. It will have a voltage sensor at the battery not on the alternator. This will compensate for split diodes or losses on cable runs to the battery.


7. A Balmar regulator has a “small engine mode” that allows you to cut the output to 50% with a switch to reduce the alternator load on the engine when you suddenly need extra power in a big sea. It also has belt manager to reduce the load on the alternator. A 100 amp alternator set to 70% will run cooler and produce 70 amps at a lower speed.


Have i I missed something???

Yes. The external regulator cannot reduce the output voltage below that set by the internal regulator so if the internal regulator is set at the 14.5 volts normal in current alternators, the benefit of being able to charge at a bit higher voltage for a short period isnt great. If your boat is properly wired the voltage drop between alternator and battery terminal should be tiny but yes there is a small advantage in effectively eliminating any voltage drop.

If the internal regulator fails in one direction, then the external regulatior is a back up. When my internal regulator failed and ran batteries up to 18v, the external regulator was useless.

 

[pvb]

Yes. The external regulator cannot reduce the output voltage below that set by the internal regulator so if the internal regulator is set at the 14.5 volts normal in current alternators, the benefit of being able to charge at a bit higher voltage for a short period isnt great. If your boat is properly wired the voltage drop between alternator and battery terminal should be tiny but yes there is a small advantage in effectively eliminating any voltage drop.

That's why the internal regulator has to be disabled if the external regulator is to achieve a float voltage.

 

[Sarnia]

No, you have to remove or disable the internal regulator.

So my options seem to be either I install an alternator, either the 110-603 or 602, both have internar adjustable regulators, without the addition of an external one as well,
or, as above but disable the internal, (in which case why have an alternator with an internal regulator) and fit an external one, or, install an alternator without an internal and fit an external one.

I am not clear quite as to the benefits of or how I would use the internal adjustable regulator, would I set it at installation and leave it, or if not under what circumstances would it require adjustment.

 

[Sarnia]

Yes. The external regulator cannot reduce the output voltage below that set by the internal regulator so if the internal regulator is set at the 14.5 volts normal in current alternators, the benefit of being able to charge at a bit higher voltage for a short period isnt great. If your boat is properly wired the voltage drop between alternator and battery terminal should be tiny but yes there is a small advantage in effectively eliminating any voltage drop.

If the internal regulator fails in one direction, then the external regulatior is a back up. When my internal regulator failed and ran batteries up to 18v, the external regulator was useless.

How did you get around the failure of the internal regulator.

 

[charles_reed]

Get a new alternator - modern on board alternator controllers have made external smart controllers totally redundant - however the point about making sure the output curve suits your engine is most valid. Marine diesels tend to work at much lower rpm than most cars (and alternators are generally designed for use in road vehicles)

 

[pvb]

So my options seem to be either I install an alternator, either the 110-603 or 602, both have internar adjustable regulators, without the addition of an external one as well,
or, as above but disable the internal, (in which case why have an alternator with an internal regulator) and fit an external one, or, install an alternator without an internal and fit an external one.

I am not clear quite as to the benefits of or how I would use the internal adjustable regulator, would I set it at installation and leave it, or if not under what circumstances would it require adjustment.

Your simplest solution would be to fit a new Prestolite alternator with an adjustable regulator. On installation, you'd adjust the max charge voltage, measured at the batteries, to be whatever you want (say 14.4 or 14.5 volts). You'd then leave it.

Prestolite alternators have a good current output at lowish revs, and are essentially as good as the much-mentioned Balmar "marine" alternators (which are Prestolite alternators with a nice paint job).

 

[RobbieW]

I'll add one small caveat here; for most people an alt regulated at 14.x is fine, even better if it can be adjusted to the voltage your bank needs for optimal charging. Most folk wont run their engine for more than say 8 hrs, a channel crossing. As both a cruiser and sometime delivery skipper trips under engine of 30-40 hours are not unusual, the run time often being more to do with tank size and range. In those circumstances it becomes far more important to have either wet batteries that can be topped up or a charging system which will drop to a float value at some point.

... as the much-mentioned Balmar "marine" alternators (which are Prestolite alternators with a nice paint job).

That may once have been true but in looking around at alts earlier this year I dont think it is any longer. The only real evidence I can offer though is that there is little or nothing in the Prestolite range that matches the outputs and configuration of the Balmar & Electromaxx products especially at the higher, 120a +, end.

 

[sailinglegend420]

...I am at a loss how the alternator can think the batteries are close to it by ambient temperature, even if the batteries are well removed from the engine (mine are in my engine compartment in a wooden compartment against the hull below water level and two feet away from any heat ) I would welcome further enlightenment....

Modern alternators as supplied on new boats are cheap automotive alternators. They have become 'smarter' so they now have better temperature compensation that reduces the output voltage as the temperatures rises. This is not to protect the alternator but to protect the batteries, which it assumes are in the engine compartment near the alternator. Batteries need to be charged at a lower voltage when they get hotter to avoid excess gassing and loss of electrolyte.

Put the same automotive alternator on your boat and the temperature compensation reduces the output voltage, but on a boat the alternator is working much harder charging your deep cycle batteries, so it gets hotter and so the output voltage is reduced to a level that won't charge your batteries properly. This of course is pointless because your batteries aren't in the engine compartment close to the engine - or should't be - especially if they are sealed.

Balmar 'marine' alternators aren't just Prestolite alternators with a paint job as has been posted by PVB.

A 'hot rated Marine Alternator', like the Balmar, is 'engineered' to provide its rated output current even at a temperature of over 100 degrees C, so it will maintain that output and charge the bank much quicker. Faster charging is what we all want.
This 'hot rated engineering' may mean:

- High temperature diodes mounted on big heat sinks
- Heavier gauge stator windings
- recision balanced rotor
- Copper composite brushes
- Heavy duty bearings with high temperature grease
- Corrosion resistant materials & coatings
- Dual cooling fans
- access to field windings
- tachometer output
- maybe an isolated ground terminal

All this comes at a much higher price!

 

[sailinglegend420]

That's why the internal regulator has to be disabled if the external regulator is to achieve a float voltage.

This is no big deal!

Balmar recommend a simple two way switch that feeds the ignition positive to either the internal regulator or to the external regulator. Whilst this isn't 'automatic', like running the Sterling in parallel with the internal regulator, it does get around the ridiculous situation where the Sterling can't drop to a low Float voltage.

I regularly use my switch to use the internal Balmar regulator if I have been on shorepower and know the batteries are fully charged and I have a 12 hour motor ahead. Cleverly the internal Balmar regulator is set to 14v which well below the gassing voltage.

 

[RobbieW]

...Balmar recommend a simple two way switch that feeds the ignition positive to either the internal regulator or to the external regulator...

A consideration if thinking about doing this, or trying to add an external regulator to an existing alt, is to match the polarity of the alternator and external regulators. I believe, based on doing this a month or so ago, that many European sourced alts have N-Type internal regs, ie the regulator is wired in the return side of the field, whilst in NA the reverse is true.

My old alternator, an Iskra, had an N-Type regulator - the internal wiring has some diodes feeding the positive side of the field, to make make it self sustaining once started, which are connected to the brush box by a sort of sprung connection under the regulator/brush box. The regulator is on the return side of the field connection. To convert that, and this is currently untried - I'm just using the new alt, I've modified a brush box/regulator by cutting the reg connections and soldering a wire on each brush to come outside the alt cage. The sprung connection is pressed down a little and the pad it touched removed from the modified brush box. The idea is that the modification is reversible simply by putting back the unmodified brush box in the event of the Balmar regulator (a P-type) failing.

 

[Sarnia]

Many thanks to all those who replied, I have learnt a lot from them, thanks again.
I will be fittind a 90 amp alternator, and adding to my domestic bank also.