Hello,

Just wondering if anybody could point me in the right direction to try and locate a new Diode Splitter (for Broom 30' / Perkins 4.236 engine). Our existing diode splitter is faulty and we are having difficulty trying locating a new one. There are two alternators on the engine, so we need a diode splitter with two feeds in and four feeds out.

Thanks!

Clonony

If the vessel is equipped with two alternators, for what purpose is the diode splitter to be used for?. .

Heard these guys are good, they are based in the uk.


[www.sterling-power.com]

Quote:

P.A.D
Heard these guys are good, they are based in the uk.

[www.sterling-power.com]

Recently fitted one of these, great bit of kit, can have two feeds (Alternators) and upto 4 battery banks, easy fitted too!!

The purpose, I'd imagine, of the diode splitter (with two alternators), is to give charging priority to the engine battery firstly. Once that is fully charged, both alternators are then switched over, via the diode splitter, to charge the domestic batteries. It has been operating successfully for the last 34 years, since the boat was built, but now appears to have come to the end of its life!

Thanks very much for the advice. I will contact Sterling Power now

If the vessel only has two battery banks, (ie 1 x starting bank + 1 x domestic bank, then the prudent system when utilising a twin alternator set up, is to employ one alternator to each battery bank, and eliminate the diode splitter altogether. You will find that the time taken to fully recharge the batteries will be significantly reduced due to the removal of that most inefficient of devices that is the diode splitter.

Roland
I agree with Robert McC last post on this problem. From listening to other boat owners a few years back this twin alternator set up was that one alternator acted as standby to the other. One weakness is how do you know if one alternator has failed as the other one will Just carry on. I presume you have checked that both alternators are working. This is a job best done in the repair workshop to check that they generate the rated output. I did this in Jan of this year and the alternator was handed back with no bill. Fault was in the 70 amp engine mounted line fuse connection ( corrosion).

I know it's nice and handy to just replace the suspected faulty diode but I would suggest you consider dumping the Diode. As you may know Robert is in the boat business and I know of an Erne based hire fleet which have indeed dumped the diode and fitted 2 Alternators with 2 separate drive belts as this is the most efficient way to charge up the domestic batteries.
Robert of the Lazy Witch

The Sterling product is the new generation zero voltage drop, do you still mainain these are "most inefficient of devices " if so, why ?

Billy,

I can't attest to the Sterling product you are looking at, however when I did a rewire and Alternator upgrade, I also got rid of the diode splitter (I think it was a Vetus unit but can't remember, the branding is irrelevent they seem to be all the same design/construction), as it was clealy taking some of the charge in order to function as found by measuring the volt/amps on the alternator side and on the battery side of the circuit and comparing.

My set up is a single engine/alternator charging three batteries (1 starter and 2 domestics), and I replaced the diode unit with three heavy duty battery switches (a cheaper option also). I have total control of which battery I want charged from the alternator (1,2 or 3 or any combination of all three) and then switch to which ever one I want when the engine stops, the battery switches isolate the un-used batteries so there is no bleed of charge between batteries. It's simple and totally effective and only involves switching before and after running the engine (the battery switches are beside me in the cockpit). The quality and gauge of the wire between the alternators and batteries is important both in terms of getting the charge to the batteries and for safety reasons.

Obviously, with a two Alternator set up that makes it a bit more complicated, but I think the same principal should apply, with perhaps a cross over switch built in so either alternator can charge any battery bank.

So I agree totally with Robert McClean above, diode splitters are a waste of money and totally inefficient anyway, the slight benefit in not having to use switches is far outweighed by the cost and poor performance of the units.

Regards.

Rob

A customer of mine who purchased a Seamaster 30 many years ago, was plagued from the outset of his ownership with flat batteries. He asked me to have a look, and I suggested the removal of the Diode splitter, and some minor re jigging of the harness, would solve the issue. The customer however decided to persevere with the diode splitter for a few years, purely because His mate (retired electronics engineer and fellow Seamaster 30 owner), told my customer that "He (Me) doesn't know what he's talking about". So after maybe two years of frequent breakdowns/callouts, my customer relented, and told me to do the conversion. His mate (the electronics engineer retired) then copied my conversion onto his vessel but in addition, I,m told, produced an article in his own name in the Seamaster owners club magazine, outlining in detail the conversion which "He had designed"!!. So, the simple answer as far as I am concerned, is I wil never recommend a diode splitter of any brand in any installation, even on a single alternator setup.

A customer of mine who purchased a Seamaster 30 many years ago, was plagued from the outset of his ownership with flat batteries. He asked me to have a look, and I suggested the removal of the Diode splitter, and some minor re jigging of the harness, would solve the issue. The customer however decided to persevere with the diode splitter for a few years, purely because His mate (retired electronics engineer and fellow Seamaster 30 owner), told my customer that "He (Me) doesn't know what he's talking about". So after maybe two years of frequent breakdowns/callouts, my customer relented, and told me to do the conversion. His mate (the electronics engineer retired) then copied my conversion onto his vessel but in addition, I,m told, produced an article in his own name in the Seamaster owners club magazine, outlining in detail the conversion which "He had designed"!!. So, the simple answer as far as I am concerned, is I wil never recommend a diode splitter of any brand in any installation, even on a single alternator setup.

Installing a second belt system and extra alternator can be an awkward job in a lot of situations, especially on older engines.

This winter I installed a Sterling Power Advanced Regulator and ProSplit R 1:3.
I can confirm this model of splitter is 0V drop,
With the engine running I measure 14.4V at the alternator and the same voltage at all 3 battery banks, even at the BT battery 16-18ft.

I agree with the Roberts. My view on diode splitters is well known to long time readers here. Detest them.

My solution was to install a SmartBank - it has nearly all the advantages of Robert Chester's setup without the chance of forgetting to set the switches.

Since I installed it the company has been bought by Merlin, but the above (old) link has a lot more info. New link: [www.power-store.com]

.

Conor,

Super, didn't know such a device existed, thanks for the lweb inks. One for the files, I'm going to persist with my cheap switches for the present, I've moved on to other boat projects so when they're done I might have a look at the charging system again.

Regards.

Rob

PS: Would whoever forgot to turn off the big shower in the sky please return immediatley and switch the damn thing off !!!!!!!!!!!!

Great information. Thanks.

Quote:

So I agree totally with Robert McClean above, diode splitters are a waste of money and totally inefficient anyway, the slight benefit in not having to use switches is far outweighed by the cost and poor performance of the units

I fail to understand where this comment comes from, Diode splitters, properly speced are extremely reliable, The latest MOSFET based designs are in effect lossless as well.

Note if you have battery sensed alternators, you can easily overcome the voltage drop as well.

The two alternator strategy is very very inefficient and costly to boot. The start batteries require almost no charge so that alternator will be doing nothing most of the time, whereas the heavily used domestics require all the alternators they can get,

Note that the Smart Charge device is just a fancy relay combiner, which itself have issues.

I usually build my own splitters, using Schottky Diodes to limit the forward drop., its the simplest of devices

Dave



Edited 1 time(s). Last edit at 11/07/2012 11:44 by Dave McCabe.

Hi Rowland ,
I have just finished refitting an old RS Bermuda. The guy who did the electrics is an automotive wizard he fitted a 70amp relay between the alternator and the two battery bank. Basically I can choose which bank to charge. The boat is a family boat so battery consumption is heavy enough it works faultlessly.
David Gray is the mans name - he has fitted out a number of boats on the Shannon and is easy to pay his number is 087 2679102

Hope thats of some help


Paul Dunne
Paul@diggers.ie

Thanks very much to Billy, Ciaran, Conor, Dave, P.A.D., Paul, Robert Chester, Robert MacC and Robert Maitland for all your excellent advice. We located a second-hand diode splitter in Roosky and fitted it yesterday and all is now in great working order (for better or worse!).

Rowland

Clonony

Hi Rowland,
It was great to meet you all on Sunday morning last in Castle Harbour
Your boat is truly an example of how a restoration should be carried out
Could you please send me the contact details of the Company you
Engaged to carry out the repairs to the fiberglass.
Kind Regards
Paul Dunne
Lady Lucy

Hi Paul,

Great to meet you too last Sunday, and to see the lovely Lady Lucy being restored. We remember her well from old.

A lot of the restoration work to Clonony was carried out by Mark and Tom Leonard of Tom Leonard Marine, www.tomleonardmarine.com (ph: 00-44-28-66387806), Carrybridge, Co. Fermanagh.

We found them to be THE most superb perfectionists - their attention to detail and the quality of their workmanship was second to none.

I'm sure we'll bump into you again on the river!

Kind regards,
Rowland

Clonony