Fit a digitalalternatoregulatorPBO reader David Berry explains how heinstalled a digital alternator regulator to theengine of his Moody Eclipse 33, Ade ryn Gtas

hen we travelleddown throughthe canals ofFrance to theMediterranean

we asked the people we metwhat they considered essentialto support a life afloat in a climateso different to Britain. Theanswers generally fell into twocategories: staying cool andpower management.

To help with power managementwe fitted solar panels with 200W ofoutput that can deliver a staggering10A on a sunny day. Along with thesolar panels, another way olmaintaining maximum charge inour batteries was an advancedalternator regulator.

Choice of regulator for us boileddown to either Adverc or Sterling,with the Sterling unit marginallycheaper. Sterling reckoned theirDigital Advanced Regutator (DAR)was the most coslefiective solutionfor simple alternator installations,and as our 1 992 Volvo-Penta 20OgTfalls into that category we boughtone. In the box is the unit itself anda set of instructions.

The DAR is designed to controlthe charging power fed into the

battery bank from the alternator.Instead of relying on the defaultproportional power curve that theinbuilt alternator regulator provides,the DAR is microprocessor-controlled to provide boost powerand float maintenance poweroutputs that will ensure thequickest and fullest charge.

These units have one drawback:they require connection to thebrushes inside the alternator itself,and many people are put ofi by thethought of taking the alternatorapart. On our standard{it 50A Valeoalternator it's not too difiicult, butyou do have to be able to solder. Besure to disconnect the power fromthe alternator before disconnectingits wires (turn the 1-2-Both switch to'ofi', for example).

Installation helpThe instructions that came with theunit were adequate, and CharlesSterling also provided rapid supportto my queries by email or phone.

The best thing about theinstructions is that they walk youthrough the installation in a logical,step-by-step manner requiring youto learn necessary facts about youralternator and leading you to the

final setup for your installation.They help you determine wherre-you have a positive or negativeground system, and which of thewires from the brushes is the one.tcconnect to the device.

One point the instructions makeclear is that the output power fromyour alternator will be far greaterthan before, and you need toensure that the rest of your system- the cables, switches, terminals.connectors, the alternator drive beltand the batteries themselves - areup to it. You will also have to getused to topping up the batterieswith water more often.

They also tell you which DAR wiregoes where, but there are somealternatives that are worthmentioning - my thanks go toCharles Sterling for suggestingsome of these solutions and taklngthe time to explain a few of the finerpoints. In summary:

The red sense wire needs toknow the voltage at the battery youwant to charge. That's f ine intheory and if you only have onebattery it's fine in practice - justconnect it to the positive terminal ofthe battery and you're done. Butmost of us have a number of

batteries grouped into domesticand engine start banks, so wheredo we put the sense wire? Theanswer is as near the commonpoint of the battery banks aspossible. In my installation this isthe 1-2-Both switch - ljust have toconnect the red wire to the'common' post of the switch andthe DAR will sense the voltage therewhich should be pretty close to thevoltage of the battery I'm charging.

Unfortunately, in my case Moodybuilt the switch first and the boataround it and I can't get to thecommon post at the back of theswitch, so l fol lowed the largestdiameter wire from the commonpost unti l l found a place where Icould get the sense wire onto jt.This was back at the engine, at thestarter solenoid.

Sensing the voltage there is notperfect. but not too bad either-thewire from the switch is so large thatthe voltage drop will be small and,again, as the charging current dropsso does the voltage difference.

The unit comes with atemperature sensor which you canfit to a battery terminal. lt wil,measure the temoerature of thatbattery terminal and adjust thecharging cycle to suit. Here, ofcourse, is the next problem. lf youiit the sensor to battery 'A' andcharge battery'B'then the unit mayoverheat'B'because i t has noinformation about its temoerarure.

Sterling suggest ignoring thetemperature sensor in all but thesimplest cases and relying on theunit to sense the ambienttemperature wherever it is mounted.While this isn't going to be optimal itsounds sensible, so I left the sensorout of my installation. lf you want tofit it, the instructions show how.

The D+ terminal on the back of the alternator

This is the voltage sense and should go to a point near the battery you want the DAR to cnargeHowever, the choice is not so simple in the real world - see main text.

The B- terminal on the alternator. There are two black wires in parallel: don't separate them,they're both needed.

The instructions refer to this as a 'simple ignition feed', which doesn,t mean much to me. However,you can either connect this to aleed to the engine which is live when the 'ignition switch' is on(there isn't a wire like ihis on the 2003I which is live all the time), or you can connect it to the D+terminal on the alternator.

Join to the selected wire from the alternator brushes.

58 Practical Boat Owner 544 February 2012 . wwwpbo.co.uk

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With my original.fit Valeo Paris-Rh6ne50A alternator the first thing to do is to

disconnect the yellow wire from the terminalpost and spade connector, but leave itattached to the built-in regulator housing.Then. with a wide tool such as a tlatscrewdriver, carefully lever the main plasticcover oft the rear of the alte.natot: it's a clipfit - there are no screws holding it.

Jl The regulator may be reluctant to comeI free, in which case you have to be lirmbut careful. There are no other screws holdingit so just keep working around it with asuitable tool until it moves, In this shot youcan see the two wires running trom the whiteplastic brush holder into the potting beneaththe regulator. This is the fragile bit if youbreak these wires you will have to buy a newassembly, so don't wriggle it around too much!

You now have access to the tour slotled-head screws that hold the regulator (the

black plastic assembly) in place. This isprobably a good time to clean up a bit withsome meths. Remove lhe screws. but do notremove the regulator yet.

Remove the two slotted screws thatsecure the white plastic brush holder, lift

the end where the wires are attached and slip itout backwards and upwards.

I Disconnect the spade connectorsIl on each side of the regulator bygently easing them upwards with asmall screwdriver.

f This is the assembly you have to attachwires to. The brushes and the regulator

wires are soldered to ihe tags at the top ofthe holder and you have to attach two morewiresn one to each tag, and lead them to theoutside world. lt's a good time to clean theunit of any carbon dust with a small brushand some meths (not white spirit, since thatleaves a residue).

E 3?ifii,",ootlexible wire withinsulation that canwithstand thetemperaluregenerated by thealternator, and use a hot iron- Tin the wire andtln the tag because you want to make the iointquickly to avoid melting the existing solderedioints. I'm not sure if the brush will fall out ifyou melt its connection, so it's wise to hold itwhile you solder. The best route out for thenew wires is through one of the mouldedseals at the side ot the regulator housing.Choose the seal that has only one existingwire and carve the rubber away very carefullywith a scalpel - remember, the existingmoulded-in wire must not be cut or bared,

That's the hard bit done! Replace thebrush holder and lead the wires to

the modified seal.

Reassemble everything,remembering to remake the

spade connections lrom thealternator's regulator and toreconnect the yellow cable, Seal the lir.space around the exit of the newwires with a squirt of something that l.i.can take the engine room temperature.

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Temporarily insulate the cut ends of thenew wires to prevent them touchinganything, including each other. That's it -the alternator has been modified and youcan bolt it back onto the engine.

.ulllr*tis.

!i1r'

Practical Boat Owner 544 Februarv 201 2 . www.obo.co.uk 59

@tfl The DAR is bullt on a cilcult boardI enclosed in a case, Undoing four screwsgets you access to the things you have toselect - the ground arrangement (positive ornegative) and the banery rype, Th6 circuit iscarried on a heat sink: Sterling report that itwill happily run at 90'C, so mounting it in theengine compartment in my Moody ln the Medis not a worry.

t,! Because the Volvo 2003 is a little tight toI work on I decided to make the DAR wireconnections to the alternator beforereplacing it on the engine. Here you can seethe twin black wires on the B- terminal, andthe yellow and brown wires on the D+terminal. The yellow wire is the'ignition feed'and is normally taken to the'ignition sreitch'- a supply that is switched on before theengine can run. Since the Volvo electrics arelive all the tlme this option was not availableto me, so I took the alternative andconnected the yellow wire to the D+ terminalalong with the brown.

The orange luse is positioned to selectbetween positive and negative grounds,

and the instructions wlll tell you how todetermine which you have. The blue DILswitches are there for you to select yourbattery type - mine is 'open lead acad' and thepicture shows the setting for that typ€. Othersare'gel sealed' and'glass mat' types. Thesetting determines the charge profile the unitwill follow

With the engine runnlng, measure thevoltage from one ot the new (white) brush

whes to ground, Make sure you mark the twowlres so you can identlfy them afterwards. Ofthe two wires, the one wlth a voltage readlngbetween the 2V and 10V prodicted by theinstructions is the one |tm after. The other wlre(inset photo) measured 14.31V and is the one Itherefore don"t need. Atter the test I cut thisone back and sealed lt with heatshrink sleevingto prevent it making contact wath anything.

It's worthwhile measurlng the output trom thealternator at the same tlme, iust to be sure youralternator is up to scralch.

fl Secause I couldn't get to the back of thetl battery s€lector switch (inset photo) inmy lloody I attached the red voltage sensewire to th€ fat supply at the starter motor- Thesense wlra ls the thinner of the two red wires.This ls acceptable since the voltage loss inthe lar96 supply cable as minimal duringcharglng. However, don't take this easy wayout il you can do better. Get the end of thesense wlre as close as you can to thebatterles you want to charge.

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The white wire can be switched - I useda crimp bullet connector - which allows

you to disconnect the unit {or whatevelreason. One good reason is to see thedifference in charglng voltage when the unitis working. It everything works, you shouldget a pretty light show when the engine runs.

Has it workedin practice?lrlid we benefit from fitting alJdigital alternator regulator?lronically, maybe notfor our Medcruising. We fitted the unit inFrance before sailing to Greeceand expected there to be aconstant supply of wind as wesailed south, but in fact the windwas either too much or too little:hands up those who've heardthis before. This meant wemotored much more than weanticipated and the batterieswould have been fully charged

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by the normal alternator-regulator combination. We alsohave those lovely solar panelswhich provide lots of amps whilewe rest in the heat of the day,of course.

In Britain, we often foundourselves swinging on a mooringor on anchor for a few days andhaving to run the engine forhours to top up the batteries.This is bad for the engine,especially with a turbo, and notmuch good for the crew. So myview now is that, if this is yourcruising pattern in Britain, youcould benefit from fitting a digitalalternator regulator,David Berry sails his Moody Eclipse 33 Aderyn Gras in the lonian

Practical Boat Owner 544 Februarv 2012 . www.obo.co.uk

Adverc Mk.lVa Std €213Available for single or iwin alternators inpositive or negative excitation guises,andtor 12Y or 24V, Adverc claim theirMk.lVa unit can charge a battery toover 95% of its capacity compared with70% tor a conventional regulator.I www.adverc,co.uk

BalmarARS-5 €384.1ODesigned for a single alternator, the

ARS-5 features five programs forcharging deep-cycle flooded. gel,AGM and spiral-wound batteries, plusa universal default program for

standard flooded batteries. Belt Ioadmanagement software allows you to

reduce the load to limit belt slippage and wear.I www.balmar.net

Balmar Max Gharge MC.6l2.DUAL €446.39Intended for use with dual alternators on the sameengine, the MC-612-DUAL has seven user-adjustable battery programs designed forstandard and deep-cycle flooded, gel, AGM,spiral-wound AGM batteries, voltage-sensitive halogen systems, plus adefault program that Balmar say is safefor most batterytypes.Iwwwbalmar.net

Driftgate X.ALT From 81OgDriftgate's X-ALT regulator is available in three forms:the single-battery Buccaneer; Skipper, sensing up tothree batteries, or two with a single pointtemperature control; and Captain, which can handleup to three batteries and two alternators withtemperature compensation and alternatorover-temperature protection.

I www.dg2k.co.uk

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Merlin AItlIS 12V 8163.39Merlin's Alternator ManagementSystem ofiers four-stage charging, andcompensates for voltage drop problems bysensing at the battery. Suitable for floodedlead-acid, gel and AGM batteries, the unit alsohas builfin temperature compensationI www.power-store.com

Sterling ProReg B 8119.9OThe unit fitted by David Berry has been supersededby Sterling's ProReg B. Although the same in theessentials, the new model has support for US-specsealed gel batteries.I www.sterling-power.com

Sterling ProReg De 179.90

An alternative oroduct fromSterling, the ProReg D adds the facility for aremote panel, is compatible with both 12V and24V systems, and has an e)dra cooling tan tocope with larger alternators.I wwwsterling-power.com

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T . + 4 4 ( 0 ) 1 4 8 9 5 7 0 7 7 0E. info@rolls-battery.com

Available from al l good marine stockists www rol ls-battery.com

Practical Boat Owner 544February 2012 . www.pbo.co.uk 6r