Barrus Shire 12V 90 amp Alternator Upgrade Job in Islington.

Travel out to Islington, London to work on a Narrowboat with a Barrus Shire engine and failed alternator. Customer couldn’t find anyone local willing to do the job and Barrus wanted IRO £500 for a direct replacement. I fitted my 90 amp upgrade kit and customer was very pleased and impressed with the fit and finish.

This has been a familiar job which I’ve fitted to well over 100 Barrus engines. It involves fitting a much larger 90 amp alternator, smaller pulley, longer XPA Quadpower belt, simplifies the original charging circuit and I often increase cable size to 35mm. It supplies around 45-50 amps at tickover which is usually more than the original “80” amp alternator can supply at any speed.

The quality of the new package and fit and finish is a significant improvement on the original. My customers are always pleased.


Isuzu 38 & 42 Canaline Charging System Upgrade. Narrowboat.

The latest charging upgrade I have available involves fitting a high quality 120amp domestic alternator, high speed pulley, Gates Quadpower belt and 50mm -ve and +ve charging cables. This offers massive improvements over the factory fitted setup right from engine tickover speeds. This is suitable for some Isuzu 38 and 42 engines fitted with the original 70/80 amp alternator.

Also available is an upgrade for the single alternator engine fitted to many ex Black Prince narrowboats which gives significant improvements.

Photos coming soon.

Dometic / Electrolux 3.5 Travel Power Generator Rebuild.

This is part of the process in a typical rebuild on the Bosch Travel Power alternator. A new slipring is epoxied and then soldered on. An engineering firm turns the slipring down so it’s perfectly straight. New bearings are fitted and the rotor is re-magnetised. I have rotors rebuilt to this stage so a generator can be turned around more quickly. It’s not always necessary to replace a slipring – some tend to wear more than others for no obvious reason. Only quality parts are used.


It’s important a travel power alternator is serviced from time to time as it’s possible bearing failure can destroy an alternator. The rear bearings fail more frequently than the front. If there’s any play or roughness bearings should be changed.

The earlier Bosch alternator is a re worked low voltage unit popular in the 70’s and 80’s and was never designed to run a poly-V belt system. It’s very easy for owners and engineers to over tension the belt which can lead to premature failure.

Beta Marine often fitted soft aluminum alternator pulleys and often these wear and loose their poly v profile leading to belt slip and over tensioning. I have smaller 50mm freewheeling pulleys which run dramatically smoother than a fixed pulley and increase belt grip and lower belt tension required.

Lister ST Alternator Upgrade. Small XPA Pulley.

Called out to battery problems in Stone on a recently purchased narrowboat. Lucas A127 55amp alternator output poor and doing very little at tickover. Adverc ok. Tidy but badly installed system by well known and reputable boatyard (not in Stone) : cable sizes poor and Adverc battery sense fitted to common post of 1-2-both switch however long cable run  (6mm cable/yellow crimps to domestic batteries) after the switch. Alternator pulley large. Fit a 90 amp marine alternator modified for Adverc. New long span laser cut curved adjusting arm, longer bolts, shims and 60mm custom XPA pulley. Gates Quadpower belt. All cable sizes including earth increased to 35mm and re-routed to shorter runs. Transformed alternator performance quickly jumping to 14.4V at low engine speeds.


The ST drives alternator at 1/2 speed off cam shaft alternator output is often poor at lower engine speeds. ST’s can often be improved relatively easily as the cam pulley is normally a reasonable size. I’ve fitted this alternator to 5 ST’s now with great results.

Alternator problems on Narrowboat with Lister Alpha LPWS.

Call-out to Bollington to look at problems with a 4 cylinder Lister Alpha. Newly purchased narrowboat where the previous owner fitted the best equipment which looks good on paper. Smartgauge, Victron BMV, 2 large Victron AGM batteries, 24V 150A Mastervolt Alternator, Victron Multiplus etc.. Problem was with the ridiculously over spec’d Mastervolt alternator (like using a power station to supply a house). Mounting system was complicated and engine vibrations causing all the engine mounts and engine brackets to continuously work loose. This had been an ongoing problem. My solution was to fit a standard 60 amp 24V alternator with a smaller custom 65mm XPA pulley and single Gates Quadpower belt; Remove the 16mm charge leads (150A alternator!) and increase to 35mm due to lack of intelligent charging. Charging system is great and a match for the 220AH 24V battery bank. Engine runs smoothly and transforms the boat. Customers delighted.listeralpha

Sabb 2JHR Alternator and Charging Upgrade. Narrowboat. Adverc & Trojan T105.

A charging system upgrade I did on this beautiful Dave Harris tug with sweet 30hp Sabb 2JHR engine.

Original alternator was a low output Motorolla. I fitted a 110amp 12V marine alternator with custom 60mm XPA pulley, 50mm cables; Adverc system; Victron BMV700. Replaced 3 110ah house batteries with 4 * 6 volt Trojan T105’s. Installation has transformed the domestic charging system. Excellent output (50 amps) at tickover. On this job I fitted a extra small 60mm pulley which I’ve had made.

Using a smaller alternator pulley reduces belt contact area and puts more heat into the belt. You have to use Gates XPA Quadpower belts and it’s a compromise between belt life and alternator performance at lower engine speeds. Smallest pulley size you can go down to is 55mm and generally I fit 65mm.

Vetus M4.14 Alternator and Charging Upgrade on the South Coast.

Travelled to Chichester Marina to work on a beautiful and superbly restored classic 1960’s wooden racing yacht Blue Saluki. Re-engined with a Vetus M4.14 6/7 years ago and the charging system has never been good. I’m not used to working on the south coast but I was up for the challenge and this was a special yacht. Customer couldn’t find a local engineer who was used to working with Adverc systems.



The charging setup on this generation of Vetus engine has been badly thought out: The original factory fitted alternators have low output right across the engine rpm range. Alternator spec according to Vetus ranges from 40-60 amp (optimistic figures), alternator pulley size is large, crank pulley small and output at tickover pathetic. The replacement cost of this poor performing alternator from Vetus is extortionate.

My brief was to sort out the charging system. An Adverc system was already fitted with 1-2-Both switch. I fit a 120amp split charge diode; 90 amp Marine Alternator with custom smaller high speed pulley and Gates Automaster belt. Domestic charging cables increased to 35mm (some of original circuit was as small as 6mm. Rewire all batteries (3 domestic, 1 start) with new HD post terminals and marine spec 35mm cable. New Blue Sea isolator switches.



Charging performance has been transformed and customer is very pleased. With jobs like this I tend to load my van with a range of different alternators. There seem to be some differences in the front timing cover of these Mitsubishi engines and it isn’t always possible to fit the one I intended. Have to play around with pulley sizes as Gates Automaster sizes are limited. Clearance between wet manifold and alternator stud terminals was incredibly tight. I had to grind terminals down slightly and fit all cables before I fitted the alternator. Also access is poor – pretty sure some fitters would insist the engine lifted out to do a job like this.