Many original factory alternator charging systems are poor and have become dated. They can be upgraded to meet the high demands of modern electrical systems and the latest battery technology and I’ve developed some awesome setups that I’m really proud of. With the move towards Lithium it’s quickly become a big and exciting part of my work.

This page ties in with my work fitting Alternator Controllers – The Wakespeed WS500 and Mastervolt Alpha Pro have some amazing features to opimise lithium charging and realise the full potential of a big alternator setup.

Isuzu 200 Amp Bosch Alternator Upgrade.

The excellent Isuzu Canaline engines are let down by a particularly poor factory domestic charging setup. I have a 200 amp alternator upgrade running a freewheeling clutch pulley & custom 6PK poly-v crank pulley conversion. This series of Bosch alternator is used in the £2k+ Mastervolt 14/200 package. Available for most of the 4 cylinder engines. Custom stainless steel adjusting arm and mounting bracket. Options on alternator pulley sizes giving upto 4.2:1 pulley ratio. This upgrade transforms charging performance. Works best with an alternator controller to limit alternator load at low engine speeds. Please call for details.

Isuzu Canaline 42 200 Amp Bosch Upgrade

Beta Marine Engines

It’s possible to replace the troublesome solid aluminium poly-V pulleys fitted to the travel power and domestic alternators on pre ~2011 Beta engines. A smaller freewheeling pulley is available for the 95 Amp Iskra and there’s an option to replace with a 175 amp alternator as fitted to the later engines – I keep this in stock as a kit along with the custom Beta-made freewheeling pulley and new belt. The poor performing 12 & 24 volt Delco Remy alternators can be replaced with a top quality Iskra 12V 175amp/24V 100 amp. These engines can suffer crank pulley issues potentially destroying the engine. This is a particular problem when charging big lead-acid and lithium with the large alternator loads they create. An alternator controller works so well here limiting loads at low engine speeds and increasing the load at the 1200rpm (that Beta specify for charging) & looking after the expensive battery bank with it’s adjustable voltage and max charge rate.

Beta bv1505, Beta 35, Beta 38 90 amp alternator with small 65mm pulley, wider XPA belt upgrade and cable sizes uprated to 35mm. Transforms charging performance from the standard original setup:

For the later Beta 38 with 6PK crank pulley setup there’s a 200 amp Bosch upgrade available. A alternator controller must be installed to de-rate the alternator loads to suit engine power at low speeds.

Vetus Engines

Vetus engines only offer disappointing V pulley drive systems. This gives limited charge options unable to take advantage of a high power poly-v drive setup with large alternators and good pulley ratios. It means it’s relatively expensive to get modest continuous charge currents for charging Lithium. On the job below I squeeze in a high quality 150A Bosch alternator + Mastervolt Alpha Pro. A custom XPA pulley is fitted and a Gates Quadpower belt used – this belt sits higher in waterpump and crank pulleys (slight increase in crank pulley diameter) and the XPA (12.5mm) alternator pulley can transfer more power than the factory 10mm setup. The Mastervolt controller is setup to limit current to belt limitations and manages and controls alternator temperatures to below 100 deg C. Fitting such a large alternator means that it can run at a continuous high current without overheating. Max current is set at 110 amps and a very impressive 70amp continuous output is available just off tickover.

The setup gets the very best out of the poor V pulley setup and takes full advantage of the Mastervolt controller’s clever features allowing a large alternator to be setup right on the edge of belt limitations.

Barrus Shire Engines

**New** 200 amp Bosch alternator setup for some Barrus Shire 40 & 45’s. 6PK poly-v crank pulley conversion with freewheeling alternator pulley. Can replace the discontinued 110 amp Prestolite RDG5725. Custom folded stainless steel mounting bracket & adjusting arm. Unstrained & powerful, transforming the original setup. This kit isn’t suitable for all of the Barrus 40/45’s – call me for more details.

If you have a Barrus Shire 45/50 with the 240 amp Prestolite alternator you may experience poor charging performance due to the extremely low 14.0 to 14.20 voltage regulator set point, and also belt performance issues due to the 6PK belt setup which is unable to transfer anywhere near the 240 amp current through the solid alternator pulley. This job shows a 200A Bosch upgrade on the 240A Prestolite achieving a reliable 180A continuous.

Engines Plus Canaline 42 12V 200amp Bosch Alternator Conversion.

For the 42HP engine with 6pk multi v crank pulley. Replaces the discontinued 110A Prestolite 35214420. Massive increase in performance throughout rev range. I use a custom alternator mounting bracket and adjusting arm, and fit a freewheeling alternator pulley which improves power transmission, helps stop belt squeal/chirping and makes for a smoother running engine. Can go down to a 50mm freewheeling pulley giving an excellent 4.2:1 pulley ratio. The photo shows a 175amp Mahle alternator and I’m now using a 200amp Bosch unit..