**Update early 2025: Firmware updates improving ‘small engine feature’ mean I now only fit the Wakespeed WS500 on my lithium battery installs (no longer using the Mastervolt Alpha Pro). This page is out of date. For now please checkout my Instagram page to see all the 2025 jobs featuring the WS500. https://www.instagram.com/four_counties_marine/ **
Official UK dealer for Wakespeed. WS500 PRO Marine & Motorhome kits in stock. As part of my service I can modify the factory fitted alternator or supply a suitable upgrade kit.
I always install an external regulator on lithium battery jobs—it’s by far the most effective method for alternator charging. Check out the case studies on my Lithium page to see real-world examples of these regulators in action.
This new generation of external alternator regulator completely replaces the internal regulator and provides adaptive and optimised control taking full advantage of a large alternator and Lithium’s ability to accept charge.
‘Small Engine Feature’. (AKA ‘Adaptive Pullback’, ‘Power Curve’, ‘Small Engine Mode’, ‘White Space’). Decreases the brutal alternator load on the engine at lower engine speeds. For high output alternators used for Lithium charging it’s essential – arguably more important than any other feature.
Fitting a large (eg. 12V 150+ amp) alternator to a typical narrowboat engine (Canaline, Barrus, Beta Marine etc..) creates excessive loads at in-gear tickover speeds and causes serious engine running issues. On the Beta 43 & 50 engines it increases the likelihood of the disastrous crank pulley issues. For the factory 12V 175A Mahle output is set around 160A at 1200 rpm and I program to around 50-60A at tickover.
This tool makes it possible to fit a much bigger alternator to an engine or belt drive system than you would normally be able to use. The alternator load is dialled down to work closer to the edge of belt or engine limitations and the larger alternator enables unstrained reliability and continuous high output.
Alternator temperature sensing. Enables a maximum alternator temperature to be set, and alternator output settles at a steady continuous rate. It gets the most out of the alternator while keeping winding temperatures safe and comfortable. A 50% rule is often bandied around about max continuous alternator output. With so many variables (engine speed, pulley ratios, ambient air temperature, alternator type etc.) the rule just doesn’t work. In typical conditions a well setup system with good pulley ratios and a decent alternator enables far in excess of this 50%. With temperature sensing output is dynamic and always optimised.
Derate max alternator output. Good quality Lead Acid & Lithium batteries have a recommended max charge rate. This function can derate max alternator output to suit, or set a max alternator load based on belt drive or crank load limitations.
Integration with a lithium BMS. A premium lithium system with standalone external BMS such as a Victron VE.Bus, Lynx, Mastervolt or REC-BMS can enable full automatic alternator control. This completely removes the risk of a load disconnect damaging the alternator and other equipment on the load side. The WS500 is supported by Victron and the Lynx & REC BMS controls alternator charging via VE.CAN-Bus and DVCC. Alternator is displayed as a device in the Cerbo GX/Touch display, sharing monitoring data.
If you already have lithium batteries and use DC-DC charger(s), long cable runs, or a Victron current limiting BMS (12/100CL or 12/200) you are not realising the alternator’s full potential and missing out! As a service I can retrofit a WS500 and adapt an existing lithium install.
There’s a misconception you need an expensive Balmar or Mastervolt alternator – you don’t! I can fit them to all factory domestic alternators used by the big marinisers. For many Barrus, Beta, Isuzu and Engines Plus Canaline engines I’ve developed kits based around a 12V 200A Bosch, 24V 180A Prestolite, 24V 150A Bosch & 48V 100A Mahle alternator (as used by Mastervolt in their top-of-the-line 14/200 , 28/150, Balmar’s 97XD-24-190 & Balmar 96-48-100). Some with a 6PK poly-v crank pulley conversion. For narrowboats already with a 3.5 Travel Power and a Victron 12/3000/120 Multiplus it’s possible to build a simple engine charging system. The Multicontrol AC current control is used to adjust Travel Power alternator load. For the Beta 43/50 in particular it’s important to have a sensible limit on crank load at low engine speeds – other medium/high alternator loads have to be carefully managed or disabled while using the Travel Power.
Providing Boatbuilder and Engine Marinser with an alternator + regulator package for newbuild engines has become a significant part of my work. For new-builds and when starting from scratch 24 & 48 volt systems are the way to go. I have custom 24V 180A Prestolite , 24V 150A Bosch & 48V 100A Mahle alternator packages that can be factory fitted by Beta & Barrus during build.
Any queries/questions call Ed 07922 163072
The case studies below are now well out of date and mainly feature Mastervolt Alpha Pro regulators. With massive improvements to the ‘small engine feature’ in Spring 2025 firmware updates I now only install the Wakespeed WS500.
Please see my Instagram account to see the latest jobs I’m getting involved in.
https://www.instagram.com/four_counties_marine/
Example of a factory alternator being modified for charging lithium.
During build of https://falcon-tenders.com new 2021 mega yacht limousine tender they looked at ways to charge 2* Mastervolt MLI Ultra 12/5500 lithium banks from the twin Sole Hyundai engines. It was impossible to physically mount Mastervolt alternators to the standard engines. I convert the factory fitted 150 amp Denso alternators to work with the Alpha Pro’s and full Mastervolt setup.
Practically any alternator can be adapted and the factory alternator is often a better solution than a Mastervolt or Balmar version. I’ve provided this service for all of Falcon Tenders builds with different engines since.
External Regulator Retrofitted to a New Build Narrowboat.
The boatbuilder neatly installed a full Victron 660AH Lithium system using a Victron CL12/100 BMS to manage 175A alternator charging on a Beta 43. Max current was around 90A dropping to ~60A at 70% state of charge and would take many hours to recharge. I simplify the system with 175A Iskra alternator directly charging the lithium bank and controlled with a Mastervolt Alpha Pro. Now alternator charges at 150A+ throttling down to around 135 – 140A continuous.
Small engine mode reduces max output at tickover to ~60A with max power of ~155A at 1200 rpm. Beta warn against high alternator loads at tickover and this system enables it.
Big 12V 150A Alternator on a tiny Beta 20 engine.
An external regulator lets you control alternator load/output at different rpms. I convert a very nice 150A Bosch alternator for Mastervolt Alpha Pro and squeaze into a Beta 20 engine. Belt converted to 6PK drive with small freewheeling alternator pulley.
Output mapped to ~20 amps at tickover increasing to 100 amps at 1400 rpm. Integrated into the BMS ‘Allow to Charge’ of a nice Victron lithium system. The regulator enables incredible charging performance from the tiny engine.
External Regulator fitted to a new Victron Lithium system.
My customer installed a top of the range 600AH Victron lithium system with a ~60A DC-DC charger managing alternator charging from the Beta 50 engine. I fit a Mastervolt Alpha Pro and charging performance has been transformed.
With extra ventilation in the engine bay charging performance settles at around 2kW, 140A+ with alt temp set to 95 deg C. Full recharge from 30% in under 1.5hrs and customer delighted. Extra switch fitted in dash to manually disable alternator charging when required.
Barrus Shire 50 + 200A alternator upgrade charging Lithium.
Another boatyard had installed a full Victron Lithium system – 4* 12V 200Ah Smart Lithium, VE.Bus BMS, Multiplus 3000, Smartshunt, Cerbo GX, Touch 50 etc. They attempted to fit a ~£1000 Victron 100A Buckboost for alternator charging but there were issues installing it – Customer contacted me and I explain that an external regulator is a far better approach in terms of power available and reliability. The factory 240A alternator is poor for continuous high output due to belt limitations simply because it’s not possble to fit a freewheeling pulley. I install a 200A Bosch alternator + Mastervolt Alpha Pro.
A 50mm freewheeling alternator pulley achieves 3.5:1 pulley ratio for excellent cooling. Power is set to 70 amps @800 rpm tickover rising to 180 amps @1200 rpm. Engine totally unstrained with no hint of the powerful charging rates. The Alpha Pro looks after the max alternator temp, set at a conservative 90 deg C. Integrated into the ATC signal from the VE.Bus BMS and results are a reliable and powerful charging system.
150A alternator running on a V belt charging Lithium.
Conventionally you can’t fit big alternators to a V belt drive. Using a well setup external alternator regulator you can. On this job charging Lithium I use a Mastervolt Alpha Pro to derate a powerful high quality 150 amp Bosch alternator to 110A and the ‘small engine mode’ to set a 35A tickover limit. This controls the alternator belt load close to it’s limit throughout the rev range.
Features that make this possible is the quality Bosch alternator with open casing and custom 60mm XPA pulley to increase speed and running a Gates Quadpower XPA belt. Originally this Vetus engine ran 10mm wide belts but the XPA belt sits higher in the crank and waterpump pulleys (slightly increasing crank pulley diameter) and allows for increased power delivery.
The alternator temperature sensor sets a max running temp of ~85 deg C (with a 1st quick setup) and throttles current down to suit. End result is an incredible relentless 70 amps just off tickover.
Large alternator installation on Beta 38 only possible with a Alpha Pro.
Basic spec of this new narrowboat: 510AH Victron AGM battery bank. Victron 3000 Multiplus. Victron BMV712 monitor. High power demands: Wallas diesel oven, Webasto CH (no stove), small induction hob, coffee machine etc.. Engine is the latest Beta 38 Greenline with standard budget-chinese 100A alternator.
Customer finds the standard setup struggles to charge the large AGM battery bank. The factory 100A alternator (Chinese copy of a quality European Iskra) has a massive ~75mm aluminium pulley. Due to non standard shaft thread size unable to fit a freewheeling pulley. Beta offer to make a 60mm aluminium pulley but customer wants to get things right. I fit a 200 amp Bosch alternator with Mastervolt Alpha Pro & increase cable sizes to suit.
Normally, with the small Beta 38 you couldn’t install such a big alternator. The 6PK belt & freewheeling alternator pulley combination is close to belt limitations and will just about run a 200A alternator. Limiting factor is engine power. The large ~230mm crank pulley enables near full alternator output at the 800rpm tickover – which the engine just isn’t capable of running. This is the case with other popular engines too: Beta 43, Beta 50, Isuzu & Barrus. With the Alpha Pro it’s possible. Absorption voltage is set to 14.6V and ‘small engine mode’ is setup to reduce output at lower rpm: At 800rpm tickover programmed to achieve ~65 amps. In gear tickover drops engine speed slightly and output to ~55 amps. Slowly raising revs, output gradually increases to 240 amps (3+kw) at 1200rpm. We back the max alternator percentage output to 70% to suit the max charge rate of the Victron AGM’s.
Alternator temperature sensor is added and Alpha Pro programmed to keep temperatures ultra safe. With the freewheeling pulley customer notices everything is significantly smoother. Alternator performance is transformed.
200A Beta 38 upgrade + Alpha Pro charging drop-in Relion Lithiums.
My customer has had alternator issues on a Beta 38 ever since installing 300AH Relion Lithiums including 1 catching fire, poor results + another failed alternator while using a Sterling A2B. I fit a 200A Bosch alternator + Mastervolt controller.
Performance now in a different league with modest alternator temperatures. Output/load programmed to ~50 amps at tickover increasing to 150A at 1200rpm to suit the 0.5C recommended Relion charge rate. I add a control switch so alternator can be disabled when required (such as low temp engine running).
Mastervolt Alpha Pro + 12V 175A conversion on Isuzu to charge Valence Lithiums.
My customer has installed a 390AH Valence battery system along with other kit (Victron 3000 Multiplus, Victron BMV 712 Smart, Solar etc) and has found the standard 80 amp alternator on the Isuzu Canaline 42 doesn’t work with Lithium. I install my custom 6PK poly-v crank pulley upgrade along with a high quality & powerful 175 amp Iskra alternator & freewheeling pulley.
A Mastervolt Alpha Pro is added and absorption voltage is set to the recommended 14.2V. It’s important to keep max absorption voltage conservative with most lithium’s to protect cells from over voltage. Often the BMS is built in and a disconnect due to cell over voltage can potentially damage the alternator. Small engine mode brings alternator current down to ~ 55amps @ 800rpm tickover dropping to ~35amps at in-gear tickover. Full power is dialled back to ~130amps at 1100rpm. Without small engine mode alternator load is just too high – Engine runs very badly almost stalling on tickover and won’t rev.
An alternator temp sensor is added – as alternator temperatures rise over a pre-set level, output is gradually backed off and never exceeds a very safe 90 degrees C. The setup is superb and takes full advantage of the large alternator without compromising reliability or engine performance/refinement. I add a control switch in series with the ignition switch so alternator can be shut down when required. This is an important feature particularly useful for drop-in type lithiums with no alternator BMS control. My customer is delighted with the new setup. The video clip below shows the Alpha Pro’s current control – There’s a slight lag with sound due to the Victron BMV Smart connection.
Mastervolt Alpha Pro fitted to Barrus Shire 40 to charge 200AH Relion lithium on new build.
Customer originally installed a Victron Orion 12/12-30 DC to DC converter. I fit a Alpha Pro to the factory 12V 150A Prestolite AVI144 domestic alternator. Derated to suit the Relion drop-in 200AH battery. Temperature sensor to keep alternator temperatures modest. Customer delighted with the new simple efficient setup and ability to recharge so quickly.
48V 100A Mahle + Wakespeed WS500
I supply a 48V 100A + WS500 package. It’s a straight swap for the 12V 175A Iskra used on the Beta 43/50 and Canaline 42 engines.
Example of a Dometic Travel Power swapout for 200A Bosch alternator + Alpha Pro.
The boat had a failed 3.5 powerbox and expensive estimate for repair. I fit a 200A Bosch + Mastervolt Alpha Pro package as a replacement and my Engineer customer believes it’s far superior to the old Travel Power.
Features alternator temp sensing and small engine mode make this such a great option. For Lithium it enables charging far in excess of the typical Victron Multiplus 3000/120 + 3.5 Travel Power system, and uses ‘small engine mode’ which the Travel Power setup doesn’t have.
Alongside I install the full CAN-Bus Mastervolt kit with MasterShunt, MassCombi & Easyview display. And fit a new set of Leoch AGM Lead Carbon batteries with leads to perfectly balance. A great feature of the Alpha Pro is you dial the current back to suit max charge rate of the AGM batteries.
