Lithium (LiFePo4) batteries are a big deal and offer huge benefits for liveaboard off-grid boaters particularly in the winter. I work on the systems surrounding them installing equipment required to fit them. It’s quickly become a big part of my work and is something I’m passionate about.

I’m happy installing a complete system from scratch, working on specific components of a system, or make improvements and additions to a previously installed system (such as alternator/charging upgrade or battery monitoring and control).

Having a powerful and reliable charging system is critical to take full advantage of a lithium setup. Any deficiencies quickly become apparent. Many original engine mariniser setups don’t adapt well and haven’t been designed with lithium batteries in mind, and I have specific upgrades which transform charging performance for some of the most popular engines:

  • For Isuzu Canaline engines a complete kit using a Bosch 200 amp alternator with 6PK Poly V crank pulley conversion.
  • For some Barrus Shire 40 & 45 a 200 amp upgrade kit with a 6PK poly V crank pulley conversion.
  • 12V 175 amp or 24V 120 amp Mahle (Iskra) with Beta’s custom freewheeling pulley replacing the original 12V 95 amp Iskra or poor performing 12 & 24 Volt Delco Remy on the Beta 1903, 43 & 50.
  • For the 3.5 Travel Power there’s a 12V 200 Amp Bosch, or 24V 110 amp Mahle alternator conversion available.
  • On a new-build it’s well worth selecting an engine carefully even if there’s no plan to install lithium batteries at that stage. Some engines are far better suited than others. At this point it’s well worth considering a 24 volt or even 48 volt system.


External Alternator Controllers are so useful when charging Lithiums and have many advantages over the well known methods using Victron kit to limit alternator charging. I keep both the Balmar MC-614 & Mastervolt Alpha Pro in stock for a supply and fit basis along with an uprated alternator as part of a package. You don’t need the expensive Balmar or Mastervolt alternator and in some instances I’d advice against them due to inability to run a freewheel clutch alternator pulley. When running a poly-v setup a freewheeling alternator pulley makes for far smoother power transfer and handles large loads so much better than a solid alternator pulley. I keep brush boxes for the Iskra alternators on Beta & Engines Plus engines and for the Iskra/Mahle & Bosch alternators that I supply & fit.

Key points that Mastervolt & Balmar alternator controllers offer in respect to charging lithium batteries:

  • Both have alternator temperature sensing. Damage caused by the alternator overheating is a real risk without any temp sensing. This is an important point as engine bay air temperatures can become incredibly high particularly in warmer weather and limiting current alone isn’t always enough.
  • They enable an alternator to be easily shut down – either with an engine panel mounted switch, or automatically with a lithium BMS or a Battery Monitor. This means you are not disconnecting the output load which risks destroying the alternator. Doing this safely is complicated in itself requiring a dump load.
  • Absorption voltage can be adjusted to a safe, conservative level – so you generally don’t need to rely on a Battery Monitor or BMS completely disconnecting and disabling charging as is done with other methods.
  • The Balmar MC-614 and the full Mastervolt setup can be used to de-rate the alternator.
  • Mastervolt Alpha Pro has a ‘small engine’ feature where output is throttled back at low engine speeds to improve engine driveability but at a selected engine speed full power (or an adjustable percentage of full output) is unleashed. This is an awesome feature and fully enables the fast recharge ability of Lithium while protecting the engine and alternator.
  • The Alpha Pro’s small engine function is especially useful for Beta 43 & Beta 50 engines where uncontrolled high alternator loads below 1200 rpm increase the risk of the crank pulley issues associated with these engines.


The nominal current that an alternator is rated at isn’t the output that’s possible or you would want to achieve continuously. It’s really important that the system is setup based on how it performs when putting in gear at engine idle speed. There’s a balance between the achievable alternator output while maintaining smooth in-gear tickover, against not having a ridiculously high idle speed in neutral with no alternator load (when running engine after batteries are charged). And there’s various ways to limit current (and alternator load on engine at tickover): creating a controlled voltage drop using cable runs, Balmar MC-614, full Mastervolt kit, or using some of the Victron BMS’s.

For narrowboats already with a 3.5 Travel Power and a Victron 12/3000/120 Multiplus it’s possible to build a great simple setup. The Multicontrol AC current control should be dialled to put a limit on crank loads at tickover. For the Beta 43/50 in particular it’s important to have a sensible limit on crank load at low engine speeds & high alternator loads should be disabled while using the Travel Power.

I have the equipment to program and setup all of the Victron and Mastervolt kit.

Any queries or if you need this type of work doing please call Ed 07922 163072.