There’s a lot to like about it, especially an iOS app to actually program it with.
The FAQs (I hate FAQs) don’t make it very clear when and where the Zeus is compatible.
There are internally regulated… and externally regulated alternators…
Can I use it with my existing alternator? Yes…
Would I need to add the $200 Balmar external conversion kit to get my alternator to work with the Zeus? That would end up being nearly double the price of the Balmar 618 conversion kit with harness and temperature. I could probably find someone with an Android to help me program the Balmar.
The Zeus, Wakespeed, and Balmar 618 all have one thing in common, they
only work on externally regulated alternators. Regulators work by varying the field current to control the alternator's output. The alternator can't have 2 different controls trying to control it. In your initial post you said you have a Valeo alternator that is not externally regulated. Thus, in order to use any of these regulators it would be necessary to either to convert your existing regulator to external regulation or acquire a new externally regulated alternator.
It would also be worth considering changing the belt system to a serpentine belt system. The upper limit for a standard v-belt is about 100a of alternator output. Your current alternator is right at that limit. Changing to a serpentine belt will make the alternator more efficient and reduce belt wear due to slippage.
This thread is getting a little long, so it is hard to remember all the details, so I may be redundant. First, there is no cheap way to convert to LFP batteries. On the output side of the system, the conversion is pretty straightforward and simple, connect the battery to a Class T fuse and then to the system. It is the charging side that gets expensive and touchy. There are 2 charging routes, direct to LFP or to a LA battery and then charge the LA from the LA battery.
For direct to LFP battery charging you need:
- Externally regulated Alternator
- External regulator programable for LFP batteries and temperature compensation
- A method for charging the start battery (FET or DC to DC charger)
- A monitoring system
For LA to LFP charging you need:
- A DC to DC charger
- A monitoring system
(Note: there will undoubtedly be some other bits and pieces needed for the install, like new cabling, however, those are very boat specific and depends on what's already installed. Also, this does not include shore power charging.)
On first glance, it would seem the LA to LFP charging path would be simplest and easiest way to go, looks can be deceiving. The LA to LFP system sacrifices one of the biggest advantages of LFP batteries, a high charge acceptance rate, that's important because a high charge acceptance rate reduces engine runtime for battery charging. Consider, a 100ah AGM battery takes around 5.5 hours to reach 100% SOC from 50% SOC, it takes that long to restore just 50 ah of capacity to the battery at a .4C charge rate (40a). Apply that 40 a charging current to a 100ah LFP battery at 50% SOC and the battery will reach 100% in a little over an hour. Compare that to an externally regulated alternator with 100a out put and the battery is recharged in just 30 minutes, saving 5 hours of engine operation.
The apparent economy of the LA to LFP charging route begins to erode when the costs are considered. There are limited choices in DC to DC chargers, essentially Victron, Mastervolt, and Sterling. For any of these products expect to pay around $700-800 to achieve 50a DC to DC charging. It is possible to buy smaller less expensive DC-DC chargers, however, that will increase charging time. Depending on the alternator, it may not be able to supply adequate current for enough time to really justify the cost of a large DC-DC charger. The ~&500 difference between a Victron 18a DC-DC charger (adequate for LFP to LA charging) and a higher capacity charger, that $500 could be better spent on a new regulator and alternator.
There are 2 cases in which the LA to LFP route make some sense. If the boat is frequently at a marina and on shore power or as part of a multi-seaon upgrade plan. In the first case, LFP's benefit of lots of useable capacity in a small light package may be the goal. Weekend cruisers and racers would find this advantageous. In the second case, those of us on more limited budgets may find it easier to finance and to sell the conversion to the family's CFO.