Charging lithium with stator system?

DIY
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1

I have a Suzuki DF140 outboard with a stator charging system.
Can I charge a LIFEpo4 lithium battery directly from my stator charging system (no lead acid battery for a buffer) by using the Orion-Tr Smart DC-DC
Non-Isolated Charger?
( Victron Energy Orion-Tr Smart DC to DC Charger (Bluetooth) - 12/12-Volt 30 amp 360-Watt - Battery Charger for Dual Battery Systems - Non-Isolated)

Or is there something like this that will allow me to do this? (I have heard that when the BMS shuts off, it will fry my stator unlike lead acid would).

2

You need to have a lead acid battery on the stator output to buffer the voltage control. People who have used Orion DC to DC direct from alternators report large voltage and current cycling.

Some companies sell alternator to battery chargers, these are more expensive as they need extra control circuitry. Victron do not sell these. I have no experience of these.

3

I’ve been using a Suzuki DF15A with light charger system to directly charge a 12V lithium pack.
The behavior of the Suzuki regulator is a little strange on the 15Hp outboard.
When there is no battery connected it will protect, giving ~2V output.
At Idle, it gives about 5A charge, at higher rpm this drops to 3.5A.
So, if your regulator behaves similarly, you would be able to charge the lithium battery through a BMS type protection switch, that will disconnect the charging in the event of a cell over voltage. This will cause the regulator to shut down, and produce little or no current. I would also test to see that no over-voltage spikes occur if the battery disconnects.

4

This isn’t the answer I was hoping for.
However, it is likely the correct one.
I was hoping to avoid having a crappy lead acid battery.

5

This makes sense. I would expect Suzuki, and others design their charging systems for their small outboards to run with or without a battery.

6

Hi Todd,
I find the voltage limits of 12V lithium are NORMALLY compatible with the regulated voltages usually used for charging Lead batteries. this assumes a max voltage of 14.4V - 3.6V per cell -this does give some margin.I would set this up with the lithium battery being charged by the outboard, with normal nav systems on, and see what the voltage rises to. If it looks like going over 14.40 then you can kill the engine before anything disconnects.

7

Does it have the 40A alternator? 30A will be too big you should look at the smaller ones you can’t adjust the charge current it just does 30A and that’s it. I have a Honda 130 with a 65A alternator and a 12/18. The current going in is around 21A. I imagine you would be around 35A in.

8

You might try a supercap instead

9

What is a “super cap”

10

They are large 16V caps in parallel with a small lithium.

11

Lithium is optional, in this case better without, as the charger has no real regulator

12

Yeah, they make them with a 20AH Lithium and a small BMS with a charge regulator. It’s the only way to do it. I nearly bought one but stayed with lead acid for crank and house.

1 Like
13

That’s pretty neat. However, I don’t see how this would protect my STATOR charging system.

14

The BMS in the lithium is really small and charge current limited. Demand on the alternator is very small. They look pretty good but I have a big boat so staying with lead will not save a lot of weight. A hybrid like this is the best option for cranking lithium.

15

That makes sense. Thanks!

16

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