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jeanmar avatar image
jeanmar asked

OUTBOARD ENGINE STARTING SETUP BMS 12-200, ALTERNATOR AND SYSTEM+ PORT BRIDGED

dear fellow boaters and engineers

Here is what I asked Victron and would like detailed professional answer based on the facts and data....

Dear Victron

Please forward my question to your experienced engineers.

I am a power electronic engineer. I have been working with the boat and Yacht industry for over 25 years. Last few years small boats with and outboard engine started putting Lifepo4 batteries mainly because of anchor lock mini electric engines (like Minkota, Garmin, Haswing etc)


I want to make a workable setup by starting outboard with your 330Ah battery that has a peak of 400A. That current is sufficient for the vast majority of small outboard engines.

I know that starting an outboard with Lifepo4 battery is not recommended but here we talk ONLY about your biggest 330Ah battery and setup that can work with it.


Will you please carefully look at my proposed setup and answer the basic question:

CAN ALTERNATOR PORT OF BMS 12-200 BE BRIDGED WITH SYSTEM+ PORT?


As the current direction of the system+ port is OUTward I presume that there will be no negative consequences of this setup? After the outboard has started it will continue to charge the battery through the alternator port?


If this setup proves functional I am sure your sale of 330Ah batteries will skyrocket along with BMS 12-200.


Please respond with the highest quality answers.


Thank you very much


Looking forward hearing you


very best regards


Jean Maro

bms-12-200-yamaha-f115-outboard-boat-setup.jpg


setup
bms-12-200-yamaha-f115-outboard-boat-setup.jpg (573.6 KiB)
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klim8skeptic avatar image klim8skeptic ♦ commented ·

@JeanMar Not much can go wrong with that ^. WRONG!

Bypassing features of the BMS by connecting the alternator and load output ports together. Eg charge current limiting.

Grossly overloading the BMS load output every time you start the engine.

No battery connected to the alternator results in rectified AC output. Probably not good for the BMS, or alternator output regulation. Also should the BMS disconnect, the voltage spike will probably damage the alternator and any DC loads connected.

Legal liability. Should the modified BMS / battery fail to start the engine when required, or burst into flames. Using products off label is bad enough, bypassing features is criminally liable.


There are drop in Lithium starter batteries available. Less risky than what you have proposed.

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1 Answer
Justin Cook avatar image
Justin Cook answered ·

"CAN ALTERNATOR PORT OF BMS 12-200 BE BRIDGED WITH SYSTEM+ PORT?"

No.

Per the user and installation manual, and all laws of physics and safety. Please consult a reputable and experienced marine systems installer to further discuss your system and design needs before you potentially cause system/component failure that would be unwarrantable and thus possibly thousands of dollars of your own hard-earned money lost in the best case, or fire/property damage/injury up to and including loss of life in the worst case.

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