Outboard Motor Suzuki 250 Stealth and Lithium Batteries

Q&A and troubleshooting
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1

I have just put money down on a new 2025 Suzuki 250 motor. The motor is going on an old Champion 203 which is currently heavy in the rear end due to all the batteries. My effort was to install Lithium trolling batteries (3- 12V 100AH batteries for trolling) (1 12V 140AH dual use cranking battery) I have been informed by my dealer that Suzuki does not like Lithium batteries so I am trying to do due diligence to find a way to protect the ECU and the BMS. I am open to any suggestions any of you might have in regards to the best way to do this. If I cant and need to go with a traditional lead acid or AGM battery then I will do that. I read on some forums that this manufacturer had a product that would do this. I would appreciate any input you may have.

Thanks,

David

2

To protect the alternator, it’s best to use a small AGM battery directly connected to the engine.Then to charge the lithium’s via a dc/dc converter. This will prevent any overcharge to the lithium batteries causing problems - typically if an alternator looses the battery when running fast, it will blow the regulator in the alternator.This can happen if a lithium BMS disconnects on overvoltage. IF you are sure that the output voltage from the alternator will never exceed the maximum voltage for the lithium’s BMS, then a direct connection may be possible.