Peak Charge Acceptance: 165 amps for one minute

[Kwasham]

I know the LifePO4 battery posts are quite frequent on here but I have a question that I don't think has been addressed in depth. As part of the Mercury Bulletin 2022-19R1 one of the requirements is:

• Peak Charge Acceptance: 165A at 20-130 degrees F for one minute

When reviewing specs for LifePO4 cranking batteries very few of them actually show this as part of their specifications (Relion does but as I understand they are affiliated with Mercury). Another requirement on the bulletin is "Max Charge Alternator Size: 150A at 20-130 degrees F". It is common to see battery companies advertise "Max. Charge Current (Outboard Alternator)：150A" which I would interpret as meeting the Max Charge requirement.

Question: What is the difference between "Peak Charge Acceptance" and "Max Charge Alternator Size"? I called Mercury support and they don't know. I want to add a LifePO4 dual purpose battery to start my 150 Pro XS four stroke (2021), which is one of the approved motors, but need to understand the "Peak Charge Acceptance: 165A" requirement. Also, how many amps is the Pro XS 150hp capable of sending to a battery?

[yam911]

Mercury Marines website shows the alternator output of a Pro XS 150 as being 60 amperes. https://www.mercurymarine.com/us/en/...tem-af3b4df6d2

[yam911]

I am interpreting the Max Charge/Alternator size as the maximum that an alternator can output. 150 amperes in the case of the bulletin.

[yam911]

Can the supplier of the battery that you desire to use tell you that the battery meets all of Mercury Marines specifications?

[EuropeanAM]

Can the supplier of the battery that you desire to use tell you that the battery meets all of Mercury Marines specifications?

^^^^^ This is the take-away from the bulletin.

And the Max-Charge Alternator is critical: We have V8 engines out there with 115a Alternators (and that's ignoring the V10 and V12's outputs).

[Kwasham]

All suppliers I have reached out confirm that they meet or exceed Mercury's 2022-19R1 requirements and there are no issues using their batteries for my outboard. I can't find a clear answer from Mercury OR battery manufacturers on the "Peak Charge Acceptance: 165A" bullet point. I'm hoping someone on here who has a better understanding of the bulletin can explain it in layman's terms.

[yam911]

Google AI shows the Peak Charge Acceptance as referring to the maximum amount of electrical charge that a battery can absorb in a short period of time.

[yam911]

After reading more about "peak charge acceptance rate", my understanding is that it is the maximum amount of current that can be allowed to flow into a battery while the battery is being charged.

That is, in Mercury Marine's case, even if the alternator can output 200 amps, the BMS must be designed to limit the input current to 165 amps.

https://www.google.com/search?q=peak...hrome&ie=UTF-8

While it is nice to better understand how stuff works, I have found in my life that at some point I have to move on with a lesser understanding than I might like.

If Mercury Marine says they want X to be met, and the battery supplier is saying that X is met, that is good enough for me.

Take horse power for example. The parent of Mercury Marine, Brunswick Corporation, owns companies that make boats. Some of those boat makers may specify that a boat is rated for a maximum of Y horse power. Someone does not need to have a detailed understanding horse power. All they really need to know is to not exceed whatever the horse power rating is.

Good luck with your new lithium battery. Let us know how it works for you. I suspect that you will be pleased.

[Jbass123]

Very common sense below. Imo we see way too many posts on these forums of guys wanting to gain an engineer’s knowledge in 2 minutes on the internet. Some things it would be helpful for us to know, and some things it would help us to take at face value, because we’re never going to be able to utilize the answer/s sought, or at least it will not be advantageous in the real world for us to have that knowledge. I get a lot more done because I do not ponder “why the sky?”

After reading more about "peak charge acceptance rate", my understanding is that it is the maximum amount of current that can be allowed to flow into a battery while the battery is being charged.

That is, in Mercury Marine's case, even if the alternator can output 200 amps, the BMS must be designed to limit the input current to 165 amps.

https://www.google.com/search?q=peak...hrome&ie=UTF-8

While it is nice to better understand how stuff works, I have found in my life that at some point I have to move on with a lesser understanding than I might like.

If Mercury Marine says they want X to be met, and the battery supplier is saying that X is met, that is good enough for me.

Take horse power for example. The parent of Mercury Marine, Brunswick Corporation, owns companies that make boats. Some of those boat makers may specify that a boat is rated for a maximum of Y horse power. Someone does not need to have a detailed understanding horse power. All they really need to know is to not exceed whatever the horse power rating is.

Good luck with your new lithium battery. Let us know how it works for you. I suspect that you will be pleased.

[EuropeanAM]

"Max Charge Alternator" is pretty simple: The battery needs to be able to accept an extended output from the engine alternator at 150 amps.

If the battery is not capable of accepting a charge at that rating, from the engine, at any temperature between 20F and 130F, it does not meet the spec.

[Kwasham]

Thanks Yam, Jbass, and Eurpoean for your responses here. I have a better understanding of the subject now. Appreciate it.