An interesting read:

https://panbo.com/abyc-ratifies-e-13-their-first-lithium-battery-standard/?fbclid=IwAR3-AT-GbBo7rJfU2voilljCzyCLS679BumrVTByjt6Z27TciXrYO31Uy0I

 

With best regards,

 

Mark

 

Skipper

Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - Tahiti, French Polynesia

www.creampuff.us

 

Thanks for that Mark !
VERY interesting indeed, not so much the actual "standard" which appears to me to be full of holes, but the comments below the article, especially those from Bruce Schwab.
The single biggest issue still seems to be how to handle the potential sudden disconnect by the BMS when it detects an over charge or over temperature condition.
The comments about paralleling a FLA or AGM battery to deal with this, and the consequences if that battery should fail and draw huge currents from the Li bank....VERY intreresting.
Thanks again
Cheers

Alan
Elyse SM437

There is a good, albeit expensive, solution to many (but not all!) of the problems caused by a BMS sudden shut down.  Unfortunately, it can not be implemented with “drop in” batteries with an integral BMS.

If separate shut downs are provided for the charging sources from the loads a shut down can be a lot more graceful.  If the batteries are being overcharged, there is no reason to disconnect the loads.  Likewise, if the batteries are approaching the lower limit of the allowed state of charge, there is no reason to disconnect the charging sources. This complicates wiring a bit, needing a separate bus for loads and one for charging sources, but nothing too messy.

A BMS with a proper “pre shutdown” alarm circuit can turn off the field current to the alternator BEFORE the charging bus is disconnected. Another contribution to an elegant shutdown.

I am hoping that the existence of an approved and official ABYC standard (even an imperfect one) will help with the issues around insurance that have popped up from some underwriters.

Bill Kinney
SM160, Harmonie
Halifax Harbor, Grenada
http://www.cruisingconsulting.com

On Fri, Sep 30, 2022 at 05:27 PM, Alan Leslie wrote:

The comments about paralleling a FLA or AGM battery to deal with this, and the consequences if that battery should fail and draw huge currents from the Li bank.

Hi Alan,
That's why the use of Class T fuses is very important. 

Personally, I'm rather bemused by the current view that upgrading from Lead to LFP batteries is somehow dangerous because of the possibility of disconnection at an inappropriate time.  The simple solution to that problem (and a number of others) is a hybrid system using a AGM or GEL (Lead) battery permanently connected (and fused appropriately) in the system.  However it seems the use of lead batteries is somehow now deemed "too dangerous" in a boat.  It was the starting point for goodness sake!

Of course when we look at where the vested interests lie, maybe its not surprising that the proposed solutions involve the purchase and installation of more and more complex bus architectures and associated equipment. 

I previously had 13 lead acid batteries in my battery compartment, now I only have 3.  That's a lot less acid and potential hydrogen blow-off.
That makes me happy :-)
 
--
Dean Gillies
SV Stella *****,  Amel 54-154

Bill