hlpdata DIY bms

[dawnthreader]

Hi,

First post here for me.
I have a boat with a 12v 3*92ah AGM house battery bank, a 100w solar panel with charge controller and an attached 1500w inverter.
(2 diesel engines with 60 amp alternators)

I am thinking of switching to a lifepo4 system instead.
One of the concerns is to not overheat the generators when charing the batteries.
for that this BMS seems to offer a simple (and cheap) solution http://hlpdata.se/index.php/en/

i could not find it mentioned anywhere in these forums.
* Does anyone have experiences with this particular BMS ?
* Anyone with experience with controlling the alternator via the voltage sense cable ?

thanks for any input!

 

[solarbot]

Hi, this is my first post on the forum. Caveat: not an electrical engineer; only an amateur marine engineer; am a software engineer; am learning solar power engineering from the net and especially this forum. I will jump because the deafening silence suggests that either nobody on the forum has that particular experience, or someone does but did not notice your post. So, bump.

Have you seen this? https://shop.pkys.com/Alternator-Lithium-Battery.html

Lots of food for thought. One big point: lithium battery systems are prone to sudden disconnect, another sword of Damocles hanging over the head of your alternator. You solution needs to address both over-current and voltage spikes.

Maybe consider keeping one of your AGM batteries in your system as a low tech way to soften the disconnect blow, and also to avoid ending up dead in the water due to low voltage disconnect, should you live in a part of the world that presents that problem. Not the whole answer by any means, but perhaps an easy way to soften the hard edges off this problem.

I am currently working on my own, 48 volt system design, which includes a 12 volt subsystem. I will use an old school flooded lead acid battery on the 12 volt side. The low voltage disconnect issue made up my mind on this question. My alternator will thus be charging the lead acid battery and everything on the 12 volt side stays pretty much as is. At least, I expect to reduce the size of my 12v bank by drawing power from the 48v side. Also an interesting subject, for later.