Charging Batteries by Balmar Alternators

[SKM]

I have seen a few posts on charging batteries from the alternators, but I didn’t find any discussion on externally regulated alternators like Balmar. I am sharing what I have learned so far and my forward plan.  In my Trawler, the house batteries are charged by Shore power/Generator, Solar and Alternator.  I knew that Balmar alternators with MC-624 or MC-614 external regulators can be programed for Bulk, Absorption and Float voltage and duration to fine tune charging profile for LiFePo4 batteries.  However, I didn’t know how to safely disconnect charging in an HVD situation avoiding damage to the alternator. There is a work around using BTB (Victron or Renogy) which utilizes another battery (start battery) as a pass through and cushion.  This wasn’t ideal for me as my start batteries are fed by another smaller alternator.  After a bit of research and communication with Balmar, I now understand that the Balmar alternators can safely be turned off (in a HVD sItuation) by just disconnecting the + ignition ( brown) wire from the external regulator. So, I believe I can use one of the Ext IO as Type 1 (with SSR?) to switch off the ignition wire to the regulator.  Any comment or suggestion is welcomed.

[Dacian Todea]

LiFePO4 will only need bulk charging after that charging will need to be stopped as battery is full.  And alternators are just not designed to deal with battery being disconnected.

Thus people have a small starter battery Lead Acid and from there a battery to battery charger to charge the LiFePO4

Not sure that Balmar can handle being disconnected from battery but I guess you can try.  In any case charging from alternator should be avoided as it is so extremely expensive at around 50x more than charging from solar PV.

PV has cost amortization done for around 25 years but since alternator charging is 50x more expensive that means if you where to charge from alternator for half a year then cost will be the same as the cost of PV panels that where able to provide that same energy and from there PV panels will still last 25 years thus 50x cost difference is very extreme and this only considers the fuel cost not the alternator or other equipment.

[TheoW]

Yes, that's how I have my boat, and a number of others I know are wired using the Brown wire to stop the alternator charge.

I'd also recommend to use the Alt temp sensor if you're not already doing so.

Cheers,

ted

[Marinepower]

SKM,

not directly applicable to your 2 alternator set up - but take a look a Stan Honey's notes on integration of a BMS with a Balmar regulator.  

http://honeynav.com/lfp-battery/

[SKM]

Marinepower, thx for forwarding the link.  Interesting read.

[Marinepower]

BTW  - this is a bio on the author:  https://en.wikipedia.org/wiki/Stan_Honey