I think I have read enough threads on this topic to make me a new mainsail
though admit I have not read the entirety of this particular thread....
I have an older 30' racer cruiser
that I recently acquired, that is in need of an electrical
update. The 100 amp house battery needs replacing, the regulator
should have gone to the scrap heap along time ago, and the alternator
is showing signs of age. I have a single
bus bar and separate on/off switches for start, house and combine. I don't use lots of current, and only use one charging source - the alternator
. I'm not doing extended blue water
trips, just shorter coastal stuff.
Taking the LiFePo4
path is appealing if it can be kept relatively simple which I would like to think is doable in my situation. Here's what I am considering:
- Keep my existing lead-acid start battery for now
- Replace the house battery with a 50amp "drop-in" style LiFePo4
- for example Smart Battery's product.
- Keep using my existing 60 amp alternator until it needs replacing
- Using a Balmar
programmed to some yet to be determined voltage below 13.9
- Victron BMV 700 monitor for the house battery
- Keep the existing single
bar set-up - cuz that's what's there.
While I think I understand the concerns with the "drop-in" batteries, with my small system needs, seems like using one makes sense? BMS and HV/LV is built in, and the MC 614 regulator gives an added layer of protection with the battery and alternator temperature sensors and programmable lower charging voltage.
I was considering the BMV-702 to allow for swapping the start battery to LiFePo4 as well at some point, but not sure if there is much advantage in this. Also, I think the lead-acid start battery provides additional protection to the alternator if for some reason the HV cut-off on the house battery is triggered. I still might go with the 702 to allow for more flexibility in the future though.
When running the motor
, the "both" switch would be on, so charge current would go to both batteries. I think this is ok at some yet to be determined voltage? and this gives a place for the current in case the HV cut-off on the house battery gets triggered. It is relatively easy for me to take the start battery home and leave it on a good multi-stage charger
overnight every month or so to avoid undercharging damage.
For me KISS = keep it small