Originally Posted by familycruisers
100ah of storage means 80 ah of usable storage so opposed to 50 ah.
A more fair comparison would be the real usable capacity of LA batteries is about 30-35% or 50% SOC to 80-85% SOC due to acceptance current limiting.
Unless you are at a dock
every day when you can "full charge" your LA batts then you're likely not starting out at 100% SOC where you would have 50% usable capacity.
On day two away from the dock
your real usable capacity becomes about 30-35% because charging beyond 80-85% SOC becomes a time consuming waste of fuel
With LiFePO4 you can charge right back to about 99% before the batteries begin "limiting" current or you've achieved a charging voltage that just won't push any more current into the bank. With LA batts this limiting can start as low as 70% SOC and as high as 90% for some AGM's. The last few % take hours and hours and hours....
I think it is important to ask a few questions before installing LiFePO4:
1- How am I going to charge the bank? Can my battery charger be custom programmed (most can not)?
2- How am I going to charge my bank via alternator? Do I have an external regulator
that allows for full customization of the charging voltages?
3- Are my solar
controllers able to be fully customized for charging LiFePO4?
4- How do I plan to terminate charging when the bank is full?
5- Can I live without an alt sensed tachometer when the alternator charges the bank to full
then cuts the field?
6- Can my alternator and belt system handle the massive current suck from LiFePO4, most can not?
7- What will I use to keep my alternator from melting down? Do I have temp sensing of the alternator?
8- Do my solar
, battery chargers or alt regulators have the ability to 100% disable temperature compensated charging (especially if "ambient sensed")?
9- How will I initially balance my pack? Do I have a bench top power supply to do so?
10- How will I keep my cells balanced?
11- What BMS system will I employ (it's looking like a BMS will be a "minimum" requirement)?
12- How will I terminate the alt regulator
when the bank is full or an high voltage event (HVE) occurs? Regulator power feed cut, field cut etc. Balmar
recommends a B+/power cut for the regulator power wire.
13- How will I terminate the solar or wind controllers in a HVE? Can my controller be "open circuited" without harm?
14- How will I terminate a shore charger in an HVE? What relay will I use?
15- What will I use for bank over current protection?
16- If a charge management device was used previously to keep "two banks" charged how will I now charge the second bank?
17- How will I "band" the cells.
18- How will I monitor cell level voltage?
19- How will I keep track or % of charge or "capacity"?
20- How am I protected against a low voltage event (LVE) situation? What relay/contactor am I using to disconnect the loads?
21- Will I employ a dual bus system, as in a charging bus and load bus??
There are many more that perhaps others will add, gotta run...