LiFePO4 batteries

[snailor]

We replaced our three 8D Lifelines with three Relion 8D LiFePO4s two years ago.  We've kept our two Lifeline 4D AGMs for our starting/backup house bank.  It was a little bumpy at first and it took me a while to zero in on something approaching optimal settings for all of our charging sources.  I probably had the most trouble getting our Victron MPPT controller to cooperate followed by several rounds of adjustments to our Balmar MC-614 regulator.  I also replaced our main charger/inverter with a Victron 2,000 watt model that's supposedly smart enough to deliver the right charging profile for lithium Batteries.  We still use our other three chargers in parallel using their AGM settings and this seems to work just fine.

In our experience the lithium batteries work well with AGM settings but we've managed to optimize settings in equipment having that capability.  I think Relion recommends a charging voltage for their 8D of around 14.2V but I think its okay to go up as high as 14.6V - similar to AGMs.  However they also recommend holding charging current to 50A.  Since we have two banks 1X8D (300AH) and 2x8D (600AH) we runup to as much as 80-90 amps and see no distress in either bank. We wish we had room to even up the two banks with 2X8D each but alas the first bank only has physical space for 1 8D and 1 4D. 

Our main house alternator is a Balmar 210 amp controlled by the MC-614 regulator equipped with both alternator and battery temperature sensing.  We monitor the two banks through two Xantrex LinkPROs and a Victron monitor as well.  These have alarms set should the battery or alternator temperatures rise above the recommended 60 degree C limit.  At the moment we've limited the charge levels using the internal settings (which escape me at the moment).  I think we can go higher but I sometimes worry how hot the alternator getting hot in warm weather while charging at full capacity.  In any case we find we can run the batteries down to 50% and be back up to near capacity  in a couple of hours of motoring.  We occasionally run them even lower than 50 percent but old habits die hard and I think even ReLion does indicate the cycle life is shortened by deeper discharges.  Nevertheless, these things are supposed to go 5-6,000 cycles through deep discharge so they'll probably outlast me.

One other thing I did was to install an echo charger from one of the house batteries over to the AGM bank to provide a load to the alternator at all times - even if the internal BMS in the lithiums disconnects them from the alternator.  This is a safety measure to prevent blowing the diodes out of the alternator if that ever happens.  It also keeps the starting bank fully charged. So far we've never seen high charging temperatures or signs of overcharging with our system.  Overall we're pretty satisfied with the performance of the new batteries. One thing I like is these lithiums can discharge pretty far without experiencing much of a voltage drop.  They also have low internal resistance and therefore charge much faster that we were able to achieve with the AGMs.

If I had any advice it might be to stick with one manufacturer for as much of the system as possible.  It would make the programming and integration simpler and easier to follow.

[jt11791]

I just took the plunge and replaced our six 8D AGM batteries with four ReLion LiFePos.  I had to hire some yard guys to remove the heavy AGMs, but otherwise I did the work myself.  It was close to a "drop in" replacement.  I changed the charging profiles on my inverter/charger, alternator regulator, and solar controllers, but made no other changes.  My main concern is that my batteries are scattered around the boat and the cable lengths are all different.  I'm told this may be a problem as the batteries will see slightly different charging voltage, but I will monitor closely and time will tell if I need to make further changes. 

Here's the best part:  6 AGM @150lbs each = 900lbs  while  4 LiFePo @75lbs each = 300lbs.
And:  6 AGM @50%DOD = 750aH usable capacity while 4 LiFePo @80%DOD = 960aH usable capacity.

Anyone else make the conversion?  Share your experiences here and we'll build up some group knowledge.

[snailor]

We replaced our 3 Lifeline 8D AGMs with 2 LiPO4 300 AH Relion 8Ds and have kept rolling with the same chargers and settings on our charging system for our H-46.  They told us the AGM settings should work fine with the Li batteries and so far they have.  I watch my voltages and battery temperatures pretty closely but they tell me the BMS in these are pretty sophisticated and are programed to shut down at the first sign of trouble. Ask me again in a year and I'll be able to tell you if it all really works out. Brace yourself for the cost though.

[CabezonBD]

Yep, I saw the new ad for the Trojans. Yes, the technology is changing fast. I see the advantages of the new Li(xxxx) batteries as almost the Holy Grail. If installed properly, they should be 10 year batteries with very little maintenance. The power advantages of them are astounding for every aspect of being a live a board.

[joel]

FYI, Trojan is coming out with 'drop in' batteries with built in BMS under the Trillium label.

Hard to plan ahead when the tech is evolving as we speak.

[CabezonBD]

Unfortunately I have new flooded golf cart batteries ordered. I couldn’t afford to make the plunge at the moment to LiFePO4 batteries considering I need to change my charging system. I have 5 different sources of charging. I will change them over the next 18-24 months with the intention of going to Lithium batteries. I plan to convert from 900 ah (configured 225ah in 4 separate locations) of flooded cells to 500 ah of lithium(try to stay with same 4 locations- 4 house batteries and 1starter battery) I am looking for suggestions on specific chargers, solar and wind gen controllers, inverter/chargers, and how to program my alternator system(160a Balmar & 65a Yanmar standard alternator) with 1 - Balmar Mc-612 regulator. Boat is a 2006 Hylas 49 if there are other Hylas owners who have switched, I’d love to hear how they kept the use of the “Tie Switch” on the Boat.