LFP Battery Install, or Argh! ...More Fuses!

Nov 21, 2007
642
Beneteau Oceanis 34 Kingston, WA
I posted my original question about whether it would be worth upgrading to LiFePO4 batteries last November Mid LiFePO4 Cruisers. Finally, in about post #70, I posted about what I thought would be my preferred choice for battery brand, capacity, additional components, and budget. I thought that I should post a follow up to that thread, to let you know that the new batteries are now IN!

I haven’t had the chance to put them to the test away from home, yet. But, so far, everything appears to be working normally. I have had no alarms or notifications of problems with any of the batteries or components, and they have been in place and powering what few devices have needed current for two weeks. Their biggest draw, so far, was powering my domestic water pump for the spring recommissioning of my two 34 gallon fresh water tanks. I am also occasionally powering on a specific components, one at a time (like Navigation/chart plotter or my heater), and then watching the current value from the Victron SmartShunt to see what it draws.

First, let’s get to the social media acceptable proof (pictures or it didn’t happen)…

The before house bank was 2 FLA G31 located in engine compartment, and the start battery was a single FLA G24 located in the aft berth next to engine compartment;
Batteries - 1.jpeg Batteries - 2.jpeg

The after now has the FLA G24 start battery alone in front of the engine, and house battery bank comprised of 3 Epoch 105 AH LfFePO4 battery packs located inside the base of the aft berth.
Batteries - 3.jpeg Batteries - 4.jpeg

Here’s what I upgraded
I’m really glad that I managed to limit the scope of this project! With a starting budget (from the previous post) of $1220 - $1600, I wanted to install an additional 200 AH of capacity to the house battery bank, plus a DC - DC charger to install between my start battery and the new LFP bank, and a smart shunt to add some monitoring capabilities.

Preliminarily, I have spent have now spent a little over $2,000. Approximately $1500 on the batteries, SmartShunt and Orion charger, plus more than $500 on new battery cables and fuses! I did not have a proper understanding of what cables I would need to relocate the start battery, or the total cost of all of the new fuses (and spares!) that I needed. While I’m not pleased at missing the boat (Ha!) on the additional details, I am pleased that I didn’t just let myself continue to purchase big items like an inverter/charger just because I found a sale on batteries.

My significant purchases were;
  • Three Epoch 12V/105 AH LiFePO4 batteries at ($339/ea.) $1186 using a Black Friday discount code, last December. This total price also included a 12V 15A AC charger for the batteries.
  • Victron SmartShunt Bluetooth battery monitor $130
  • Victron Orion XS 50A DC-DC charger $358 ($101 above the original budget for a 30A DC-DC)
Other purchases;
  • Class T fuse and fuse block for the house bank
  • 2 ANL fuses for DC-DC charger
  • One additional pair of 2/0 parallel cables for house bank
  • 2 new 2/0 cables for relocated start battery
  • New MRBF terminal fuse block and fuses for start battery
  • Miscellaneous hardware and fasteners for securing and screwing things up
In its current configuration, I have the house battery bank being charged by my shore power charger, my Victron MPPT solar charge controller, and the Victron Orion XS DC-DC charger. The (still FLA) start battery is being charged only by the engine alternator. I will likely replace the start battery with an AGM when I find a decent sale on one.

It was a tight fit! I measured, and was confident that the three new LFP batteries would fit into their new space. But, what I didn’t understand was how much space would be required for some of the other pieces. I seriously underestimated the size of the new class T fuse block. And, the photos of other installations that I have seen must have been in a completely open space, with nothing else in the picture to provide relative scale. It took a lot of time and physical contortions to complete the relocation of my start battery and solar controller, and to install the new fuse blocks and wiring. But ultimately, everything fit where I wanted it to be, and I can’t wait to see how the upgrades perform away from the marina!

Thanks, to everyone, who posted on the original thread and helped me with information, education, and tips! And, thanks to @mainesail, for always being in the right place, with the right information, at the right time! Your Amazon storefront is the first site that I’ll visit as I continue with my upgrades!
Batteries - 5.jpeg
 
May 17, 2004
5,150
Beneteau Oceanis 37 Havre de Grace
Thanks for the report! The AGM bank in our 37 reached end of life a couple seasons ago and we went with direct replacement. Next time we might switch to lithium too, so it’s good to hear how it fits in the 34.
 
  • Like
Likes: jssailem
Nov 6, 2020
132
Mariner 36 California
Nice clean installation. Watch the temps on that Sterling charger. It looks a little suffocated. Sterling has a remote monitor for that charger that can show you the charger temperature while running. I have an Epoch 300Ah battery and am extremely happy with it. Good choice.
 

Johann

.
Jun 3, 2004
428
Leopard 39 Pensacola
Very nice installation. I‘m on year four of our LFP install and I have a couple of suggestions. First on the Sterling shore charger. I looked at its LFP voltage settings and they are way too high for me. I would set a custom profile with the “high charge“ voltage of 14.0V-14.2V and a ”float” and “maintenance“ voltage of 13.25V-13.4V. If you use less than 13.4V for float/maintenance it will drop the SOC below 90% so before you depart the dock restart a charge sequence by power cycling the Sterling.

If at the dock long term set the MPPT at absorption and float of 13.1V-13.4V to prevent the MPPT from daily overcharging the LFP.

Change the SmartShunt “Charged voltage“ to 14.0V. The default low value leads to false synchronization to 100%. Also be sure to set up the Victron smart network and connect the shunt, MPPT, and Orion.
 
  • Like
Likes: SoSound
Nov 21, 2007
642
Beneteau Oceanis 34 Kingston, WA
...Watch the temps on that Sterling charger. It looks a little suffocated.
It's definitely suffocated, I will keep watch over the temps for it and for the Orion XS nearby. Luckily, the water temperature in this area keeps things in enclosed spaces in our boat pretty cool.

First on the Sterling shore charger. I looked at its LFP voltage settings and they are way too high for me. I would set a custom profile with the “high charge“ voltage of 14.0V-14.2V and a ”float” and “maintenance“ voltage of 13.25V-13.4V. If you use less than 13.4V for float/maintenance it will drop the SOC below 90% so before you depart the dock restart a charge sequence by power cycling the Sterling.

If at the dock long term set the MPPT at absorption and float of 13.1V-13.4V to prevent the MPPT from daily overcharging the LFP.

Change the SmartShunt “Charged voltage“ to 14.0V. The default low value leads to false synchronization to 100%. Also be sure to set up the Victron smart network and connect the shunt, MPPT, and Orion.
I have set the Sterling to a Custom charge profile. After reviewing a long thread on the Epoch support FB group, I'm using 13.95V for my high charge voltage. I think I'm using 13.4V for absorption and float, but I don't have my notes here, and I didn't screenshot any of the three charging devices when I programmed them. I'll also check the SmartShunt to see if I have updated the setting for Charged Voltage.
 
Jan 11, 2014
11,639
Sabre 362 113 Fair Haven, NY
I have set the Sterling to a Custom charge profile. After reviewing a long thread on the Epoch support FB group, I'm using 13.95V for my high charge voltage. I think I'm using 13.4V for absorption and float, but I don't have my notes here, and I didn't screenshot any of the three charging devices when I programmed them. I'll also check the SmartShunt to see if I have updated the setting for Charged Voltage.
Panbo.com just published an article on charging Epoch batteries (and by extension most LFPs) and recommends reducing the absorption voltage to 13.8 or 13.9 which is lower than the usual 14.1v recommendation. Apparently long charging periods at high voltages causes dendrite formation which shortens the batteries life.

Stein also noted some BMS's will time limit the charge when charging at a higher voltage. I've noticed that on my single Kilovault LFP. The BMS will shut down the charger after an hour regardless of the SOC. In my case the charger is set at 14.2v and it is a 50a charger. I suspect the BMS is monitoring its own temperature and that is causing the shutdown. When I use the Orion 18a charger the BMS allows charging to 100% SOC. Currently only one of three batteries connected to the large charger with charge rate at ~.45C with all 3 batteries installed the charge rate will drop to about .17C which is consistent with the 18a charger. I'll be reprogramming my charger to a lower voltage.


 
  • Like
Likes: SoSound

Johann

.
Jun 3, 2004
428
Leopard 39 Pensacola
I have set the Sterling to a Custom charge profile. After reviewing a long thread on the Epoch support FB group, I'm using 13.95V for my high charge voltage. I think I'm using 13.4V for absorption and float, but I don't have my notes here, and I didn't screenshot any of the three charging devices when I programmed them. I'll also check the SmartShunt to see if I have updated the setting for Charged Voltage.
Even better. I have a 48V 100Ah Epoch on the way as part of my Genset replacement scheme and my plan is to use an absorption charge voltage of 55.4V, which equates to 13.85V in the 12V world. With my 12V LFP bank I use 13.8V for shore charging and float at 13.25V when we‘re aboard. The Multiplus won’t allow an absorption time less than 1 hour so I’m using the lower 13.8V to mitigate any overcharging. When off grid I have the MPPTs set at 14.2V absorption since you can set a shorter time, or a tail current to exit to float.

With your 13.95V absorption you may want to set the Shunt “Charged voltage“ to 13.85V.

This is a pretty good site for some technical aspects of LFP.
 
Nov 6, 2020
132
Mariner 36 California
Even better. I have a 48V 100Ah Epoch on the way as part of my Genset replacement scheme and my plan is to use an absorption charge voltage of 55.4V, which equates to 13.85V in the 12V world. With my 12V LFP bank I use 13.8V for shore charging and float at 13.25V when we‘re aboard. The Multiplus won’t allow an absorption time less than 1 hour so I’m using the lower 13.8V to mitigate any overcharging. When off grid I have the MPPTs set at 14.2V absorption since you can set a shorter time, or a tail current to exit to float.

With your 13.95V absorption you may want to set the Shunt “Charged voltage“ to 13.85V.

This is a pretty good site for some technical aspects of LFP.
That absorption time is probably perfect though. I have a 300Ah Epoch battery and bulk and absorb to 13.8 also. When the cells hit 3.45v each I absorb for one hour and its at 99-100% SOC.
 
  • Like
Likes: Johann