mcp 36 Posted August 16, 2020 Share Posted August 16, 2020 If you are interested in the size differences and electrical differences of lithium Iron Phosphate and Lead Acid AGM batteries, I have started to put my battery compartment together this weekend. On the left is a Vision FM100 AGM battery, 100ah @ 12v nominal, which is my start battery [currently running the fridge and lights] and on the right are 12 x 150ah LiFePo4 cells, 450ah @ 12v nominal. On the left the AGM weight is 32kgs and on the right the LiFePo4 pack weights all up 34kgs. On the left we have 30ah usable @ the recommended 30% depth of discharge and on the right we have 360ah usable @ the recommended 80% depth of discharge. On the left its costs $395 on the right $2800 [included in this price is $895nzd of shipping] On the left cost per usable ah = $13.16 and on the right cost per usable ah = $7.77 On the left lifespan/cycles 500-700 and on the right 3000-5000 [or more, but there's a caveat to this]. On the left charge efficiency 85-90% and on the right 98-99% 4 Quote Link to post Share on other sites
vesper1 3 Posted August 16, 2020 Share Posted August 16, 2020 That's so cool, I recently did a delivery on a yacht with lithium iron batteries and what astounded me was the rapidity of the recharge the yacht had electric auto helm and electric fridge and I definitely felt the lithium iron was a disruptive technology same as H. F. Radios are being displaced by Sat phones. Quote Link to post Share on other sites
CarpeDiem 538 Posted August 16, 2020 Share Posted August 16, 2020 9 minutes ago, mcp said: On the left cost per usable ah = $13.16 and on the right cost per usable ah = $7.77 Nice. What battery management system / charging solution are you using? Is that per ah cost inclusive of the BMS? Quote Link to post Share on other sites
Clipper 375 Posted August 17, 2020 Share Posted August 17, 2020 I'm very interested in this. Which brand, how are they managed, what charging system you use etc. And if all that's shipping cost, you obviously bought these overseas from somewhere, not local. Whereabouts? 1 Quote Link to post Share on other sites
MartinRF 76 Posted August 17, 2020 Share Posted August 17, 2020 Where did you get those efficiency numbers from? The reason for asking is I looked into this (for non-vehicle reasons) a few years ago and what I found then was not that high. /Martin Quote Link to post Share on other sites
Adrianp 137 Posted August 17, 2020 Share Posted August 17, 2020 Very interested in seeing the finished system and how you do it as this is on my to do list. There seem to be many many ways to approach this! One of my mates has just imported 900ah of Winston cells and REC BMS for a roll Royce system. Another has imported some other cells himself and is just starting the build. And another mate got a 400ah 24v system from Blue Cars on Waiheke, who seem to have pretty good pricing on cells they have in stock. https://bluecars.nz/shop/206ah-module/ My AGMs are dead so it's time to upgrade. All my chargers are Li ready too now so I really have no excuses. Quote Link to post Share on other sites
Island Time 1,313 Posted August 17, 2020 Share Posted August 17, 2020 If you are going to build your own banks, may I suggest that this is MUCH more difficult for you to get right than many believe. It can be done, but PLEASE tread carefully! It can also fail, sometimes spectacularly, and cost you your investment, your boat, or more. May I respectfully suggest that you START your reading here https://marinehowto.com/lifepo4-batteries-on-boats/ and do a lot of research before you commit. 1 Quote Link to post Share on other sites
Dtwo 157 Posted August 18, 2020 Share Posted August 18, 2020 And read this series of articles. This is quoted by many people as extremely useful in understanding Lithium technology. Quote Link to post Share on other sites
Adrianp 137 Posted August 18, 2020 Share Posted August 18, 2020 I've read that Marinehowto recently and there is very useful info contained within its poorly formatted and repetitive page! Worth the effort though. There is a interesting facebook page that is useful too: https://www.facebook.com/groups/427372107686109/ Quote Link to post Share on other sites
Dtwo 157 Posted August 19, 2020 Share Posted August 19, 2020 19 hours ago, Dtwo said: And read this series of articles. This is quoted by many people as extremely useful in understanding Lithium technology. Woops http://nordkyndesign.com/category/marine-engineering/electrical/lithium-battery-systems/ Quote Link to post Share on other sites
mcp 36 Posted August 23, 2020 Author Share Posted August 23, 2020 On 16/08/2020 at 9:10 PM, CarpeDiem said: Nice. What battery management system / charging solution are you using? Is that per ah cost inclusive of the BMS? I have a BMS that was less about $90 usd and the chargers I am using have a relay control. Quote Link to post Share on other sites
mcp 36 Posted August 23, 2020 Author Share Posted August 23, 2020 On 17/08/2020 at 12:51 PM, Clipper said: I'm very interested in this. Which brand, how are they managed, what charging system you use etc. And if all that's shipping cost, you obviously bought these overseas from somewhere, not local. Whereabouts? These are CATL cells, ex china. I will be using Victron MPPT chargers, Mastervolt smart reg. Quote Link to post Share on other sites
mcp 36 Posted August 23, 2020 Author Share Posted August 23, 2020 On 17/08/2020 at 5:54 PM, MartinRF said: Where did you get those efficiency numbers from? The reason for asking is I looked into this (for non-vehicle reasons) a few years ago and what I found then was not that high. /Martin Anyone that has charges this type of chemistry through a shunt with a coulomb counter can verify these are about 99% or more efficient. On 17/08/2020 at 10:52 PM, Island Time said: If you are going to build your own banks, may I suggest that this is MUCH more difficult for you to get right than many believe. It can be done, but PLEASE tread carefully! It can also fail, sometimes spectacularly, and cost you your investment, your boat, or more. May I respectfully suggest that you START your reading here https://marinehowto.com/lifepo4-batteries-on-boats/ and do a lot of research before you commit. This post was not intended to be a tutorial or a how to in any way. While these batteries are far far more forgiving than most people say, these are not drop in replacements and require a certain level of knowledge to set up and manage. These are not set and forget and certainly not she'll be right, I know what im doing setup. I saying all that, I'm not sure how you would loose your boat if these failed, you would certainly loose your pride and a large handful of cash. 1 Quote Link to post Share on other sites
Island Time 1,313 Posted August 23, 2020 Share Posted August 23, 2020 MCP, I agree these are much more stable than other forms of lithium batts, but things can still go wrong, sometimes badly. Here is an example (but not a boat) http://www.batteryvehiclesociety.org.uk/bvsorguk/forums/viewtopic.php?t=1825 Quote Link to post Share on other sites
MartinRF 76 Posted August 23, 2020 Share Posted August 23, 2020 3 hours ago, mcp said: Anyone that has charges this type of chemistry through a shunt with a coulomb counter can verify these are about 99% or more efficient. So the data is your own? /Martin Quote Link to post Share on other sites
mcp 36 Posted August 23, 2020 Author Share Posted August 23, 2020 38 minutes ago, Island Time said: MCP, I agree these are much more stable than other forms of lithium batts, but things can still go wrong, sometimes badly. Here is an example (but not a boat) http://www.batteryvehiclesociety.org.uk/bvsorguk/forums/viewtopic.php?t=1825 Hmmm, I suspect someone didn't fuse their wiring or some other act of stupidity near something combustible....or they actually had a cobalt/manganese variety of Lithium Ion, which has a electrolyte that is a hydrocarbon. The reason why companies like Tesla are moving to LiFePo4 are because they don't got into thermal run away and almost impossible to catch on fire. 4 minutes ago, MartinRF said: So the data is your own? /Martin Yes I can measure this? Is this what you are asking? You are being rather vague in my interpretation of your post sorry? Quote Link to post Share on other sites
2flit 52 Posted August 23, 2020 Share Posted August 23, 2020 28 minutes ago, mcp said: ....or they actually had a cobalt/manganese variety of Lithium Ion, which has a electrolyte that is a hydrocarbon. The reason why companies like Tesla are moving to LiFePo4 are because they don't got into thermal run away and almost impossible to catch on fire. I read thru about 1/2 the post. His batteries were LiFeP04 cells. These cells can overheat if mismanaged. Most Electric Vehicle LiFePO4 batteries are bottom balanced. The fire occurred when he was "Equalizing" so his charger was topping off. In this situation; a bottom balanced cell can certainly overheat and start a fire, it's a real issue and big problem, his BMS did not have temperature sensing. (and it's a bit scary that he used the word "equalizing"... not balancing Quote Link to post Share on other sites
MartinRF 76 Posted August 23, 2020 Share Posted August 23, 2020 8 hours ago, mcp said: Yes I can measure this? Is this what you are asking? You are being rather vague in my interpretation of your post sorry? I asked for the source of the efficiency figures appearing in your first post. That was all. /Martin Quote Link to post Share on other sites
Clipper 375 Posted August 23, 2020 Share Posted August 23, 2020 14 hours ago, mcp said: These are CATL cells, ex china. I will be using Victron MPPT chargers, Mastervolt smart reg. Cool, Thanks. Am upgrade from my single 130ahr lead acid battery has been on my mind for a while, but costs have been prohibitive with local suppliers, so keep us informed on how it all goes. Quote Link to post Share on other sites
idlerboat 116 Posted September 2, 2020 Share Posted September 2, 2020 Not to nit pick....but I can get a 200amp AGM for $335 retail.... That changes the dollar per usable for the AGMs to $5.58....... Commercially graded AGMs have a 20 year constant use design time. "Cycles" as such, is very hard to quantify. The actual percentage of discharge before a recharge event may be anywhere from a percentage of 1% to the full 30% (assuming that your system has a system regulator that wont allow it to discharge any further.) This of course is the same for any battery system in a boat. High end and proper charging for LiFePo4 should have a temperature sensor on every cell , they are very sensitive to charge irregularities... The biggest (and only ) advantage at the moment (and its a big advantage if you want to race or have a lighter displacement boat) is the weight savings. Quote Link to post Share on other sites
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