270ah DIY LiFePO4 build

[Zing]

That's a lot of blue. I think Stephanie is considerably better endowed in the wonga department than me. Looking forward to part 2 though.

Sponsored maybe? Those Victron lithiums (like Mastervolt) are ridiculously overpriced.

 

[vas]

Sponsored maybe? Those Victron lithiums (like Mastervolt) are ridiculously overpriced.

sit back and wait, wont be like that for long I guess!
Useful writeup no mater what though, bookmarked to check before the 2023 season starts (I guess that's when I'll be considering to replace my Trojans)

 

[Poey50]

Sponsored maybe? Those Victron lithiums (like Mastervolt) are ridiculously overpriced.

Victron lithium kit is expensive and of course you can't easily cherry pick the various components of a Victron LFP system (other than the chargers). But they have found a market and developed excellent integrated systems. I have far more respect for them than companies trying to flog off 'drop-in-replacement' LFP batteries through misleading advertising.

 

[gregcope]

I wonder how much all that Victron kit cost ...

I be fair I am a Victron customer. I think their kit is on the whole well made. I like their bluetooth app.

 

[Poey50]

Update:

After 8 days of electrical work over four weekends the new LFP system aboard our Sadler 32 is now installed, working, and ready for sea trials. Incidentally, I have now dispensed with the perspex cover. There are heat sinks on the boards which generate a fair amount of heat when top balancing. The perspex rested on these and stopped the heat dissipating so easily. The ordinary plywood battery box cover provides sufficient protection and there is no routine reason to go into the battery box.

One surprising thing from lead acid mentality is how entrenched the idea of getting batteries back to full charge becomes. The opposite is true of LFP - ensuring they are not left at full charge. To that end I decided to fit an isolating switch between the new Balmar 100 amp alternator and the MC614 external regulator so I could run the engine without charging the battery. Balmar offer no advice on this and a search on the forums offered (as usual) a variety of 'expert' opinions with some favouring the blue field wire, some the brown ignition wire and some the red power wire. If anyone is in a similar quandary - the blue wire is completely wrong (it can cause a voltage spike), the ignition wire is probably OK, but the red wire is the one to choose (according to Rod Collins of Marine How To) and is designed for safe shut down and restart.

The other modification to the Balmar instructions (again via Rod Collins) is to have both the positive sense wire and the negative of the MC614 to be wired direct to the battery rather than the alternator to avoid voltage drop, accurate voltage sensing being even more important for LFP charging than lead acid.

I also included a small programmable voltage sensing relay in the same red wire, set to stop charging at 14.0 volts and restart at 13.8 volts. This is a further line of defence in case of external regulator failure. This is a German make with no English instructions which made for a happy couple of hours on Google translate.

V-Guard II – programmable battery monitor 12V and 24V, with LCD: Amazon.co.uk: Car & Motorbike

 

[nfluester]

loving this, just had conformation my Lifepo4 cells are on there way from China so will be joining you on your journey ?❤

 

[Poey50]

loving this, just had conformation my Lifepo4 cells are on there way from China so will be joining you on your journey ?❤

Well done! I hope you will post on plans and progress.

 

[Mikedefieslife]

I saw on facebook there was concern of RJ Energy shipping out used or B rated cells with the cell QR scratched out.

I was concerned about mine considering they had a scratch or two on a terminal here and there, and a different colour cell wrapping on one of them. The original etched QR codes are all intact though.

 

[nfluester]

I will ? hoping to put the hole thing on my Youtube channel.

re the balmar i have purchased the balmar 614 in readiness, im guessing our usage and setup is a little different to yours as we are a motor boat on the thames and generally we go out most weekends and for a few weeks over the summer. my plan was to have the Balmar's absorption and float voltages to say 3.5v / 3.6v so whilst we are using the boat we have a reasonable State of charge we can make use of whilst we are away and then set our shore power charger to absorb and float at 3.2 / 3.3v we leave the fridges on all the time so whilst we are not using the boat they will discharge to a comfortable storage voltage.

i am in a quandary as to which BMS to choose

 

[Poey50]

I saw on facebook there was concern of RJ Energy shipping out used or B rated cells with the cell QR scratched out.

I was concerned about mine considering they had a scratch or two on a terminal here and there, and a different colour cell wrapping on one of them. The original etched QR codes are all intact though.

As said at the bottom of #2 I've no great confidence that these cells are new, grade A or that the certificates that R J Energy have on their website are genuine or that he represents a real factory. They may be but I'm not confident. This is why it is important, in my opinion, to do a proper capacity test straight after a top-balance. If the pack capacity is correct then the cells are well enough matched and the individual cell capacity is true. The biggest purchaser of these cells that I have come across is 'Ghostwriter on the DIY Solar forum. She has been importing from Carl for years and capacity tests every batch. I know at least two occasions where the warranty was honoured without questions and cells exchanged. Worst case scenario is that these cells are second-hand, originally 300ah and have lost capacity. I would still get enough use out of them for the price to see out the rest of my sailing days.

 

[Poey50]

I will ? hoping to put the hole thing on my Youtube channel.

re the balmar i have purchased the balmar 614 in readiness, im guessing our usage and setup is a little different to yours as we are a motor boat on the thames and generally we go out most weekends and for a few weeks over the summer. my plan was to have the Balmar's absorption and float voltages to say 3.5v / 3.6v so whilst we are using the boat we have a reasonable State of charge we can make use of whilst we are away and then set our shore power charger to absorb and float at 3.2 / 3.3v we leave the fridges on all the time so whilst we are not using the boat they will discharge to a comfortable storage voltage.

i am in a quandary as to which BMS to choose

Brilliant - I'll look out for that on YouTube. I guess there is a fair amount of tweaking you can do with the various charging sources. I'm generally going to keep in the 20-90% SOC range but will occasionally charge to 3.6 volts per cell so they can balance. As you know I have the 123SmartBMS which only starts balancing at 3.4 volts per cell.

I was in a similar quandary over a BMS but opted for the 123Smart as it is mid-range cost, well documented and I've had excellent support from 123 Electric and GWL. Previous versions attracted some moans about bugs and the end boards going out of balance but this may be because people haven't been charging to full occasionally. REC Active and Orion Jnr are popular, good units, but more expensive by some way. Chargery BMS seems popular among the lower priced units but I wanted bluetooth.

 

[nfluester]

I originally planned to go with RJ and had good communication with a lady there called Alice who emailed me pretty much daily and then suddenly disappeared and dint respond

I then heard a lot of good things about Xuba on Diy solar forum who "apparently" sell EVE cells which are "apparently" good I spoke to someone there called Amy who has been amazing, they had a special deal running and i got a great price on 8 cells that i plan to run as an 2p4S 560ish AH pack they even send you a personal picture and test video showing the voltages of each cell which is a nice touch i also ordered a custom case for my batteries

 

[Poey50]

I originally planned to go with RJ and had good communication with a lady there called Alice who emailed me pretty much daily and then suddenly disappeared and dint respond

I then heard a lot of good things about Xuba on Diy solar forum who "apparently" sell EVE cells which are "apparently" good I spoke to someone there called Amy who has been amazing, they had a special deal running and i got a great price on 8 cells that i plan to run as an 2p4S 560ish AH pack they even send you a personal picture and test video showing the voltages of each cell which is a nice touch i also ordered a custom case for my batteries

View attachment 99179

Yes, also heard good things about Xuba and Amy.

 

[nfluester]

so i like the app and interface for the 123 smart bms however i am not a fan of the boards and the use of a relay always consuming power plus the wiring to the boards and the relays seems a bit like a science project with the push small fit connectors.

the Rec and orion seem very expensive

the new Daly FET based ones look better and can now do higher amps upto 300 but not sure how much faith i want to put on them with my nice new Batteries and boat

chargery originally seemed positive but is expensive once you add in the Contactors and after watching Will Prowse's video on it and the terrible screen Ui i am put off

my current plan (subject to change) is to use a JBD 150A FET based BMS as they seem to get good feedback on the forums and test it over the winter at home and then switch to a 123 smart if it doesn't meet the grade

i need a maximum of about 100 - 120 amps through the inverter for the immersion heater in the morning for showers so hopefully have a little head room

 

[Poey50]

so i like the app and interface for the 123 smart bms however i am not a fan of the boards and the use of a relay always consuming power plus the wiring to the boards and the relays seems a bit like a science project with the push small fit connectors.

the Rec and orion seem very expensive

the new Daly FET based ones look better and can now do higher amps upto 300 but not sure how much faith i want to put on them with my nice new Batteries and boat

chargery originally seemed positive but is expensive once you add in the Contactors and after watching Will Prowse's video on it and the terrible screen Ui i am put off

my current plan (subject to change) is to use a JBD 150A FET based BMS as they seem to get good feedback on the forums and test it over the winter at home and then switch to a 123 smart if it doesn't meet the grade

i need a maximum of about 100 - 120 amps through the inverter for the immersion heater in the morning for showers so hopefully have a little head room

I don't know that BMS. Would be interested to hear a report when tested.

Not everyone appreciates the 123 boards - usually people complain about having to solder on their own wire! the interconnecting push fit connectors do look a bit alarming at first sight but the connections are sound (having tried to pull one out without the special tool). Actually one of the attractions of the 123 smart relays are that they are bi-stable and therefore very low power. They are rated at 120 amps so probably not enough headroom for your use.

 

[nfluester]

I don't know that BMS. Would be interested to hear a report when tested.

Not everyone appreciates the 123 boards - usually people complain about having to solder on their own wire! the interconnecting push fit connectors do look a bit alarming at first sight but the connections are sound (having tried to pull one out without the special tool). Actually one of the attractions of the 123 smart relays are that they are bi-stable and therefore very low power. They are rated at 120 amps so probably not enough headroom for your use.

I was looking at the 123 smart in conjunction with the 200a victron smart battery protect relays that should be ample for my needs and low power consuming, though will get it all top balanced and built and see how this JBD / overkill solar one performs before splashing more money on the 123

 

[Poey50]

I was looking at the 123 smart in conjunction with the 200a victron smart battery protect relays that should be ample for my needs and low power consuming, though will get it all top balanced and built and see how this JBD / overkill solar one performs before splashing more money on the 123

I looked at the Victron Battery Protects but was unclear whether they offer cell level protection. They do if connected to a Victron VE.Bus BMS but Victron are quite clever about making their LFP gear non-compatible with other systems. They would offer protection at pack level but if cells are out of balance, as you probably know, it's possible for one cell to get too high while the pack voltage stays under the threshold for high voltage disconnect.

 

[nfluester]

i don't think their BMS would work with a DIY Lifepo4 setup however their battery protects as a larger amp low consumption relay instead of the 123 smart relay is very interesting

 

[Poey50]

i don't think their BMS would work with a DIY Lifepo4 setup however their battery protects as a larger amp low consumption relay instead of the 123 smart relay is very interesting

View attachment 99197

Is this showing a 123SmartBMS controlling the low disconnect Battery Protect? If it really can do that it is fine for the load side.

 

[nfluester]

yes though i think u could also use one in reverse for high voltage cut off on the charge side