270ah DIY LiFePO4 build
- Thread starter Poey50
- Start date
Kelpie
Well-known member
I have also pulled the trigger on my cells, at long last.
Went with Shenzen Basen on Alibaba. £350 for four 280Ah cells including delivery. I don't know what will be added to that price on arrival, possibly UK VAT, but even so the resulting £420 is still much cheaper than buying the equivalent capacity deep cycle lead acid.
I haven't purchased my BMS yet. I considered Daly, mostly on the basis of Will Prowse's reviews, but there were also a lot of negative comments around, and I thought that the balancing current and low voltage disconnect were pretty lousy. For similar money the JBD/Overkill offers an apparently much better out-of-the-box solution, with double the balancing current and a more realistic LVD. And it appears to be totally configurable.
My broad system design remains the same- a second totally separate parallel installation, not connected to my boat's existing 12v. It will charge only from the new solar panels, plus the option of B2B charging if that proves necessary. And it will power new systems that I have yet to install, e.g. fridge, inverter. I will transfer the cabin lighting across to it, but critical nav equipment and autopilot will remain on the old lead-acids, as will the engine.
I swithered about how to tie in the inverter. The simple but brute force option was to buy a massive 300A BMS, but I didn't really like the idea of running all that current through the FETs for long periods. I am hoping that whatever inverter I end up buying will be capable of remote switching at low current, and if that isn't possible I will investigate using the BMS to trip a relay on the AC side. Worst case scenario is to use a big 300A SSR, but this should still work out cheaper and more reliable than buying a 300A BMS.
It's looking like the total battery cost will be about £600 for 280Ah. Compare that with a set of Trojans, £690 for 225Ah usable. Lifespan should be at least three times as many cycles, with much better charge acceptance and charging efficiency.
I will update the forum in two months time when the cells will hopefully be here...
Went with Shenzen Basen on Alibaba. £350 for four 280Ah cells including delivery. I don't know what will be added to that price on arrival, possibly UK VAT, but even so the resulting £420 is still much cheaper than buying the equivalent capacity deep cycle lead acid.
I haven't purchased my BMS yet. I considered Daly, mostly on the basis of Will Prowse's reviews, but there were also a lot of negative comments around, and I thought that the balancing current and low voltage disconnect were pretty lousy. For similar money the JBD/Overkill offers an apparently much better out-of-the-box solution, with double the balancing current and a more realistic LVD. And it appears to be totally configurable.
My broad system design remains the same- a second totally separate parallel installation, not connected to my boat's existing 12v. It will charge only from the new solar panels, plus the option of B2B charging if that proves necessary. And it will power new systems that I have yet to install, e.g. fridge, inverter. I will transfer the cabin lighting across to it, but critical nav equipment and autopilot will remain on the old lead-acids, as will the engine.
I swithered about how to tie in the inverter. The simple but brute force option was to buy a massive 300A BMS, but I didn't really like the idea of running all that current through the FETs for long periods. I am hoping that whatever inverter I end up buying will be capable of remote switching at low current, and if that isn't possible I will investigate using the BMS to trip a relay on the AC side. Worst case scenario is to use a big 300A SSR, but this should still work out cheaper and more reliable than buying a 300A BMS.
It's looking like the total battery cost will be about £600 for 280Ah. Compare that with a set of Trojans, £690 for 225Ah usable. Lifespan should be at least three times as many cycles, with much better charge acceptance and charging efficiency.
I will update the forum in two months time when the cells will hopefully be here...
Poey50
Well-known member
Assuming the delivered cost will be £420 that is exactly £200 cheaper than pretty much the same cells than I bought about 10 months ago. That is astonishing and I would anticipate a growth in DIY builds. I can see that with a lead acid to take care of safety critical systems you can get away with a relatively unsophisticated BMS. If I was going to do it again I'd look closely at the Electrodacus with direct on/off control of charging systems. Looking forward to hearing more about the delivered cost and your install.
vas
Well-known member
so it's 690 quid for 4X6V T105 up there, right?
vas
Well-known member
very much interested to follow this bit, especially the VenusOs integration!
I've spent a fair amount of time during the winter lockdown and now have a raspberrypi 3B+ on board with the official 7in display running venusOS, connected to Victron MPPT and BMV (and waiting for integration with Multiplus as well).
Currently on T105REs and looking for 8X280Ah LifePO4 for next winter most likely but concerned on Multiplus/alternator (Sterling) integration.
V.
sailaboutvic
Well-known member
Just a quick up date .
It's been over five weeks since we started to using lithium , so far so good .
One mistake made using the 123 BMS smart , there three Manual on line and when I first down loaded it I happen to get the older Manual since then some of the info they had on that one had been up dated and some of the setting are not the same , so be where of you using 123 smart that you get the rights Manual.
Other wise all working well ,
I set my MPPT to Abs 13.8 v and the float to 13.6v ,
I'm using the Victron B2B and have an Abs set to 13.6v as the min Abs time is an hour and I don't wish to have it on Abs at 13.8v for and hour , so rather let the solar take it up the rest of the way .
13.8v should give me around 95% soc .
Max load so far been 2600W voltages stayed around 13.2v
If your useing 8 cells and one BMS as I am , the setting are not clear in the manual , if you should entered 8 or 4 cell bank , the answer is 4 cells .
It's been over five weeks since we started to using lithium , so far so good .
One mistake made using the 123 BMS smart , there three Manual on line and when I first down loaded it I happen to get the older Manual since then some of the info they had on that one had been up dated and some of the setting are not the same , so be where of you using 123 smart that you get the rights Manual.
Other wise all working well ,
I set my MPPT to Abs 13.8 v and the float to 13.6v ,
I'm using the Victron B2B and have an Abs set to 13.6v as the min Abs time is an hour and I don't wish to have it on Abs at 13.8v for and hour , so rather let the solar take it up the rest of the way .
13.8v should give me around 95% soc .
Max load so far been 2600W voltages stayed around 13.2v
If your useing 8 cells and one BMS as I am , the setting are not clear in the manual , if you should entered 8 or 4 cell bank , the answer is 4 cells .
sailaboutvic
Well-known member
He going to have to add on extra stuff on that like the BMS and some way to charge them from his alternator like a B2B
Then there cables , relay , fuses all the stuff people over look
But in the end he have a good batteries bank
vas
Well-known member
Vic, sorry I'm 24V so 8S configuration. Not decided on BMS, but for sure it's going to have to integrate with Victron stuff very tightly, hence my interest!
V.
V.
sailaboutvic
Well-known member
If I had the room I think I might had gone for 4 more cells and had a 12v and a 24V bank for the larger loads ,
I suppose I could had gone 24V and put in droppers , but for now it seen to be working fine , still to try out my 1.5Hp water maker pump , but Chris says he works fine so hoping I get the same results.
Off out for a 10 day sail later this week so I soon find out .
All my mppt and B2B is victron so its easier to set up to lithium setting,
Although the B2B can only be set to a min ofn1 hour on Abs so I set this lower and the same as float .
Many folks seen to say to charge them to 14.2v 14.4v but I'm keeping my lower to 13.8v around 95%:I don't think the little I know about these batteries there much point charging higher the 13.8v
Kelpie
Well-known member
Yes, when I last checked that was the best price that I could find for four T-105 batteries, genuine branded Trojan, including delivery.
You could save a bit off that by going with US Batteries, although you also lose a few Ah. And you could save even more going with some own-brand clone, but then you're into the territory of wondering if they will last as long as the real deal. At best you could knock off £100 that way.
guardian
Active member
My Daly BMS' have arrived, the cells have only just been sent, heres the 500A model with BT module also got 200A model too. as i got confused regarding peak output from the inverter (4000W) and ordered the 500A model by mistake. Will install the 200A model.
I watched Will's review of the electrodacus BMS, very impressed. Will see how i get on with the daly unit first.
*EDIT* A handy guide
I watched Will's review of the electrodacus BMS, very impressed. Will see how i get on with the daly unit first.
*EDIT* A handy guide
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Frankklose
Member
Why did you not use the Daly BMS with separate ports f
or charing and discharging?
I don't understand why people are afraid of Mosfet switches. All house solar installation use mosfets. The BMS components were developed for solar installations. The semiconductors for balancing ,voltage measuring are all made by the big semiconductor companies.
I have on the roof 10kw solar and a 6000ah battery which gets charged and discharged almost every day and it works without any Relais. Perhaps we should look at the big boys for BMS and not for the self developed ones. They usually depend on one person.
or charing and discharging?
I don't understand why people are afraid of Mosfet switches. All house solar installation use mosfets. The BMS components were developed for solar installations. The semiconductors for balancing ,voltage measuring are all made by the big semiconductor companies.
I have on the roof 10kw solar and a 6000ah battery which gets charged and discharged almost every day and it works without any Relais. Perhaps we should look at the big boys for BMS and not for the self developed ones. They usually depend on one person.
Poey50
Well-known member
Last time I looked the charge port on the Daly was limited in capacity. I needed something to handle charge up to 120amps from my Balmar alternator.
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Kelpie
Well-known member
If the purpose of the exercise is to compare the costs of Lithium with lead-acid, you have to be quite careful.
A big chunk of my budget is going on things that I simply wouldn't have without lithium: the induction hob, the inverter that powers it, and relay that protects that. So let's not count any of that.
Another chunk of the budget would be the same for either lead-acid or lithium. The solar charge controllers, the cabling, the fuses.
The B2B is something that is very useful with lithium, because it allows you to both protect your alternator and improve your charging efficiency. It's useful to fit one on a lead-acid system too, but let's count it as a necessary cost for lithium only.
Most boats will only have high current loads for the starter and windlass, which will be taken from the starting battery. So the domestic bank will handle fairly low currents, maybe 25A max. That means you can run it all through the BMS without relays etc.
So the lead-acid route is £690 for 225Ah usable, maybe £550 if you go absolute bargain basement unbranded (and probably only 210Ah usable). Cost £2.70-£3/Ah. You can go cheaper using basic leisure batteries of course, but then you're talking 200 cycles or so, vs 800+ for deep cycle.
The lithium route is £420 for the cells (I've only paid £350 but expecting a VAT bill), 280Ah of which about £252Ah is usable.
Add to that a BMS, the cheapest option is something like a Daly, less than £50 for something that can handle all normal domestic yacht loads (I'm assuming you keep a lead-acid for engine starting and for the windlass).
Something to keep the cells in, this is hard to price as it will be a DIY affair. Let's call that £50 too.
The B2B charger will be about £150 new.
So total cost for a very basic lithium system would be around £670, or £2.65/Ah. A big chunk of that is the B2B, which skews the figures. If you take it out of the equation the lithium system costs only £2/Ah.
This type of system would have limitations, of course. You can't start your engine with it, or power your windlass or bow thruster. It may drop out on you without warning, which could be problematic if you're using it with an autopilot. And you'd have to be careful about low temperature charging, Getting around these limitations is what adds a lot of cost and complexity.
Personally I think the attitude towards lithium may change. When cells were the biggest cost, you would do everything possible to protect them. The cells are now substantially cheaper per Ah than 6v deep cycle lead acid. So they only have to last four or five years to be a better buy. It becomes a bit harder to justify £1k+ on top of the line MPPTs etc with the aim of protecting the cells from any conceivable damage.
Poey50
Well-known member
It is certainly the case that the BMS's primary task is to protect the cells which of course protects the investment. But - at the risk of being boring - on a boat the protection of the cells can't be separated from protection of the boat itself and its human occupants. Occasional and limited overcharging or over discharging will take cycles off the life of LFP as several have found but that is not the whole story. Unregulated charging (e.g. a malfunctioning mains charger) could lead to thermal runaway, unregulated discharge can cause the 'time bomb' effect that Zwerfcat describe - both of these being potentially life-threatening on a boat given the massive energy density. LFP's much vaunted stable chemistry has its limits. And of course, as I've said many times with drop-ins, a BMS shutdown in the back of a RV is an inconvenience whereas the same in a shipping channel at dead of night is a different order of problem.
Personally I think Nordkyn's 5 principles of design for a marine system that I began this thread with still hold up.
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sailaboutvic
Well-known member
Taking for myself , I know very little about lithium probably not much more then most here if we don't include Chris who bern using them for some years .
I spend 8 weeks reading everything I could and watching YouTube.
Mine cells alone cost me 1400 , I did try and order them from China but after my order was taken and I paid for them, I got told I'm in a remote country and they couldn't deliver, so I ended up buy from Gremany around 400 euros more but hey thats life.
Personally I moved onto lithium because A I was very disappointed with my Trojan and B I wanted to start using less of my Gen which mean I needed something that would except large loads .
To be honest if all I wanted out of batteries was to draw nav equipment and light fridge I would had gone back to cheap LA .
As I speak the hob on and so it the hot water heater 2500w being used and the cells are at 3..32 v batteries 13 .3v soc 84% by morning we be down to around 65% we would had used 250ah out of our 370 we be back upto 95% by around 1300 then next day .
Am I working then hard , yes I am I not spent over 2k to hardly use them so they last 5000 cycle, if I get 2000 out of them I be more then happy and by that time lithium be much cheaper .
Couple of things I done which others may not agree with , I connect the shore charger to the b2b , I won't get as much charging Amps but I don't have to worry about the shore charger playing up and killing the cells.
I also only charging the cells to 13.8v , where most are saying they charge to 14.2 14.4 v
I don't feel I need to push the charging rate any higher , as my panels are doing a good enough job to charge them up to 95% leaving me part of the afternoon to draw high load for say the water heater.
This project is now getting close to 3 k with new 3000w PS inverter cells , relay, B2B , bms, cables, and all the other stuff we all the sudden realise we needed to make it work .
I spend 8 weeks reading everything I could and watching YouTube.
Mine cells alone cost me 1400 , I did try and order them from China but after my order was taken and I paid for them, I got told I'm in a remote country and they couldn't deliver, so I ended up buy from Gremany around 400 euros more but hey thats life.
Personally I moved onto lithium because A I was very disappointed with my Trojan and B I wanted to start using less of my Gen which mean I needed something that would except large loads .
To be honest if all I wanted out of batteries was to draw nav equipment and light fridge I would had gone back to cheap LA .
As I speak the hob on and so it the hot water heater 2500w being used and the cells are at 3..32 v batteries 13 .3v soc 84% by morning we be down to around 65% we would had used 250ah out of our 370 we be back upto 95% by around 1300 then next day .
Am I working then hard , yes I am I not spent over 2k to hardly use them so they last 5000 cycle, if I get 2000 out of them I be more then happy and by that time lithium be much cheaper .
Couple of things I done which others may not agree with , I connect the shore charger to the b2b , I won't get as much charging Amps but I don't have to worry about the shore charger playing up and killing the cells.
I also only charging the cells to 13.8v , where most are saying they charge to 14.2 14.4 v
I don't feel I need to push the charging rate any higher , as my panels are doing a good enough job to charge them up to 95% leaving me part of the afternoon to draw high load for say the water heater.
This project is now getting close to 3 k with new 3000w PS inverter cells , relay, B2B , bms, cables, and all the other stuff we all the sudden realise we needed to make it work .
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Poey50
Well-known member
Recommended voltage targets to end constant current charging have been dropping for years as people have understood LFP better. 13.8v sounds good to me.
guardian
Active member
For this first build i'm following Will Prowse' specs and the guy from Freely roaming on YT & copying both as i dont fully understand everything yet.
sailaboutvic
Well-known member
New up date for them worried about charging .
First note we are in the Med where there more sun shine this time of year then back in the UK and my PV is 750W
We just done a 9 days on the hook and used the batteries as if we was on shore power.
Micro wave, kettle,electric Rad heater on at times, induction hob, charging for PC, ipad,phone, hot water heater .
On very cloudy days we managed to get the batteries back up enough for them to be used the following day , it taken almost two good days of Partly sun shine to get them up to 95% after that, has they where very low .
On the move we had to turn off the b2b by late morning and half the panels,
there was more going in then we could ever take out and because the engine was running we couldn't use power on the hot water heater .
In reality in the summer months if we wasn't using the electric Rad heater I say we could managed three very cloudy days before having to turn on the Gen to top up.
One sunny day between cloudy days and we back where we started from.
So for tho who going to use lithium for weekend and a few weeks away , with the help of panels , I would hold off buy any expenses alternator/Regulator until you used them for a while , you probably find with a bit of management you won't need them.
My view on our 400 ah pack , so far very happy and as a full time liveabourd its made life a lot more comfortable, saving fuel on the Gen , cut down on noise and pollution as well as gas, although it come with a price to pay in the cost of buying and building them.
First note we are in the Med where there more sun shine this time of year then back in the UK and my PV is 750W
We just done a 9 days on the hook and used the batteries as if we was on shore power.
Micro wave, kettle,electric Rad heater on at times, induction hob, charging for PC, ipad,phone, hot water heater .
On very cloudy days we managed to get the batteries back up enough for them to be used the following day , it taken almost two good days of Partly sun shine to get them up to 95% after that, has they where very low .
On the move we had to turn off the b2b by late morning and half the panels,
there was more going in then we could ever take out and because the engine was running we couldn't use power on the hot water heater .
In reality in the summer months if we wasn't using the electric Rad heater I say we could managed three very cloudy days before having to turn on the Gen to top up.
One sunny day between cloudy days and we back where we started from.
So for tho who going to use lithium for weekend and a few weeks away , with the help of panels , I would hold off buy any expenses alternator/Regulator until you used them for a while , you probably find with a bit of management you won't need them.
My view on our 400 ah pack , so far very happy and as a full time liveabourd its made life a lot more comfortable, saving fuel on the Gen , cut down on noise and pollution as well as gas, although it come with a price to pay in the cost of buying and building them.
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sailaboutvic
Well-known member
I'm not sure any of us understand every thing yet,
The problem is there so much confusion in the info we read and get,
On one posting else where I was told by someone who contributed a lot to lithium fourm charging them to 13.8v that I'm not even getting to 75%soc and I need to charge to 14.4v
I know that isn't true,
but If it was three months ago I would had then taken that as gospel and ramped up the voltages.
For most of us its all a learning curve.
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