Poey50
Well-known member
The DIY Solar Forum is a good place to eavesdrop the best vendors. This post, for example, but there are always several on the go. EVE or LISHEN
270ah DIY LiFePO4 build
- Thread starter Poey50
- Start date
The DIY Solar Forum is a good place to eavesdrop the best vendors. This post, for example, but there are always several on the go. EVE or LISHEN
sailaboutvic
Well-known member
As Poey said Eve , I was going to buy mine there even paid for them then they said they couldnt deliver to Sicily as it remote , they did refund me after five days but I did lose The credit card fee .
I ended up buying mine in Germany , it did cost a few hundred more but it was worth it to get them quickly plus if here any problems it was easier to deal with , if you interested let me know I put a few people on to him and he done everyone a deal
I ended up buying mine in Germany , it did cost a few hundred more but it was worth it to get them quickly plus if here any problems it was easier to deal with , if you interested let me know I put a few people on to him and he done everyone a deal
guardian
Active member
Pulled the trigger on these today, should get them in 50 days time:
200A Daly BMS
4 x 3.2V 280 Ah Batteries
Have been reading Will's forum and watching his YT vids the past couple of months sussing the form and feel reasonably confident in building my own lithium pack. Aliexpress is like currency trading at the moment where LifeP04 is concerned: you put the batteries in your 'trolley' and in one instance went from $400 to $650 in the time it took me to put in my payment details.
Another vendor wanted $300 postage to UK for $400 worth of batteries, eventually went with 'Soonbuy' as recommended by Freely Roaming and a few others around the interwebs.
Whole lot so far including the busbars stands me in £600.
200A Daly BMS
4 x 3.2V 280 Ah Batteries
Have been reading Will's forum and watching his YT vids the past couple of months sussing the form and feel reasonably confident in building my own lithium pack. Aliexpress is like currency trading at the moment where LifeP04 is concerned: you put the batteries in your 'trolley' and in one instance went from $400 to $650 in the time it took me to put in my payment details.
Another vendor wanted $300 postage to UK for $400 worth of batteries, eventually went with 'Soonbuy' as recommended by Freely Roaming and a few others around the interwebs.
Whole lot so far including the busbars stands me in £600.
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Poey50
Well-known member
That sounds a good price!
As you may have seen from the start of this thread, a desirable (I would say 'essential') design feature is to be able to separate the charge bus from load bus so that if there was ever a low voltage cut-off you could still charge the battery, or conversely if there was ever a high voltage cut-off you could still draw a load. Your Daly BMS doesn't seem to allow this. So the question to ask is how will your system manage an LFP disconnect? Of course, it may be that you are not installing this on a boat (Will Prowse of course mainly deals with static installations) in which case ignore. Daly do a version with separated ports but according to Will Prowse there are problems ... BMS common port vs seperate port
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sailaboutvic
Well-known member
This seen to be a problem some people I spoken to who are drawing huge amount of power , one cat I know does every thing from lithium , cook, heat,watermaker,winches and so on and he had problem the batteries dropping out on passages .
I could have the same problem with my relay , the BMS control both the load and charging through the relay so mine couId if too much of a load was used at the same time .
I think I have over come this by stopping my solar which are going to be my main charging supply to 14.v I may raise that to 14.1v once I can experiment a bit more but it's looking like 14v will be fine , that will charge the cell around 3.5 v I done the same to the b2b no chance of a lock out from over charging.
On the load side I made a note what the load would be if every bit of boat equment was working then added my biggest 240v electric power I might use at any one time and it worked out as long as the cells are above 3.2v the batteries should not drop out.
So hopefully I should be ok but to safe guard my self I'm also going to fit a switch to connect both lithium and started batteries to gather in case at some point my starter batteries died .
The 123 smart BMS smart I'm using and I think you too , GWL seen to do a relay that you can use to separate the load and charge but it's only 100A and my top draw will be around 220 A I think which is my water maker , which I Won't know till I decommissioni it and that will only ever be used when we fully charge and plenty of power going in.
A battery lock out while on the move for us will be very unlikely .
The relay I'm using is what used on BMW and MBens , when I tested it , when it does lock out its only out for one min or how ever long it talks for the cells to recover , of course when it does reconnect as soon the cells drop or go up above the set valve it just lock out again.
It's all a learning curve for me so only time will tell .
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guardian
Active member
Hi Poey, yeah this pack is going in my van. One thing I observed when putting together my component list was the lack of available BMS' so have gone with the Daly unit as it's convenient for my needs but may well switch to the 123BMS you guys are using. This based on my experiences of QA probs when purchasing Chinese electronics previously so will see how it goes.
Cheers
Cheers
Poey50
Well-known member
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Poey50
Well-known member
No problem at all in your van. In fact, a good choice for that.
Poey50
Well-known member
The 123Smart doesn't tie you to any particular relay. There are much bigger ones it will control than the 120amp ones that I use. Personally I wanted a system where a complete lock-out is designed out.
Poey50
Well-known member
And, while I'm back on this hobby horse, I thought the recent article in Yachting Monthly on LFP batteries was irresponsible in not even mentioning the risks from combined charge and load bus. The built in BMS of the eye-catching drop-ins was always portrayed as a desirable feature rather than a disadvantage to be overcome. But, you know - advertising revenue ...
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crisjones
Active member
The problem many people face with Li systems is having a combined inverter charger unit (Victron Multi-Plus etc).
While it is best to have seperate Load and Charge busbars, each with it's own main disconnect relay/contactor this is not easy when the inverter charger is both a load and a charge source. It is probably best to have it on the load busbar since over-discharge is the biggest risk when using the inverter and many systems will hardly use the unit as a charge source.
Victron Multi-Plus units can be configured to be connected to a BMS unit that can then switch off the charging function or the inverter function for high or low voltage levels. This works very well but it does mean that your BMS must be able to be correctly connected to the Victron MP or you need to install extra switching relays. Not all BMS units can be configured to do this.
nfluester
Active member
slow progress being made on the build trying to juggle time between work and boat stuff! preasure is building as we would like to get away 2nd week of Easter once UK restrictions are raised ? I managed to get the cells together and in the case with uprated bus bars at the weekend!
here's part 3 of the build
here's part 3 of the build
Poey50
Well-known member
You're a natural presenter, Neil. Well done! Good to know you have well-insulated bottoms - mine were bare metal.
You may well have these next steps in mind so ignore if this is the case. Several people (me included) use blue Loctite to seal the studs in place. This should prevent damp getting down between the aluminium and stainless steel creating galvanic corrosion and it also strengthens the otherwise vulnerable stud-terminal connection. Copper on aluminium is also another potential galvanic issue so I used Ox-gard to smear on that and all ring terminal connections. This has zinc in it as well as being greasy to avoid damp and corrosion. It is itself also a conductor. You need to lightly sand everything before assembling with Ox-gard. Heat shrink on the exposed sections of bus bar and liquid insulation on anything left showing is also a good idea to prevent things turning green and to guard against tool drops. Accidentally welding a tool to create a dead short is a scary prospect with that much energy.
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vas
Well-known member
nice,
never seen that tool but tbh for a soft metal like copper, I'd just do what I always do, fit an grossly oversize drill bit, low speed, no pressure and touch it on to chamfer the hole edges. Got too many tools as it stands to get another for this easy job
remind us what BMS are you going to be using!
V.
never seen that tool but tbh for a soft metal like copper, I'd just do what I always do, fit an grossly oversize drill bit, low speed, no pressure and touch it on to chamfer the hole edges. Got too many tools as it stands to get another for this easy job
remind us what BMS are you going to be using!
V.
nfluester
Active member
i am going to heat shrink the bars but hadn't thought about corrosion so thats the next bit of learning thanks ?
nfluester
Active member
im going to be using a REC ABMS connected to a Victron Cerbro GX to control the inverter and MPPT and fingers crossed a wakespeed WS500 to control alternator output all connected via CAN busnice,
never seen that tool but tbh for a soft metal like copper, I'd just do what I always do, fit an grossly oversize drill bit, low speed, no pressure and touch it on to chamfer the hole edges. Got too many tools as it stands to get another for this easy job
remind us what BMS are you going to be using!
V.
Poey50
Well-known member
Great system! New alternator?
nfluester
Active member
Yes but out of all of this build that is the biggest challenge and unknown, I have a Balmar XT170 on route but A: i think it will be too physically big to fit and B i am going to have to throttle it back as i cant go any bigger that our single V belt so hence the wakespeed to try and cap it at about 90 amps max to avoid shredding belts, I went for the XT170 as it has one of the best (on paper) low RPM output which with the low pulley ratio and our low RPM river cruising would be perfect.
I have a worrying feeling though it will end up on Ebay and I will be looking for a plan B either the 621 - 100A Balmar or some other 1" mount option with field output
Poey50
Well-known member
Yes, single V belt sounds a problem. I was able to get a serpentine belt and pulley upgrade for my 29 hp Nanni and that is on a Balmar 60 series 100 amps.
nfluester
Active member
if my XT 170 doesn't fit I'll do you a swap ??
