mitiempo
Member
Some do, but a lot less DIY. Victron and Mastervolt both produce systems that are plug and play with components all their own. At a very high price.
270ah DIY LiFePO4 build
- Thread starter Poey50
- Start date
Poey50
Well-known member
As previously said, there are so many variables and those who are ready to go the DIY route generally have gained enough knowledge to make their various choices. The big players are offering integrated kit for those with plenty of money and there are now some smaller players such as X2 offering various packages as featured in the lithium build on RAN Ssiling YouTube videos. But these also don't come cheap.
BMS Kit – batterybalance
gregcope
Well-known member
Here is a thread on DIYSolar about the JDB BMS <->Victron driver;
Victron VenusOS driver for serial connected BMS available - LLT/JBD / Daly Smart / ANT / JKBMS / Heltec
vas
Well-known member
cheers Greg, and following is a similar thread by the same person in VictronOS community forum/board:
Victron VenusOS driver for serial battery BMS - LLT/JBD / Daly Smart / ANT / JKBMS / Heltec (VenusOS v2.80 compatible) - Victron Community
still studying before making the final move, but for once it seems that a higher initial integration (see cost and time!) with a rpi running VictronOS hooked to the Victron MPPT and Victron Multiplus inverter/charger pays off, as you only need a cheap BMS that only needs to send serial commands out to instruct the other devices to stop or start again charging on using the lifepo4 bank. That's a excellent development, so I don't need contactors/relays/SSRs at all. just bought a 7ton crimping tool so I'm ready to change some of the wires as well
The jist of it all is that you configure the devices to max min/no float/etc (easy to do on both devices), and if something goes off spec (which basically means cells going off sync most likely!) BMS picks it up and simply instructs Victron OS rpi via serial/usb connection. Following that, VictronOS instructs either MPPT or inverter (or both) to stop charging/discharging. The important bit is that BMS does just the serial comms call to VictronOS running on the rpi nothing more. And this guy linked above has done just that (at least that's the bit I want I think...) Then it's the job of VictronOS to act - no need for me to do anything fancy there expect configuring the OS properly (ok, not that hard, two tickboxes on the touchscreen menus iirc...)
The only non-Victron device in this setup is the Stirling inteligent whatever charger that is between my port alternator and the service battery bank. Stbrd engine alternator does the FLA starter batteries so I'm ok there - no need for split charging. I'm pretty sure that one of the wires (yellow?) if grounded (or put it another way, not supplied with 24V) simply disables alternator output, but I'm not on the boat to check that will be back next week. Other than restoring consumption from nav equipment only serious use for it is running the watermaker underway so that it can provide (in theory) around half the amps, batteries can take the rest of the load.
Still on the studying phase, went through the 60odd page manual for the chargery, need to download and figure out the s/w this guy has done as well before committing.
cheers
V.
Victron VenusOS driver for serial battery BMS - LLT/JBD / Daly Smart / ANT / JKBMS / Heltec (VenusOS v2.80 compatible) - Victron Community
still studying before making the final move, but for once it seems that a higher initial integration (see cost and time!) with a rpi running VictronOS hooked to the Victron MPPT and Victron Multiplus inverter/charger pays off, as you only need a cheap BMS that only needs to send serial commands out to instruct the other devices to stop or start again charging on using the lifepo4 bank. That's a excellent development, so I don't need contactors/relays/SSRs at all. just bought a 7ton crimping tool so I'm ready to change some of the wires as well
The jist of it all is that you configure the devices to max min/no float/etc (easy to do on both devices), and if something goes off spec (which basically means cells going off sync most likely!) BMS picks it up and simply instructs Victron OS rpi via serial/usb connection. Following that, VictronOS instructs either MPPT or inverter (or both) to stop charging/discharging. The important bit is that BMS does just the serial comms call to VictronOS running on the rpi nothing more. And this guy linked above has done just that (at least that's the bit I want I think...) Then it's the job of VictronOS to act - no need for me to do anything fancy there expect configuring the OS properly (ok, not that hard, two tickboxes on the touchscreen menus iirc...)
The only non-Victron device in this setup is the Stirling inteligent whatever charger that is between my port alternator and the service battery bank. Stbrd engine alternator does the FLA starter batteries so I'm ok there - no need for split charging. I'm pretty sure that one of the wires (yellow?) if grounded (or put it another way, not supplied with 24V) simply disables alternator output, but I'm not on the boat to check that will be back next week. Other than restoring consumption from nav equipment only serious use for it is running the watermaker underway so that it can provide (in theory) around half the amps, batteries can take the rest of the load.
Still on the studying phase, went through the 60odd page manual for the chargery, need to download and figure out the s/w this guy has done as well before committing.
cheers
V.
sailaboutvic
Well-known member
Not so much of a kit but I brought everything from lithium power store in Germany including breaker and got a very good discount .
Actually the discount covered the cost of the 123 smart BMS.
He sells the Ali cells as well as the Calbs which I end up buying but the Ali cells you can get them cheaper from china .
The advantage I found was deliver was just a week and I didn't have to worry about any duty plus if there was a problem he not far to deal with .
gregcope
Well-known member
Ah @vas thanks for that link not seen it!
In terms of kits Amy from Luyuan on alibaba can sell you the basic parts of box, bms and cells. You need to be proficient at crimping/cabling and have a good idea of assembly as there are risks with the large amount of stored energy even in a partially charged cell. There is also the complexity of initial top balancing.
In terms of kits Amy from Luyuan on alibaba can sell you the basic parts of box, bms and cells. You need to be proficient at crimping/cabling and have a good idea of assembly as there are risks with the large amount of stored energy even in a partially charged cell. There is also the complexity of initial top balancing.
nfluester
Active member
hey @vas glad you are finally taking the plunge, based on all the research i did the JBD is well loved and reliable and if we were running 24v then i would have considered it over our REC but i wanted more that 120a
in reality most BMS's are pretty the same they have a high voltage cut off a low voltage cut off & a low temp cut off they are going to either run all the current through Fets which is going to create a lot of heat and have limited output like the Daly or JBD / overkill or they are going to run the current through a big contactor to manage the cut off like 123bms, Chargery etc which have a downside of increased standby power consumption to hold the relay closed.
one thing that does vary massively on BMS's is the amount of balance current they can supply, on most of the FET based ones it can be as little as 50mA which is fine on a relatively small capacity pack but on a larger pack if it gets out of balance 50mA wont even make a dent i think the electrodacaus you mentioned is a little better at 200mA but on a 280Ah pack 200mA is not a great deal.
hope that helps add more choice and decisions ?
in reality most BMS's are pretty the same they have a high voltage cut off a low voltage cut off & a low temp cut off they are going to either run all the current through Fets which is going to create a lot of heat and have limited output like the Daly or JBD / overkill or they are going to run the current through a big contactor to manage the cut off like 123bms, Chargery etc which have a downside of increased standby power consumption to hold the relay closed.
one thing that does vary massively on BMS's is the amount of balance current they can supply, on most of the FET based ones it can be as little as 50mA which is fine on a relatively small capacity pack but on a larger pack if it gets out of balance 50mA wont even make a dent i think the electrodacaus you mentioned is a little better at 200mA but on a 280Ah pack 200mA is not a great deal.
hope that helps add more choice and decisions ?
gregcope
Well-known member
Not that it helps much @nfluester JDB seem to have released a 200A BMS that does 150ma balance current.
(No connection, never used one, etc... disclaimer) Jiabaida 4s Lifepo4 12v 100a/120a/150a/200a Smart Bms With Bluetooth/uart/rs485 And Temperature Sensor - Buy Bms Lifepo4,Bms 4s,Bms 200a 4s Product on Alibaba.com
I see some people (Off Grid Garage) use dedicated cell balancers that can do 1-5A or so, but as you point out this comes at the cost of standby power consumption.
(No connection, never used one, etc... disclaimer) Jiabaida 4s Lifepo4 12v 100a/120a/150a/200a Smart Bms With Bluetooth/uart/rs485 And Temperature Sensor - Buy Bms Lifepo4,Bms 4s,Bms 200a 4s Product on Alibaba.com
I see some people (Off Grid Garage) use dedicated cell balancers that can do 1-5A or so, but as you point out this comes at the cost of standby power consumption.
nfluester
Active member
I had the JBD 150A when I did my initial testing in my video here
and they are not capable of sustaining the published continuous current. after this experience I wouldn't want to pull more than 100A continuously through a FET based BMS it's just not reliable long term
Poey50
Well-known member
I bought a set of Heltec active balancers on the strength of Andy's (Off Grid Garage) initially very positive video. He later found that because they balance the cells at all states of charge rather than just at the top end, they could result in imbalance when charged to full. One answer to this and the residual current problem is to wire in a switch and only switch on when charging rapidly to full to balance above 3.4v or 3.5v per cell.. For the moment they remain in a drawer together with a more primitive set I bought around a year ago. Fortunately in the scheme of things they are not expensive.
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gregcope
Well-known member
@nfluester Is constantly pulling near the max Amp capacity long term your plan?
I would have thought normal use cases would be around 10A (or less) with very occasional bursts. I think you might have mentioned a water heater in the past.
I see the 200A JDB has a finned heatsink. Their others just have Ali covers so I would expect them to get warm pulling near their max. I would agree that using Mosfet based ones near their max Amp rating for longer durations is likely to generate heat and possible failure.
Interestingly Sun Fun Kits (on youtube) downrate their BMS in the software to 65A. (
)
I would have thought normal use cases would be around 10A (or less) with very occasional bursts. I think you might have mentioned a water heater in the past.
I see the 200A JDB has a finned heatsink. Their others just have Ali covers so I would expect them to get warm pulling near their max. I would agree that using Mosfet based ones near their max Amp rating for longer durations is likely to generate heat and possible failure.
Interestingly Sun Fun Kits (on youtube) downrate their BMS in the software to 65A. (
nfluester
Active member
For us one of the main reasons for switching to lithiums was to run the immersion heater in the mornings before we set off for a shower so that generally pulls about 120A for about 30 mins then we have just installed a new combi oven and microwave which is about 120 amps too (never have them on at the same time) we have a Victron Multiplus 3000 KVA inverter which tops out at about 2200KW.
i don't have the ideal installation the battery is in the engine bay with 2 thumping volvo diesels so it's already hot in there, I also start one of the engines of the lithium bank (sorry to disappoint but we are a motor boat (i think most people here are sailing)) and the way in which the batteries were originally configured is there was a parallel pair of 110AH FLA engine start battery for one engine and the other engine started of the house bank there is then a link switch to combine if either one is totally drained.
i have subsequently replaced the 2 x110ah lead acid start batteries with a 90AH lithium winston 12v battery whish although not done a lot of testing seems to crank ok and got another one on the bow thruster now
I didn't really want to mess with the engine starting wiring too much as when we come to sell the boat i will remove the lithiums and take them to a new boat and throw some cheap lead acids back in.
im really pleased so far with the Rec ABMS it talks to the victron Multiplus, solar and wakespeed regulators so if there is any over or under voltage situation it should instruct everything to shut off
i don't have the ideal installation the battery is in the engine bay with 2 thumping volvo diesels so it's already hot in there, I also start one of the engines of the lithium bank (sorry to disappoint but we are a motor boat (i think most people here are sailing)) and the way in which the batteries were originally configured is there was a parallel pair of 110AH FLA engine start battery for one engine and the other engine started of the house bank there is then a link switch to combine if either one is totally drained.
i have subsequently replaced the 2 x110ah lead acid start batteries with a 90AH lithium winston 12v battery whish although not done a lot of testing seems to crank ok and got another one on the bow thruster now
I didn't really want to mess with the engine starting wiring too much as when we come to sell the boat i will remove the lithiums and take them to a new boat and throw some cheap lead acids back in.
im really pleased so far with the Rec ABMS it talks to the victron Multiplus, solar and wakespeed regulators so if there is any over or under voltage situation it should instruct everything to shut off
vas
Well-known member
no it doesn't, not kidding!
doing lots of studying, still some gray areas in how things work. Let me explain some of my concerns based on your second para above:
from my understanding there are two schools of thought:
A. BMSs with internal mosfets or whatever transistor method to "switch on and off" loads/charging
B. BMSs with no internal switching that simply "instruct" the switch on and off of loads/charging.
[then there's also BMSs with separate charge and load ports, but I'll leave that out and concentrate on common port ones]
Now, considering I'd like to run my multiplusII with watermaker and a few other things, option A is out of the question unless I pay lots and I generally avoid it if I can. Further to my mind it's conceptually wrong. No way I'm getting a 50 or 100A BMS for a 280Ah pack.
Now, option B means you need massive external devices (ok, slight exaggeration but not a 10euro fake 40A SSR from the depths of China) to do the job.
As I stated in #804 above, having a fully integrated system with solar, charger and inverter talking to each other via the raspberry pi running VenusOS it seems absurd to me NOT to use this capability and start adding contactors and whatnot.
Cell off scale? BMS notifies VenusOS and that turns off MPPT and multiplus charger (if it's cell overvoltage) or multiplus inverter if it's undervoltage. Job done, right?
Well, from my reading ppl seem to be reluctant to do so and prefer to still use external contactors... No serious explanations given sort of that's how it's done mate, get used to it. This is rather backwards thinking and reminds me a v.good joke/behavioural experiment with 5 monkeys in a cage and a banana
So still at the stage of sorting out what I may be missing, anyone care to help?
didn't realise you're a fellow moboer ;-)
same situation, planning to go a step further and since I do have a slight listing to stbrd (where the generator lives) and removing 120+kg of trojans to replace by 40odd kilos of lifepo4 on port side is not v.smart. So idea is to leave the trojans as a backup in case of lifepo4 disconnect and have them charged from the other alternator that does the engine start fla batteries via a vsr.
Problem then is that instructing a disconnect to lifepo4 should come with an immediate contactor connect to the old trojans - ok can do that manually with a big rotary switch I guess. Guess not that difficult and not that urgent anyway since boat will be in port till next June, will have to think about it.
Would ideally like to decide soon and order from Amy the 8 EVE280Ah cells together with a BMS16T chargery (hasn't got an 8 and the only other BMS she's selling is only 4S) Shipping to Greece and customs is an issue and don't want to mess with many different providers anymore.
could you please elaborate re passive ballancing? the chargery mentions 1.2A, do I divide that by 8 (I'm building 8S) to get the current flowing out (as in "burnt") by each cell at max, or is it 1.2A per cell, or is that 1.2A grossly exagerated?
cheers
V.
nfluester
Active member
i just looked at the Chargery manual and and it states 1.2A per cell so thats good, i did originally like the chargery but was put off by the old style graphics on the display and i think will Prowse did a video on it and wasn't impressed by it (I'm sure they have fixed everything and made lots of updates since then)
for SSR i would go with a Victron Battery protect they do upto a 200A continuous version. i have a 100A one that i never got round to fitting that i was going to put on the 12v house loads as a last resort if all else failed.
electrodacaus stacks up well on paper and if they now have CAN support thats a great addition again i originally looked at this but didn't like the yellow circuit board style case looks too much like a science project but being open source they are making fast progress with new features
for SSR i would go with a Victron Battery protect they do upto a 200A continuous version. i have a 100A one that i never got round to fitting that i was going to put on the 12v house loads as a last resort if all else failed.
electrodacaus stacks up well on paper and if they now have CAN support thats a great addition again i originally looked at this but didn't like the yellow circuit board style case looks too much like a science project but being open source they are making fast progress with new features
sailaboutvic
Well-known member
Hi neil
Watching your video and the reading you was getting I wonder if you can explain some thing to me .
Your said you charged your to 3,6v cell
Bank is 560ah and you was drawing 1500w around 123A .
The voltage started 14.4v and no soon you turned it on they drop to 12.5v , this is where I'm a bit confuse .
I'm comparing your to mine .
If you look at the photo , you see mine where fully charge ,
now I say fully charge mine to 13.8v ( 3.45v cell) so not 100% although the photo says 100% .
My bank is 400Ah
If you look at the next photo you see I drawing 170A and and they drop from 13.5v to 13.1v and stay there .
So my question is why do your drop so much more where they started at a higher voltages nearly a volt hight and drop to .6 v lower then mine in second where. Mine will stay at 13.1v .
Also I'm drawing 170A aguist your 123A
I'm Asking the question as you know I'm only a year onto lithium and still very green .
I know different make will perform differently but I'm surprised in the difference on voltages drops .
Cheers
Vic
PS just to say mine will stay at 13.1v for a very long time At that draw ,before there any more drop in voltages .
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nfluester
Active member
i am pretty sure it was down to the loose bus bars as i mentioned further in to the video once i tightened the voltage went up
sailaboutvic
Well-known member
Cool thanks I did see you had a loose connection but wasn't sure if there was some thing else involve .
Hope all going ok , the most we draw so far is 240A at any one time and they seen to be holding up well .
Look forward to more of your posting .
vas
Well-known member
Will Prowse is an .... Nice face, playing with lots of kit, slow, annoying slow videos, incapable of reading manuals, doesn't do justise to the kit he's "testing". Most of his issues with chargery later proved his mistakes. Videos only good to have a look around a product and see it working (and possibly wired wrong a few times before getting it right
) Not reliable imho, but anyway.Yep a Victron BP200A will be needed I guess as a last resort disconnect.
Main issue seems to be getting a Victron driver that will deal with a BMS I'd like to buy, atm things are a bit better for Chargery and worse for Electrodacus.
BTW, anyone know of a place I could get the non fet electrodacus (the SBMS0 ) in EU?
As it stands I'm between the two. Electrodacus seems a bit more well thought device, Chargery is simple and does what I want.
BTW, the "light" 30p manual of Electrodacus is an excellent resource and highly recommended reading no matter what BMS you end up buying imho.
I'll keep on reading till the w/e and order on Monday. Then I guess I'll be back in January with more news
cheers
V.
gregcope
Well-known member
Another fuse question.
If you have a fast fuse (e.g. T-Class) in your battery do you need to fuse the battery again? I would assume not as the cable is now protected?
Also another fuse, unless its a faster T-Class, is likely not to blow before the T-Class in the battery.
I am assuming the above goes to a positive distribution system that has each load also individually fuse with std fuses.
If you have a fast fuse (e.g. T-Class) in your battery do you need to fuse the battery again? I would assume not as the cable is now protected?
Also another fuse, unless its a faster T-Class, is likely not to blow before the T-Class in the battery.
I am assuming the above goes to a positive distribution system that has each load also individually fuse with std fuses.
Poey50
Well-known member
I don't think so. if it ever arrives, my 225 amp Class-T will protect the main battery cable up to that ampacity and will safely manage a dead short up to 20,000 amps. That's the single main battery fuse with separate leads (in my case) to a positive load bus bar and a positive charge bus bar. Smaller branched cables then have their own fuse (not Class-T) matched to the ampacity of the smaller cable. Any cable leading off the bus bars that is the same size as the primary battery cable is not separately fused as the Class T protects.
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