when I'm sad, I watch this blogger and I feel more cheerful. for one thing I will learn something interesting and useful

@OffGridGarageAustralia

2 жыл бұрын

Thanks a lot!

thank you for these videos, and for all the tools and equipment list that you use. Often time people skip on minor things like a crimping tool, nut size, washers. Most have these things lying around, but some of us are brand new to this and have to buy every single little thing.

100% agreed with you. As a beginner, sometimes it’s really difficult to understand why you do this why you do that, This is rally helpful for new beginners. Thanks

I can't believe as many of your videos I've watched and just now found this one with this bms. This bms is what I Want For Sure now. That contactor is great.

@OffGridGarageAustralia

Жыл бұрын

Well, not so much if you keep watching the videos from this point onwards. The problem with the relay is, that it disconnects both charging and discharging. That is less than ideal. This BMS was designed for forklift operation or golf carts where you only discharge during operation.

Andy, you are the man! GOOD JOB 👌👍!!!

I doubt those small resistors do balancing. They can’t dissipate enough heat so it would take forever plus 3 days to balance a bunch of 100Ah cells. Those are voltage dividers so the chip can measure the charge levels.

Thats why I make LONG videos! Show ALL STEPS!!!💥👍👍👍

@OffGridGarageAustralia

3 жыл бұрын

Just subbed to your channel. It's you! Wow 🙂

Good after evening.. we should definitely say that from now on

4:53 it does look like there are resistors as well but the brown components are capacitors i think

@OffGridGarageAustralia

3 жыл бұрын

LEDs apparently...

Glad you didn't stay discouraged from your last video. You are also building a massive 16s battery, not the 12v or small cell ebike ones most videos show. Nothing wrong with a longer video. 4awg cable might be ok at 200a. The voltage drop may be higher than what you want, but it probably has 90c rated insulation and won't melt.

@OffGridGarageAustralia

3 жыл бұрын

Thanks for your feedback

The big resistor is probably for spark avoidance, first you connect trough the resistor till the condensers in the load/inverter are loaded and the you make the "right" connection (w/o resistor). The BMS looks pretty solid! 👍 Only thing I personaly dont't like is the way how the balancing is done, by "burning" the excesive charge

@OffGridGarageAustralia

3 жыл бұрын

Thanks for the explanation. As I have solar and the balancing should not be used often (charging to 80% only), I'm not too worried about that loss. Its free energy.

50microA coil current is impossible for a contactor of that size. According to the EVR300CPES datasheet the coil current depends on the driving voltage 12V/24V. The worst case value is 2.4W for the coil. This power heats up the contactor while it drains your battery at the same time. That is one of the reasons why most BMS use power MOSFETs or solid state relays. That little chickenfood near your balancing connectors are resistors and capacitors. They are needed to comply with EMC and do not work as balancer loads. That is the job of that huge 10W resistor, as other viewers already noted.

@OffGridGarageAustralia

3 жыл бұрын

Thanks for looking up the specs. I could not find them anywhere but didn't look to intensive. I don't think you can balance several cells through one resistor at the same time though.

@djrrmml7514

3 жыл бұрын

Latching relay...

The silicone insulation is rated for 200°C. The cable is 200A capable but will get quite hot.

Hi ; thank you for the information about this interesting BMS ; But i still have a question : is it possible to use it in an 8S configuration ? On various sites, they show wiring diagrams for 13..16S , but not the 8S - although they all advertise the product as a "7S 8S 10S 12S 13S 14S 15S 16S 17S 20S BMS" ; does the documentation provide a wiring diagram for an 8S configuration ? Thank you in advance !

My Orion BMS also uses a contactor to disconnect the battery, but it's only used for "emergency" shutoff. The BMS uses either CAN-bus or digital outputs to control chargers/loads. You never want the contactor to be shut off except in emergency situations because it can cause loads of other problems. That is one advantage of the MOSFET based BMS units is that they can block current directionally. Meaning the BMS is capable of blocking charge current but still allowing discharge current and vice versa. The problem I forsee that you may encounter here is this: Let's suppose during charging one of your cells reaches 3.65v. The BMS will see this and "disconnect". But since the load and charge both go through the same contactor, now your inverters have been disconnected from the battery as well. Another problem is the opposite issue: Say the battery gets low from overnight discharge loads and shuts off. Then when the sun comes up in the morning the MPPT will be disconnected from the battery and unable to recharge it. You might assume you can set your cut-off voltages on the inverter and charger to avoid this. And while you probably can when the pack is new, as cells get out of balance this will no longer work as reliably. (Ask me how I know) It would be ideal if the BMS could communicate with the MPPT to just tell it to stop charging when a cell gets high (or low) instead of having to cut the contactor to stop charge/discharge.

@OffGridGarageAustralia

3 жыл бұрын

I thought about this problem since I started thinking about the solar and battery system I'm gone build. At the moment there is no way for any communication between the BMS and the MPPT and I'm not sure if Victron does a 48V BMS which can communicate with their devices. I have set the shunt as the second device now, so if the BMS shuts off the shunt will not work and communicate with the MPPT any more. I had to make a decision at some stage, so that's it for the moment. Is your Orion talking to your Victron gear?

@JeremyAkersInAustin

3 жыл бұрын

@@OffGridGarageAustralia Yes my Orion offers two ways to control charger / inverter. 1) It offers digital outputs which can be used to either directly control devices or can be used to open / close a relay. On the MPPT there is a set of terminals on the bottom, all the way to the right hand side that control whether the MPPT charges or not. By default there is a wire in there that jumps the terminals together to short them out. I can't remember if it needs to be pulled high or pulled low: But basically the Orion can directly connect to digital inputs that need to be "pulled low" to ground: When charging is allowed Orion pulls the digital output low to ground. This can be wired to the on/off port on the Victron MPPT to control it. It likewise has a digital output to control "loads". So one digital output wire to control charger, another to control loads. These can be wired to relays and you can use the relays to control bigger loads / chargersor if the load/charger has a digital input (Which Victron does) it can often be wired directly to that digital input. It also has a 3rd output, which is analog rather than digital, which varies from 0 to 5v to indicate the max charging rate. As the battery gets closer to 100% SOC the BMS will lower the voltage on this output to instruct a charger to slow down charging. 2) The 2nd method Orion offers, if you pay a little extra for the CAN-bus version of their BMS, is it can communicate via CAN-bus. This requires getting the Victron Color Control GX (Or one of the other Venus GX products from Victron). With this setup the BMS sends CAN-bus messages to the Color Control, which receives those messages and then the Color Control commands the MPPT, Inverters, etc based on what the BMS sends it via CAN-bus. For example when my battery gets to 98% SOC: My Orion tells my Charger to slow down charging. (The max charge amperage is one of the messages passed along in CAN-bus) this way my cells have time to balance but I don't have to completely stop charging. As cells continue to get closer to 3.65v the BMS continues to lower the charging amperage. It's much easier on the equipment than constantly turning them on/off over and over during top balancing. So even if you don't want to use CAN-bus, I would at least want a BMS that had some sort of digital output that would at least let you control a relay so you have a little better control over when charging is allowed vs discharge, etc.

@JeremyAkersInAustin

3 жыл бұрын

@@OffGridGarageAustralia I just went out and looked at my Victron MPPT. The terminals that are used to enable/disable charging from the MPPT are labeled "Remote". They ship with a wire jumper installed between the two, but you can remove this jumper and then wire these terminals to a relay or other switch (Presumably one controlled by your BMS) to tell the MPPT to charge or to stop charging.

@OffGridGarageAustralia

3 жыл бұрын

@@JeremyAkersInAustin That is all great information, Jeremy. Thank you very much!

The short bit of 4gauge, should be fine, I would feel fine with 150 amps from that bit of 4 gauge cable, as long as it's short! 200amps peaks maybe, do they offer this BMS in 7s liion, 3.7/4.2v cells, 29.4v I need atleast 225-275 amps continuous, I'm looking for a better BMS, this seems nice! I'm interested to see hows it goes!

Do you keep all the balance wires the same length? I was told that you need to keep all the battery wires the same length in DC systems?

@OffGridGarageAustralia

3 жыл бұрын

I have extended some. It's just for voltage sensing so there is no current (and hence no voltage drop) unless the BMS balances this cell.

Yes, this bms seems to be high quality and has 5 stars reviews but no loger available. I would have gotten a caple to play around.I got 6 Daly last week for some testing too. The problem with relay is that they are more prone to failure and not as efficient as mosfet type bms.

@OffGridGarageAustralia

3 жыл бұрын

Hmm, not sure if this relay is not more efficient considering the huge amount of heat created in other BMS's.

@JeremyAkersInAustin

3 жыл бұрын

@@OffGridGarageAustralia You should measure the amount of power the contactor draws when it's closed. The coil on most 200A contactors draws around 20 watts: It takes a decent amount of power to keep that big electro-magnet pulling that spring loaded contact closed. This is another advantage of the MOSFET based BMS units. The MOSFET units waste more energy under high loads (From the heat generated from the voltage drop across the MOSFET) but the contactor type BMS is always pulling 20 watts even if nothing else is pulling energy from the battery. 20 watts may not seem like much, but that's almost 0.5 kWh for an entire day of usage. It really just depends on your use case. For me I needed to build a system that could offer sustained power outputs of 10,000 watts. So it made more sense to go with a contactor. If you're not going to be pulling that much power continuously then MOSFET's may be a better option.

Why is it a problem if the wire is getting warm? Should they be cold when pulling 200A? What temp is warm? 45°C ? 50?

can the daly or the bms connect to another daly or bms for serial communications between battery packs?

I do understand about what you are saying about the cable being underrated, but the rating standard is for a 1 meter length (?), whereas your bms cable looks like less than half that length.

@OffGridGarageAustralia

3 жыл бұрын

Current rating has nothing to do with the length of a cable though. It does not matter if you send 100A though 1inch or 1mile of cable.

@yodab.at1746

3 жыл бұрын

@@ursodermatt8809 my bad though, I was getting mixed up with voltage drop... But voltage drop is a result of resistance over length.. So if over a length you have x voltage drop, then halving that length will halve the voltage drop. If voltage drop is a result of resistance, the current carrying capacity will go up the shorter the length, or the heat generated by resistance would go down.

I have daligreencs 200A BMS, 8S280Ah , Blue tooth APP, I followed the installation instructiona and everything worked fine. Two days ago I did something so I lost the output voltage from BMS. I tried to disconnect BMS, short circuit B-and P- but nothing help.The next day I try again and it works again. OK I start charged battery again and everything works well. Then I tried connect BMS to PC via UART cable. Because I couldt find app I gave up. But now again BMS not work. No voltage. No blue tooth. I thing BMS is in some slipping mode. Have you any idea what to do. p.s. I love your frogs.

The chinese always overestimate the specs of their products by about 35-50%. I like the bms with the relay/contactor option and i'm surprised about how low the I draw is. Nice teardown my friend 👍

@georgedemean2228

3 жыл бұрын

@@ursodermatt8809 Maybe...lol

@georgedemean2228

3 жыл бұрын

@@ursodermatt8809 It's all relative to price...lol

I have the same batteries as you and find that they do seem to need a fair amount of balance charging after a decent discharge. I am a little worried about the small balance current offered by that BMS. I would keep an eye on the cell balances for a bit.

@diydan6045

3 жыл бұрын

Would buy these batteries again or go for another brand?

@jasondevine6014

3 жыл бұрын

@@diydan6045 yes I would. Really good price point. Just need to be aware that they are not as well matched as say calb cells.

@OffGridGarageAustralia

3 жыл бұрын

I plan to charge the cells to 3.35V only, so I'll the MPPT to charge to 53.6V max. If one of the cells gets say to 3.45V, the BMS will start the balancing. So in theory, balancing will not occur as long as all cells stay under 3.45V. That's how I will start.

@jasondevine6014

3 жыл бұрын

@@OffGridGarageAustralia wouldn't you need to push them slightly up the voltage curve so that you can balance. I balance 3.4 and charge to 3.5.

@RJ-cc1fz

3 жыл бұрын

@@jasondevine6014 yes he needs to balance lifepo4 when the cells are at the steep part (top end)of the discharge curve. If he doesn’t then the cells might be balanced to the same voltage but their capacity could still be very different

Do you have a Link ,where to Order that relax BMS?

You should check out diyBMS. A lot more modular and customisable for diy.

@OffGridGarageAustralia

3 жыл бұрын

YES, seen that. Adam Welsh has made some interesting videos about it...

05:07 Ist there a short between the IC Pin 5-6 on the measurement IC ??

@OffGridGarageAustralia

3 жыл бұрын

Not sure, I didn't look.

I,m a bit apprehensive in the way the lugs are bolted to the current sensor shunt. 200amps not sure it can perform this on a continues basis.

@OffGridGarageAustralia

3 жыл бұрын

Time will tell, I guess. It looks good to me...

It would be a latching relay, they only need a short pulse to switch its state.

@OffGridGarageAustralia

3 жыл бұрын

Best reply. That could be the case. I will measure it tonight and post a video afterwards. Got the BMS connected for 1.5 days now and the BMS is cold even the relay is closed.

For off-grid, use of relays is not at all my ideal since the coil consumes so much of the stored energy. I designed and built my own solid state relay network using MOSFETs, which consume next to nothing at all, and because I over-sized them for the current handling they will perform, the heat is minimized, so I really don't see that one is gaining function going to relays. All the off-grid folks I know always steer away from electro-mechanical relays.

@unionse7en

2 жыл бұрын

mechanically latching relays, zero idle current....but! have to worry about failsafe logic..won't return to a non powered state

Three of the logical processor legs are shortening due to soldering defect.

Do they have a higher current version? 300-400 amps, I like to have a bit of headroom with bms, FET based or not, about 3-4 times nominal use, and about 30%-40% over peak, I tend to stay below 2500w and above 24v, but can get above 3500w on occasion, I hace been into solar for years, and worked as electrician for years, and worked with DC power since I was a kid, but more recent started getting into electronics and electrical engineering, I have just learned the basics so far, I like your videos because it make me think more about the things I tend to forget about, and you help with ideas, thank you!! Great videos, even if you are crying about no tools, ha-ha, good day(summer day, it's COLD here!!

@OffGridGarageAustralia

3 жыл бұрын

Thanks James. It's win win, you guys helped me a lot thinking about things I would have forgotten about... They don't build these any more. Hope that's not a bad sign :\ off-grid-garage.com/battery-management-systems-bms/

@fathergratwick

Жыл бұрын

@@OffGridGarageAustralia JBD/heltec does still make these only in a different enclosure/branding

Hi.If the bms cut off the battery from the Solar charge controller, the SCC will be destroyed right? Since most solar charger need to be connected to the battery first. Any tips to prevent those costly accident. Thanks

@intheyear2510

3 жыл бұрын

Apparently victron say this won't be an issue , other charge controllers may be different case for sure , its a good question as this is a problem for sure , I use a seperate port bms which would negate this issue you describe

@PeterMilanovski

3 жыл бұрын

I'm not sure about victron but just about every other charge controller will blow up if the solar panels are connected and active without a battery connected on the other end! This is a trap for young players! It's the one thing that must be included in the design plan, my son found out the hard way! He had one of those all in one MPPT brand charge controller/inverter/AC battery charger, they are not cheap! And he disconnected the battery during a sunny day and the panels were active! He won't be doing that again anytime soon LoL... Unless the manufacturer states it clearly, you should always treat it like it will be damaged if the batteries are not connected while solar is!

@OffGridGarageAustralia

3 жыл бұрын

There is an official statement from Victron in their forums saying it does not destroy the MPPT. But with other it might be the case. The blue JNGE MPPT can handle the solar without battery as well just fine. I have burned a cheap WPM controller though by disconnecting the battery.

@PeterMilanovski

3 жыл бұрын

@@ursodermatt8809 well there you go! It seems that the only charge controllers I have fail because of this very reason and from what I have seen with other people must have been designed poorly! This doesn't seem to be common knowledge, it may be printed in the manual but I didn't realize how serious of a problem it will become if this isn't understood as a golden rule! I have watched many videos that review charge controllers and no one ever made a mention that "oh! This one is one of those that need to have a battery connected to it before the solar input otherwise it will blow up!". I have a DC to DC charge controller for the car that has inputs from the alternator and a solar panel that is designed to charge a secondary battery which always will choose solar panels first if solar power is available, it's also dead and I'm suspecting that it has also suffered the same fate! At the moment I have it taken apart and from what I have found so far is it's diodes are blown, they chose to use a double diode in a transistor style package which are not cheap but I just finished watching a video from diodes gone wild in which he was repairing a computer power supply and saw that some have these things in them, I have heaps of power supplies which I can salvage parts from but I got my legs sunburnt badly on Sunday at the beach in beautiful Sorrento here in Melbourne Australia, it was an overcast day, there was no direct sunlight and I got caught out! So basically I'm waiting till I can walk around again till I can get to fixing these charge controller's.. Edit: I just had a thought, my batteries are protected against all the usual stuff, and if too much current is drawn, they will shut down and that means the charge controller will die! I'm thinking that maybe if I fit a 50V capacitor to the output of the charge controller, it might protect it if that situation ever occurred! Just as a precaution, I generally overrate everything so basically I won't be drawing more than 1.5A max from each of the 12V batteries in the system so I don't see any problems there but as they always say, to be sure is to be sure!

@evil17

2 жыл бұрын

@@PeterMilanovski hi, I am interested in how you went with the capacitor idea, as I had exactly the same thoughts as I read ur comment. I have been using caps for some time in this way mainly for the extra boost they can give inverters and to help filter ripple & surge from batteries, but reading this thread of comments has given more reasons as to why we should use caps in this way in a solar system. Ive recently been experimenting with large caps on the 60v PV side of a 12v mppt system with some very interesting results. Hope it all worked out for ya, Cheers

QUCC BMS doesn't look like it can actually do cell balancing, just cell voltage sensing?

@OffGridGarageAustralia

3 жыл бұрын

All their BMS's have balancing function from looking at it. off-grid-garage.com/battery-management-systems-bms/

What's the paste on the screws fixing the busbars ? I understand this is to avoid galvanic corrosion due to the material difference right ?

@SciBee

3 жыл бұрын

That is glue to keep the screws in position even if they slightly move for thermal reasons. It is also used to fix e.g. big capacitors or inductors in vibrating environments.

@OffGridGarageAustralia

3 жыл бұрын

Yeah, it was already hardened stuff, thought it's just glue...

@gregoryfierens001

3 жыл бұрын

@@OffGridGarageAustralia So possible discussion topic : is there a risk of oxidation / corrosion by using "unplated" copper busbars ?

Where do u order that BMS in the box at first video? I think it in close box like this will be safe from dirt / dust. Also no Fan , use heat sink is good. The Daly use Fan. That Fan die. ur bms die too. Usually Fan last about 40,000 hours....

@OffGridGarageAustralia

Жыл бұрын

All links are on my website off-grid-garage.com/

Intresting to see the inside for sure. Im thinking could run several of these bms in parallel to ease the load or how to say.

@jmaus2k

3 жыл бұрын

BMS relays and disconnects shouldn't be in parallel.

@JPHER217

3 жыл бұрын

@@jmaus2k Hmm are you sure about that? I saw Will Prowse trying it out: kzread.info/dash/bejne/hp-NuaancqrZgZc.html

@OffGridGarageAustralia

3 жыл бұрын

Interesting. This may work as these are not programmable BMS's and all parameters are the same, programmed into he chip already. Thank for the link.

@jmaus2k

3 жыл бұрын

@@JPHER217 Yes, it is against the electric code. I commented on Will''s video too. One test is not proof that it can work every time. What generally happens is one BMS will have slightly less resistance and start getting all the current. Eventually, it will heat up and then MOSFETs will fail on. Bad news if you had an overcurrent situation.

@JPHER217

3 жыл бұрын

@@jmaus2k "My understanding is that yes this applies to regular transistors but the opposite applies to MOSFETs (as used in BMS units).MOSFETs are actually quite good at currentsharing (they parallel lots of them in inverters & they share current nicely). If a MOSFET gets hotter, its onresistance rises = less current flow, so next device carries more current, heats, equalizes, etc My concern with parallel BMS's with load switching would be one switches on/off before/after the other leaving one to carry the load. For cell monitoring/balancing it shouldn't matter much." With this statement it should be the opposite of what you are saying right? I mean the hotter they get the higher resistance and less current flowing thru that unit.

OL on your meter is Over Limit (over range of the meter), not Overload FYI. The RS485 port is for continuous monitoring without using Bluetooth

@JeremyAkersInAustin

3 жыл бұрын

Are you saying this BMS has an RS485 port? Isn't RS485 usually used to provide CAN-bus? Where did you see the RS485 port in the video?

@jankomuzykant1844

3 жыл бұрын

@@JeremyAkersInAustin 8:14 RS485 is not CAN bus

@houstonfirefox

3 жыл бұрын

@@JeremyAkersInAustin at 8:13 you can see the RS485 port. RS485 is a communications protocol which is commonly used to communicate with industrial equipment, alarm systems, SCADA controls in chemical plants, etc. In this case it is probably being used to monitor the status of the BMS in real time.

That large resistor is part of the precharge circuit in the BMS. It will charge up the inverter capacitors slowly, preventing the large inrush current from welding the BYD contactor terminals together.

With the Electrodacus SBMS0 there is no large current going thru the BMS. the large current up to 24 amps but rated at 20 amps each goes thru the Electrodacus DSSR20's. The DSSR20's are solid-state charge controller and push everything the panel will give to the LiFePO4 battery bank but limited to a 24-volt battery. I use 2P8S 24-volt 272Ah 16 cell Lishens. totally different than what you are assembling. but is capable of controlling over 18000 watts of pv panels unlike the limits on mppt charge controllers. just a tidbit for you. nice videos- keep up the good work! 😎

@OffGridGarageAustralia

3 жыл бұрын

Thank you. This will be one of my next projects. I'm in contact with ElectroDacus... very interesting devices.

@cgmarch2359

3 жыл бұрын

keep in mind that for SBMS0 you need to match Solar panels voltage with battery

@pilgrimvalle

3 жыл бұрын

@@cgmarch2359 the sbms0 is perfect for 60 cell and 72 cell panels in parallel which is what the off-grid garage has already on his roof.

@pilgrimvalle

3 жыл бұрын

@@cgmarch2359 he has the correct panels to parallel up to the Electrodacus SBMS0 either 60 cell or 72 cell PV panels in pairs work great with the Electrodacus DSSR20's. the DSSR20's replace the MPPT. the SBMS0 is the solar battery management system and will work just fine with his MPPT. the SBMS0 will balance the cells if he sets it up as a 24-volt system 2P8S battery. the Electrodacus equipment is designed for 24-volt systems or 12-volt systems. i have 2 24-volt 16 cell Lishen 272Ah batteries being balanced using the SBMS0 and DSSR20's. each battery is 272Ah x 16cells x 3.2volts per cell = 13926.4 watt-hour potential capacity per battery.

@pilgrimvalle

3 жыл бұрын

@@cgmarch2359 2 60 cell 250-watt panels in parallel go through the breakers in parallel at about 38 volts then the dssr20 charges the battery at about 27.2 volts. the battery brings the voltage down and when it is fully charges the sbms0 turns off the dssr20's to protect the battery from being overcharged.

I just want to share my learning experience with everyone from a catastrophic failure today if you are considering different BMS systems. I had a brand new 8s pack of these 280ah cells turn to pillows with electrolyte everywhere from overcharge. The problem was a failure in the charge controller. It's high side fet shorted putting full solar voltage to the BMS. The BMS was a Daly smart BMS. The battery reached full charge and then BMS tried to turn off. Upon doing so the FET saw the full 96v solar voltage. This then shorted the charge FETs in the Daly smart BMS. Now full solar voltage was across the 24v pack. Couple of hours later, I have a mess. I will not put a MOSFET BMS in ever again without knowing it's open circuit voltage handling. My big system uses diybms with relays.

@OffGridGarageAustralia

3 жыл бұрын

Oh, no, Jason. That is not good and what a mess!!!! Sorry to hear that. Maybe these BMSs with relay are not bad after all to really protect your battery, right? Are all Daly BMSs having this problem? That would be a major design flaw. What charge controller do you use?

@jasondevine6014

3 жыл бұрын

@@OffGridGarageAustralia yes using a esmart cc. And yes relay is the go. I will put a diybms on this one when replacing. The open circuit voltage handling of these get based BMS is the problem. Then other option is to put a crowbar circuit onto the system for this kind of failure mode so that fuses would blow.

@chriskemp695

2 жыл бұрын

@@jasondevine6014 @Jason Devine I'm a beginner looking at building my own battery and looking at using a JK BMS with integrated active Balancer but I believe they use fets so was wondering what you mean by a crowbar circuit? Thanks

The big white 10W resistor can only be used for one thing! And that's to dissipate heat! The more that your cell's become unbalanced, the harder it's going to work! Some BMS systems use multiple smaller resistors and will dissipate excess energy across multiple cell's if needed, this unit seems to only have one large resistor and possibly only discharges one cell at a time! I wonder how it's going to cope if more than two cell's reach full charge if it can only discharge one at a time? It might be a good idea to connect 3 cell's with one cell slightly discharged to see what happens? Maybe even take the BMS out of the case and so you can keep an eye on the resistor temperature 🌡️... Is it going to discharge just one cell while over charging the other full cell? Or will it disengage the relay while it brings thing's back under control and then finally reconnect the relay? Hmmm interesting not sure how it works! Oh! And good after evening to you too! LoL 😆

@OffGridGarageAustralia

3 жыл бұрын

You think there is only one resistor for all the cells? How do the balance at the same time then?

@JeremyAkersInAustin

3 жыл бұрын

@@OffGridGarageAustralia I was thinking the same thing as well. That row of components you pointed out as resistors are more likely diodes and/or fuses. Most BMS units have a diode (and sometimes an inline fuse) between each of the cell measurement taps to allow the BMS to measure the voltage between each tap while preventing current from flowing the wrong way through the taps (Which is why you can't mess with wiring with the BMS connected, because if any of those diodes see anything over around 5v, they burn out. If you skip a cell tap they would see 3.2vx2=6.4v which is why disconnecting a single cell can damage the BMS) Sometimes self resetting fuses are placed inline to protect the diodes in the case of a wiring mishap. Those components do seem a bit small to dissipate the heat created during balancing. Even the largest SMD resistors can typically only dissipate a max of .25 watts of heat. 200 ma of balance current would generate around 3 times that wattage at around .75 watts Based on that I doubt they are the balancing resistors. I'd bet that big resistor is the ones used for balancing. I wouldn't be surprised if it can only balance one cell at a time. These BMS units really don't deal well with packs that get out of balance. I ended up adding "active" balancers to my pack for that reason. I'd certainly be interested in a closer look at those PCB components. It's really nice you took it apart and gave us a look inside but I couldn't really get a good look at that board. :)

I don't see any info on the BMS you used in your build link.

@OffGridGarageAustralia

3 жыл бұрын

off-grid-garage.com/battery-management-systems-bms/

1:05 - Yes, however the pursuit of perfection is the other end of the spectrum that proliferates LifePo4 battery videos which while great for discussion and theoretical limits doesn't represent real life usage or performance.

"Don't turn it on. Take it apart!" Dave from eevblog

@OffGridGarageAustralia

3 жыл бұрын

I always do that with all devices I buy (except smart phones)

Seems that QUCC no longer carries this BMS wonder why?

@OffGridGarageAustralia

3 жыл бұрын

Yeah, that makes me wonder too. I have asked them and they have a different version of this now. But it looks like a bad DIY job from some random guy in the middle of Australia or so...

Can you adjust the battery cut out voltage?

@OffGridGarageAustralia

2 жыл бұрын

Yes, the QUCC has 56 parameters which can be set with the app as per your individual needs.

@izzzzzz6

2 жыл бұрын

@@OffGridGarageAustralia Nice. I'm thinking to do a build with the one that has the grey solenoid. I don't really want a cell cut out i just want to see the cell voltages so i can decide for myself when to stop. lol I have my own fast balance charger. One thing that i would like to know is does the BMS balance the cells while they are under load being used in the application? In other words. If once cell is a bit weak and it drops a bit lower than all the others, will the bms feed it power from the other cells (not while charging but while the battery is in use) so that that one cell (or a few weak cells) is or are not the cause of the battery shutting down? I don't care about charging with a BMS just to try to keep any weak cells as topped off as the strongest ones while in use. The rest is a waste of power running the bms. I just don't want to kill the cells so i really only need to monitor them if the bms can't boost weak cells during use then i don't really need one.

Shunt based BMS will draw more power on idle vs mosfet.

@OffGridGarageAustralia

3 жыл бұрын

No current when idling, so no loss. This has nothing to do with the shunt but rather with the relay which always draws a bit of power...

@Foxfried

3 жыл бұрын

Yes sorry I meant relay, there is more power consumption with a relay vs mosfets. And relays generally get very hot when being in high loads.

@OffGridGarageAustralia

3 жыл бұрын

@@Foxfried Yeah I just measured the temperature on the BMS and it's still the same as last night. Relay is active all the time. I guess they are using very high resistance coils for such relays. These are been used in EVs to connect the HV battery to the drive train. No heat so far...

Do you have a link to the BMS seller, details?

@OffGridGarageAustralia

3 жыл бұрын

Watch part 2 of the video... kzread.info/dash/bejne/hGtlxdZrkryTkaQ.html

Some of us not living in the tropics would need a low temperature cut-off in the BMS as well. Not negotiable. I find it hard to believe a relay that size can draw only fifty microamps. Milliamps, maybe. But microamps?

@OffGridGarageAustralia

3 жыл бұрын

I'll measure it in the next video. You can program the low voltage disconnect in the BMS. I've seen the option.

@lyfandeth

3 жыл бұрын

@@OffGridGarageAustralia Thank you. The low voltage cutoff usually is programmable, but large parts of the US routinely see -20° C in the winter, and few BMSes include a critical low *temperature* cut off.

Like the way you make your vids but suddenly there are way too much commercials. Thumbs up anyway!

@OffGridGarageAustralia

3 жыл бұрын

Oh, I have to have a look at this. KZread does it automatically... Thanks for the feedback.

plz check relay after loud. it may be very hot.

@OffGridGarageAustralia

3 жыл бұрын

Nope, not even hand warm. Got everything running for a few days now.

@svajunasslavickas8141

3 жыл бұрын

@@OffGridGarageAustralia good bms then :)

What does "BMS" stand for?

12/24V contactor .. but isn't this a 48V bms? Does that not matter?

@jasondevine6014

3 жыл бұрын

I am sure the BMS will only drive the contactor at 24 or 12v.

@PeterMilanovski

3 жыл бұрын

I'm sure that if we had a better look at the PCB, I'm sure that there would be a voltage regulator on there somewhere that would drive the relay, there would also be a 3.3V voltage regulator to drive the digital circuitry as well... What I'm currently concerned about is that I only saw the one bleed resistor! That's the big white 10W jobbie! What if two or more cell's need to be discharged at the same time to get the pack in balance? I guess that we will have to wait and see what happens!

@OffGridGarageAustralia

3 жыл бұрын

I think the BMS runs on 12V only as it is a 7s to 20s.

@PeterMilanovski

3 жыл бұрын

@@OffGridGarageAustralia yes but I think that if you probe around with your multimeter while it's operating, you will find voltages of 3.3V, 5V and 12V, naturally the 12V will be to power the relay but the other voltages are needed to drive the microcontroller, you can always Google the controller part number and find it's datasheet pdf which will confirm it's operating voltage! It's not important but if for any reason it didn't work and you wanted to fix it yourself and you have the tools and techniques to make the repair, then it's relevant, otherwise, not really important for this channel!

for high amps I trust relay more than chines mosfet

It’s not the video length, it’s the editing.

its 20s, that cable is fine

@taison03251970

3 жыл бұрын

What does 20s mean? I saw BMS has 3s, 4s, ..., 24s, etc, wondering what the 's' means?

@bl0wfish

3 жыл бұрын

@@taison03251970 series. So 20s is 20 in series

No jewelry while working on electronic equipment. Even with power unplugged static electricity can cause component failure,

@OffGridGarageAustralia

3 жыл бұрын

OK, so on this ring situation. How would I even possibly touch both contacts with two separate un-isolated tools at the same time and they short directly at the ring?

Static Electricity and fine electronics != Good , easiest way to fry electronics.

@OffGridGarageAustralia

3 жыл бұрын

Board has a coating

@eksine

3 жыл бұрын

there is nothing fine about the electronics inside

Yes, if its under 5 minutes it is not worth my time to watch.

Stop touching discreet components with your unfounded fingers, static can fry them!

@OffGridGarageAustralia

3 жыл бұрын

All electronics is covered in clear goop.

You never commented on your posting title. "Why I didn't buy a Daly"! So why didn't you buy a Daley BMS??? Deceiving title and lack of information!!!