hey guys Frank here today I want to talk about be a messes I know that this has
got a lot of people have a lot of different opinions on BM s's which ones
are good ones which ones are bad ones should use them should you not use them
I am under the opinion that you don't have to use them and that you could and
there's different types and different ways to use BM s's but for me and some
of the stuff that I'm doing currently I'm gonna be using some BM essence and
there are really simple ones they're not anything elaborate I know there's some
really nice bait reham BM s systems out there the type of battery packs that I'm
building I cannot seem to figure out if bay tree and will actually support them
or not because I'm actually putting all of my batteries into a full cell pack
where the ones that I've seen they'll do it based on you know the long mods are
actually attaching to each cell set so it would be equivalent to one cell a 4.2
volt cell or 3.7 nominal hen I would like to use something like that that I
could actually go back to a monitoring system where I could hook it to a
computer and actually see the results and see where things are as far as my
batteries and where my cells are and how they're balanced and which ones are low
and which ones are high and if I'm having any issues but at this point I'm
just gonna have to stick with the good old-fashioned smaller units so here I
have a few BM s's that these here came in used these I got some 36 volt packs
battery packs and these came with those battery packs that's why they're all cut
off on their ends here this I believe is an 8 s unit and I haven't toured all the
way down but looking at the circuitry on the back I would be surprised if it's
more than 20 amps I'm thinking it's probably gonna
be you know 15 to 20 amps it might be 30 but I don't know I don't know for sure
because I haven't looked into it but these are examples of some this here
everything that's on this one is in languages I'm not sure of but you can
see the circuitry there and this is also an 8 s BMS so they have different sizes
and these came like that ones that I've been using that I've used a little bit
is this this unit here which is for my 4 s systems and this BMS is only rated at
30 amps so it's not something I can put a lot of amps through it so I use it for
smaller things like my battery pack here you see the BMS in here on the on the
case so this here is is one that I have built up for carrying around I've you
know I can carry this thing around and I have power with me just might wherever I
want to go and right now I'm yeah it's at 13 7 so it needs a good charge but
you can see the BMS in here and this has come in handy because when I first built
this I had issues and I wanted to share this with you it I had it tied to my
heat blanket if you look back on this video up here
I had a heat blanket and I was using it one night and I went to sleep and I woke
up the next morning and this was dead which was known but I plugged it in and
I couldn't evil the jet of it is zero it was nothing and it turns out that one of
the cell banks in there got over discharged and a drug ran those cells
right down to zero and I could not revive them they just died the rest of
the cells were fine but that one cell pack in there was dead and so that's
when I decided to start using a BMS and so I added this BMS and I have not had
an issue since when it gets down to being too far discharged for any of
these sells it shuts off this also has
balancing on it so it keeps the cells the four cell packs in sync with each
other so that I don't lose that so this is something to consider if you
especially on a small kit like this it's very helpful to be able to have the
ability to control the amount of voltage in and out and keeping the cells
balanced so that's kind of my take on BM s's I think that some of the things that
you should look for when you're trying to find a BMS is I think it's important
to have a battery balance feature there are a lot of them out there that
actually don't state that they're balanced they'll just say they're you
know battery management systems and so what they'll have is they'll have a
charge discharge shutoff point and that's really all that's there and
having that balance I think is important especially when you get into some of
these cell sets you know your 4s success 8s 13s when I go to my power wall stuff
you know it's gonna it's going to play a difference in how those cells stay
balanced and stay functioning there are there is some stuff I want to play with
and I'm not sure how I'm gonna get to it and that is when I I'd like to take and
do like their a Raspberry Pi or something along those lines one of those
smaller computer modules and actually build out my own BMS system to manage my
power wall stuff something very simpler similar to patreon but more of a DIY
thing because I want to save some money and try something out so I may be doing
that I'll leave another link here to another video that I watched where guys
actually doing it he's actually got he's actually got a raspberry I think it's
Raspberry Pi that he's using to to balance out his systems so I may be
wrong don't quote me on that it's been a couple weeks since I've actually watched
the video but it is something that I want to do in regards to BMS so a couple
other points on BMS this pack here has a lot of amps in it this is a large amp
system so I needed to get one that's higher the
these only do 30 amps 12 volts at 30 amps is not a lot of throughput I know
that if I were to even try to bring this up because if you think each cell so
let's look at capacity C okay in 18 650 s the capacity of the cell is C so if
you have a 2 mm milliamp so that's a 2 amp cell what you're gonna
run into is C is 2 amps meaning I can only run I only want to run because
these are a lot of times these are harvested cells I only want to run one C
out of those so I only want to run a maximum of 2 amps and if I have a
hundred and some-odd cells here technically I could run a hundred amps
because that's 1 C per cell if if I met you know 2 2 amps per you know that's
like closer to actually 200 amps that I could run out of this pack but my
inverter that I'm using only will wants to get around 100 amps so I don't want
to over push it or I I know it's gonna have its own shut off but what I'm gonna
do is try to control that by using the BMS so I put a hundred amp BMS on there
to allow for flow mainly just to protect the cells this is another breaking point
where you don't want to overdo it now then one last point on BMS is there are
different types of batteries you have lipo you have lithium-ion so on and so
forth be sure that when you get a BMS that it supports lithium-ion and if
nothing else strive to find it that supports 18 650 18 650 lithium ions run
different they have different voltages so if you just go and buy a BMS cuz BMS
is a BMS right well it's not if you get one that doesn't support lithium-ion and
is for lipo you might be able you might hurt the cells or you'll actually hurt
the BMS itself more likely you'll hurt the cells so my
recommendation is is make sure that when you're getting a BMS specifically refer
18 650 cells that it supports 18 650 lithium ion that will help protect your
cells and it's something you need to do a lot of you are harvesting cells so
they need to be you need to make sure that you're using the correct
BMS instead of just trying to make it happen those are some things and they're
not very expensive they're not I mean I'm talking well this one was a little
bit more I think I paid like $15 for this one but this one he's here like
three bucks three or four bucks they're not really a whole lot he's I got free
cuz I harvested them off of a thing but I don't have anything that's 36 volts so
I guess I could give these away right alright so that's my take on BMS is
maybe that'll change over time please leave your comments below if you find
this interesting please subscribe and I will get back to any comments you have
about BM s's or batteries in general thanks for watching it have a great day