I did connect without any problem with my iPhone. ?
JK (JiKong) BMS - 4S
- Thread starter JanVJ
- Start date
I did choose the JK (JiKong) because I like the app. Also, the balance funcktion looks like ?
I will post more details later in spring. ?
Agree ?
Turned out it was tons of support for such «stupid» idea out there.
But hey; thats life; sometimes the flow turn against you.. and sometimes it does not. Stay positive ?
BigBrosMo
New Member
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- Feb 6, 2021
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I use it with my Android no problem!
hwse
Solar Enthusiast
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- Jan 2, 2021
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I am building two 12v batteries using 280ah cells with completely different requirements. I plan to use the JK BMS 2A4S20P with a 12v/24v boost converter as the BMS for both.
One is for my sailboat house bank which is replacing a Lifeline 4D AGM with consumption of less than 150ah/24hr. It will be 2p4s using the JK BMS. The boat currently has no big drains with the largest being a 500W anchor windlass which I only use when the motor is running. I will a EVO 1212F 1200 watt inverter / 60A charger for shore power charging. At 200A (350A surge) the JK should be plenty.
The other battery is for my all-electric motorhome house bank. The current bank is (6) 6v / 215ah FLA golf cart batteries which gives me a 12v bank at 645ah but I use about 400/600ah/24hr. I use the LFP to 50% SOC when dry camping so it has a useable capacity of 320ah. That means that I need to run the generator at least twice a day. I would like to replace this bank with (12) 280ah cells for total bank capacity of 840 which at 80% will give me 672ah usable. I have a Magnum MS2000 inverter charger installed which has 100A charger and can be configured to CC/CV charging.
Question: Can a single JK BMS 2A4S20P (200A/350A surge) on a 3p4s configuration supply enough power to the Magnum MS2000 or do I need to build (3) 4s batteries, each with their own BMS?
One is for my sailboat house bank which is replacing a Lifeline 4D AGM with consumption of less than 150ah/24hr. It will be 2p4s using the JK BMS. The boat currently has no big drains with the largest being a 500W anchor windlass which I only use when the motor is running. I will a EVO 1212F 1200 watt inverter / 60A charger for shore power charging. At 200A (350A surge) the JK should be plenty.
The other battery is for my all-electric motorhome house bank. The current bank is (6) 6v / 215ah FLA golf cart batteries which gives me a 12v bank at 645ah but I use about 400/600ah/24hr. I use the LFP to 50% SOC when dry camping so it has a useable capacity of 320ah. That means that I need to run the generator at least twice a day. I would like to replace this bank with (12) 280ah cells for total bank capacity of 840 which at 80% will give me 672ah usable. I have a Magnum MS2000 inverter charger installed which has 100A charger and can be configured to CC/CV charging.
Question: Can a single JK BMS 2A4S20P (200A/350A surge) on a 3p4s configuration supply enough power to the Magnum MS2000 or do I need to build (3) 4s batteries, each with their own BMS?
RCinFLA
Solar Wizard
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- Jun 21, 2020
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This statement in the manual, is not technically reasonable and invalidates all their wiring diagrams for 16s and above.
"Pls note: the charger voltage must more 4V higher than battery packs, then
can make bms power on.
Like,your battery is 50v, then your charger must min 54v."
Their use of the word 'charger' makes it confusing. It is the booster supply above battery to B+ of BMS.
I believe what they mean is if battery is less than 36v the initial inactive B+ terminal pin voltage must be greater than +5v + battery voltage above C- voltage. This would happen when BMS switch is open before it starts up.
"Pls note: the charger voltage must more 4V higher than battery packs, then
can make bms power on.
Like,your battery is 50v, then your charger must min 54v."
Their use of the word 'charger' makes it confusing. It is the booster supply above battery to B+ of BMS.
I believe what they mean is if battery is less than 36v the initial inactive B+ terminal pin voltage must be greater than +5v + battery voltage above C- voltage. This would happen when BMS switch is open before it starts up.
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The BMS just turns on when you put on the 'charger' or solar charge controller. If the battery sits at say 49V (16s battery), and you have your charge parameters set to 3.4V per cell (54.4V), the BMS will turn on.
RCinFLA
Solar Wizard
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That would make poor design sense for it to have anything to do with your system charger being active.
Since the BMS is initially off, there will be no voltage on inverter/charger or charger and detecting no battery voltage present they will not apply a charging voltage so BMS would not activate until you manually jump start it.
The new version has a power button; I should get it in the next few days to test.
I like the fact that this BMS can turn itself fully off, meaning it won't drain the battery further with its own self consumption after a low voltage disconnect.
Edit: I just realized I wrote "or solar charge controller' in my last message. That obviously won't work since the charge controller needs the battery voltage in order to turn on as RCinFLA also pointed out.
I like the fact that this BMS can turn itself fully off, meaning it won't drain the battery further with its own self consumption after a low voltage disconnect.
Edit: I just realized I wrote "or solar charge controller' in my last message. That obviously won't work since the charge controller needs the battery voltage in order to turn on as RCinFLA also pointed out.
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A single one will do, since 12V / 200A = 2400W and the inverter is only 2000W
Note: There seems to be a 4S version coming this year. That would save the hassle with a boost converter to power it on and so.
Heltec (JK) 200A Smart BMS with 2A Active Balance
thank you @Mark81 for posting the photos of the BMS internals, hope it can work again soon
diysolarforum.com
This (new) user @Nami seems to be affiliated to Hankzor or so, so this might be true.
I would love to see such a BMS. Currently using a JDB 200A one, but that one does only have passive balancing, where as those JKs have active balance. So curious to see how this price will be.
@JanVJ first off, thank you for not getting discouraged and giving up when everyone started criticizing you! We need more guys testing outside the box!
I'm hoping to do similar to you. And would love your advice.
I have 8 eve 280k cells ( 8 x 3.2v @280ah). I plan on running them at 12v for my camper and using the JK BMS 8s/2A/200A/BT
I know I'm going to have to run series/parallel in order to get 12v. But what's the best way of going about that with the BMS? If I jump it to activate it and reprogram for 12v, will that make the balance leads only look at 4 cells?
I could always parallel 2 cells and series the 4 sets. And put balance leads to each parallel set of cells. But wouldn't it be better to series 4 individual cells to make 2 x 12v packs, and them parallel the 2 12v packs? That way I could monitor and balance each cell individually.
Would love to hear from others on this. I'm pretty new and trying to learn, but it's a LOT of information to take in.
I'm hoping to do similar to you. And would love your advice.
I have 8 eve 280k cells ( 8 x 3.2v @280ah). I plan on running them at 12v for my camper and using the JK BMS 8s/2A/200A/BT
I know I'm going to have to run series/parallel in order to get 12v. But what's the best way of going about that with the BMS? If I jump it to activate it and reprogram for 12v, will that make the balance leads only look at 4 cells?
I could always parallel 2 cells and series the 4 sets. And put balance leads to each parallel set of cells. But wouldn't it be better to series 4 individual cells to make 2 x 12v packs, and them parallel the 2 12v packs? That way I could monitor and balance each cell individually.
Would love to hear from others on this. I'm pretty new and trying to learn, but it's a LOT of information to take in.
hwse
Solar Enthusiast
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On my boat, I have a fiberglass battery box formed into the settee which is 27¾" x 9½" x 10¾"H. Given that space, I can configure two options (2) 4s 280ah batteries each with their own BMS or one 2p4s with a single BMS. I will be doing the latter with the JK BMS.
2 questions... One might answer the other...
1. Why the 2p4s over the 2x4s? Just to save having to buy a second BMS?
2. Could you do the 2x4s with a single 8s JK BMS?
Would it not be better to be able to balance each cell individually instead of pairing them up? I understand pairing cells essentially makes them 1 larger cell. But can't you run into issues if they aren't perfectly matched? I guess you could run into the same issue when pairing 12v battery banks too though...
I have a feeling I'm way over thinking this. But it's a lot of time and money and I want to do it right to first time.
P. S. I guess that was a lot more than 2 questions... Lol
hwse
Solar Enthusiast
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1. I am looking at the 2p4s for simplicity and reducing the "can-o-worms" congestion of wires from two seperate batteries, each with its own BMS.
2. If you connect the cells into a pair of 4s batteries, each requires a bms.
Horsefly
Solar Wizard
You can't use a single 8S BMS to manage two 4S batteries.
Many of us here prefer to have 2 separate 4s (in this case) batteries, each with their own BMS. It provides a level of redundancy, so that if the BMS on one battery shuts down the other battery can continue. Some of us also think that a BMS best serves it's purpose when it is managing 1 cell per balance lead, as intended. If you put two cells in parallel then the combination is only as good as - and will only last as long - as the weakest cell.
There are others here who argue the other side: It's fine to put cells in parallel and build a battery that way. Mostly it just saves the expense of a second BMS, but otherwise I don't see much advantage.
Loud and clear! Thanks for the reply.
May I ask why you can't run 1x8s BMS on a pair of 4s batteries in parallel? Is it just because the BMS will be expecting 24v and only seeing 12v? If so couldn't you just trick the BMS like in Andy's video (linked at the beginning of this thread) ?
Horsefly
Solar Wizard
An 8s BMS expects to check the voltage of each cell by measuring the difference between consecutive balance leads. So if you have an 8s BMS is has 9 balance leads, and to check the voltage of cell 4 it will look at the difference between the B4+ lead and the B3+ lead. Now if you try to hook up to 2 separate 4S batteries, it will assume that the B5+ lead (the sixth of your nine balance leads) will indicate the voltage of the 5th cell, by comparing it to the B4+ lead. That won't work, and the BMS will try like hell to balance and it can't. Moreover, it will probably shut down with an under-voltage since it will look like cell 5 is something like -9V.
I watched the video you are talking about from Andy some time ago. I don't have time to watch it again right now, but as I recall the "trick" he did was to use an 8S BMS (or maybe it was 16S) on a 4S pack of cells. For some BMS's that will work, if you leave the unused balance leads unconnected to anything.
Ah ok, thank makes perfect sense. Pretty obvious once you know how it works.
