How to balance big lithium ion battery packs with Bloc Balancers
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- čas přidán 15. 08. 2018
- Do you have a large or difficult to balance battery pack and are wondering how to balance it? Get a quick overview of two new products from BatteryBlocs designed just for that. www.batteryblocs.com.
I've been building a home battery bank to offset the cost of electricity th aircon draws in the summer at night time. It works great but i had a hard time balancing it. I did the math and worked out the degrees of voltage seperation and figured id unhook the entire bank and manually balance them once a month to be safe.
Needless to say this was tedious.
Thank you so much for pointing out this neat little device! Yiu can bet im ordering some as soon as my collage age budget allows for it.
Pretty cool!
I balance that 6s part of the battery kit one cell row says 4.13 v others about 3.95 it’s a turnigy 6 accucell I’m balancing with should I keep it goin as it’s on a timer so stops after 2 hours or something
I do not see these products in your web site Batteryblocs.com. Are they for sale?
Hi Shawn I have a 14s 5 p 52 v kit I use on my ebike 1000 watt motor I get about 10 mile range they all new cell or they were Samsung 2600 but lot of them failed so use mostly 25r now.want to make a spare pack of 52v was goin to parallel them in a buggy trike on back of bike to get more range or just use spare battery to switch over to get home.so do u use the batterybloc balancer on the bike when running or just before I go out and what kit would I need for my 52v 14s5p battery .steve.uk
hi are you still doing the balancers if so how much i need enough for a 14s do you ship to the uk
Cool circuit most needs for lithium.
This is ideal. I have a suggestion. If possible, make the balancing voltage adjustable with a pot. That way you can sell these to cover all manner of different lithium battery chemistries. Eg Titanate lipo, lifepo4 etc. Have the user calibrate them.
If you can do that, and have a competitive price, you will be onto a winner, I would personally buy that for sure. The market is flooded with either cheap chinese crap or very overpriced balancers (batrium), and no middle ground.
Outsource your PCB's to JLCPCB, they are very cheap and very good, that will bring your PCB costs down massively. I imagine the circuit is fairly simple, so keep the price low as you can.
If you are not already, get on the facebook groups for DIY powerwalls, and Jehu's Powerwalls and DIY electric vehicles, I'm sure they would be interested.
Thank you, these are great suggestions. I would like to talk to you in more detail and send you a couple Balancers for your evaluation. Could you contact me at shawn@batteryblocs.com.
Thanks.
Do you have any products suggestions, seeing as this domain no longer exists. Building a 20p10s battery and I don't trust a $100 bms is gonna cut it..
Ok thanks Shawn I’ve got the drok rigged up to charge battery what voltage would u feed battery from drok it’s on 14.4v at present but being 4s think it says up to 16.7v that right ?on car battery it’s usually about 14v from alternator
Yes, 4S is charged from 16 to 16.8 volts.
I don't see the bloc balancers on your website
how do we get them and how much are they?
My drok has arrived just waiting for the bench power supply might have to ask you about them soon is that ok Shawn ?
Mmm, sure, but use my company email for those questions.
I am following these videos closely. I have been harvesting used 18650 cells to start a solar generator project. Right now I am strongly considering your Bloc kits for the project. I love the design you have. Based off of the readings on your power supply in this video, is it a safe estimate that these Balancers have an idle power draw of around 280ma? Or is it less than that, but the Fluke meter is drawing the bulk of the amperage?
Great question. At 3 volts, as measured with my top-end Fluke, they draw .05 amps, or .15 watt. At 4 volts they draw .07 amps, or .28 watt. So, over the course of 24 hours they burn 3.6 to 6.73 watts per Balance Bloc. So, if you have a 13S battery your overhead for cell monitoring for the entire battery over each 24 hours would be between 46.8 watts to 87 watts. I'll let you decide if that is nominal or excessive.
I don’t believe that is an excessive amount if the balancers are on a system with daily cycles. But something to consider if the battery pack is intended for backup only use, sitting for days or weeks without use.
Thank you for your calculations. I will use them as a reference when designing a system.
I am waiting on a battery tester to arrive. After that I will start to test my harvested cells. When I know how many good ones I have, I will contact you for some of your products.
Thanks for your great comments. To be fair the draw would have to be compared to other balancing systems. I don't notice it on my 20P14S ebike battery and certainly not on my 100P13S power wall. Lithium also has a self-discharge rate of 5% in 24h, then 1-2% per month that should be factored in....
I think on the wiring diagram it’s your way Shawn so will try that first is there a way I can test or will it just smoke ?ha
Sure. To test disconnect the JST-XH connector from the BMS. Hook up the wires. You should be able to count up the voltages on the JST-XH connector. 3.6, 7.2, 10.8, etc. If all are good, hook up the JST connector to the BMS.
In my case, I would like to control the top balance voltage - e.g. top balance to 4.00v or even 3.90v. Is the balance voltage settable or changeable by the purchaser?
Yes, it is programmed to your specifications when purchased.
hi shawn just wanted ask about my electric longboard with rear hoverboard motors and dual esc.after first run volts went down to 31v so recharged .it went well about 2 mile range by sea.on recharge some dead cells .using overboard charger.so rebuilt and put 5s2p x2 with 5s bms on each and balance using turnigy accucell6.so is it best to keep 2 separate packs and i had 5s connectors and bms already.had swap in lower capacity cells say 4 but balanced to same volts.thanks.steve
Hi Steve,
Is it best to keep two separate packs vs a 4P5S single pack? If you don't mind the extra management of two packs, yes because: If a parallel group goes down it takes fewer cells with it. Swapping out batteries reminds you that you are halfway. Sounds like you have the situation understood and working well.
Ok 👍
How to order and how much
hi shawn my bms 4s come for my battery it has multi coloured balanced leads but I have red /black balanced leads they usually go first red to positive then alternate black to negative of cells don't they?steve
I start with the negative wire from the BMS. There is only one. It should be marked on the board. Then I connect the remaining positive wires in order to each positive terminal of the battery pack. You should have 5 wires, one to negative, the remaining 4 to the 4 positive terminals in order from the negative up.
Ebike school does it other way round don’t they are all bms same wiring also Tommy Calloway says positive first then remaining all go negative that’s what I did with bms they sent me from eBay shall I show u wiring diagram I have
Ok, so you will have to decide.
Hi I want to build a 18650pack to power my car satnav an old one for my ebike what can I use 3or 4s with voltage regulator .have some low capacity cells to use from laptop .steve
Please contact me at shawn@batteryblocs.com with your specs and I can help you then.
Any plans for a unit with a lower cut in voltage. I'm nursing my batteries so don't charge above 4.0v
They are programmable. You can specify the resistor burn voltage and the high and low voltage alarms. I will program for your needs.
Hello I am from Brazil and I would like to know where I can buy both
Jonas I am now recommending active balancing for large lithium packs. I use these on my power wall:
www.aliexpress.com/item/1768384410.html?spm=a2g0s.9042311.0.0.27424c4dQnZ2nh
I just found my 52v 14s 5p pack keeps losing cells.this time Samsung 25r just one row of 5 cells was low 1.5v do I need to use bms shawn?one guy just uses bms for charging he doesn't connect main power thru bms.when I used one it didn't last long.the bike stopped.
Steve, this may be an extended conversation. Let's talk about it via my email: shawn@batteryblocs.com
@@shawname2 shawn@batteryblocs.com
If I build a 20s16p 72V 40Ah battery pack and then attach one of your BabyBloc's @ each block of 16 parallel cells (total: 20 BabyBlocs), do I need any other type of balancer? Or can I use pretty much any 72V CC/CV charger?
Hi Michael,
Yes, you have it right. You will not need any other type of balancer. You may still decide to use a DC circuit breaker. You can use any charger or power supply of the correct voltage. (There is one exception, a power supply designed to deliver a constant current no matter what the voltage is, but they are very specialized and rare)
Your charger voltage at 72V is to low for a 20S. 72/20 is 3.6 volts per parallel group. You would need an 80 to 84 volt charger for a 20S. An 18S would be right for your 72V charger.
@@shawname2 Yes, I should have said charger designed for 72V, I stand corrected! As I am replacing my 72V 20Ah AGM pack are you suggesting that I could actually use the cheap Chinese charger that came with my bike? (I know it is a slow-charging puppy and I'll likely purchase a high-quality one to replace it, but just wanted to know for sure)
Sure, use the cheap Chinese charger for a while and keep it as a backup. Given the watts of the charger and the watt hours of the battery we can calculate how long the little charger would take.
@@shawname2 Directly related to this: my cheap Chinese eScooter currently has a "48V" circuit breaker off the 72V AGM battery. I'm going to want to replace this with something better, but I'm having trouble finding 80V + high-Amp circuit breakers. Do you have a source? (I'm also going to replace the controller with something that can channel more Amps to the motor. Planning on upgrading to 6AWG wire)
@@shawname2 I'm thinking of this 5A charger as a modest upgrade from my current cheap Chinese one: www.ebikes.ca/shop/electric-bicycle-parts/chargers/cycle-satiator-72v-5a.html
I cant find these balancers on your website. Are you selling them?
Not any more. I am using Active Balancing on all my projects- I think it is superior.,
@@shawname2 do you have schematics for these? They seem like a nice balancer
Hi sir,
I'm wondering if you know this puzzling issue with my old laptop battery. I left it sitting on the shelf for 3 years and now I just checked it, 2 of the parallel cells in series still holds 3.9V. How is that possible? I was under the impression after all this time it would've self-discharged to sleep mode and the voltage would be low around 2.5V or dead.
No one seem to be able to answer this question. Appreciate if you can offer some insight.
Thank you.
I am not surprised- If the cells were at 4.2 volts when the battery was put on the shelf. Are the other cells dead?
@@shawname2 - Yes, 1 of the cell pair was 0V, that was why the battery circuit shut it down. The other 2 cells that I mentioned were good cells, but they were drained or should've been drained sitting on the shelf for 3 years. From some other people, they said that those cells should still work, but probably lost a lot of capacity. I was going to use them to recell my current battery, but now I think I'll just buy a new one.
Thanks for your help!
@@carrickmchwain2296 Good idea- use the leftover good cells for something like an ebike light battery...
Oh, another question -- as I am planning on using these on an eBike, can these BabyBlocs be potted?
Sure- you can coat them with a heat resistant potting material- The on-board resistor can get hot.
@@shawname2 so a silicone conformal coating would do the trick?
For the BabyBloc Balancers you would not cover the bottom- as it makes electrical contact there. I can't see why potting would not work. I have never potted them. @@MJSfoto1956
@@shawname2 well my intent was to mount the positive connector to a bus bar with an SS screw first. Then use 6 coats of spray silicone conformal coating, masking the exposed contact area of the bus bar of course. Keep in mind this would be for a custom welded battery pack.
Michael, contact me at shawnwiththewind@gmail.com @@MJSfoto1956
How can I order these? I don't see them on your site
Hi Dave,
I am discontinuing these because I am now using active balancing. I believe it to be superior. Look for a youtube video soon.
I would like to purchase but not listed on the website?
HI CD,
As they say, the better is the enemy of the good. I have switched to active balancing techniques for all my products, not time yet to do a video. Send me an email with your project and I will try to help.
@@shawname2 hi Shawn, left an email via your website. Looking for simple cost effective way to keep 320ah 7S diy 18650 power wall balanced. Am not keen on the overly complicated Chinese offerings been burnt too many Times.
I like it, but how do we fuse each cell in case one cell has reverse polarity or short out in a 60P pack?
I have never seen this-I see a lot of people take very elaborate measures for something that has very small odds of occurring. Sure, I have seen people deliberately short out a cell and cause it to out gas and eventually flame up. But I had a report from anyone about this happening to them in a well constructed battery. A battery that is soldered together without positive terminal insulation is another story. I have seen a cell gradually go bad, lose capacity faster than it's cellmates and eventually die becoming a drag on it's cellmates. But it's hard to detect one dead cell on a 60P. What does happen is that one parallel group charges faster and discharges faster. This means that it is weaker. So this one might have a dead/dying cell, or it might simply be the weakest parallel group. At least with BatteryBlocs if you suspect problems you can take the parallel group apart, check all the cells, replace any dead/weak ones, and reassemble. I guess I just never heard about someone with a well built battery that, all of a sudden, has a cell fail, and then that the fact that that cell was fused saved the battery. Anyone care to share their story please?..... So, bottom line, imho, it is a lot of work for the XXXXXX % chance of this type of failure.
I hear that, but I had a 4S pack and I was charging it and noticed I had a bad cell. I purchased a few battery meters that also balances and it said the third cell is reversed, I took the battery out and tested it with a couple different multimeters, the positive became negative and the negative became positive, I never knew this could happen either. I still have this cell, I can mail it to you for testing. I don't know how this happened and I'll probably never see it again, I used this to power a boom box for months with no problems. The battery still held a charge of -3.85v???
Totally weird, I agree, that this cell should show positive on the negative end, and negative on the positive end. It sounds like a manufacturing defect doesn't it? If it was installed "upside down" it should have gotten quite hot and you would have smelled it.
Totally weird to say the least. I was thinking it was defective, but I did charge this small pack of 4 cells many times all season last year. The cell didn't get hot when I pulled it immediately after and it held a negative charge was the most bizarre thing I ever seen with a single cell.
It really wasn't holding a "negative charge", that is not possible. It was holding a positive charge but the negative and positive terminals were reversed.... Who was the manufacturer?
it's a waste of energy... dissipating it in a resistor.... TI and LT make active balancing circuits that transfer the energy to the lower cells...
At what current do the do that? The TI systems starts at 4.3V from what I have read, that is way beyond your threshold for those batteries
@@drsolar the balancing active type ic's can be proggramed with the tenssion you want... it goes as high as 10A balancing active... with external components they can go as high as 100A...
Can you point me to where I can find it
@@drsolar just google active balancing ic ... :)
@@ElectronicMarine thank you
It's not a balancer. It's a bleeder for one cell
that is what a bms does. it bleeds the top cells until the lower cells catch up. the only problem is, with the little resistance the bms systems have they can not bleed enough of the power to allow the lower cells to catch up and it eventually shuts down the system before all the cells are charge leaving the pack unbalanced. this continues until the cells are so unbalanced that they pack eventually burns one of the cells and eventually destroying the whole pack. do you get what I am saying. Shawn, let me know if I got it right, I believe I do in a simple way have it correct so anyone should be able to understand it.
also, if you would look at the battery bank that Shawn made, he has other systems going that help balance the cells as they charge. The points being made here are mainly for mobile devices for bikes and longboards etc. I hope that helps anyone who had a bit of a problem figuring it out.
@@melcak.4802 no, that's not what a bms does. A bms disconnects the cells if they go outside the safe range
What's ur email
shawn@batteryblocs.com
Sent email Shawn
This is obsolete now..
how come?
@@MrDingaling007 Cause burning the energy to balance is a bad idea, there are better alternatives.
Can you show me what you would use then for a 320ah/7s (24v system) diy powerwall I am building at the moment.
@@MrDingaling007 Search for "active cell balancer", they do not have resistors in them but converters. They are pretty cheap on aliexpress.
@@honumoorea873 any proven tried and tested ones that stand out because Im not keen buy any of these items, as they seem to burn our and not last (most BMS/balancers from China).