BMS with optional Bottom and/or Top Balancing

Batteries, Chargers, and Battery Management Systems.
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BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 09 2020 6:44pm

deleted due to interference
Last edited by eMark on Feb 11 2020 5:07pm, edited 2 times in total.

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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 10 2020 9:16am

deleted due to gobblydygook interference
Last edited by eMark on Feb 11 2020 5:10pm, edited 1 time in total.

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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 11 2020 9:50am

Oh, well no great loss :)
Last edited by eMark on Feb 11 2020 5:10pm, edited 1 time in total.

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Re: BMS with optional Bottom and/or Top Balancing

Post by zeccato » Feb 11 2020 12:39pm

useful information :bigthumb:
Full susp. folding 20 swxh r. (2011),. 02 2020 MacT8. batt. 48v. 25A Life (2012), and 48 7,5A a123 (2018?). Controller programmable EB3 12 FET. Charger Balancer 14s: TP1430C. Gophert CPS-6011 60V 11A. Mercury (rarely). Buzzer. https://www.google.com/url?sa=t&source= ... 6dXxc9-lNW

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Re: BMS with optional Bottom and/or Top Balancing

Post by john61ct » Feb 11 2020 12:58pm

I personally would prefer a balancer that did not impose any changing to my normal charging routine.

Periodic maintenance routine, not hooked up while in use nor run every cycle, only when needed.

That could balance at any voltage / SoC level. My first choice being at the midpoint if a protective BMS with per-cell LVC is in place during use, otherwise bottom balancing.

A higher balancing rate better than a slower one, for medium cells (60+Ah) 2A for 150+Ah say 5A. That rate ideally independent of the imbalance delta's.

Rather than linking to an eBay auction that will likely expire, here's some description text should make this one easy to find.

What d'yall think?

______
Active, efficient, energy transfer balance
Support 2S to 24S battery packs;
Single cell voltage collection range: 1V ~ 5V, accuracy: ± 3mV;
Support all pool types such as : Li-ion, Lipo, Lifepo4, LTO, super capacitors and other batteries
The balance current is set independently in the range of 0.1~2A, independent of the cell voltage difference;
Support balanced cascading to apply to more than 24S of battery packs, in theory, can be cascaded indefinitely; for exsampel , can 28S , 32S , 36S , 40S ... and so on
Support Bluetooth communication, equipped with mobile APP, real-time view of battery status;
Equilibrium line resistance detection, abnormal contact failure is found in advance;
Power supply range: 40V~ 100V;
Low voltage shutdown function to prevent battery damage;

https://www.google.com/search?q=%22Supp ... initely%22



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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 11 2020 5:29pm

zeccato wrote:
Feb 11 2020 12:39pm
useful information :bigthumb:
When john saw your post he couldn't stand someone having something complimentary to say about my threqd so he had to intervene and let you know his truth. Hopefully i've made his day by deleting my previous posts and letting him take ownership of this thread or maybe fechter will remove the thread from this Battery forum.

Whatever john61ct prefers is what's important being that his seniority overrules me as one of the most prolific posters and one of the most knowledgeable ebikng/battery contributors on this ES Battery forum as well as other ES forums. His post was more important than anything i had to say ... thus best for me to have deleted by previous posts with no intention of continuing.

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Re: BMS with optional Bottom and/or Top Balancing

Post by john61ct » Feb 11 2020 8:59pm

Wow just wow.

I do not think I even disagreed with anything you posted, much less criticized you, your post was indeed helpful and clear IIRC.

This is an open forum, and open discussion is the whole point.

Differing points of view is how we (and lurkers for posterity) learn from each other.

Picking up your toys and going home in a sook is not helpful to the community.

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Re: BMS with optional Bottom and/or Top Balancing

Post by billvon » Feb 11 2020 10:01pm

eMark wrote:
Feb 11 2020 5:29pm
When john saw your post he couldn't stand someone having something complimentary to say about my threqd so he had to intervene and let you know his truth
Uh - no. He had a comment. That's what forums are for.

However, if comments in a thread you start will make you sad and upset, I agree that it's best to not post on forums.
--bill von

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Re: BMS with optional Bottom and/or Top Balancing

Post by zeccato » Feb 12 2020 8:40am

eMark wrote:
Feb 11 2020 5:29pm
zeccato wrote:
Feb 11 2020 12:39pm
useful information :bigthumb:
r [/][/b]

A little disappointed that you took away useful information, if there's any resentment, I don't see it positively, tolerance, forget, and not pay attention to it.
I prefer that you put the info back,
for the good of all.
Thus demonstrated more maturity.

(Sorry about the translation.).
Full susp. folding 20 swxh r. (2011),. 02 2020 MacT8. batt. 48v. 25A Life (2012), and 48 7,5A a123 (2018?). Controller programmable EB3 12 FET. Charger Balancer 14s: TP1430C. Gophert CPS-6011 60V 11A. Mercury (rarely). Buzzer. https://www.google.com/url?sa=t&source= ... 6dXxc9-lNW

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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 12 2020 9:48am

zeccato wrote:
Feb 12 2020 8:40am
I prefer that you put the info back,
for the good of all.
Not for the good of all as john61ct's method is far superior to my Blinky posts. Apologize for MY gobbledygook interference posts. john61ct is right-on (as usual), so hopefully he will take ownership of this thread. Evidence of my gobbledygook post(s) was that possibly an administrator "Xed" my second post two days ago, while i was final editing my third post yesterday. Have not had an "X" option since last November so it couldn't have been me that "Xed" my second reply posted two days ago. Still don't have an "X" option to "X" a previous post (only current post) so it couldn't have been me to "X" what was apparently a gobbledygook post. Thus, the reason for deleting my previous Blinkety blink (XZQ?%@&) posts.

Hopefully, john61ct will assume ownership of this thread. Perhaps, an administrator can change the title to "... Middle and Top Balancing" as most all BMSs for DIYers are those cheap/inexpensive BMSs that are BPSs (Protection only) with no middle balancing and narley any or no top balancing. So come on guys lets encourage john61ct ...
john61ct wrote:
Feb 11 2020 12:58pm
I personally would prefer a balancer that did not impose any changing to my normal charging routine.

Periodic maintenance routine, not hooked up while in use nor run every cycle, only when needed.

That could balance at any voltage / SoC level. My first choice being at the midpoint if a protective BMS with per-cell LVC is in place during use, otherwise bottom balancing.

A higher balancing rate better than a slower one, for medium cells (60+Ah) 2A for 150+Ah say 5A. That rate ideally independent of the imbalance delta's.

Rather than linking to an eBay auction that will likely expire, here's some description text should make this one easy to find.

What d'yall think?
______
Active, efficient, energy transfer balance
Support 2S to 24S battery packs;
Single cell voltage collection range: 1V ~ 5V, accuracy: ± 3mV;
Support all pool types such as : Li-ion, Lipo, Lifepo4, LTO, super capacitors and other batteries
The balance current is set independently in the range of 0.1~2A, independent of the cell voltage difference;
Support balanced cascading to apply to more than 24S of battery packs, in theory, can be cascaded indefinitely; for exsampel , can 28S , 32S , 36S , 40S ... and so on
Support Bluetooth communication, equipped with mobile APP, real-time view of battery status;
Equilibrium line resistance detection, abnormal contact failure is found in advance;
Power supply range: 40V~ 100V;
Low voltage shutdown function to prevent battery damage;

https://www.google.com/search?q=%22Supp ... initely%22
Finally, a smart P-group equalizing BMS thanks to Ali at a reasonable price (page translation feature) ...
https://h5.aliexpress.ru/item/329941773 ... 2994177376 ... and ... https://www.amazon.ca/Balancer-Equalize ... B07SFCY36G ...
I love the programmable nature of this 2amp cell active balancer. The app is hard to find but it's name is enjpower. Their website is the same name and I asked them for the app which thankfully they provided a link.

It really does shuttle 2amps between high and low cells. Bluetooth on the mobile device needs to be on then the app has to be opened. From there the balancer will be seen. For the first time connection the password is 1234. Everytime the app connects to the balancer it will beep 3 times, which is convenient to know the unit is fully operational.

Initially I thought the board wasn't balancing but cycling power to the power wire (furthest from the red led) allowed it to work properly. It is quickly balancing all 16 cells in my lifepo4 5.1kwh solar bank! After 4 days the voltage difference was 2millivolts! This is amazing however since my solar bank is always being charged and discharged, the cells will tend to drift apart electrically hence the need for this balancer.

Another awesome characteristic is the balancer's ability to measure cell internal resistance. As the cell ages the resistance goes up. Really good way to know the health of my cells!

I do not use BMS boards because they are practically useless since I do not overvolt nor undervolt my lifepo4 battery. I use a din miniature circuit breaker as overcurrent protection.

Highly recommended although I wished the price was lower. I intend to buy another soon.
Hopefully, john61ct can provide a link to availability and cost of just 10S, 12S or 14S for less cost than this smart 2S~24S ...
s-l1600.jpg
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So forgot about even using a couple balance leads (i.e. 2-5S or 2-6S) and a couple used Blinky's to check the health of your 10S or 12S ageing pack ... by then it's probably too late ... instead get a Smart BMS not one of those cheap BPSs that can't balance the P-groups in your DIY pack. You can always attach a couple balance leads (5S, 6S, 7S, 8S) and a couple of these 8S cell logger alarms to your DIY pack ... https://www.commonsenserc.com/product_i ... ts_id=2862. You probably couldn't ever find even one of these Blinkety blinks on ebay that would also show the average voltage of each P-group in your 10S or 12S pack ...
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Also, my intention of other posts about the Tenergy 5-in-1 Intelligent Balancer, the BattGo 8S (14S or 16S pack) or having provision for splitting a pack in two for balance charging with a 2S~6S duo balance charger is just more Gobbledygook. Serious ebikers should be smart enuf to buy a Smart BMS :thumb:

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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 12 2020 12:32pm

Just ordered a couple Common Sense 8S low voltage Alarms for my 10S5P pack (split provision for balance charging at 1.5A (0.5C of P-group Samsung 30Q 15A rated 3000mAh cells) with my HTRC duo 2S-6S balance charger (when needed). Being that i already have the two 5S balance leads going to each of the two combined 5S5P packs on my 10S5P 30Q pack. The two 5S balance leads to the five P-groups with exposed 5S balance lead connector to plug into the two adjustable 8S low voltage alarms (and into the HTRC duo balance charger, when needed). The two CC 8S low voltage alarms can be plugged into the two 5S balance leads when the 10S5P pack is split into two 5S5P packs. That was the plan with my BattGo 8S or Tenergy 5-in-1 7S when discharge balancing the P-groups. The two CC 2S~8S Voltage Alarms can be plugged in either when the 10S5P is split into two 5S5P packs or when joined together as a 10S5P battery during etrikng. Thus giving you a low voltage alarm during ebiking should P-grouip voltage go below your preset level.
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For those interested in purchasing a CC 8S Voltage Alarm you don't have to wait until June for more to arrive. Common Sense is expecting another 100 next week so will receive mine in 2-3 weeks. Really like the push button feature for setting the low voltage alarm. In my case probably first set it to 3.7V depending on how far from home. Then reset low voltage alarm to 3.4V low voltage alarm and if necessary pedal the rest the way home if the alarm goes off again ... https://www.commonsenserc.com/product_i ... ts_id=2862 ... Got a large Plano storage container mounted between the rear wheels of my adult etrike. Just enough room for my 10S5P pack, my little guadcopter and a snack :wink:

Those Common Sense 8S Alarms is just what is needed for the well-being of my DIY Vruzend 10S5P Samsung 30Q 18650 NMC pack. Also for tracking any progression of Samsung 30Q high self-discharge tendency that's been reported by other ebikers with their DIY 30Q pack (15A-High Drain cell rating). Thus my reason for beginning this thread as P-group cell balancing is critical to extending the cycle life longevity of my 10S5P Vruzend DIY pack of 50 Samsung 30Q high drain cells.

The Samsung 30Q is one of the cells being tested by docware ... viewtopic.php?f=14&t=103092&start=225 ... although 30Q has one of the lowest IR's its capacity potential looks to be lagging behind other contenders for achieving greater cycle life longevity when reaching 80% or 70% of remaining useable capacity. Very informative thread for those deciding which 18650 cell to buy for their DIY battery. If i would have waited until docware was this far along in his "ageing tests" i wouldn't have purchased the 30Q cells based on their low IR, but rather the LG Chem M36 cells (IMR clearance at $2.99, while they last, same goes for MJ1s). My mild-mannered conservative etriking (averaging 8-10mph 80% of time) is NOT raw performance (top speed of 12mph +80% of time), so didn't need 50 "high drain" 15A rated 30Q cells. Fifty M36 5A rated cells was a better fit ... saving me $50 (IMR 30Qs were then on sale for $3.99).

zeccato wrote:
Feb 12 2020 8:40am
A little disappointed that you took away useful information
Wasn't all that useful. Hope you find john61ct's excellent post, my two followup posts and docware's thread more useful :thumb: :thumb: :thumb:
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zeccato   100 W

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Re: BMS with optional Bottom and/or Top Balancing

Post by zeccato » Feb 12 2020 3:47pm

Right now I'm looking forward to this one under.
i don't use bms, on my lifep4 i have buzzers,
(but in the future I buy li-ion).
I'm interested in LV alarm and HV alarm (for charge) with warning beeper (this also has led),
what do you think about?

I was thinking smart bms,
but I want to have as few things as possible, and simpler.
I have a balance charger, and I also need it to build my future battery.

http://www.litrade.de/shop/BMS,Balancer ... am=monitor

battery cell monitor BM16 2? or 3S-16S, (chargery.com).
similar?:
Battery cell monitor Saver BCM16 3S-16S,
(enjpower.com).

viewtopic.php?f=14&t=55601&p=831520&hil ... LP#p831520
Full susp. folding 20 swxh r. (2011),. 02 2020 MacT8. batt. 48v. 25A Life (2012), and 48 7,5A a123 (2018?). Controller programmable EB3 12 FET. Charger Balancer 14s: TP1430C. Gophert CPS-6011 60V 11A. Mercury (rarely). Buzzer. https://www.google.com/url?sa=t&source= ... 6dXxc9-lNW

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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 13 2020 3:53pm

zeccato wrote:
Feb 12 2020 3:47pm
I was thinking smart bms,
but I want to have as few things as possible, and simpler.
KeepItSimple is a worthy goal and a smart BMS is the way to go. If only they weren't so pricey. If you're going to integrate a BMS get a good one assuming you're bluetooth app savvy. Maybe this one ... http://www.litrade.de/shop/BMS,Balancer ... kabel.html ... the new 1.1 specs are just what you've got in mind. Do your due diligence before whatever smart BMS you buy, which you're doing :thumb:
zeccato wrote:
Feb 12 2020 3:47pm
I have a balance charger, and I also need it to build my future battery.
To maintain your future battery for extending cycle life longevity with the right cells ... for the right application.

It's not easy to KeepItSimple with advancing technology everywhere, everywhere. It's getting so one can barely change a headlamp bulb on your car without having to take it to the dealer. A smart bluetooth BMS is the way to go, but pricey. Would be nice if it had at least a 5,000 km warranty. Technology is great, but i don't mind getting my hands dirty if i can save some money.

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Re: BMS with optional Bottom and/or Top Balancing

Post by zeccato » Feb 13 2020 4:51pm

eMark wrote:
Feb 13 2020 3:53pm
zeccato wrote:
Feb 12 2020 3:47pm
I was thinking smart bms,
but I want to have as few things as possible, and simpler.
KeepItSimple is a worthy goal and a smart BMS is the way to go. If only they weren't so pricey. If you're going to integrate a BMS get a good one assuming you're bluetooth app savvy. Maybe this one ... http://www.litrade.de/shop/BMS,Balancer ... kabel.html ... the new 1.1 specs are just what you've got in mind. Do your due diligence before whatever smart BMS you buy, which you're doing :thumb:
zeccato wrote:
Feb 12 2020 3:47pm
I have a balance charger, and I also need it to build my future battery.
To maintain your future battery for extending cycle life longevity with the right cells ... for the right application.

It's not easy to KeepItSimple with advancing technology everywhere, everywhere. It's getting so one can barely change a headlamp bulb on your car without having to take it to the dealer. A smart bluetooth BMS is the way to go, but pricey. Would be nice if it had at least a 5,000 km warranty. Technology is great, but i don't mind getting my hands dirty if i can save some money.
Thanks for the advice, In 2011 I had a cheap bms, but it gave me problems, then I decided to do without it, and I'm satisfied with latest 8 years, and battery 8 years, that the bms had tried to kill her, leaving her unbalanced.

I have no problem with bt, and even the price of bms doesn't scare me, I'm looking for the best and simple solution for my case.

For now I'll check with the test, and maybe I'll try to connect the buzzers during the final charge, hoping that I don't damage something with the buzzers.

I was just looking for a simple non-BT monitor HV alarm with warning beeper like the cellog.
Full susp. folding 20 swxh r. (2011),. 02 2020 MacT8. batt. 48v. 25A Life (2012), and 48 7,5A a123 (2018?). Controller programmable EB3 12 FET. Charger Balancer 14s: TP1430C. Gophert CPS-6011 60V 11A. Mercury (rarely). Buzzer. https://www.google.com/url?sa=t&source= ... 6dXxc9-lNW

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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 14 2020 10:31am

zeccato wrote:
Feb 13 2020 4:51pm
I was just looking for a simple non-BT monitor HV alarm with warning beeper like the cellog.
What is a "what if" scenario where you believe a HV alarm is more important for your use than a LV alarm? Most decent chargers can be set to your preferred cut-off voltage, such as 4.1 volts instead of 4.2 volts. A reliable CCCV charger is by far more important than a cheap/inexpensive BMS that is really a BPS ... if it is even trustworthy? Thankfully, you've already come to that conclusion. Thus, one reason for using a duo 2S~6S balance charger for bottom, middle, top or all three and cut-off set for one hour or whatever (if you aren't around or fall asleep), and set P-group capacity limit cut-off. Then stay close to keep an eye on the remaining balance charge, especially top balancing the P-groups, when enuf is enuf.

Or just try bottom balancing and/or top balancing so you can watch the balancing progress. With a new pack you may not need to balance charge more than once a month. When the P-groups min-max is over 30mV or whatever you decide is your allowable min-max disparity before it's necessary to balance charge as the pack ages. At first you should be able to balance charge the P-groups within 3-5mV or each other or at least 5-10mV of each other.

Your choice of the duo Chargery 12S, two 2S~6S ports ((if that is your choice) looks AOK ... http://www.chargery.com/C4012B.asp ... specs are better than my inexpensive HTRC duo balance charger. Bought it because it can also read IR of the P-groups. Has a 1 yr warranty. Manufacturers still make them primarily for RC Lipo pilots (12S ~ two 2S-6S charging ports).

When, oh when, will ebikers be able to purchase a duo balance charger for a 14S ebike Li-ion pack or even a 15S or16S pack? My pack is only 10S5P so all i need is a duo 2S~6S balance charger ... https://www.amazon.com/HTRC-Charger-Bal ... P5GW6E7V05 . The only two settings i'll ever use are balance charging at no more than 0.5C (1.5A) and checking the P-groups IR as the pack ages. So, far i really like the little bugger, hope it serves me well.

Ok, the Chargery 16S Lipo/LiFePO4 Monitor is a balance charger when wiring two balance leads (7S or 8S) on a 14S or 16S pack. You may want to purchase it instead of that 12S Chargery even though your current plan is building a DIY 12S pack, but maybe a DIY 14S build down the road :thumb:
Last edited by eMark on Feb 14 2020 12:09pm, edited 2 times in total.

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Re: BMS with optional Bottom and/or Top Balancing

Post by john61ct » Feb 14 2020 12:03pm

Disconnect at the serial midpoint before charging each half.

Few hobby chargers' outputs are isolated.

There are some 10S chargers still even 12S but higher than that is very rare, going modular with 6S units really opens up lots of less expensive options, 8S also bit less so.

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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 14 2020 12:43pm

john61ct wrote:
Feb 14 2020 12:03pm
Disconnect at the serial midpoint before charging each half.

Few hobby chargers' outputs are isolated.

There are some 10S chargers still even 12S but higher than that is very rare, going modular with 6S units really opens up lots of less expensive options, 8S also bit less so.
That's why my 10S5P pack has to be split/disconnected into two 5S5P packs for true active balance charging (e.g. HTRC duo 2S~6S Balance Charger) with dual ports for the two 5S P-group balance leads and with dual banana plug ports for balance charging each split 5S5P pack (using either deans or XT60 connections). When using either a Chargery 2S~12S dual Monitor (no dual banana plug ports) or 2S~16S dual Monitor (no dual banana plug ports) you still may need to make provision for splitting the pack whether "charging" or "discharging" ... is that correct?

When just using either a Blinky to see if there is any P-group disparity above 30mV, or two passive 6S, 7S or 8S cell-loggers or two LV alarms with either say a 10S4P, 12S6P or 14S8P battery it doesn't need to be split into two separate packs before plugging in either the two passive cell-loggers or two 8S LV alarms into the the two passive balance leads with battery at rest. At least that's the way it is with my 10S5P battery when the two 5S5P packs are joined together to make a 10S5P battery. The two cell-loggers and two LV alarms can be plugged in when the two 5S5P packs are joined together (10S5P) when ebiking. That way you have active LV alarms you can set to your LV preference when ebiking and a visual reading of each P-group voltage (min-max voltage disparity).

I realized this when coming across a thread several weeks ago showing a diagram for how to wire a pack with two balance leads for monitoring with a Blinky, a Tenergy 5-in-1 7S discharge balancer, a BattGo 8S discharge balancer ... or ... with two active CommonSense 8S cell logger LV alarms while ebiking. I only use the two discharge balancers (for comparison) when the 10S5P battery is resting after an eride to check P-group voltages when at rest. I don't need to separate into two 5S5P packs when checking the min-max of the P-groups with either a Blinky, the Tenergy or BattGo discharge balancer. The Tenergy 5-in-1 can also check the P-groups IR.

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Re: BMS with optional Bottom and/or Top Balancing

Post by zeccato » Feb 14 2020 3:26pm

eMark wrote:
Feb 14 2020 10:31am
zeccato wrote:
Feb 13 2020 4:51pm
I
What is a "what if" scenario where you believe a HV alarm is more important for your use than a LV alarm?
I need it to charge 2 battery 16s lifepo4 without the bms, up to 90-97%.,
with this:
CPS-6011-60V-11A-Precision-PFC-Compact-Digital-Adjustable-DC-Power-Supply-Laboratory.jpg
CPS-6011-60V-11A-Precision-PFC-Compact-Digital-Adjustable-DC-Power-Supply-Laboratory.jpg (10.7 KiB) Viewed 1327 times
It was better if there was a buzzer HV alarm,
but I don't find any.

On a long trips towards the end i put the buzzers.

I already have the balance charger 14s
and sometimes i balance

It was better if there was a buzzer HV alarm,
but I don't find any.
Full susp. folding 20 swxh r. (2011),. 02 2020 MacT8. batt. 48v. 25A Life (2012), and 48 7,5A a123 (2018?). Controller programmable EB3 12 FET. Charger Balancer 14s: TP1430C. Gophert CPS-6011 60V 11A. Mercury (rarely). Buzzer. https://www.google.com/url?sa=t&source= ... 6dXxc9-lNW

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Re: BMS with optional Bottom and/or Top Balancing

Post by john61ct » Feb 14 2020 5:03pm

Better to get a charger that will stop automatically.

Alarm or HVC - means cutoff - is just in case that fails so keeps charging, cutoff charger source is best.

Mark pls clarify, shorten simplify your question one at a time without all the extra verbiage, as it is now I don't understand it. Connect sib-packs for discharge of course, disconnect for charging & testing etc only

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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 14 2020 5:57pm

zeccato wrote:
Feb 14 2020 3:26pm
It was better if there was a buzzer HV alarm,
but I don't find any.
Sounds like you previously got burned and now may be overly concerned. Get a decent adjustable bulk charger so you can charge to 4.1V if that's your plan. You may only need to use your balance charger once a month with a new DIY 12S pack. Then when you do use your balance charger keep a close eye and don't stray too far away so it doesn't overcharge.

What about the programmable capacity setting lower on your balance charger. That way not even one of the P-groups is ever overcharged beyond your desired max P-group mAh capacity setting. Then to top off your pack's P-groups to say 4.1V you may have to baby sit your pack with no HV alarm feature built into your balance charger. john61ct could probably design a HV alarm or modify a LV alarm to a HV alarm. Would have to be plugged in series using two other extension balance leads with two HV alarms for your dual/duo balance charger.
john61ct wrote:
Feb 14 2020 5:03pm
Disconnect at the serial midpoint before charging each half.

Alarm or HVC - means cutoff - is just in case that fails so keeps charging, cutoff charger source is best.
Being that john61ct knows about everything there is to know he'd be the one to recommend a HV alarm/buzzer (if one even exists) that can be preset to say 4.1V when balance charging to 4.1V. Maybe a programmable HV alarm/buzzer function exists out there on some balance charger. If a stand alone programmable HV alarm does exist for LiPo/LiHV/LiFe/Lilon 2S~6S (or 2S~8S) similar in size/looks and price as a 8S cell-logger LV alarm or as an extra function on a balance charger john61ct would know.

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Re: BMS with optional Bottom and/or Top Balancing

Post by john61ct » Feb 14 2020 10:19pm


eMark wrote:Being that john61ct knows about everything there is to know he'd be the one to recommend a HV alarm/buzzer (if one even exists) that can be preset to say 4.1V when balance charging to 4.1V. Maybe a programmable HV alarm/buzzer function exists out there on some balance charger. If a stand alone programmable HV alarm does exist for LiPo/LiHV/LiFe/Lilon 2S~6S (or 2S~8S) similar in size/looks and price as a 8S cell-logger LV alarm or as an extra function on a balance charger john61ct would know.
please stop that dude

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Re: BMS with optional Bottom and/or Top Balancing

Post by billvon » Feb 14 2020 11:16pm

john61ct wrote:
Feb 14 2020 5:03pm
Better to get a charger that will stop automatically.
Agreed. Relying on a BMS (or a buzzer) to stop a charge or a discharge is a bad, bad idea. Lithium ion batteries can go up in flames quite easily; have at least two methods of preventing overcharge and overdischarge (like a working BMS and a voltage limited charger.)
--bill von

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Re: BMS with optional Bottom and/or Top Balancing

Post by zeccato » Feb 15 2020 3:16am

john61ct wrote:
Feb 14 2020 5:03pm
Better to get a charger that will stop automatically.

Alarm or HVC - means cutoff - is just in case that fails so keeps charging, cutoff charger source is best.................
If you are referring to balance charger is ok,
but I already have it.
And I already have the charger Adjustable 0-60v 0-11A c.c c.v.
I have also an old battery (8 years) 16s 30Ah lifepo4
and when I don't want to balance it,
I charge it (without bms) at 95%.,
for when I make a quick charge,
for this for more security I'm looking for a HV alarm 8s or 16s, NOT a HVC. not Bms.

I found this 16s, but I don't know if it's good, see:
viewtopic.php?f=14&t=55601&p=831520&hil ... LP#p831520
Full susp. folding 20 swxh r. (2011),. 02 2020 MacT8. batt. 48v. 25A Life (2012), and 48 7,5A a123 (2018?). Controller programmable EB3 12 FET. Charger Balancer 14s: TP1430C. Gophert CPS-6011 60V 11A. Mercury (rarely). Buzzer. https://www.google.com/url?sa=t&source= ... 6dXxc9-lNW

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Re: BMS with optional Bottom and/or Top Balancing

Post by eMark » Feb 15 2020 5:28am

zeccato wrote:
Feb 15 2020 3:16am
I have also an old battery (8 years) 16s 30Ah lifepo4
and when I don't want to balance it,
I charge it (without bms) at 95%.,
for when I make a quick charge,
for this for more security I'm looking for a HV alarm 8s or 16s, NOT a HVC. not Bms.

I found this 16s, but I don't know if it's good, see:
viewtopic.php?f=14&t=55601&p=831520&hil ... LP#p831520
At the top of that 2013 thread he mentions using the "Cell log8s" as a comparison for alarm overcharge function. He's referring to the CellLog 8S - Cell Monitor & Logger ... https://www.nexusmodels.co.uk/celllog-8 ... ogger.html

According to the specs it has both LV and HV alarm programming functions ...
  • It can be set Individual Voltage Alarm and Pack Voltage Alarm, Overvoltage Alarm, Low Voltage Alarm, Differential Voltage Alarm and Time Over Alarm. What’s more, the extra alarm output can be linkage controlled by the users.
    It has 8 sets default monitor alarm settings, which can be selected for different battery packs.
It's currently unavailable, but you might try contacting Nexus to see if it will be available again or if they know of another Cell Log 8s with overcharge alarm function as a key feature. If you call their "expert customer service" tech dept they might be able to help you.
Also, try contacting HobbyZone (Spectrum) as they may be able to help you find a 8S Cell Log with an overvoltage alarm.

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Re: BMS with optional Bottom and/or Top Balancing

Post by john61ct » Feb 15 2020 6:09am

zeccato wrote:If you are referring to balance charger is ok, but I already have it.
Whether balancing type or not, it is not "a charger" if requires a human to terminate charge.

> And I already have the charger Adjustable 0-60v 0-11A c.c c.v.

That is a power supply, not a charger.

If you get a proper adjustable HVC that cuts off the charging when target voltage is hit, that is fine.

The BMS HVC is there as a backup, failsafe, to protect the pack when the primary control fails.

Just using an alarm is A Bad Idea.

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