Battery Hookup new listing “Case 100x 3.3v 2200mah - 200x 18650 Lifepo4” for $100.00 + shipping

[eccerr0r]

BTW what are you doing with the old 24V BMS since you took one apart, could you take photos of it? My current hypothesis is that the water damaged the temperature sensor portion enough so that the board thinks it's overheating... I'm not sure if I want to just nix the thermal sensor circuitry to see if my hypothesis is correct or not, yet. Perhaps if I pulled one sot23 transistor that I think is causing the shutdown due to the false thermal sense.

oh wait... BH has a photo don't they... alas that glue is not helping...

[sam_sam_sam]

BTW what are you doing with the old 24V BMS since you took one apart, could you take photos of it? My current hypothesis is that the water damaged the temperature sensor portion enough so that the board thinks it's overheating... I'm not sure if I want to just nix the thermal sensor circuitry to see if my hypothesis is correct or not, yet. Perhaps if I pulled one sot23 transistor that I think is causing the shutdown due to the false thermal sense.

oh wait... BH has a photo don't they... alas that glue is not helping...

I will try to do this a little later on today once I get the other battery pack ready for charging so I can see how well the MPPT that I just received in the mail yesterday is preforming it is nice and sunny today great for this type of testing

[eccerr0r]

IMHO MPPT doesn't shine (pun somewhat intended) when it's bright, sunny, and everything's perfect; it's when conditions are suboptimal (shade, clouds, mismatched panels, changing temperatures, etc.)...

[sam_sam_sam]

IMHO MPPT doesn't shine (pun somewhat intended) when it's bright, sunny, and everything's perfect; it's when conditions are suboptimal (shade, clouds, mismatched panels, changing temperatures, etc.)...

Yes I agree with you and know about this as well but I will also test it on days that are not perfect for testing as well when it is partly cloudy and sun is playing hide and go seek but I at lest have an idea what to expect for 70% of the day because I have so many trees in my yard I only get sun on my shed from about 11 am and 5 pm I loose the sun because of the trees so that is about 6 hours of sun light that I can use them basically nothing until sunset

Here is a place where I just bought 4 solar panels at half price

https://hqsolarpower.com/hqst-100-wa...ah9OmEFqezXMFi

Now I am out of project money again for sometime again

[eccerr0r]

I need more space to put panels... Then I need a bigger GTI.
Yeah it sucks having to stash them in my yard. During the summer I get sun from 9 to 6ish where the edges it's really oblique; outside this time, my fence or my neighbor's houses shade the panels.
During the winter the shade doesn't end till 11-ish and shaded by 3. I get about 4:1 ratio in terms of energy collected between summer and winter -- though I don't re-angle my panels.

[sam_sam_sam]

Here are the pictures that I promised to take for you about the 24 volt battery packs that we bought

I hope this helps you with what you are trying to do I right now do not have any that I can sacrifice for science destruction purposes if something goes horribly wrong I need all the ones I have as of now unless I decide to make a double the current and use a higher current capacity BMS balancing board which might happen if the high current boost converter that I recently bought will work on the solar panels that I have just bought then I might have one to experiment with and let you know if I can figure out how to do it

[eccerr0r]

thanks yeah that's a lot more clear than the corroded mess I have. However, just wondering where that other terminal of the thermal sensor is connected under that white RTV.
that thermal sensor apparently opens up at 65°C or so, just like a thermal fuse, but it's auto reset.

[sam_sam_sam]

thanks yeah that's a lot more clear than the corroded mess I have. However, just wondering where that other terminal of the thermal sensor is connected under that white RTV.
that thermal sensor apparently opens up at 65°C or so, just like a thermal fuse, but it's auto reset.

When if I have some time I will see if I can trace down where the thermal reset able fuse connections are but it might not be until the weekend before I can get to it

[eccerr0r]

oh wait n/m the connections are on the mosfet side not under the RTV.

[sam_sam_sam]

oh wait n/m the connections are on the mosfet side not under the RTV.

Looking at this circuit layout I am being to think that trying to modify this BMS balancing board might be a lost cause because I have not seen one layout done like before because the ones that I seen that you can do this the layout is completely different from this one that has the ic controller on it

[eccerr0r]

JACKPOT. BMS is now fixed!

And it looks like I'm getting 12V!

Now somehow I need to test that this BMS is still working like a BMS...and whether it will still balance!

These are the days I wish I had a full analyzer...

---

Definitely can get 2A or so, lights up a car brake light bulb brightly!

Connected to a CCCV PSU @ 500mA to charge as a test: Cells are a little mismatched

3.25V
3.26V
3.26V
3.26V

I think that first cell is a bit weak or discharged, but strong enough to pass 2 amps.

[sam_sam_sam]

JACKPOT. BMS is now fixed!

And it looks like I'm getting 12V!

Now somehow I need to test that this BMS is still working like a BMS...and whether it will still balance!

These are the days I wish I had a full analyzer...

---

Definitely can get 2A or so, lights up a car brake light bulb brightly!

Connected to a CCCV PSU @ 500mA to charge as a test: Cells are a little mismatched

3.25V
3.26V
3.26V
3.26V

I think that first cell is a bit weak or discharged, but strong enough to pass 2 amps.

Can you show the pictures of what you bypassed in order for you to be able to set the amount of battery cells that you want to use

Nice work and it looks like you were able to get some where

Those temperatures sensors are available on EBay and other places but I would use something like 40*C for better thermal protection yes it will trip sooner but better in the long run ( I will probably do this myself if I decide to do fast charging from my MPPT charging controller ) because I do not want to babysit it while on charging mode )

Remember that what I have found with these BMS balancing protection boards is that if you let the BMS balancing board turn off the discharge cycle then very slowly charge the battery pack until all of the battery cells have the same voltage basically within 0.01volts which basically is in balance according to the individual battery cell monitoring module that I have and use then when the battery become balanced then go into fast charging mode until you see the voltage climbing up very fast and you will notice that the battery pack become very unbalanced again very normal behavior for this BMS balancing protection board from the testing that I have done so far

One way to get it back into balance is to individual load test them one at a time and let the voltage drop to 2 volts and recharge them back to 3.7 volts at a 500 milliamperes and then let the BMS balancing board go through a discharge cycle and then recharge it with the BMS balancing again and see if the results are better than it was

One note on this type of BMS balancing protection board that you have to cycle it twice before it behaves like it should the battery voltage will go high the first time in the charging cycle and the same thing happens in the discharge cycle mode will be a lot lower than normal operation once you have cycled it once then it functions normally again

The two pictures below are a screenshot of two different messages that appear on the bottom of the screen one shows that the battery pack is balanced and the other shows that it is very unbalanced

When I do testing on these battery packs again I can give you the voltage reading and when the message changes as they become unbalanced to the extreme and this will help greatly because I was not sure how much difference is still considered still in balance which I was a little surprised that it was this close and what these parameters were

Also remember that these battery packs are four years old now according to the manufacturers data code so the balance is not going to be perfect as it would be if they were a lot newer but for a new one they run around $11.00 each not $1.25 each which is what we paid for them

[sam_sam_sam]

Now somehow I need to test that this BMS is still working like a BMS...and whether it will still balance!

These are the days I wish I had a full analyzer...

I think that you could come very close to what you need for decent battery testing

You could use a SkyRc b6 version 2 with a firmware update and use in the monitoring mode that way you can see what the BMS balancing board is doing in real time but do not buy a knock of version because they do not have a firmware update for this function

Here is an eBay seller that shows you the letter of the original SkyRc seal of approval

But if you buy one please do the firmware update to be able to do the battery cell monitoring otherwise the battery tester will try to balance the battery pack which will not give you the results that you are looking for

https://www.ebay.com/itm/19189752754...Bk9SR7CtoofdZQ


Here is a battery testing machine but you can not charge these battery packs with it unfortunately but you can discharge them through

https://www.ebay.com/itm/29732077176...3ABFBMtsPXh91l

There are two versions of this individual battery cell voltage monitoring module one with 2.0 pitch connector and a 2.54 pitch on the same board or a 2.54 pitch connector only I would recommend getting the one that has both

https://www.ebay.com/itm/29623921573...Bk9SR_LlrojdZQ

Or

Get individual voltage meter modules and make your own individual battery voltage monitoring system device a little bit of work putting all together in an enclosure but it can be done but remember that you might need individual power supplies to power each meter module depending on which type you buy for this project

The more important thing is that you can monitor individual battery cells in real time so you can see how the BMS balancing protection board are functioning

The charging system is what I have to design but I not sure exactly how to go about it because I really do not want to use my battery testing machines to do this function

But what I am after is to make it in such a way that all you have to do is turn a switch and your voltage and current is set for a certain type of battery cell and make quick and easy to use

The problem with using the switching power supply that has voltage and current that are adjustably is that you can only charge the same configuration battery packs at one time you can not charge battery packs with different voltages at the same time and these switching power supplies are not cheap to buy unfortunately

[eccerr0r]

uhoh. top balance not working well or the cells are poorly balanced... one cell got to 3.8 volts while trying to charge the pack to 14.4V, and another was 3.4V. Tried charging that one low cell by itself for a while... and then let off.

After resting a bit the cells got down to 3.33 or 3.34V, I suspect the pack is 90-100% full at this point.

hmm.. not sure if this bms hack is good or not and will burst into flames...

[sam_sam_sam]

uhoh. top balance not working well or the cells are poorly balanced... one cell got to 3.8 volts while trying to charge the pack to 14.4V, and another was 3.4V. Tried charging that one low cell by itself for a while... and then let off.

After resting a bit the cells got down to 3.33 or 3.34V, I suspect the pack is 90-100% full at this point.

hmm.. not sure if this bms hack is good or not and will burst into flames...

The cutoff voltage for charging is as high as 29.6 to 30.1 volts for the hole pack
but senses you have cut it in half now your voltage range would 14.6 to 15.6 or a little bit less than that on the higher end

That translates to a battery cell voltage could goes as high as 3.9 volts for each battery cell if tt goes that high it does not stay there for very long if it working properly

The big thing is that when you do a charging and discharging cycle again then the BMS balancing protection board behaves better the second time around more in line with the voltage closer to normal cutoff voltage which is around 3.7 to 3.8 volts

One thing you need to keep in mind is when any battery cell reaches around 3.9 volts it terminates the charge current and then it is supposed to completely done

[eccerr0r]

hmm... That might be what I'm seeing or something. I was using 14.4V CCCV so it would never hit 14.8 or 15.05V, The charger stopped charging when the voltage hit 14.4V as it detected a drop in current flow. hmm. just wondering what's supposedly 'safe' or 'safe for limited amount of time' ... perhaps the bms is working after all? don't know...

I just tried a 24V pack plus this hacked 12V pack in series to power my GTI. I have a resistor in series to current limit, but it's weird (or not so weird)...

ResistorΩ ResistorMaxW ResultCurrentFlow@36V
0.1Ω 10W ... GTI drew 9+ amps, stopped it before it went above 9A to protect my wire and batteries.
0.67Ω 25W ... 7 amps
1Ω 20W ... 6 amps
2.2Ω 25W ... 4 amps
4Ω 50W ... 2 amps

I'm using clip lead wires which are around 20AWG and they are NOT happy at >5A...

I guess it's both curious and not so curious that the lower the resistor the current went up, but more curious is that the amount of power dissipated in the resistor used stays surprisingly similar, most likely due to MPPT.

Calculated Watts dissipated in current limiting resistor
0.1Ω 10W ... 8.1W+ (stopped before it got higher) / 324W dumped to GTI
0.67Ω 25W ... 32W (overpower) / 252W dumped to GTI
1Ω 20W ... 36W (overpower)/ 216W dumped to GTI
2.2Ω 25W ... 35W (overpower)/ 144W dumped to GTI
4Ω 50W ... 32W/72W dumped to GTI

In any case 32W dissipated in the resistor is wasted power that should have been dumped onto the grid by the GTI and the smaller resistors were expectedly "more efficient" despite running more amps through the system. Alas the resistor wasn't for efficiency.

I need a switch mode current regulator.

[sam_sam_sam]

I need a switch mode current regulator.

Are buying one already made or are you building one

If the battery is getting up to 14.4 volts and then cutting off this is probably normal but just to be sure I would put it on a bench power supply at 15 volts @ 500 milliamperes and see if it stops pulling current once it reaches 14.4 to 14.7 somewhere in this range I would recommend doing this a couple of times just to make sure that it really functions properly or not


Another words charge it up to this voltage then discharge it for about 30 minutes at about a amp or so then recharge it and see where the voltage gets to before it turns off again

I personally would not be dumping it power in the grid until I knew that the BMS that was damaged somewhat and modified dose it work correctly would be my concern once I knew that it function correctly then I would be concerned about this situation next and I would want to know if it function correctly doing the discharge load test as well dose it turn off when it is supposed to because this is as much of a factor as it doing the charge cycle and discharge cycle they both need to work correctly

Please share what you did to this BMS balancing protection board as a patient to get it working on 12 volts I am really interested in this project that you seem to have gotten it work from what you have posted on this post

Try use a automotive head light and see if your results are similar or not I find that using an incandescent light bulb seems to give you better current limiting than a resistor does or that is my experience of doing things like this


On the MPPT charging controller that I bought that you can adjust the voltage to a certain extent which is a nice feature as far as I am concerned because you can use both types of Lipo 4 and a regular lithium ion battery and you could also probably use nicads battery packs as well just have to adjust the voltage a little lower than the normal battery voltage just so you do not over voltage them and just creating a bunch of heat

[eccerr0r]

Build. Can't afford to buy. Or I could just waste the power with resistors, but that's kind of a waste of energy

Still need to figure out how to best deal with switching the batteries in and out of the system, as they need to be charged somehow with some charge controller. 24V isn't enough, I need 36V for my GTI. I happen to have a morningstar 24V PWM/bang-bang charge controller alas now I know it's not useful. My solar panels at Vmpp is just about 36V which isn't sufficient to charge the batteries.

[sam_sam_sam]

Build.Still need to figure out how to best deal with switching the batteries in and out of the system, as they need to be charged somehow with some charge controller.

I have the same issue because in the description it says that the battery pack needs to be hooked up before you hook up the solar panels I still have to figure out how do this without damaging the MPPT charging controller

One issue is that this type of controller needs to be powered separately from the battery packs and the solar panels so you do not have voltage spikes or brown out issues could be done with relay logic you would need some sort of timer system to do this efficiently

Just thinking out loud about how to achieve this goal

Step one disconnect solar panels from the MPPT charging controller

Need some type of detection system that can detect no current flow to the battery pack but you solar power available it also needs to detect voltage at the battery pack to know when to disconnect the solar panels

Step two disconnect battery pack from the MPPT charging controller

Question how long to keep it disconnected before connecting the next battery pack for charging this needs to be interlocked to prevent two different battery packs from being connected at the same time might not be easy to do

Step three connect battery pack that need to be charged to the MPPT charging controller

This should only happen if there is a battery in the queue waiting to be charged

Step four connect solar panels to the MPPT charging controller

Monitoring battery voltage and current levels to determine weather or not to go back to step one and start over again

[sam_sam_sam]

Here are some pictures of the 24 volt battery split into two battery packs now I hooked one of them and testing it out on the battery testing machine

I had to hot glue the battery cells back together when I split it into two half's because they were all loose then
I also put a little bit of hot glue underneath the BMS balancing protection board as you can not see at the moment

******I am not impressed by this BMS balancing protection board it cutoff voltage is around 15.5 volts but it turns right back on again several times but the battery cells have become a little bit warm because it not functioning properly and I not going to use it for this project I will have to try another BMS balancing protection board that functions properly for this project*******

******Update when I ran another charging discharge cycle then the BMS balancing protection board worked the way it should this was challenging because I not use to BMS boards behaving like this when you first hook them up to a battery pack*****

I also put it on the MPPT charging controller and it behaved like it should and it did fully charge the battery pack now it just needs to go into battery enclosure ready for use but before this I need to order more 5 pin BMS connector wiring harness for this part of this project so I can see how well this BMS balancing functions on this board this is next before putting it in the enclosure

One note I looked at some PWM solar charging controllers and a lot of them are fully automatic adjusted for a certain number of battery cells and you can not adjust the parameters oh no this not going to work for me the ones that you can adjust the charging and discharging cutoff voltages are more expensive than the automatic detector type really surprising enough

One thing I noticed is that all of these types of solar charging controllers do not have an option for controlling the current I wonder why this is not an option this surprising to me why this is not offered I even looked at some that do not offer the display screen and this version does not offer this option either

Because some PWM controllers do offer a current control option of course they are more expensive if it has this option

On a different topic update my modification to my soldering desoldering station has been working falsely for about a year now and I could not be happier about this modification project