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

[eccerr0r]

Yeah it's one of those 24V heatshrink sealed packs like you got, cannot access BMS without cutting the heatshrink. I didn't even try discharging the pack. Just did a quick go/no-go by measuring voltage.

And remember, minimum cost, minimum cost... I got this PSU for free

[sam_sam_sam]

I going to try to test more battery packs out of this box to make sure that I do not have any battery packs that are having issues that I take care of them ASAP to lose the window of a warranty issue because if I remember correctly it is 30 days after you receive your order

[sam_sam_sam]

Yeah it's one of those 24V heatshrink sealed packs like you got, cannot access BMS without cutting the heatshrink. I didn't even try discharging the pack. Just did a quick go/no-go by measuring voltage.

And remember, minimum cost, minimum cost... I got this PSU for free

If you attempt to charge it and it did not wake it up then you have an issue with either the battery cell to far out of balance or very low or no battery voltage on some battery cells or a bad BMS protection board

I can not imagine that all battery cells being very low in voltage but if that is the case then you can assume that the BMS board has an issue of some kind and I would not re-use it if this is the case

Now if there are battery cells that are very low voltages and some are not then you have a situation that the ones with low voltages are at the end of their life and should not be reused unless you have a battery pack that is made up with all the battery cells in the pack have the same issue then the BMS protection board can handle that situation easier

One note you need to be very careful not to recharge any battery cells that are below 1 volt the chances that it can be recharged are very slim and not worth the risk I have attempted this several times and the success rate is very low and not worth the time required and spent because charges are they will be what is known as heater battery cells and are worthless

Ok sense it the same ones that I bought if you carefully cut the heat shrink tubing right where the battery cables are down the middle and each side all way around the battery pack do not go very deep though and cut it in such a way that you can re-tape it afterwards you should be alright doing that I did not care about the heat shrink tubing that is on it because I want to do comprehensive battery testing on these battery packs to use them in my battery backup which I will be able to do but I have to find the battery terminal plastic bar so I can test the battery packs in it

One word of caution and advise is to discharge them first dose not matter the current level as long as you are not close to maximum capacity of the BMS protection board the reason for this just in case the battery cells are a little unbalanced you can get them back into balance by running the battery pack until the BMS board shuts down then if you are able to slow charge ( around 200 milliamperes is best recommendation for best results ) it until the battery voltage by mathematically dividing by 8 and getting a result of 3.3 X 8 = 26.4 volts then put it on fast charging it should stay pretty balanced at that point until it gets very close to 3.9 X 8 = 31.2 volts and the BMS protection board shuts off ( remember that it does not stay at this voltage level for very long it climbs very quickly and shuts off ) the charging current which it will become very unbalanced again but this does not really matter much because this gives you the best running time resulting from the testing that I have done on them

Also remember that so far I have only tested two them comprehensively and checked two other ones for voltage because I did not remove the plastic tray from the box to get to the next level inside of the box yet because I find that when you remove everything from a very neatly packed box you can not seem to make it neat again and right now I have the box on a shelf in my shed

[eccerr0r]

Well I was hoping that it wouldn't have come down to this but it did... ugh... so RMA request? That's why I don't know if I should cut and investigate... if I can/need to ship back.

[sam_sam_sam]

Well I was hoping that it wouldn't have come down to this but it did... ugh... so RMA request? That's why I don't know if I should cut and investigate... if I can/need to ship back.

It has been my experience that they do not want them back but they just want verification that you have a bad battery pack but you can check first and see what they tell you about what they want you to do and how they want you to do it but they have not had an issue in the past when I have taken the battery packs apart and showed them the results that I got from the battery pack in question

But senses you are having issues with one of them have you tested the voltage on all of them if so and you only had issues with one of them that pretty good but now I need to get very busy and get all of mine tested I have to write a very quick charging and discharging testing routine so I do not have to watch them constantly now that I know what parameters to use

Discharging = 1 amp until it reaches 24.5 volts
Discharging = 0.500 amps until BMS turns off or 0.200 if you want a deeper discharge voltage out come
Optional wait command before going into the next step if desired 5 to 10 minutes is plenty for me most of the time
Charging = 0.200 amps until battery voltage is 25.5 or 0.100 for a closer balanced voltage value but does take longer to do
Charging = 1 amp until battery voltage is high enough for the BMS protection board to turn off the current
Optional put wait command for 120 minutes to see what voltage the battery pack settles down to

I will not do the 10 amp load testing with a routine I do not trust these very much at this point to do with a routine type of setup at least not now until I get the battery backup set up for testing then I might have the battery testing machine record the voltage and amperage is as long as it does not go over 10 amps if it does then I have to do on a different battery testing machine model that can handle 20 amp load

Next battery to test go to the being again

I am still debating whether or not to split one of them into two separate battery packs for 12 volts each I just not sure how easy that would be to do and better jet would the heat shrink tubing come apart the way I do not want it to and then I would have to separate all of them which I really do not want to do

I have tried this in the past when they are crazy glued together like these are the out come is not good

[eccerr0r]

I didn't/can't do an extensive test, so all I test is voltage and rough DC ESR/internal resistance. I just used a 25Ω 25W resistor and checked the voltage while it was discharging. I can't leave the 25Ω resistor connected for too long, it would fry after a while.

Now the next issue is charging them to make sure they're kept at 50% to minimize time related wear...

[sam_sam_sam]

I didn't/can't do an extensive test, so all I test is voltage and rough DC ESR/internal resistance. I just used a 25Ω 25W resistor and checked the voltage while it was discharging. I can't leave the 25Ω resistor connected for too long, it would fry after a while.

Now the next issue is charging them to make sure they're kept at 50% to minimize time related wear...

Get your self a couple of automotive type head lamps from a car junkyard and wire them in series and you have a discharging device and if you have a decent multi meter with a 10 amp load capacity this should work fine

Or buy two battery load testing devices that have a flat metal strip for a load and wire them in series a little bit more expensive but with this you could add a cooling fan or you could build one out of a room heater just gut it out and just use the heater metal and put a 24 volt cooling fan to keep the air moving so you do not over heat the heater element and you can create your own load current with a little bit of experimentation I would probably do one that is 15 to 20 amps for these battery packs

As far as 50% charge voltage I would have estimated that for you when I run the next battery pack test I give you the voltage to get to for approximately 50% one way to do this would be charge at one amp for about 2.5 hours and would roughly get you to 50% rate of charge

If you are wanting to only discharge to 50% you basically do the same thing but in the reverse direction in other words you discharge only to a certain voltage and be done with now they do sell battery fuel gauges for different types of battery cells they are not that expensive to buy or make your own with a bar graph ic chip I can not remember the part number right now but they even sell a complete kit for under $20.00 the last time I priced one

Now if you have the load test results from this battery pack like I do for the ones that I bought I know that they are testing a ten amp load and I am getting just a little over 5.010 amp hours or a little more than that and if you only load test it at one amp the amp hours would be a little higher than that you take the amount of running hours and divide by 2 and you would have the value of time that you could run before you get to 50% but a battery fuel gauge would be the simplest option for what you want to do

You could leave your 250 ohm 25 watt resistor on for a while but you would need to use a cooling fan if it a wire wound resistor this should be fine

Or use a battery operated water heater element for warming coffee but you would need two of them unless you can find a 24 volt version just need a big pale of water to keep it cool enough for it not to burn out

[eccerr0r]

I have a LM317 and a 1Ω resistor, that makes a 1.25A CC load... Shouldn't be too hard to make a latching circuit to cut off if a voltage drops below a threshold. Now it's just a matter of time.
I don't think I'll be using LM3914 to make a bargraph display however. Probably doesn't have to be way too accurate either, just need to make sure it's not almost full or almost empty.

[sam_sam_sam]

I have a LM317 and a 1Ω resistor, that makes a 1.25A CC load... Shouldn't be too hard to make a latching circuit to cut off if a voltage drops below a threshold. Now it's just a matter of time.
I don't think I'll be using LM3914 to make a bargraph display however. Probably doesn't have to be way too accurate either, just need to make sure it's not almost full or almost empty.

Just make sure that you have a decent sized heat sink for the LM 317 is it a t3 format or is it a t220 format I think it might be better to use a t3 format one would be better for longevity

[eccerr0r]

Okay. 60% efficiency of this linear psu will be a problem in the long term but okay for experimentation for now... though if I set up more solar panels the energy will be wasted anyway.

The transistors on the PSU get quite hot as expected, alas, need some way to charge, alas, this is the only psu that can get more than 100W to charge batteries.

Still need to complain about that dud pack to batteryhookup...

[sam_sam_sam]

Still need to complain about that dud pack to batteryhookup...

I would do the same thing if I got a bad battery pack as well
This is the reason I need to at at least test four between now and tomorrow late afternoon I need to be finished with testing them hopefully I can finish all of them but we will see how far I between now and tomorrow early evening

Unfortunately I had to work four this morning at work so I am already starting late with this task

[eccerr0r]

I still find it kind of amusing on batteryhookup's website in the t&c's:

You also agree that all batteries and battery related accessories purchased are for upcycling reuse in solar energy storage applications. You are responsible to take end of life lithium batteries to separate recycling or household hazardous waste collection points. You agree not to send end of life lithium batteries to a landfill or put them in the regular trash.

meaning, we'd be breaking contract if we were using it for energy arbitrage or powering equipment/robots/... that are charged using wall power?

[sam_sam_sam]

I still find it kind of amusing on batteryhookup's website in the t&c's:

meaning, we'd be breaking contract if we were using it for energy arbitrage or powering equipment/robots/... that are charged using wall power?

I am not sure why they thought that they needed to point out the up-cycling statement this does not make sense to me because not every battery cell or pack is going to used by solar panel power and hooked up to a battery pack

I do not care about breaking this agreement I agree to buy battery cells and battery packs from them and I am sorry if it is not used in a solar project

You realize that this is the lawyer talking Battery Hookup is covering there ass nothing more than a car junkyard dose when you go pull yourself it so they can not be sued

Another words you are on your own if something goes horrible wrong you can not sue anyone but yourself this is why I sometimes make the comments about doing things professionally looking for this very reason

Just like you are suppose to get an electrician to do wiring in your house oh really if you know what the electrical code is and you understand what it telling you who care I would not be doing this undertaking if did not know what is required to make it a safe place to be in

This the same thing about solar power system and battery power stations and it's storage system what is the safest way to do things is a must
This includes but not limited to charging systems and device loads using BMS systems and it support components

This is reason I do a lot of research testing to get educated about this subject I have had different ideas about what could work but when I have done a proof of concept testing I realize that the concept is flawed in some way

Here is a perfect example of what I am talking about is when I was trying to find a solution about testing BMS balancing protection boards and destroying my battery testing machines by doing it this was a proof of concept that did not go as planned because I did not know about how the charging circuit was designed and did not realize that the battery machine controller was only adjusting the current not the voltage this was a case of not understanding how the system was suppose to work and not understanding exactly what the BMS circuit was doing to the charging circuit on the battery testing machine

Once I understood these concepts and there limitations I found a work around these limitations was the battery testing machine designed for testing BMS balancing boards no and it does not mention anything about BMS balancing protection devices at all

Like you I want a way to effectively charge battery packs using solar panels my issue is what type of charging controller circuit do I use I do not have any experience with any of them just like I had no experience with battery testing machines either and for the most part it was self learned and a lot of YouTube videos and a lot of trial and error along the way

I would like to avoid some of trial and error parts that are well known issues to avoid some things work very and something do not work at all or it is not the result that you are looking for

I have the testing method work out and putting together very balanced battery packs with new battery cells

I have not done any with slightly used battery cell pack yet because I do not have a testing jig made for testing 18 volt battery packs yet but I am still working on some designs issues and how I want to design it to be able to test different battery tool packs because each one is different from what should be a standard way which would make this process easier to do

I have an idea about modifying one of my voltage current switching power supply to run on solar power battery bank but I still have to do more research and testing this concept and see if it doable and is it worth doing it and how efficient would this be

Now there is one that I have seen from an eBay seller that is already made for this purpose but it runs around $100.00 for one I still have give this a lot more thought about weather or not I want to go down this rabbit hole or not

( I might go head and buy one to see how it is designed so I can see if modifying the ones that I have are designed basically the same way or not and yes it is a Chinese made design and and manufacturer in China which do not share very few of there designs on the internet )

One limitation it has is that it is limited to 80 volts I could still use my individual battery cell voltage monitoring module but the question is how do I make sure that the solar panel power supply voltage does not ever get higher than 80 volts or what ever the maximum voltage limit is

To answer the question about cutting the heat shrink tubing around the battery pack that we have been talking about the answer is yes you can reuse the heat shrink tubing as long as you cut it in half and very carefully removing it without distorting it and just putting packing tape on the two half or just cut along the cable end and you only have one section to re-tape it and you are done

It is a little harder to remove the heat shrink tubing from the battery pack but it would easier to tape back together so to me it would be worth it in the long run I plan on doing a couple of them this way with a individual battery cell voltage monitoring cable to hook up to the battery voltage monitoring system module

This is the cheapest I have seen this battery testing machine advertised on eBay

Battery Capacity Power Performance Tests Charge and Discharge Tester

If you are interested in one I will post the website link to it

US $43.24/ea
or Best Offer

You might never see this price again this is one of them I use it is limited to 24 volt charging so the battery packs that we talking about it would not be able to do but it can test individual battery cells all you would need to do is solder temporarily hook up wires so you can test the individual battery cell it will do 20 volt power tool battery packs with out any issues and you can check the BMS protection board just as long as you put the voltage sense wires on the battery cell output side not the BMS output side the power output of the battery testing machine goes on this end

The software is free you could even use a windows XP computer for this the best operating system to use this software is windows 7 it works best for this purpose
I would not recommend windows 11 computer because it not very stable and sometimes it is hard to get it back working again

[eccerr0r]

I'm not sure how you'd integrate solar into any battery charging/testing system unless it's already integrated into the system -- I don't think MPPT works well if it doesn't know what kind of batteries it has coupled with the system ahead of time especially with an arbitrary voltage battery tester. Maybe it would be best to just have the solar grid tied and you have the tester powered off of grid, then the two become decoupled...

No Windows here... And I think I've exceeded my budget for the quarter at least... depending if I can do without that dead pack.

[sam_sam_sam]

Here are the test results from the best 24 volt battery pack that I have tested so far

[eccerr0r]

The BMS did its job or this still stopping at a preset threshold?

For fun, the 153Wh LiFePO4, a 144Wh LiCoMn, and a 240Wh (20Hr rate) PbH2SO4 batteries. I was planning to use the LiFePO4 instead of the lead acid battery when it dies... The acquired used lead acid battery has survived a few seasons already plus I've added a few, and I've just started using the LiCoMn pack.

LiFePO4 8x32650 153Wh, about 3 pounds
LiCoMn 12x26650 144Wh (about 1.5 pounds, though I wonder if this is real watt hours or is it "chinesium" watt hours, but it's in the ballpark of feasibility IMHO)
PbH2SO4 2x12V10Ah 240Wh (heaviest, 12 pounds?)

[sam_sam_sam]

Nice I do not see any reason why it should not work with the Lipo 4 pack
You can get 26650 battery cells with that high of watt hours but bigger question is the quality of the battery cells that is used

The two lead acid battery packs what is the voltage with no load on it does it get to a voltage around 28.00 if so it should work fine for this application as well
If not you might have to have an external battery pack charger for it or modify the voltage output of the charger that you have it would be nice if the charger that you do have goes in floating charging mode if it does then this would be even better

Or remove one battery cell from the battery pack and disable one of the BMS input leads by removing it components and then it will work with the charger it might run the motor a little slower but that might not matter

[eccerr0r]

I'm just not sure exactly how many amps the mower uses (specifically, inrush/stall current), and with a 15A BMS it probably is close to limit -- so I was expecting to use two in parallel.

Oddly enough I think both my scooter and mower both use 250W motors. The scooter has a controller, I thought the mower did not as it has a contactor.