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

[eccerr0r]

I don't have an outbuilding to store these so I probably have to stick with iron phosphate, not to mention that the cycle durability matters per kWh if I plan for payback. However another thing that has been bugging me is that iron phosphate should be cheaper than cobalt dioxide in terms of metal cost -- though manganese should be fairly cheap too. Energy density of iron phosphate is lower so that too is a negative. All in all for the positives and negatives I would hope iron phosphate and cobalt oxide should be about the same price, paying for weight/volume energy density... the cycle life really doesn't or shouldn't increase costs of making these cells, though it is a desirable quality.

My luck with used cobalt/manganese lithium ion batteries have not been good... well at least with cycle life. Yeah these are what's used for technology devices and have had to toss a lot already after they no longer hold enough charge to be useful. In fact I still have a bunch pending disposal... For fixed energy storage I have no experience with iron phosphate but suspect there will also be those cells that go flat moments after hitting full charge...and if in a pack, it makes the pack useless...

Oh and that power one PSU I'm fixing...yep that will be the battery charger I suspect...

[sam_sam_sam]

I do not have experience with them either and I am sure that they require a special BMS protection board as well and if they cost a lot more than what I am use to paying for this option probably would not work for me for another reason where would I find a recycling company that gives battery cells a second life in another device because I do not always want to buy new battery cells for every project I want to run a proof of concept on

Another issue is that my testing machine might not be able to test them properly either not knowing what parameters should be used for best practice and results to many unknowns to deal with

This might be the reason for the poor performance that you have experienced with these battery cells and there life span because if the battery cells that you been getting are near the end of life any way how are going to know what to expect in performance

Here is my suggestion for this dilemma buy brand new one to just make one battery pack or buy a brand new battery pack already made the only issue that you might have do you know what is a good brand from a bad brand manufacture standpoint because believe or not this makes a difference in the quality out come and weather or not it is made in China or not make a difference as well

Here is the reason I bring this up when I first went to buying Lipo 4 battery cells I bought from an eBay seller that said they were in storage for a while but did not reveal for how long I did not know better at the time but when I received them and tested a few I only got 750 milliamperes and they were heater cell once you got to 3.00 volts they were not worth anything you could not use them at all yes I got burned but I learned from that experience a lot be careful of battery cells that have been in storage for a long time

[eccerr0r]

It may well be cell quality. I have to admit, so far my OnePlus phone's battery hasn't degraded way too much over the ~3 years I've had it, and likewise a Nokia battery took 9 years + to degrade to 50% capacity, both with constant use. On the other hand my Asus phone didn't nearly last that many cycles. I think I only had around 100 cycles and lost at least 40% capacity. I have an eeePC with a dead battery (holds nothing). These all should be cobalt batteries I'd assume.

I also wonder how fast I'll kill the batteries discharging them at 1C +... though technically for my arbitrage I can do 0.25C so it will last the four hour period that have the high cost power period.

[sam_sam_sam]

I did a little bit of research on these types of battery cells “cobalt/manganese lithium ion batteries”

Couple of things that I noticed right away was they are not readily available in quantities and the cost of them is a lot more expensive to buy and as far as getting used ones is difficult because mostly found was electric vehicles that use this type of battery cells one option would be to find a battery exchange for electric vehicles and see if you can buy at a reasonable price now you can buy 18650 battery cells that are high current variety but they are expensive meaning that one 18650 battery cell is $16.00 each ( this company was not in the USA and weather or not they will ship to the USA is another story ) compared to regular 18650 that is around $6.00 to $8.00 new ones

I have to question weather or not it is a great choice or not mainly cost and availability of them especially used ones or slightly used one

For my personal purposes this would not be a good option for me it is hard enough to find good quality BMS balancing protection board but getting slightly used battery cells is a lot easier to find and testing them is very easy to do my biggest issue is spent battery cells and what to with them

One mistake I think you are making is that the battery cells that you are trying to get high current out of them they are not designed for this type of application you need to find high current type of battery cells that are designed for this type application and there a big difference in the way the charge and discharge curve looks when doing 2 to 5 amp load testing on them and the cells get very warm very fast if they are not high current versions this might be the reason why you are having such a high a failure rate

You can find very high current 18650 even higher current one for 21700 battery cells on the order of 50 amps and maybe even a little higher than this but they are more expensive the higher the current rating they are but you will save more money in the long run


And yes they are little bit more expensive than low current versions are but there performance is considerably different when you use the right version for the application

You need to pay attention to the data sheet showing maximum discharge rate and follow them for best results and performance

I will do a comparison test on regular low current battery cells at 4 amps and high current battery cells that are high current versions and you will see the difference in graph curves one is how steep the curve in a certain amount of time

The curve will have very tight step down something like a ladder and will be consistent for certain amount of time before it rolls off because of the battery cell out of power this is the high current version

When you do this with low current battery cells instead of the ladder effect you get almost a smooth downward curve and it is very quickly moving downward and when the testing machine stops because you hit the target voltage it climbs back very quickly but your cell will become very warm to the touch where the high current ones will be maybe a little higher than room temperature

And these battery cells are a well known brand and series one that are used for comparison

[eccerr0r]

well, it's also a matter of overprovisioning too. More batteries = less average current per battery. Alas that increases cost that needs to be recuperated...
I don't think it's discharge rate that killed the cells I've had, after all, they came with these batteries. Also I don't think there's ever been Li-ion cells that can't be discharged at 1C though charging them is a different matter.

Okay the math was wrong for battery cost recuperation. Based on my usage I can at most recuperate about 30¢/day during winter demand power because that's how much electricity I use when it's dark out (as long as I decide to milk the system -- this is about 1.2kWh). Summertime it's around 15¢/day (about 600Wh) because solar panels cover most of the usage already. However I can still keep on powering during off peak hours but only if I used solar power to charge the batteries, else might well use grid power since it costed the same. So it looks like recuperating $60-$70/kWh will take a very, very long time unless electricity costs go up. Yes, my electricity is fairly cheap as it is except during demand time of day pricing (and then again, is probably still cheaper than some places.)

On the other hand I have some underused solar panels that I should use for charging batteries... and using them at night...

BTW this is disregarding having battery power if grid power goes down...which rarely happens...

[sam_sam_sam]

I mentioned this earlier in this post about how these BMS protection boards do not seem not to function correctly I have decided to test them in a different way and see if this makes a difference or not

https://batteryhookup.com/collection...-lifepo4-cells

But received my order of 6.4 and 9.6 BMS protection boards that I need to test as well I might get to this today sometime later on today

I might work on this project today and see if I can do some testing on the BMS protection board and see if I can run my blue capacitor tester I might have to use a diode in series to drop the voltage down from 9.6 volts to 9.00 volts

[eccerr0r]

Voltage dropping has never been very consistent for me using diodes, which is expected as the voltage drop depends on current draw...

And I was staring at the 24V battery pack for my weedwhacker... and just realized again that "24V" manganese/cobalt Li-ion (6S) is way different than "24V" iron phosphate (8S)... which is not that different than my lawnmower "24V" which is 12S lead-acid (actually 2S 12V)

hmm...this will be more pondering... after needing to pay out several kilobucks to uncle Sam (unfortunately for you, not you) in 2 days...

[sam_sam_sam]

https://batteryhookup.com/products/n...rismatic-cells

Here is a listing on battery Hookup that I bought about 6 or 8 months ago and today I started charging one of them the battery charging curve looks really good in fact with at 4 amp for two hours it only went up about 0.100 volt from where it was at once it settles down with the voltage

I originally bought it for jumping off a car when needed but I think that once I decided which GTI I am going to buy I going to make a battery pack for it but I only have four of them at the moment in order to make a 24 volt battery pack I will need 4 more of

These battery cells are from Japan not China which is a big plus and these battery cells are definitely brand new the only issue is that you need the nut for the post and a buss bar to join them together and of course a decent BMS balancing protection board

I will have to have a lot of time to test each battery cell 72 amp hour divided by 4 amps would take 18 hours to charge up completely I think I going to use my 40 amp battery testing machine instead and charge it at 30 amp which would probably take a little more than 2 hours this would be the first time I would be using this battery testing machine at this charging rate so I would be giving it a good workout and see if it holds up well with that current

One note about changing from lead acid batteries depending on your charger it might not like 8S you might have to do 7S this is true with battery backup battery packs because 13.8 X2 =27.6 and 8 X 3.6 =28.8 and maybe a little higher than that depending upon the type of lithium ion battery that you are going to use because in the battery backup the maximum voltage is just over 27.5 volts if you are lucky if using Lipo 4 with 3.6 fully charged it would not make it that why you have to go with 7S not 8S now if you provide a battery charger that can do 8S then that does not matter

This is a new listing on Battery Hookup it is used but they claim that it checked out nearly full capacity weight is a little over 30 pounds it is two kilowatt hours for $79.00 but you would need a BMS protection board for it but the balance wire are there but might not match the BMS board connections

https://batteryhookup.com/products/8...on-49-kwh-copy

[sam_sam_sam]

I might work on this project today and see if I can do some testing on the BMS protection board and see if I can run my blue capacitor tester I might have to use a diode in series to drop the voltage down from 9.6 volts to 9.00 volts

I had some time today to put together a 3S2P Lipo 4 cells that I bought from Battery Hookup that are China so far the BMS seems to work fine but one thing that I was surprised by when first turned on the current went to 1 amp and then dropped to 100 milliamperes then back up to 1 amp several times before it became steady and stayed at 1 amp but lets see what voltage it turns off at

https://batteryhookup.com/collection...-lifepo4-cells

As you can see the BMS balancing protection board does turn off at 10.95 and back on at 10.75 and just keep repeating it self this not a BMS balancing protection board that should not be left on when the battery is fully charged because eventually it would over charge the battery cell and become warm to the touch

In the second picture shows the second current spike it probably that the mosfets on the protection board probably turned on to hard for some reason or this has something to do with controller board not seeing the current correctly or really do not know for sure what is causing this but

This behavior is apparently normal because when I used to use a bench power supply I would turn down the voltage just above the turn off voltage and set the current so it would climb very slowly with the voltage and see what the turn on and off voltage was and what current would make the BMS protection board from switching on and off to rapidly and make it as smooth as possible which is what I did in this case

But seeing these results I am going to use a modified battery testing machine that got damaged because of testing BMS protection boards and just use a switching power supply that you can adjust both the voltage and current to keep from damaging the battery testing machine unfortunately they are not cheap to replace from doing this type of testing

From the results that I see on this graph my suspicion was correct about the fact that when the battery voltage goes near the set point it cycles on and repeats until it gets to the maximum turn off voltage and stays off but the charging curve reveals that the voltage climbs very quickly and drops very quickly at about 10.75 to 10.95 volts it is very rare to find a BMS balancing board that once it hits the maximum voltage it stays off until you reactivate it I personally prefer this type of BMS protection boards

Now I have a question about having a steady 9.00 volt steady power supply I am not sure a buck converter would work very well in this application because they recommend a minimum of one volt above the output voltage more would be better for best results

Now I wonder if a boost / buck converter would work better in this application with this situation I do not know the answer to question because I have not tested in this way if someone has please chime in and in light me on weather or not this idea would work or not

[sam_sam_sam]

Here are the results of BMS balancing board cutoff voltage very impressive results it turns off but does not restart again I have seen some BMS balance board do this crap and I do not like this nonsense

So it looks like about 3 hours and 15 minutes of running time very good results for Chinese made battery cells for around $0.70 each including shipping

Now I have to find an enclosure for this battery pack and BMS balancing protection board

Can someone please explain what they are seeing on the screen when it first starts charging because I saw weird stuff it was doing yesterday when I first started charging the battery pack

It looks like this episode lasted about a minute or so and then it went back to normal charging I have not seen this before in a BMS board usually when you start seeing this behavior is when it gets near the cutoff voltage set point you expect this not when you first start charging the battery pack

Here is a better picture of BMS balancing protection board in the last picture

How do I make a stable 9 volt battery power supply I could use a diode for this but someone made the comment about if the load is light the voltage might not be exactly 9.00 volts I mentioned about using a boost / buck converter module but I am not sure if it would go from buck mode to boost mode when it drops below 9 volts by itself or would you have to manually switch the mode

This probably would not matter because once it gets to 9 volts there is not much running time left

Now might use a 9 volt zener diode a 5 watt one should work fine for the load that I have in mind doing but I would have to put a switch to turn off the circuit when not in use

One note about using the setting up the steps charging and discharging and wait functions you have to setup it up so that when just before the voltage starts going up rapidly you adjust the current down so it does not cycle on and off until it gets to the cutoff voltage so it minimizes the cycling effect so you do not put stress on battery testing machine circuitry

[eccerr0r]

so this board you have does or does not have top balancing? looks like it does...?

[sam_sam_sam]

so this board you have does or does not have top balancing? looks like it does...?

The description of this BMS board does not mention this but my guess is that it does something when it gets to around 9.7 volts it does this 970 milliamperes down 150 milliamperes then up slightly to 250 milliamperes and it does this several times but the charge curve is very slow climbing when it reaches about 10 volts and very slowly climbs up until it gets up 10.8 volts then it starts climbing a lot faster until it gets to around 10.9 volts then starts turning off then when the voltage drops to around 10.5 volts it turns back on again

When this BMS balancing protection board has a load it drops the battery voltage about 0.500 volt from the 3.2 stated voltage for this battery cell interesting results from this BMS balancing protection board

I did not see this the first time I had done the load test where it turns off at a certain voltage level and turns back on again and does this several times hun interesting results

i have use BMS balancing protection boards in the passed that did not behave like this one does so I am a little puzzled about the way this one works



This concludes the testing of this BMS balancing protection board testing on this particular board I have one more to test that is a 9.6 volt board now I have to build a 6.4 battery pack and test BMS balancing protection boards ( I have four of them ) and see how it behaves when tested

[sam_sam_sam]

Here is the link to where I bought these BMS balancing protection boards from I am going to also buy these BMS 12 volt version as well to make a 12 amp battery pack for some high current car devices that I have

https://www.batteryspace.com/PCM-wit...ack-at-12.aspx

One note there website is not easy to navigate for certain types of BMS protection boards but have all kinds of BMS protection boards available yes some of there prices are higher than what you can find on eBay but you are very limited to the type of BMS protection boards you can find I did a google search to find this company that has BMS protection boards for sale of different types of BMS protection boards that they have available for sale

With these results it should keep the battery fuel gauge on the 9 volt device to not show that the battery is about to be out of power until the voltage starts dropping off and rolls down to nothing and turns off not bad results

I said that this conclusions the testing not quite yet I going to use my multi battery cell monitoring voltage meter module and set it up to monitor the individual battery cells and see what is really happening when it does this turning on and off it does at certain voltage levels and show theses results as well this is a case where I have time to basically babysit this testing to take pictures of this process while it is taking place

When the size of the graph changes the time frames to condense it - it looses the how step the curve really is but the discharge curve is the most stable of the two curves which is very interesting I would not have expected this to be so stable output voltage at a certain current level you do not see this when testing battery cells with out a BMS balancing protection board the two curves are very similar in nature

[eccerr0r]

hmm..do i want to take a chance at buying 24V packs and hack them into 12V packs by modifying the BMS board (and reconfiguring the pack of course...)

[sam_sam_sam]

hmm..do i want to take a chance at buying 24V packs and hack them into 12V packs by modifying the BMS board (and reconfiguring the pack of course...)

I will reply later

[sam_sam_sam]

hmm..do i want to take a chance at buying 24V packs and hack them into 12V packs by modifying the BMS board (and reconfiguring the pack of course...)

To answer your question I will do this in two parts

First one

Do you have a dermal tool and the accessories for more importantly a small cutoff wheel
Do you have steady hands and nerves working with a potential bomb if you happen to cut to deep or cut into the cell it self

Then you can proceed to the next step

Second one

Are looking for high current battery cells above 50 amp load capacity continuously if so then you have to be concerned about two things weight being one of them and the second one is are you looking for slightly used or new or are you looking for something less than 70 % life left

Are you up to cutting buss bars because on some of these battery packs the battery cells are welded together not stud and nuts and are not removable
Now sometimes they offer battery packs that have removable buss bars because they have threaded inserts or just threaded in the battery post

or

Are you just into using something like 18650 21700 26700 and other size in this type configuration or are you interested in the type that has studs on each end of the battery cell


or

Are you interested in pouch battery cells now if you have the tabbing wide enough to put holes in them for bolts is the best for higher current capacity continuously output but you need to nerve of steel to make this happen and what ever you do do not be in a hurry to do this undertaking

I personally would not recommend soldering them this very hard to do and getting a good connections I am suggesting that it can not be done correctly but it very difficult to get it done correctly

There are some battery packs I would strongly stay away from because they are very difficult to do without short circuit the battery cells that you are trying to separate I mentioned this earlier in this post the big the battery cell is round the more difficult it is to do unfortunately because most times the tabbing is much thicker on high current continuously being output than lower current output battery cells

With all this said above it depends on what level of difficultly you are willing to deal with and how much time are you willing to spend to save money in the long run as far as buying brand new battery cells

I would highly recommend and suggest that if you can buy Japan made battery cells that are over stock never used is your best bet in the long run granted they are not necessary new stock just made but I can tell you that Japan made hold up better than Chinese made battery cells that have been in storage now they have some what degraded but it is not by much from what I have seen now you can find Chinese made battery cells that are very close to this quality but the problem is how do you know what is good quality from bad quality is the question the only way you can answer this question is to do a lot of testing and taking chances some will turn out good and some will not

Now just recently I listed one such battery cells that are made in Japan that I put on the testing machine at 4 hours at 4 amps and it was about 16 amps hours in to the charging cycle and it was going to take 17 hours to charge up completely now each battery cell is $22.00 to me this is not a bad price at all for what it capabilities are and it has post are threaded and is capable of using buss bars to make the connections between battery cells unfortunately the shipping is a little pricey because of its weight but there really is nothing you can do about the shipping cost you just need to be smart about how to get around there nonsense about how go about figuring out how to rape you out of your money

It really depends on what running time you are looking for
It really depends how much money you want to spend
it really depends on how long you want the battery to last
It really depends on weather or not you have the tools for the job you want to do yes you can do it the hard way to save money but are you really saving money when you figure in what your time is worth

It really depends on how much time you want to devote to this undertaking especially if you only want to use very used battery cells is worth buying very cheap battery cells and taking the chance of getting about 50% or more not re using battery cells near there end of useful life but the bigger question what do you do with a lot of bad battery cells but this is biggest issue for me is the amount of time testing battery cells that you really do not know the history of I have done this in the past and I had to make a decision about weather or not this was a good thing to or not and I come to the conclusion that unless you can really can re use the enclosure for a project that you are wanting to do then my answer was no it was because I am loosing money in the long run because I charge for my technical knowledge and services starting $30.00 to sometimes over $50.00 depending on how difficult the task is

I have been in the place you are and asking the same type of questions and even more that you have not revealed in this post yet
I had to ask myself some very difficult questions about what am I really wanting to risk in buying used battery cells and packs not knowing what the history is in some cases and some cases only knowing the voltage of each battery cell is helpful but dose not tell you much with out testing them which does take a lot of time and time is money

I am not trying to discourage you from buying or doing this undertaking but I want to be realistic about what I have learned over the years of messing around with them this is one reason why I post the results of my battery testing and testing the BMS balancing protection boards because I want to have the knowledge about this subject to make informed decisions about the purchases that I am making and is worth the money I am spending and how much time will I have to spend on this undertaking

I sent you a PM message about a month ago did you receive it I just curious if you got it or not

Now if I was making a lot less money than I do I would probably only buy new old stock and I would only buy one and do all of the testing first instead of buying what I need for a project and then doing the testing and knowing for sure what I am buying in quantity first then buy the rest of what I need to have for the project that I have in mind doing

But this is hard to do with some of what Battery Hookup offers in a lot of cases this is not possible so it would seriously limit what I could buy and I like I mentioned earlier I do use Affim 4 payment plan for 95% of my purchases at Battery Hookup so I can spread out my payments over time

One note about the place that I bought some of the BMS balancing protection board they have the highest shipping rate that I have seen in all the places I buy from I really have to look the other way because unfortunately no other place offers what they have to offer and unfortunately I need to have simi high current BMS balancing protection boards for high current capacity of the battery cells that I going to use for the other project that I going to build very soon that is why I bought these BMS protection boards first

For the low current battery cells I bought I do not need these more expensive BMS boards but what I have in mind doing is to use them to charge the lower current battery cells and just use a BMS protection boards that do not have the balancing feature in them they are lot cheaper than ones that do have this feature

I hope what I have mentioned above is going to help you with the decision making process that you need to make about what you want to do I hope this helps

[sam_sam_sam]

hmm..do i want to take a chance at buying 24V packs and hack them into 12V packs by modifying the BMS board (and reconfiguring the pack of course...)

Be very careful with what type of BMS boards you buy because some of them are very difficult to do or nearly impossible to do because of the battery management ic chip they decided to do yes I have done this in the past and yes it does work and I can tell you that the BMS balancing protection boards are the easiest to do because they use a battery management ic chip that makes it easy to do

In most cases all you have to do remove the components that are not populated on boards have more battery cells
Also make sure that you do not forget to jump the pads that are jumped and remove the jumper that were on there for the configuration that it was designed to be in it was made for these are the easiest to do and if I plan on doing that to a BMS balancing protection board that is the type of board that I buy

But I would highly recommend and suggest that you look at some YouTube videos on this subject because that is how I learned about how to do this in the first place

If you are referring this battery pack I just ordered a case of them I will let you know what I think of them and post the results when I have them

https://batteryhookup.com/collection...y-with-bms-24v

The shipping costs for the case was a little bit higher than I expected it to be but there are 12 of them in the box

https://batteryhookup.com/products/f...bms-24v-74-kwh

If you are referring to this one I am not sure how easily it would be modified it but to use it as is possibly a good buy at this one says that they have tested them in the past which is helpful to know you would be less likely to have issues with them your risk would be low

https://batteryhookup.com/collection...4-module-w-bms

Little bit more than 2 of to make up for 1 kilowatt at $65.00 plus shipping cost

[eccerr0r]

Well I need to get some 24V solution for a scooter and/or lawnmower so would be nice to be able to interchange between them and any other use...

[sam_sam_sam]

Well I need to get some 24V solution for a scooter and/or lawnmower so would be nice to be able to interchange between them and any other use...

What battery cell size is in there now in the scooter
What battery cell size is in there now in the lawnmower

I have a question for you if you are wanting to be able to use the same battery pack in either one

How easy would it be to remove the battery pack from the scooter
How easy would it be to remove the battery pack from the lawnmower

The reason I ask is because I have see the scooter battery pack foot print
The reason I ask is because I have a lawnmower battery pack and from what I know the battery pack foot prints are not the same

Are you going to modify both of them to use the same battery pack foot print if so

You will have to do a couple things to be able to do this successfully

One you probably need to create a charging station for this configuration setup

Do you plan to use the controllers in each device if so you probably need to remove the BMS protection system from or modify the wiring in both to a connector type of connection so you can make it easier to do if done correctly you might still be able to use either charging device from either device to charge the devices and keep the individual BMS protection systems for each device

If I was doing this project I would decide what battery pack foot print would fit in both devices make the wiring the same footprint for both devices so the same battery pack could be used in both devices

Its going to take a while to do this yes it can be done this way but the planning of it and the way you implement it is going to take the most time to do
The main reason the BMS protection system are properly not same format which is how and the way you go about making the battery pack being able to be used in both is going to hardest part of this process to accomplish and make look professional looking and neat looking in appearance but safety would be my biggest concern about doing this process in doing this project

Now if I was doing this project what type of battery cells would I use

Question would be are the same type of battery cells used in each device if so this is going to make life easier to do

Second question is are you wanting the longest running time possible choosing the right battery cell type would be the best option for this particular project

High current type battery cells would be my first choice Battery Hookup dose have however you would have to harvest them from a all ready made battery holder enclosure and the one I would use I have already bought a few of for a very reasonable cost for one unit it is very easily taken apart and would be a great choice for this project

Unfortunately they are out of stock at the moment but when they have them they cost $15.00 each

Now I can sell the amount of battery cells that are in this battery pack clear of tabbing remains and individual tested for $20.00 plus actual shipping cost me to ship it from my area to you

Or I just sell you the hole battery pack minus the circuit board and just test each battery cell rail for the same amount that Battery Hookup sells them for the reason for removing the circuit board is to make it easier to test the individual battery cell rails and loosen the screws that hold the battery holder together for you as well

If you are interested in please pm message me to work out the details or you can wait until they get them back in stock again they have had this item for quite a while now and from time to time they have been out of stock several times before

Battery Hookup 48v 6.4ah 307.84wh Battery with Panasonic Cells - $48/kWh

Here is the listing for it might not stay up for very long when they are out of stock

https://batteryhookup.com/products/p...37417514860706

One word of caution about taking the battery cell holder apart there are two or three very long screws that hold it together but the screw heads a torque head type if I remember correctly it is either aT15 or a T20 type bit but you need a very long shank to be able to reach the screw head do not use a power tool on the head of the screw unless you have it broken loose first otherwise you will strip the screw head and depending upon where it is located on the battery holder enclosure it going make it hard drill the screw head off of it

The reason I have not done anything with them if I remember correctly it one half of the battery pack has a certain amount of battery cells and the other half has four less cells and was hoping that each side was the same size but unfortunately they are not but could be reconfigured to match each other but what I originally bought them for was going to take to much time to do decided to use a different approach for the battery pack I need but I have plans to use this battery holder for a battery pack that I have in mind to do with some individual battery cells I bought several years ago which I tested one on the BMS board on those Chinese made battery packs that I just recently bought so this might be something that you will be seeing soon I just have to buy some tabbing for it to make hooking each battery cell easier to do

[eccerr0r]

They both used two lead acid 12v 9Ah/10Ah packs -- 24V system -- so that's the amount of space I need to work with, and not much room for hacking. So ideally small cells are better though they may not be best $/kWh though that is still a concern. And yeah all of these are cyclic versus backup. (note: my mower's Pb-H2SO4 10Ah packs are okay but I suspect these won't last forever...unsure how long they will last.)

Don't know, would be best to get all of the same type and size of cell to be able to standardize and swap between them, and it's okay if I have to solder/use connectors. Yeah it would be nice to get specific ones for each use... but only if both types are good $/(cycle*kWh)

Then there's the other desire to get 12V packs just because I have several power inverters... and the 24V GTI...