Battery Hookup has a Labor Day Weekend Sale 20% off of regular price which in my case covers the cost of shipping

[sam_sam_sam]

I have been looking at some battery packs that they recently brought in and I was debating whether to buy them because of cost of the shipping especially one of the two battery packs that I had bought from this sale that they have going on right now

https://batteryhookup.com/products/1...44780299845794

bought one of them

https://batteryhookup.com/products/3...ttery-with-bms

bought two of them

I posted this sale in case someone else is interested buying some batteries and give them a second chance in another project

The first one in the list is going to be a battery pack for a battery battery backup that has a weird battery pack size I have two of them but I want to try this out and see if it will work with out any issues before I attempt this on the second one

The other battery packs I not sure exactly what I going to build with them right now but why I was interested in them is because it has a barrel plug for charging port I will probably change the voltage and use a different BMS protection board in them

[eccerr0r]

hmm... need more Wh per $ ... factoring in needing a BMS as additional cost...

[sam_sam_sam]

I did another order last night for some fuse type tabbing and some barley fish paper battery insulation tape and couple of Lipo 4 BMS protection boards and couple and two high current relays and this time the total cost of shipping was not total offset by the 20% off but most of it was so that was a good thing

It is time to make a high current battery pack out of some battery pack that I bought a couple of years ago I just need to retest a couple of them to see how much less amp hours I have now compared to the results I got when I first bought them that is the reason I bought a couple of high current relays one is for this project and I have not decided what other high current battery pack I am also going to build

[eccerr0r]

https://batteryhookup.com/products/p...2450-needs-bms I wonder what's wrong with the BMS, is it repairable...

[sam_sam_sam]

https://batteryhookup.com/products/p...2450-needs-bms I wonder what's wrong with the BMS, is it repairable...

In fact I bought one similar to this and one set of battery cells were bad and I have not had the time to test a bunch of battery cells to put in the enclosure but the BMS board might not be good in this situation either but what I have in mind to test it is to use just 4 battery cells and run some test on it to see if BMS board is working properly or not

One note on the these battery packs is there no battery separators between battery cells when I redo mine I going to use battery separators in it yes you can not get as many battery cells but the issue is less likely to happen when you battery separators in it

It might be but it might pay you to buy more than one of them if you can not find replacement parts for it

or buy this and be done with it just in case you can not repair them

https://batteryhookup.com/products/l...s-with-balance
I have used them and they work pretty good for what they are

I personally have not tried to repair any of them I just tested them on the SkyRc B6 ( just make sure that you have the latest firmware update and turn off the balancing function for this to be done this does not work on the clone version of these units ) battery tester and if it has the right results then I use it but I would like to learn how to repair them safely which is what I do not know how to do exactly but willing to learn

It could be that the BMS does not turn on the output when power is applied I have had some that had issues not being able to be activated for whatever reason from either it was over current at some point I have some battery packs that have a two amp limitation for BMS protection board and if you exceed this it refuses to turn back on again I found out the hard way on these battery packs

Now what I have done on a version of BMS board that has the same exact parts for the voltage monitoring here is an example of one that this can be done to ( You need a 7 battery cell count if you are using it for a 24 volt battery backup because your battery pack will not be fully charged if use 8 battery cell BMS protection board )

https://www.ebay.com/itm/28573470024...Bk9SR_7p98G2ZA

When you cannot find the right battery cell count I would just remove those components and now you have the right battery cell count that you need this can only be done on some BMS protection board and it can not be done on all version of BMS protection board buyer beware of this if you are trying to do this yourself

I had bought one of these battery packs but it was the 24 volt version and it did not have the enclosure or other accessories except it had the battery clamps and the connection plates and some battery spacers and bought extra spacers and battery plastic holders because I was going to reconfigure the battery pack voltage to 12 volts instead 24 volts and higher current capacity and the price was a lot lower than what they have this one if I had a lot more money than I have right now I might buy one complete unit and reconfigured it to some other voltage not sure what voltage at this point

https://batteryhookup.com/products/3...v-power-module

[eccerr0r]

Yeah they sell $40 for the battery with broken BMS and $69 for a fully functional tested battery with full life. I wonder how good the cells are in the $40 unit ...

All of this is for is backup... energy arbitrage is too expensive with today's batteries... Currently I have a ~10 year old 12V 35Ah SLA battery for backup electrical energy. Dunno how long it will last.

Technically my 800W tiny genset with full tank of fuel is about 4KWh of energy...has to be compared with battery power...

[sam_sam_sam]

All of this is for is backup... energy arbitrage is too expensive with today's batteries... Currently I have a ~10 year old 12V 35Ah SLA battery for backup electrical energy. Dunno how long it will last....

How get SLA to last 10 years I will be lucky if they last 3 sometime 4 years what do you do to get them to last this long what is the brand name of these batteries that last that long

When Japan made SLA were available I use to get 5 to 6 years out of them sometimes more than that but that's if you were lucky and the device was not hard on the battery

In battery backup and because we have so much power fluctuations you would be lucky if they lasted 3 years sometimes less than 3 years before one cell would go open or have no load output or you would have voltage around 12 volts and act like it just down on charge

I going to see if I can get better results with a Lipo4 battery with a BMS board that is for 7 cells so the battery cells will completely charge up and still be able to connect back once power is restored with 8 battery cells this just dose not allow the battery cells to fully charge unless you have an external battery charger then you have disabled battery backup charging circuit for this work that way unless I am missing something which is possible which I am not in favor of doing this because of safety reasons

I had done this to a battery backup that I used 7 Lipo4 battery cells that I modified to the BMS board but the issue was the if the power stay offline to long the BMS board would turn off the power and you would have to jump start the BMS protection board which is somewhat of a pain in the a** to do when it in corner of your entertainment center and the couch and the wall which is my case

These were new battery cells when I bought them and they last about 5 years which I was surprised that it lasted that so what I paid for them they were a great value

I just wish I could overcome the problem of the battery cells not getting fully charged when using 8 battery cells or find an easy way to jump start the battery BMS board when using 7 battery cells but make it as safe as possible which is a challenge but I would like to overcome

The issue with regular lithium ion battery cells is that if you use 8 battery cells you have the same issue with the battery cells not charging all the way up but if you use 7 battery cells it is the same problem you have to find a BMS protection board that you can modify the voltage monitoring circuit and not all boards can be modified easily especially when it uses the new ic chips that are made for battery management it is not easily manipulated to accept less battery cell configuration plus you still have the issue with the BMS protection board turning off if the battery backup stays on too long and you have to jump start it

Because the cutoff voltage on most battery backup are around 10 volts sometimes a little bit lower but you have to do a cutoff test on the battery backup that you plan on using because of the rapid battery roll off voltage that is known for lithium ion battery cells and for Lipo4 battery cells as well this is something that you can not control unfortunately

If you have any suggestions on how to overcome these issues I am all ears this is something that I have been thinking about for quite some time now and I have not found a solution for this issue

I just looked at the 7 Lipo4 battery BMS board from Battery Hookup and the cutoff voltage 2.5 volts so X 7 would be around 17.5 volts which would work maybe depending on the roll off voltage of the batteries cells used

[eccerr0r]

as far as I can tell the battery is still fine, mainly because it's been kept charged and in comfortable locations (not too hot)... But I expect it to be nearing its end so I should get non-car backup electricity storage, though money is tight. Yes most of my other SLA's have croaked well before this.