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

[eccerr0r]

I actually have a decent idea of how efficient my solar panels are... which is pretty bad. I have current/voltage meters on solar input and a kill-a-watt on the grid tie output. It's pretty darn bad considering the ratings of the panels to what I see on the kill-a-watt. It's just a hair above 50% efficiency from nominal panel design point to power recorded on the kill-a-watt on hot summer days. The GTI by itself is only 85% efficient. Heat and the hack I did for the amorphous panels I have contribute to their inefficiencies. Water cooling the panels makes a significant increase in efficiency alas this costs water and pumping electricity...

I think heat (up to 25% loss on hot days, it's much better on cool days when it only goes down 10-15%) + wire loss (~1%) + inverter (15% loss) is the conversion rate of my panels to what I see at the output.


However, back to BH, I wonder how many full drain/charge cycles I'll get out of these before they drop below 22Ah ...

https://batteryhookup.com/collection...12v-40ah-512wh

[sam_sam_sam]

I However, back to BH, I wonder how many full drain/charge cycles I'll get out of these before they drop below 22Ah ...

https://batteryhookup.com/collection...12v-40ah-512wh

If you had a battery testing machine that you could see the charging and discharging curves graphs you could maybe tell by how steep the curves are and long one cycle takes but you have to run this test several times to get an educated guess but what you also need to know is what temperature of the battery case ( this where a thermal camera would be very useful for this particular purpose ) is and is it consistent if so you could have quite a few cycles but this also depends on how old these battery packs are as well

Now that you are only paying $29.00 the cost of them are lot more than this new

You should be okay with this purchase because they have been tested
However keep two things in mind

One the way these battery packs are designed is they are individually battery cells that are tightly packed together and on top of each other when loaded they will generate heat the more current you draw from them

This battery pack they do not show the brand of battery cells used and what size they could be 18650 to 32700 now I am pretty sure that would be Lipo 4 type battery cells which is not a bad thing

I would highly recommend that you keep the maximum current limit should be followed and not exceed for best results

I would also recommend that if you plan on doing the maximum current load unit they are depleted that you monitor the battery pack temperature and do not let them get to the extreme temperature this will degrade the battery cells if this happens to many times

I would also recommend that you do not extremely fast charge them this also affects there longevity more so than maximum discharging them at maximum current also depending on the BMS protection board when you do extreme fast charging them this also effects the individual battery cells do not get fully charged and you are more likely to get an unbalanced battery battery pack

Now if the BMS protection board has the balancing feature depending on how well it does this function will also reflect how long your battery pack will last and you would still get a 22 amp hour results

Now if you are asking me would I purchase one doing what you have in mind doing probably but this is a situation where a rack mount battery enclosure would be the best option if you were to implement the concept for longevity

These are used battery cells for $20.00 each

https://batteryhookup.com/products/c...prismatic-cell

Or something like this which is brand new never used for $15.00 each

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

But I would probably use a different type of battery cell that is made for extreme current dumping in a short amount of time and there extreme fast charging is more tolerable than smaller battery cells are but unfortunately this type of battery cells are more expensive now Battery Hookup does sell used ones but you have to pay attention to several things one big one is the battery cell swollen if so do not consider buying they have been damaged by something and there longevity will be compromised greatly also do not choose any battery cell that is below the recommended discharge voltage limit

If the battery cell has been load tested you should be alright

But if it only been voltage tested and it is around 3.0 or higher you might be alright but this would be a crapshoot of a purchase the lower the cost the better in the long run now you might get lucky and they still have 80% life left in them but you would the one that has to test them and determine what there health is and choose battery cells that closely match each other for best results

Now here is one that I would consider purchasing for what you have in mind doing these are used $20.00 each they have only been voltage tested but because of the cost of them the risk might tolerable but if can have a good method of testing your battery cells then you could ask for a refund if you have extremely low preference out of a particular battery cell I have done this myself several times in the past but nothing recently

[eccerr0r]

I was staring at the bare cells but the $/kWh is not very appealing due to not including BMS. I also want to keep my options open: I'm not sure I can stick with 24V so being able to pivot to 12V would be nice -- so it all depends on the BMS. So it would be nice to keep with 12V increments if I can for now. I also have some lawn equipment and scooter that could use 24V so would be nice to be able to switch between 12V and 24V.

I suppose I want the batteries to be able to do at least 2000 cycles at 1C (where C is the capacity at time of purchase, not original capacity) and still be total under ~ $70/kWh. I don't expect to draw more than 400W or so either, though may have short bursts that are higher.

Charging I don't expect to charge faster than 100W as that's about my surplus energy from solar at this point. It may go up if I solve my 60-cell issue and get a better solution for my amorphous panels. My MPPT grid tie inverter does not like working with the PSUs I'm using to convert the amorphous panel voltages -- a CV PSU does not behave well with a MPPT inverter that's dealing with other solar panels... (I have 240W worth of amorphous panels and these I'm getting just about 50% of their rated power due to severe losses from the preconverter PSU. 120W is still better than the 0W I get from the two 100W 30-cell panels in series.)

[sam_sam_sam]

You might be interested in this battery hookup offer

https://batteryhookup.com/products/2...enclosure-fans


They do not always have this particular one at this price

You can reconfigure it for 12 volt battery packs the only downside is that you will need a BMS board now you could use two for each bank but might need to go that route if the BMS board that you use has the balance feature but you might pay a little bit more the BMS board module but it would pay for itself in the long run

[eccerr0r]

not sure I need battery cooling... it's the solar panel cooling that's needed...

[sam_sam_sam]

not sure I need battery cooling... it's the solar panel cooling that's needed...

Probably not which in the description says that it is easily removed

I posted it because these units are not available very often for this price the ones that have had in the past for a very long time is the 36 volt version they have offered this one more often in the past

I giving it some thought to buy one before they are out of stock again but change its configuration to 12 volt battery pack but double the amp hour

Battery Hookup has had in the past a better set of pictures of what is inside of one of these units