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diy solar

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Problem with any system that at one end is trying to minimize money spent but on the other allow increasing capacity is the system framework. Suppose you start with one PV panel, a SCC, battery and inverter. All of these will be sized based on each other and the cost to use them. Now try to add in more solar panels. Suddenly your SCC, battery, inverter and wires are inadequate to make full use of it. So they need upgraded and additional cost are incurred. However if you start with a more expensive SCC (more capacity) and larger inverter to begin with you could upgrade panels and add in another battery in parallel.

Constrained systems such as the "solar generators" that are battery power packs often disappoint their purchasers because they do not produce enough to satisfy the loads.

It has been said many times that the first thing you should do is establish how much loads you need to cover and than build a supply system that will do this (with some extra to cover overhead).

Many of us solar hobbyists however do go at it backwards and start with a supply and than see if it will run anything. I have been on that path now for many years. :)
 
280 watt hours a KG? I looked up a prismatic eve, a 280 Ah cell and they run around 160-165 watt hours a KG.
I am disgustingly American so I measure everything in anything but the metric system. In ar-15 football fields (LBS) Thats 127 watts a lb.
So a kilowatt is...7.88 lbs? Dang thats LIGHT!
How much did they cost and where did you get them? That is the ultimate in mobile but durable cells!
 
It just might be. :)

I take it the Wh/kg information comes from the Evlithium store. :) If so, I have no idea where they got those numbers from. A quick napkin math says it's 170Wh per kg.

A single EVE C40 cell is 3.2V 20Ah and weighs 375 grams/0.82 lbs. That's 64Wh per cell or 1024Wh for sixteen cells with a total weight of about 6 kg or 13.22 lbs, which comes down to 170Wh per kg or 77Wh per lb.


Add another 0.6kg/1.3 lbs for the BMS, wiring, busbars, lock nuts, and cell plastic holders and the battery assembly is at 6.6 kg or 14.55 lbs. Still, a 6.6 kg/14.55 lbs for 1kWh battery is pretty lightweight! That's almost half of that of an off-the-shelf 12V 1280Wh battery! The fact it's a 48V battery with all the benefits that come at that voltage is just icing on the cake :)


I bought mine from NKON here in the EU, which comes with the M6 studs. In total 40 cells, just shy of 10€ per cell, shipping included. For the best price, it's best to order either 20 or 40 pieces because of the shipping which doesn't cost a lot, but every little bit helps to make the cost even lower.

All in all, it comes down to €157.2 or $170.67 per 1kWh. It may not be the cheapest per kWh, but it certainly is the cheapest 48V battery I'm aware of, and this little beauty packs a punch. :)


LE: Last time I checked, the price was similar in the US, minus shipping.
I figured that figure was off. Thats NMC level weight. Still very nice. Most 100 AH 12 volt batteries are 25 lbs without any features.
That means you could have a luggable 40 lb 3 kw battery. Not bad at all!
 
It just might be. :)

I take it the Wh/kg information comes from the Evlithium store. :) If so, I have no idea where they got those numbers from. A quick napkin math says it's 170Wh per kg.

A single EVE C40 cell is 3.2V 20Ah and weighs 375 grams/0.82 lbs. That's 64Wh per cell or 1024Wh for sixteen cells with a total weight of about 6 kg or 13.22 lbs, which comes down to 170Wh per kg or 77Wh per lb.


Add another 0.6kg/1.3 lbs for the BMS, wiring, busbars, lock nuts, and cell plastic holders and the battery assembly is at 6.6 kg or 14.55 lbs. Still, a 6.6 kg/14.55 lbs for 1kWh battery is pretty lightweight! That's almost half of that of an off-the-shelf 12V 1280Wh battery! The fact it's a 48V battery with all the benefits that come at that voltage is just icing on the cake :)


I bought mine from NKON here in the EU, which comes with the M6 studs. In total 40 cells, just shy of 10€ per cell, shipping included. For the best price, it's best to order either 20 or 40 pieces because of the shipping which doesn't cost a lot, but every little bit helps to make the cost even lower.

All in all, it comes down to €157.2 or $170.67 per 1kWh. It may not be the cheapest per kWh, but it certainly is the cheapest 48V battery I'm aware of, and this little beauty packs a punch. :)


LE: Last time I checked, the price was similar in the US, minus shipping.
I have some Redodo mini 12V 100Ah they are 19.8lbs for 1280Wh, using 16 pouch cells. Currently $225 with 10% discount. That is nice to have a small 48V battery though. Closest I can think of are the DC house/ecoworthys 48V 50Ah at around $500 but those are very heavy at nearly 60lbs for 2560Wh.




Screenshot_20240409_151435_Chrome.jpg
 
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A matter of preference I guess, but I'm not a fan of the pouch-cell batteries. No doubt, it does have the advantage of being lighter and more compact than the equivalent with the prismatic cells.

Interestingly enough, if some of the battery brands were to pick up on the EVE C40 cylindrical cells for their new 48V offering, with laser welded busbars, they could easily make it as light and as compact as the one with the pouch cells.

Now, that would be something! :)


On the other hand, EcoWorthy 48V 50Ah seems like a very good option to me. (y)

The only thing that I'm not sure of, is the cost for the OCPD for each battery in parallel. Then again, if the planned load does not exceed 24A-ish per battery, I can think of a fuse I'd use, that might do the job just fine. ;)


I guess what the 'nanocube' has going for itself the most in comparison to either of the two batteries, is that it's serviceable. Of course, since it's a DIY battery, that's a given. Nothing surprising there.

Still, if any one cell starts misbehaving badly down the road, it would only take a €10 replacement cell and the battery is once again, fully operational unlike either of the off-the-shelf options.
I think those cylindricals are what is used in my ecoflow Delta 2 max (2000Wh, 2400VA/1800W inverter and two 500W mppt ports) at 50 lbs.

Compared to a ecoworthy 24V 100aAh "mini" and a full size djlb 24 100ah, redodo minis to the right
20240304_173412.jpg
 
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