DC House 48V 50AH batteries x2 for $640 on ebay

[yabert]

Maybe somebody else will chime in on some reasonably priced fast blow t-class fuses

yeap: https://diysolarforum.com/threads/eaton-amx-and-amh-fuses-alternative-to-class-t.60804/

 

[Siamac]

I just watched a few of Will's videos and he doesn't seem to fuse batteries that are low capacity like these

 

[cs1234]

I just watched a few of Will's videos and he doesn't seem to fuse batteries that are low capacity like these

Only you can decide what risks you are willing to take when it comes to fuses/breakers.

A low capacity battery can still fail and potentially start a fire on the relatively smaller wires / bus bars it uses vs a larger battery with bigger wires / bus bars.

I'm not sure if @Will Prowse would consider a 150ah to 200ah 48vdc lifepo4 system to need some fuses/breakers or not, I suspect he would, but I don't want to put words into his mouth.

 

[Will Prowse]

I just watched a few of Will's videos and he doesn't seem to fuse batteries that are low capacity like these

No, I've always said that you need OCPD. Always. Some batteries have a built in t class fuse, so those are fine without. But it still has it.

All of my blueprints have OCPD for every single conductor. And fuse blocks.

If I'm doing tests in my videos, no OCPD

 

[Will Prowse]

Only you can decide what risks you are willing to take when it comes to fuses/breakers.

A low capacity battery can still fail and potentially start a fire on the relatively smaller wires / bus bars it uses vs a larger battery with bigger wires / bus bars.

I'm not sure if @Will Prowse would consider a 150ah to 200ah 48vdc lifepo4 system to need some fuses/breakers or not, I suspect he would, but I don't want to put words into his mouth.

Yes, need OCPD. Most 48V now have them built in luckily. DC rated circuit breaker and OCPD in the BMS. Works great. Just need proper size conductor so it will work properly.

 

[Siamac]

Thanks.
So this one doesn't have a breaker. But does the BMS have enough protection to not need a fuse?

I was thinking of adding a breaker like this to each battery, but not sure if I should fuse each too

https://www.amazon.com/gp/aw/d/B0DHCF8515/ref=ox_sc_act_title_2?smid=AD8P8S3YNFFA3&psc=1&th=1

 

[wpns]

Thanks.
So this one doesn't have a breaker. But does the BMS have enough protection to not need a fuse?

I was thinking of adding a breaker like this to each battery, but not sure if I should fuse each too

https://www.amazon.com/gp/aw/d/B0DHCF8515/ref=ox_sc_act_title_2?smid=AD8P8S3YNFFA3&psc=1&th=1

Those are pretty awful, lots of poor reviews from forum posts, including welding shut and catching on fire

 

[Siamac]

So eco-worthy responded to my eBay message and said they have a backlog of orders and are not expecting to restock until next month. By the wording it sounded more like January to me not December. And they said they aren’t sure if they’ll be doing that level of pricing again but that’s a pretty open ended answer.

I’m gonna just stick with the dc house batteries I ordered, I can pull the Bluetooth bms data into home assistant pretty easily it looks like so that’s my only real need.

The ecoworthy is back in stock, but they upped the price. I'm guessing they will be 720 by the end of the week if nobody buys them at 880

 

[doc3g]

$278.50 each, if you buy two or more at once.
View attachment 258856

https://www.amazon.com/dp/B0D46DS4K4?ref=emc_p_m_5_i_atc

two pack for 499 w/ a $50 coupon = 450, so $225 each :D

Edit: I couldn't pass this up, so I purchased the 2 pack for $450. Slated to arrive Dec 9th, so I'll try to do some capacity testing and report back.

 

[ericfx1984]

Oops, misread it, yeah you’re correct it’s just for vehicles.

Really tempting to order a 15kwh battery from docan then if I can get 30% off.

My understanding on these credits is that you could have made the purchase previously, but that you can take the credit once you put the equipment into operation... Meaning if I bought batteries say two or three years ago but just pet them in storage and did not put them into a system then I would not be able to take the credit, but if this year for instance, I did go ahead and press the batteries into service, Then, even though I purchased the batteries two years ago, I could take the tax credit when I do this year's taxes...

 

[LithiumSolar]

Those are pretty awful, lots of poor reviews from forum posts, including welding shut and catching on fire

That's because every single one of those I've looked at has been rated for 48V. That is 48V max, not 58.4V. Honestly, I don't even know why use of supplementary overcurrent protection is even a question. Even if the battery has a breaker, just add an appropriately-rated fuse for safety and piece of mind. It's a few extra $$ out of a multi-thousand dollar system.

 

[yabert]

two pack for 499 w/ a $50 coupon = 450

88$ / kWh...

 

[wpns]

88$ / kWh...

IKR? It seems like it was only yesterday batteries were a buck a watt-hour.

 

[Andrewr05]

88$ / kWh...

Closer to $94/kWh unless I'm missing a deal?

Oh, if you buy 2 of these two packs you get an additional 7% off which bring each battery to $220, even still that's only $880 ÷ 9.6 = $91.6/kWh.

Still super cheap though!

 

[Martimus]

https://www.amazon.com/dp/B0D46DS4K4?ref=emc_p_m_5_i_atc

two pack for 499 w/ a $50 coupon = 450, so $225 each :D

Edit: I couldn't pass this up, so I purchased the 2 pack for $450. Slated to arrive Dec 9th, so I'll try to do some capacity testing and report back.

@Supervstech posted about his experience in buying these in another thread. His were damaged during shipment due to bad packaging. No support from vendor as yet.

https://diysolarforum.com/threads/dumb-to-buy-a-no-name-lfp.94245/page-2#post-1267403

 

[yabert]

Closer to $94/kWh unless I'm missing a deal?

No. there aren't 48V x 50Ah, but 51.2V x 50Ah. Time 2 batteries.
So, 450$ / 5.12 kWh =88$kWh.
Hard to believe I payed something like 600$ / kWh for my first LFP battery cells few years ago... well, 16 years ago.

 

[Siamac]

https://www.amazon.com/dp/B0D46DS4K4?ref=emc_p_m_5_i_atc

two pack for 499 w/ a $50 coupon = 450, so $225 each :D

Edit: I couldn't pass this up, so I purchased the 2 pack for $450. Slated to arrive Dec 9th, so I'll try to do some capacity testing and report back.

I don't need or even want batteries, but at this price, I couldn't pass it up.

I kind of feel stupid for spending $200 more on the DC House one, but I'm happy with the support I got from DC House. The $450 one doesn't come with support or warranty. But 10kwhr for $880 with fast US shipping? Can't beat that right now. Also has 70A BMS vs 50A BMS for DC House. Not sure if that matters

Now I have to figure out how to get them working and how to wire them

 

[Andrewr05]

No. there aren't 48V x 50Ah, but 51.2V x 50Ah. Time 2 batteries.
So, 450$ / 5.12 kWh =88$kWh.

Good point.

I always do my calculations off of what they're called though.
For 12 I don't do calculations off of 12.8, nor 25.6 for 24v, 38.4 for 36v or 51.2 for 48v.

Nothing against you or anyone else, it's just how my brain works and it's how I do all the other calculations for battery affordability, so I have to stay consistent.

Perhaps consistently wrong, but consistent nonetheless.

 

[Siamac]

Since these have 50A BMS, I don't need bigger than 2 AWG cable, right? If I want to oversize, max 1 AWG is needed. Am I calculating correctly?

 

[Dadoftheturkeykids]

Since these have 50A BMS, I don't need bigger than 2 AWG cable, right? If I want to oversize, max 1 AWG is needed. Am I calculating correctly?

I'm a little confused by that chart... but 6AWG copper is capable of 50amp up to 100 ft. with minimal voltage drop. The bigger the better. BUT, of course you should also fuse the wire with a 50amp or less. I have a hard time relying on a BMS to protect the wire. The BMS "should" protect the cells. Proper fusing will protect the wire.

 

[678Dave]

No, I've always said that you need OCPD. Always. Some batteries have a built in t class fuse, so those are fine without. But it still has it.

All of my blueprints have OCPD for every single conductor. And fuse blocks.

If I'm doing tests in my videos, no OCPD

Some people have accused me of having OCPD (Obsessive-Compulsive Personality Disorder)

 

[Dadoftheturkeykids]

Some people have accused me of having OCPD (Obsessive-Compulsive Personality Disorder)

I honestly thought that is what he meant

 

[yabert]

Since these have 50A BMS, I don't need bigger than 2 AWG cable, right?

Way to big for nothing.
As they can only be discharge at 50A, you can use 6 awg if the distance from the load is short (let say less than 10-15').
Even 8 awg could be fine if 50A is only for peak power and average discharge current is lower.

 

[Siamac]

Way to big for nothing.
As they can only be discharge at 50A, you can use 6 awg if the distance from the load is short (let say less than 10-15').
Even 8 awg could be fine if 50A is only for peak power and average discharge current is lower.

Thanks. It's about 1 foot to bus bar. (I'm running 4/0 cable from bus bar to inverter in case I overdo it in the future, just to future proof). Would it change anything if I'm paralleling 4 of them into the bus bar?

 

[yabert]

Would it change anything if I'm paralleling 4 of them into the bus bar?

No, each will supply up to 50A if the inverter ask 200A.
But if one or more battery disconnect themselves this could cause problem.
Worst scenario, 4 batteries give 200A to the inverter, then 3 batteries shut off, your last battery could not supply 200A and the BMS overcurrent protection need to work.
If it don't work, it's at this moment you will be happy to have your 4 batteries fused.
All this is true if your load is important, if the overcurrent protection don't work, if low voltage protection don't work. So, normally you will never blow fuse.