LFP DIY post, something maybe good, from Will Prowse!

[john61ct]

https://www.mobile-solarpower.com/de...o4-system.html

Thread rules

While assumed good things are longevity, and

the adjustability to do what **you** want with your cells,

let's try to keep away from in-depth techie detail arguments about the correct stop-charge parameters, how much C-rate current is too much, etc.

No basic conceptual LFP questions, extended howTo discussions at the 101 level, start your own thread for those, no shame they're free.

Also avoid debate on to what extent Will, or anyone else knows what they're doing, no personality-based sniping, as much as possible.

The goal is to suggest additions to improve the example setup,

what components could be substituted cheaper, or "just as good" or ideally better, including if any choices here are just not up to snuff for safety or reliability

Not necessarily what is "marine suitable" or not, ABYC rules etc. suitable for expo vehicle or off-grid shack usage to be "good enough", but

solutions to improve resistance to salt-mist corrosion of course welcome.

[tanglewood]

It's great stuff as a teaching tool, but very science-fair in implementation. Definitely not a usable system. Jumping across the ground to start the system, for example. And a BMS shut down that disconnects the MPPT in a way that will fry it. Low temp shutoff that only shuts off charging and not loads, though granted the loads can remain on until a lower temp. But it would get a good grade as a high school science project.

[john61ct]

Yah, was not expecting that each implementation detail would be canon,

more like using the post as a BoM that we could evolve into a skeleton framework,

with our own implementation details, that relative noobs could follow, at least as a starting point.

[john61ct]

For example, starting with those cells:

RuiXu rings a bell, was Newhaul test-ordering to see if those are genuine Sinopoly?

A-quality output from their factory compared to other sales channels?

Alternative suppliers covered by local (for many here North American) guarantees?

Or how compared to ordering through their Ali shop? Being careful to authenticate dealing with the same company, these are not makers just resellers.

Close alternatives (also in large prismatic cell form factor),

quality like CALB, Winston/Thundersky or GBS?

Possibility of ordering (relatively) direct from Sinopoly, as seems possible with most of the others?

[john61ct]

love the use of "bandwidth" for current rate, good analogy 8-)

[john61ct]

The use of BlueSolar (requires dongle to program) rather than SmartSolar (BT built in) I assume is just a typo?

The solar input sub-topic should maybe not be assumed, IMO peripheral to the main "implement LFP storage" point of the thread.

Inverter issues even more so, the use of adjustable LVCs to be generalized to usage with various load devices, whether inverted-AC or native-DC powered.

But it seems the use of Victron's low - temperature device (which I haven't used) may require the presence of their SC?

If it can be adapted to work standalone or with other Victron gadgets like their BMV, great.

Otherwise we need alternative temp protection designs, and as mentioned, a separate lower cutoff for the discharge buss is a must for those far from the equator.

Which btw reminds me, yes separate charge and discharge buss should IMO be the default design,

so sourcing that version of the Daly BMSs is a to-do, as well as discussing better / different BMS options.

[tanglewood]

Originally Posted by john61ct

love the use of "bandwidth" for current rate, good analogy 8-)

Glad you got it. I have no idea what that means.

[tanglewood]

So you want to do a group BMS design? Knock yourself out.


And isn't there already a thread on DIY BMS where people reported what they have done. I posted there about mine, or maybe somewhere else.

[Q Xopa]

Originally Posted by john61ct

https://www.mobile-solarpower.com/de...o4-system.html

Thread rules

While assumed good things are longevity, and

the adjustability to do what **you** want with your cells,

let's try to keep away from in-depth techie detail arguments about the correct stop-charge parameters, how much C-rate current is too much, etc.

No basic conceptual LFP questions, extended howTo discussions at the 101 level, start your own thread for those, no shame they're free.

Also avoid debate on to what extent Will, or anyone else knows what they're doing, no personality-based sniping, as much as possible.

The goal is to suggest additions to improve the example setup,

what components could be substituted cheaper, or "just as good" or ideally better, including if any choices here are just not up to snuff for safety or reliability

Not necessarily what is "marine suitable" or not, ABYC rules etc. suitable for expo vehicle or off-grid shack usage to be "good enough", but

solutions to improve resistance to salt-mist corrosion of course welcome.

Yes he does actually quite a good job. There's not many out there that show this stuff so well.
Good to see you are now being supportive of him.

He does do a few goofy things but I think he's pretty straight up and doesnt pretend it its more than it is. But he has quite a good practical and working familiarity with LFP gear.

Yes his wiring is not what I would do, he doesnt have a marine inverter or a HVC.

But its only meant to be a demo non marine system and it works fine.

He actually goes through a lot of material in that video. He especially does a good job with programming the Batt Protect. I watched the Victron videos when I got one and it took me a while to figure out some of the aspects he goes through quite simply.

[john61ct]

Well for others then,

Originally Posted by tanglewood

Glad you got it. I have no idea what that means.

Bandwidth is a term used in networking technology for how much data transfer a given technology "pipe" will support.

Ethernet has greater bandwidth than Arcnet or Token-ring.

5G wireless data supports much greater bandwidth than 4G can.

Will uses the term as an analogue for amps, or "current rate" which I believe you are already familiar with.

[john61ct]

Originally Posted by tanglewood

So you want to do a group BMS design? Knock yourself out.

And isn't there already a thread on DIY BMS

No, best to just collect information on this and other COTS BMSs.

Although there is usually some DIY element required, e.g. low temp protection as you pointed out, or

alternative means of cell-level balancing, since I've yet to see a BMS that does that to my satisfaction

and I would not rely on the BMS for HVC nor LVC functionality in normal usage, but leave it for "failsafe backup" in case a piece of my "user layer" protection fails the bank is still protected.

[john61ct]

Originally Posted by Q Xopa

Good to see you are now being supportive of him.

Well let's not overstate. Yes, to the extent adding exposure helps his SM/YT career, no such thing as bad publicity POV.

And asking his level of expertise not be explicitly evaluated here, which kinda makes your post off-topic.

Let's stick to the suggestions about adding to / correcting the substantive **content** please.

Thanks in advance.

[Q Xopa]

Originally Posted by john61ct

Well let's not overstate. Yes, to the extent adding exposure helps his SM/YT career, no such thing as bad publicity POV.

And asking his level of expertise not be explicitly evaluated here, which kinda makes your post off-topic.

Let's stick to the suggestions about adding to / correcting the substantive **content** please.

Thanks in advance.

I was saying his knowledge is quite good. I dont think this is an overstatement I havent seen him say many statement I disagree with. You dont consider this relevent. I certainly do and assume most others would like to know the expertise of the person presenting the content.

As for comments about his system I did mention some of the 'limitations' I noticed.

[newhaul]

Originally Posted by john61ct

For example, starting with those cells:

RuiXu rings a bell, was Newhaul test-ordering to see if those are genuine Sinopoly?

actually I contacted my sinopoly contact and yes they are genuine .

As I stated on other threads where I originally posted about them and their availability via Amazon . I really grow weary of repeating things to you try to keep the data straight or start keeping a written log of my (and others ) information that you report . ( please give credit for the information. Where appropriate) . Thanks .