Idiot's guide to a self build battery

[Stinsy]

Just make sure of your max voltage for the Pylontech. (Over 55v and they will require a new BMS).

So as well as the new "C" versions being 0.5V lower max charging spec when compared with older versions, they want another 0.3V below their own lower spec when using manual control.

Mine are still ok as I charge to 56.4V but need to subtract my extra cell, so its 56.4V - 3.5V = 52.9V.

But its something for others with parallel packs to watch out for, the max charge voltage should be 53.2V and not 53.5V as it says in the general spec. I certainly was not aware of that.

I seem to remember Victron recommending 52.4V for Pylontechs. Even though the BMS requests higher.

[Oldgreybeard]

I seem to remember Victron recommending 52.4V for Pylontechs. Even though the BMS requests higher.

That fits with the data that the ME3000SP spits out, which is just the data it receives from the Pylontechs. It's rare to see the voltage get above 53.0V, . Our pack hit 100% in the sunshine yesterday and the voltage reported was 53.0V at the instant the pack hit 100% and was still charging, but that quickly dropped back to about 52.0V as soon as the battery stopped charging, when the house was running off PV, so the batteries were neither charging or discharging.

53.0V is 3.53V per cell, so comfortably under the 3.65V per cell maximum, so my guess is that Pylontech have chosen to limit the full charge voltage a fair bit in order to improve the cell life, perhaps. Makes sense, as even a small decrease in the cell usable capacity range seems to give a large improvement in cycle life. I remember that someone did some independent testing on Headway cells in the early days and found that restricting the maximum charge by just 5% gave something like a fivefold improvement in cycle life.

[Tinbum]

I seem to remember Victron recommending 52.4V for Pylontechs. Even though the BMS requests higher.

Yes they do. I intercept the CAN messages and set my max voltage to 52.5v but then once a week it sets it to the pylon recommendation of 53.2v. (This way I think, if i ever have a warranty problem, pylon can't say that the batteries haven't been charged to the BMS setting).

[Colin Deng]

This is Colin's direct email for quotes.

colin@deriytech.com

Thank you so much! Joe
Good to know that we can help you with the battery needs

[Joeboy]

This is Colin's direct email for quotes.

colin@deriytech.com

Thank you so much! Joe
Good to know that we can help you with the battery needs

You are very welcome Colin, enjoy the forum!

[Colin Deng]

This is Colin's direct email for quotes.

colin@deriytech.com

Thank you so much! Joe
Good to know that we can help you with the battery needs

You are very welcome Colin, enjoy the forum!

Thank you so much Joe
Still learning how to post or reply on the forum

[Joeboy]

Thank you so much! Joe
Good to know that we can help you with the battery needs

You are very welcome Colin, enjoy the forum!

Thank you so much Joe
Still learning how to post or reply on the forum

I hope you enjoy the space. We do not allow advertising as a rule so refrain from that and its all good. A lot of people over here have worries about such large investment at such a distance. There are also sharks in the waters. Very glad to have found you and I hope your company has contacts through the forum. Cheers.

[Colin Deng]

You are very welcome Colin, enjoy the forum!

Thank you so much Joe
Still learning how to post or reply on the forum

I hope you enjoy the space. We do not allow advertising as a rule so refrain from that and its all good. A lot of people over here have worries about such large investment at such a distance. There are also sharks in the waters. Very glad to have found you and I hope your company has contacts through the forum. Cheers.

Thanks Joe

I will not put on the advertising here
We will keep up the good work
It will be learn much morn from this forum
If it ok to ask for opinion here from time to time ?
So can learn more about how the customer will fell
But i will not advertising here !!
Thanks

[Joeboy]

Thank you so much Joe
Still learning how to post or reply on the forum

I hope you enjoy the space. We do not allow advertising as a rule so refrain from that and its all good. A lot of people over here have worries about such large investment at such a distance. There are also sharks in the waters. Very glad to have found you and I hope your company has contacts through the forum. Cheers.

Thanks Joe

I will not put on the advertising here
We will keep up the good work
It will be learn much morn from this forum
If it ok to ask for opinion here from time to time ?
So can learn more about how the customer will fell
But i will not advertising here !!
Thanks

Of course you can. No worries.

[Tinbum]

A lot of people over here have worries about such large investment at such a distance. There are also sharks in the waters.

Yes I'm tempted to buy some, probably 4 sets of 16, but am vary wary.