ANT BMS. Final answer? Yes, final answer.

[heirloom hamlet]

I don't think when I began my solar energy journey I would have expected selecting a BMS to be one of the hardest parts, but it has been a long road of reading, watching and asking.
My 32 cells are due to arrive soon and I have settled on the ANT BMS that Big Willie reviews here.

It seems to have the things I most want... Easy enough setup, Affordablity, Cell monitoring, Temp cut-off, It just works, Etc...the right balance.
Just for sanity, for my 8 series, 24v connections I need the 8S version, correct? Also, if I ever wanted to double my storage capacity with one of my systems (8S2P I guess) is there a single BMS that I could use to monitor it as one battery, like the 16S version for instance?
Finally, does anyone know, Will shows the low temp charge cutoff works well, but does that also protect it on the hot end...on my 280aH cells the manufacturer appears to show 55°C / 131°F as the max temp to draw power from these.
Many thanks if you know any or all of these queries.

 

[JoseAgustinV]

You need one 8s bms for every 24v battery, if you want to get more capacity just get 8 more cells and another 8s bms to build another battery, then connect both in parallel.

 

[upnorthandpersonal]

Isn't is to that the ANT BMS has a charging current less than 50A? Discharging is higher, but charging was limited iirc.

 

[Will Prowse]

Isn't is to that the ANT BMS has a charging current less than 50A? Discharging is higher, but charging was limited iirc.

50A at 48V is 2,400W.

It does say 50A:


But considering it's common port, I bet it's incorrect. I would test it.

 

[upnorthandpersonal]

50A at 48V is 2,400W. Does anyone have a charger this powerful?

I didn't think a 70A charger and more was uncommon. Even that MPP Solar one goes to 80A on solar. A 5kW and above solar array also isn't that uncommon, is it?

When you're building a 24V, that 50A represents only 1.2kW, which is what @JoseAgustinV mentioned in his post above. Anyway, just wanted to bring it up since it could be a show stopper for someone. I don't have one of them, otherwise I'd run some tests...

 

[Steve_S]

I didn't think a 70A charger and more was uncommon. Even that MPP Solar one goes to 80A on solar. A 5kW and above solar array also isn't that uncommon, is it?

When you're building a 24V, that 50A represents only 1.2kW, which is what @JoseAgustinV mentioned in his post above. Anyway, just wanted to bring it up since it could be a show stopper for someone. I don't have one of them, otherwise I'd run some tests...

One of the reasons I went with Chargery BMS with relays, I use MIdnite Classic 200 SCC and it does put out 79A to a 24V Battery Bank. Also knowing that I will add another Classic-200 SCC & Panels (winter compensation - boost) to charge 2x-280AH + 2x-175AH LFP packs it will take a bit of juice, above and beyond a 50A Charge limit.

Just my opinion but. When people are putting together 100AH or smaller packs these BMS' which support up to 50A charge is fine... but once you get up to 200AH Cells charging & time become a problem. Of course the "need" varies along with the latitude but it's a matter of pushing enough Amps to charge within "Average" sun hours to fully charge up. Once you look at multiple packs in a bank the amount of amperage overall needed goes right up too. Considering how many of us are using 280AH cells for battery packs, their charge requirements are much higher than 100AH cells, are 50A Charge Limitations practical for a 280AH pack ?

How a BMS handles the Amp Limits can also be problematic depending on the setup. Does the BMS switch on / off in pulses, does it just disconnect with a "timeout" and so on and how the other BMS' handle it within the bank.

I don't know for sure so I am asking:
Maybe @Will Prowse has an answer to this... The Question may also make for a good Video Clip.

1) How does a FET Based BMS handle the over amperage situation ?
-- example, say BMS is limited to 50A charge input but the SCC / Charger puts out more Amps ie 75A.
2) How do they (BMS') handle it if there are multiple BMS' charging away at 50A ea and then 1 or 2 hit full and disconnect, now that extra amperage comes available to the other BMS' in the battery bank ?
3) - Not a Question - an observation. I have not seen a Will Prowse Video on using Multiple Packs in a paralleled bank and dealing with the multiple BMS' yet many are building with multiple packs within a bank. Over 50% of the people here in any case from what I see.

 

[Will Prowse]

One of the reasons I went with Chargery BMS with relays, I use MIdnite Classic 200 SCC and it does put out 79A to a 24V Battery Bank. Also knowing that I will add another Classic-200 SCC & Panels (winter compensation - boost) to charge 2x-280AH + 2x-175AH LFP packs it will take a bit of juice, above and beyond a 50A Charge limit.

Just my opinion but. When people are putting together 100AH or smaller packs these BMS' which support up to 50A charge is fine... but once you get up to 200AH Cells charging & time become a problem. Of course the "need" varies along with the latitude but it's a matter of pushing enough Amps to charge within "Average" sun hours to fully charge up. Once you look at multiple packs in a bank the amount of amperage overall needed goes right up too. Considering how many of us are using 280AH cells for battery packs, their charge requirements are much higher than 100AH cells, are 50A Charge Limitations practical for a 280AH pack ?

How a BMS handles the Amp Limits can also be problematic depending on the setup. Does the BMS switch on / off in pulses, does it just disconnect with a "timeout" and so on and how the other BMS' handle it within the bank.

I don't know for sure so I am asking:
Maybe @Will Prowse has an answer to this... The Question may also make for a good Video Clip.

1) How does a FET Based BMS handle the over amperage situation ?
-- example, say BMS is limited to 50A charge input but the SCC / Charger puts out more Amps ie 75A.
2) How do they (BMS') handle it if there are multiple BMS' charging away at 50A ea and then 1 or 2 hit full and disconnect, now that extra amperage comes available to the other BMS' in the battery bank ?
3) - Not a Question - an observation. I have not seen a Will Prowse Video on using Multiple Packs in a paralleled bank and dealing with the multiple BMS' yet many are building with multiple packs within a bank. Over 50% of the people here in any case from what I see.

What bms were you running before chargery? What FET based bms do you work with?

 

[Will Prowse]

Wait, why is anyone caring about the charge current? Just run scc direct to raw cells, set bms to top balance, and manually set absorption.

Don't use the bms or relays. You don't need it for chargers if you can set absorption. I think people are overthinking this charge limit. Just bypass it. No more limit.

 

[Steve_S]

What bms were you running before chargery? What FET based bms do you work with?

I have no FET based BMS', using only the Chargery's.
I was using 20kWh of FLA and to converting to LFP and shifting the FLA to Greenhouse Duty later this year.

Forum Suggestion: Maybe a tab next to "DIY Solar Blueprints" with "Will's Video List"

 

[Will Prowse]

I have no FET based BMS', using only the Chargery's.
I was using 20kWh of FLA and to converting to LFP and shifting the FLA to Greenhouse Duty later this year.

I think you should try other bms. There are better options out there. Also, try running without a bms on some used cells. Bottom balance and set absorption. It's super fun

 

[Will Prowse]

I didn't think a 70A charger and more was uncommon. Even that MPP Solar one goes to 80A on solar. A 5kW and above solar array also isn't that uncommon, is it?

When you're building a 24V, that 50A represents only 1.2kW, which is what @JoseAgustinV mentioned in his post above. Anyway, just wanted to bring it up since it could be a show stopper for someone. I don't have one of them, otherwise I'd run some tests...

Yes good points

 

[Will Prowse]

I like to set absorption and inverter lvd so that the bms is seen as a safety protection device. Then you will have two layers of protection if you plan to use lvd and hvd on bms. Lifepo4 is forgiving with over charging, but not over discharge event. So hvd not that important. I prefer manual control.

That's how I program most of my raw cells systems actually. 3.65V per cell for bms level, then set absorption around 3.5V depending on age and characteristics of cells

 

[Will Prowse]

I don't think when I began my solar energy journey I would have expected selecting a BMS to be one of the hardest parts, but it has been a long road of reading, watching and asking.
My 32 cells are due to arrive soon and I have settled on the ANT BMS that Big Willie reviews here.

It seems to have the things I most want... Easy enough setup, Affordablity, Cell monitoring, Temp cut-off, It just works, Etc...the right balance.
Just for sanity, for my 8 series, 24v connections I need the 8S version, correct? Also, if I ever wanted to double my storage capacity with one of my systems (8S2P I guess) is there a single BMS that I could use to monitor it as one battery, like the 16S version for instance?
Finally, does anyone know, Will shows the low temp charge cutoff works well, but does that also protect it on the hot end...on my 280aH cells the manufacturer appears to show 55°C / 131°F as the max temp to draw power from these.
Many thanks if you know any or all of these queries.

Yes it protects on high temperature as well. You can set the parameters for it.

And I would not use the chargery if I were you (like Steve mentioned). Stick with the ant BMS. I dislike the chargery. It's a pain in the butt and lower quality. Ant BMS is way better in my opinion.

 

[upnorthandpersonal]

I'm actually going to try this one (the 16S 150A version) if I can get them. They don't seem to reply to my inquiry.

 

[Will Prowse]

I'm actually going to try this one (the 16S 150A version) if I can get them. They don't seem to reply to my inquiry.

Holy cow that looks like a good deal!!

 

[upnorthandpersonal]

I think this one is similar to the one you found ( https://diysolarforum.com/threads/f...4-bms-with-low-temp-charging-protection.2884/ ), just a bigger version.

 

[heirloom hamlet]

Wait, why is anyone caring about the charge current? Just run scc direct to raw cells, set bms to top balance, and manually set absorption.

Don't use the bms or relays. You don't need it for chargers if you can set absorption. I think people are overthinking this charge limit. Just bypass it. No more limit.

You lost me here, just a little bit.
My 80a MPPT A-I-O, the one you reviewed and own, and/or the Watchpower software does not have an "Absorption" setting that I can see...it has Bulk and Float. Does there terminology of a particular setting mean Absorption, but not say it directly?
Also, if you don't mind, could you spell this proposed setup out a bit more. My cells will be 280aH, brand new.
Are you saying that I could have the MPPT's 80a SCC managing the charging above 50a, (and not worrying about balancing for a while, after initial balanced setup) and then just have the ANT BMS managing high and low temp cutoffs only? And that it's possible to do that? Am I on board here?

 

[heirloom hamlet]

I didn't think a 70A charger and more was uncommon. Even that MPP Solar one goes to 80A on solar. A 5kW and above solar array also isn't that uncommon, is it?

When you're building a 24V, that 50A represents only 1.2kW, which is what @JoseAgustinV mentioned in his post above. Anyway, just wanted to bring it up since it could be a show stopper for someone. I don't have one of them, otherwise I'd run some tests...

What are these BMS' 100a and 320a models amperage rating referring to. The load/amps that you'll be pulling from the battery and thus through it?

 

[NEWYORKHILLBILLY]

Is there anyway to use this on a 4s 12V system?

 

[Will Prowse]

You lost me here, just a little bit.
My 80a MPPT A-I-O, the one you reviewed and own, and/or the Watchpower software does not have an "Absorption" setting that I can see...it has Bulk and Float. Does there terminology of a particular setting mean Absorption, but not say it directly?
Also, if you don't mind, could you spell this proposed setup out a bit more. My cells will be 280aH, brand new.
Are you saying that I could have the MPPT's 80a SCC managing the charging above 50a, (and not worrying about balancing for a while, after initial balanced setup) and then just have the ANT BMS managing high and low temp cutoffs only? And that it's possible to do that? Am I on board here?

Oh sure, Bulk is Absorption. Or the charge limit setting.