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Seperate port bms
#1
I purchased a 60A Daly 4S LiPo SEPERATE port bms.

I really haven't been able to communicate with Daly "effectively", but I was wondering if it's possible to just connect the separate charging port (C-) to the B- and charge the pack just like a combined port?

FWIW: it does say the separate port charging current is limited to 10A
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#2
Depends on internal layout but if its made like most are they are directional aka one-way. Combining doesnt help you more than screwing things up.

With that said you can always try? Smile I havent heard of anything looked into it so far but if someone have the unit and can pick it apart you would see if its even possible.

Wouldnt it be better to buy a proper BMS with combined port if thats what you need?
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#3
It might fail to stop the charging when it detects an overcharge situation. So probably yes, but probably not a good idea.
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#4
Ok, thank you.

I'll just use this BMS as the way it was intended.
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#5
I have yet to buy a separate port BMS... kinda embarrassing to say I dont know what the advantages are over common port.

Common port still protects against overcharging right? Why bother with a separate port?
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#6
(09-03-2020, 09:41 PM)Crimp Daddy Wrote: I have yet to buy a separate port BMS... kinda embarrassing to say I dont know what the advantages are over common port.

Common port still protects against overcharging right? Why bother with a separate port?
Great question.  Chargery BMSs have separate charge/discharge relay control which I wire together - but they have different amp ranges.   
Maybe the separate port is not a feature but a way to have lower amps on charge than discharge - e.g. a cost saving move?      
Would be interested to know more about this.
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#7
(09-03-2020, 09:41 PM)Crimp Daddy Wrote: I have yet to buy a separate port BMS... kinda embarrassing to say I dont know what the advantages are over common port.

Common port still protects against overcharging right? Why bother with a separate port?

Good question. I encountered one problem with a common port BMS, that would not have happened with a separate port BMS.
I initially set the overdischarge protection too cautiously to 3.00V, and accidentally tripped it.  Now my smart solar charger (connected to the BMS common port) could no longer detect any battery voltage, and refused to charge the battery.  This would not have happened with a separate charging port, since the charging port would have (presumably) remained active.

I've since reconfigured everything so that the BMS only trips when things go really wrong.
Modular PowerShelf using 3D printed packs.  60kWh and growing.
https://secondlifestorage.com/showthread.php?tid=6458
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#8
(09-04-2020, 02:53 AM)ajw22 Wrote: Good question. I encountered one problem with a common port BMS, that would not have happened with a separate port BMS.
I initially set the overdischarge protection too cautiously to 3.00V, and accidentally tripped it.  Now my smart solar charger (connected to the BMS common port) could no longer detect any battery voltage, and refused to charge the battery.  This would not have happened with a separate charging port, since the charging port would have (presumably) remained active.

I've since reconfigured everything so that the BMS only trips when things go really wrong.

Isn't there more control over load or charging when Separate ports are used?
Wouldn't that mean that Seperate ports would be better in the long run for a powerwall?
If it's and ebike, you wouldn't have charging and load at the same time (typically) so common ports would be fine.
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#9
(09-04-2020, 02:53 AM)ajw22 Wrote:
(09-03-2020, 09:41 PM)Crimp Daddy Wrote: I have yet to buy a separate port BMS... kinda embarrassing to say I dont know what the advantages are over common port.

Common port still protects against overcharging right? Why bother with a separate port?

Good question. I encountered one problem with a common port BMS, that would not have happened with a separate port BMS.
I initially set the overdischarge protection too cautiously to 3.00V, and accidentally tripped it.  Now my smart solar charger (connected to the BMS common port) could no longer detect any battery voltage, and refused to charge the battery.  This would not have happened with a separate charging port, since the charging port would have (presumably) remained active.

I've since reconfigured everything so that the BMS only trips when things go really wrong.


Thanks.  Very valid concern with common port.  There are some wiring configurations and scenarios that I can see causing issues.  I use mine primarily for discharge protection.

In all honestly I wire my Victron MPPT directly to my battery and bypass the BMS.  I am using quality EV cells and the top balance stays on point, I regularly monitor things, and I limit the charge to 4.1v to allow for some margin or error.

I know I give up some protection, but this is a portable setup and I don't really use it while untenanted either.  Perhaps its worth while adding a separate smaller BMS to protect for top end charging, but I have yet to see a dire concern to do it.
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