Use of Type 3 and Type 4 outputs

[B0bD]

Can these be set to switch at the Voltage Lock settings, and used instead of Type 5?

I'd prefer to separate the under and over voltage breaker trips.

From the literature, I can't determine if the settings for T3 and T4 are separate from T1 and T2. 

Assuming it is possible, the second question is can T3 be set to a low voltage, so that it is open above that voltage and closed below it?  And the opposite with T4?

[Dacian Todea]

The type 1 and type 2 is what you will use for normal operation to stop a charger or a load. In case of LiFePO4 default will be 3.55V for 6 seconds for type 1 and then charge source will be stopped as battery is fully charged similarly for type 2 the default limit is 2.8V (below that the loads will be disconnected as battery is empty).

type 3 and 4 are based on SOC only so are good just as alarms mostly as SOC may be calculated incorrectly depending on how well you make the settings and how accurate is your current shunt. But they will also react as type 1 and 2 based on voltage so say you set a Load as type 4 and set the SOC to 30% then normally when battery is below 30% the Load will be disconnected but if for some reason the SOC is not correctly calculated and say SOC is 50% but one of the cells is below 2.8V then the Load will still be stopped as the cell low voltage will bypass the SOC setting.

Type 5 is the one that will react to under or voltage lock settings as those are secondary limits set at 2.5V and 3.75V default and cells should never get there unless something is faulty or installed incorrectly. So type 5 is usually used as a second level protection normally tripping a breaker and yes you will need to have separate breakers or breaker contacts for charge sources and Load's but they will be both tripped at the same time just kept separate trough separate contacts.

If this happens it will be abnormal so it will require manual intervention to restart the system and the cause should be investigated as it will not be normal operation.

Type 1 and type 2 will also react to voltage lock limits so say you have an inverter charger but you incorrectly only installed a type 2 of the inverter as remote ON/OFF and you connect the grid charger then battery will charge to 3.55V but since there is no type 1 connected to stop the AC charger (inverter run in reverse) then battery will continue to charge until 3.75V when the type 2 will also become open circuit and stop the inverter that hopefully will also stop the charging.

So all you need is normally just type 1 and type 2 as if those are installed correctly and tested (by setting them to type 0 and see if all charge sources and Loads are turned OFF).  The type 5 can be used to trip a breaker (maybe one with two separate contacts or two separate trip breakers) but it is likely that will never be used as it is super unlikely for a remote ON/OFF on a device to not work. When is last time you turned OFF a device using the power ON/OFF button and it continued to stay ON?

EXT IOx are opto isolated switches based on Toshiba TLP172GM with closed circuit for ON and open circuit for OFF so if one of the two EXt IOx wires is broken the device controlled by that will default to safe OFF position.

[B0bD]

OK, so just to confirm I understand your response - T3 and T4 are primarily SOC but they will also trigger on the voltage settings of T1 and T2.  T3 and T4 don't have separate voltage settings.

I understand the use of T1 and T2, and am going to use them as intended.

I'll just use T5 to trip the breakers.

Thanks

[Dacian Todea]

Yes your understanding is correct. type 3 and 4 are based on SOC and the initial idea was to use them as audio/visual alarms so maybe you wanted to know when SOC is below 30% to react in some way or some use that to turn OFF the inverter that may have less critical loads and keep the other 30% for some critical DC loads that will be controlled by type 2.

[B0bD]

So if I want to light an alarm LED when SOC drops to, say, 35%, can I avoid a relay if I use type 3 and set SOC to 35%.

As I understand it, then  the output would be off if the SOC is above 35% and will close below 35%, lighting the LED (5ma)

Or would the tie-in to the Type 1 voltage get in the way?

[Dacian Todea]

You will need type 4 to see if SOC has dropped under a set value.

You do not need a relay and you can just have the EXT IOx set as type 4 shorting the LED while the resistor is connected to battery
So say you have a 4s so 12V battery about 12.8V nominal then LED if say is RED will have around 1.8V drop at 5mA thus 12.8V - 1.8V = 11V 

Using a 2.2kOhm will get you close to your desired value as 11V / 2200Ohm = 5mA then when EXT IOx shorts the LED current will not be much higher 5.8mA

This way you are warned also if the EXT IOx wires are disconnected.

[B0bD]

Thanks - got it.

[Barry Timm]

I understand how Type 4 EXTIO ports work for LOADS....if the calculated SOC% drops below the SOC% for the Type 4 port, then the port is OPENED. If it is above, the port is CLOSED and thus disconnects that connected load when the battery drops to the specified SOC%.

But how does Type 3 EXTIO ports work for CHARGING? Does the port OPEN above the SOC% and CLOSE below the SOC% (thus charge between 0% and SOC% only) ....or ......

does it CLOSE above the SOC% and open below the SOC% and also open when the battery reaches the default 3.55% (thus charge only BETWEEN the SOC% and 100% and then stop to prevent overcharge?)

[Dacian Todea]

Barry,

The type 3 and type 4 where introduced mostly to be used as alarms.

In case of type 4 it may also be used to disconnect a Load like an inverter before the battery is fully discharged so that some more important Load can still be supplied.  Of course this will assume current shunts and battery capacity is set correctly so that SOC is relatively correctly calculated.  The SOC will be re-calibrated to 100% after each full charge so it is relatively OK.

But in case of type 3 that can not be used to control a charge source especially if that is the only charge source as battery will never get to full charge so SOC will not be re-calibrated and even small errors in SOC calculation will add up over time and so you may end up with an empty battery when you think SOC is much higher.

So say SOC is set at 80% for both type 3 and type 4

In case of type 4 the EXT IOx will be open circuit as soon as the SOC drops below 80% and will become close circuit again when SOC increases 3% above that so above 83%

For type 3 The EXT IOx will be open circuit as soon as SOC increases above 80% and will become close circuit when SOC drops below 77% so the 3% hysteresis so that you do not have super frequent ON/OFF cycles.

 

[Barry Timm]

Thank you. 

I am already using Type 4 for my mini-split A/C, set at 55%, and that is working perfectly.

I am considering using another EXTIO set as Type 3 at 93% for the case where I have to switch ON a LOAD with an OPEN circuit above 93%, and switch it OFF with a CLOSED circuit below that 90% threshold. (This is assuming the fridge Auto switch works in opposite state to expected with OPEN/CLOSED for 120v ac and propane.

Note: I obviously have "proper" charge sources via DSSR20s and Multiplus charger (when connected to external power or generator), on EXTIO Type 1 port.

[Dacian Todea]

The problem with reverse logic is that if the EXT IOx wires are broken the device will be on battery in this case over-discharging your battery potentially.

[Barry Timm]

Understood, but the SBMS would then still switch off all ports at at the fault threshold of 2.5v, regardless of the 2.8v threshold, correct?

[Dacian Todea]

Yes at 2.5V all EXT IOx no matter the type will be switched OFF (open circuit).

But I assume your fridge is powered trough an inverter that is controlled by a type 2 set EXT IOx so it will stop at 2.8V

The thing is that if open circuit means fridge runs on electricity then EXT IOx wire is broken (open circuit) and fridge will not switch back to propane.

[Barry Timm]

True. I will try to find a better way to "reverse" the logic while using TYPE 4.

Perhaps a relay.