Please critique my new Kisae 1250 charger programming profile for newbie

[Directshort]

I installed a 200w solar panel with 280ah Xuba metal cell lithium battery/OverkillSolar bms and just want to be sure I program the Kisae B-B battery charger correctly so as not to mess this up being a total newb.

The solar puts out 11 amps and when it switches to alternator charging at 40 amps.

----Priority for me is rapid bulk charging while driving and fully charged at 14 or 14.2v

---For setting the BULK charge I put 14.6v. (I think this is just the charging voltage and not the final charged voltage?)

---For the FLOAT voltage I chose 14.2v but don't really know how this is affected by Termination voltage? I read you don't even need a float w/ lithium but that is not an option in the menu.

---For TERMINATION voltage I chose 6 amps. Manual says it is used to determine when the battery is full when it reduces to the user defined parameter options of 1.5, 3 or 6 amps. Then it enters float mode.

I always have a mini frig running if that affects the Termination current so I chose the highest Termination at 6 amps voltage to prevent excess charging ???

 

[John Frum]

---For setting the BULK charge I put 14.6v. (I think this is just the charging voltage and not the final charged voltage?)

Good 14.6volts is 3.65 volts per cell which is full to the brim.

---For the FLOAT voltage I chose 14.2v but don't really know how this is affected by Termination voltage? I read you don't even need a float w/ lithium but that is not an option in the menu.

Thats too high.
Float for lifepo4 just means provide load assistance to the batteries.
Suggest 13.5 or 13.6 volts.

---For TERMINATION voltage I chose 6 amps. Manual says it is used to determine when the battery is full when it reduces to the user defined parameter options of 1.5, 3 or 6 amps. Then it enters float mode.

This doesn't make sense.
I would expect the value for termination voltage to be in volts.
Maybe you mean termination amps.
should be ~3-5% of the battery capacity.

 

[Directshort]

Maybe it means as the voltage slowly drops when it nears the end of the charge the trigger the amperage slowly lowers also and the point for termination is the when the amperage falls a certain definable amount ?

 

[John Frum]

Maybe it means as the voltage slowly drops when it nears the end of the charge the trigger the amperage slowly lowers also and the point for termination is the when the amperage falls a certain definable amount ?

That is not how cc/cv charging works.
During the cc phase which roughly translates to bulk the current is limited by the charger.
The charger does this my adjusting the charge voltage down to limit the current.
During the CV phase the battery controls the current flow as its voltage rises to meet the charge voltage current flow decreases.
When the current flow reaches the configured threshold the the charger enters float mode and becomes an auxiliary power supply.
Its stays like that until one of the re-bulk conditions are met.

 

[Directshort]

Also it says that once the voltage goes below 13.3 volts then it re-enters into BULK charge mode so there is a dance between that and the FLOAT and I am nor sure how this impacts the FLOAT mode? So confused.

 

[John Frum]

Also it says that once the voltage goes below 13.3 volts then it re-enters into BULK charge mode so there is a dance between that and the and I am nor sure how this impacts the FLOAT mode? So confused.

thats talking about re-bulk.
That is the criteria that causes re-entry into the bulk phase.

 

[Directshort]

Got it sorted out Thanks guys

 

[John Frum]

Got it sorted out Thanks guys

So what did you learn?
Please share so we can learn.

 

[Directshort]

So the higher the "L" parameter setting the the faster it goes into Re-bulk mode . If you have a constant load you should use a lower setting so it doesn't cycle too quickly back into Re-bulk.
I spoke to a Kisae rep and this is what I think he was saying although alot went over my head being a total newbie and I still am not sure what the setting does denotes actually it sounds like it's smply a differential setting like on a thermostat to prevent rapid cycling.

 

[redmessengerbag]

Would you be willing to share your question to and responses from the Kisae rep? They have amazing tech support, and I don't want to bother them again if I don't have to.

I have the same Kisae DC to DC charger and same Xuba cells, but will be running 400w solar (2x200w), and about ready to start hooking things up.

Thanks in advance!

 

[Directshort]

I would love to expound on what the rep said but being a newbie and overwhelmed talking to him using terms I was unfamiliar with anything I recall would be worthless.

Except that as posted: So the higher the "L" parameter setting the the faster it goes into Re-bulk mode . If you have a constant load you should use a lower setting so it doesn't cycle too quickly back into Re-bulk.

It is actually the opposite and the higher the "L" setting the longer it takes to go into BULK mode. Sorry for any confusion I wish I could help you guys better but I am not fluent enough yet.

 

[Mex Rider]

Would you be willing to share your question to and responses from the Kisae rep? They have amazing tech support, and I don't want to bother them again if I don't have to.

I have the same Kisae DC to DC charger and same Xuba cells, but will be running 400w solar (2x200w), and about ready to start hooking things up.

Thanks in advance!

The Kisae has two different possible sets of parameters for LifePo4, one is titled Lithium, the other is titled Program. Under Program you have the choice of a two or three stage profile, two stage skips "float" The manual also says if you have a constant load like lights, fridge, fans you should set the "L" current higher, not lower. Also "L" is in amps not volts....just to clarify some of these posts above

 

[Mex Rider]

Good 14.6volts is 3.65 volts per cell which is full to the brim.



Thats too high.
Float for lifepo4 just means provide load assistance to the batteries.
Suggest 13.5 or 13.6 volts.



This doesn't make sense.
I would expect the value for termination voltage to be in volts.
Maybe you mean termination amps.
should be ~3-5% of the battery capacity.

If you have 200 amp hrs or more of battery you can set it to 8, 9, 10 amps

 

[jayswain]

What are the risks of a low termination current when there are constant loads (fridge) attached to the system?

Under the direction of the kisae manual, I've selected the highest termination current setting (10a). But the battery (power queen 200ah w/ BMS) manual specifies a 4a tail current.

I've noticed odd behavior when the batteries seem to be "topping off". With the charger not just going from 14.6 -> 13.6, but bouncing around the range and also bouncing the amount of amps its sending (from 0 - 9 and back and forth). Eventually the bouncing stops and the charger enters float mode, and supplies a constant 13.6. Some other users seem to be having the issue as well: https://diysolarforum.com/threads/overkill-bms-and-kisae-dmt1250.16269/post-269369.

My theory on the odd behavior is the BMS and charger fighting each other. Is there a way to resolve the bouncing of voltage/amps? Is my system at risk of damage because of this?