xantrex sw2021 charge settings

[Bmarler]

xantrex sw2012 charge settings

i'm having a little trouble getting things set up on my charger. it will step through bulk and absorption fine, but when it goes into float it won't stay there. as soon as there's any draw on the bank, (like the fridge) it will drop back to absorption or sometimes bulk. my batteries are spending way too much time at too high a voltage.
i was thinking this charger would act like the one on my old prosine, where it would remain in float and just supply any demands as needed.
there's also an option of simply using a two stage charge and eliminate the float. i'm wondering if this might be a better way as i can set the voltage to start recharging where ever i want.
does anyone have any experience with this situation?

 

[C lectric]

Xantrex? New?
have you called Xantrex for some help?

 

[Bmarler]

sort of new, came with the new boat when i bought it. wasn't hooked up properly (kinda long story). it is a new replacement for a trace inverter that i bet wasn't bad.
in any case, i'm pretty good with electrical, electronics, stuff in general due to my work. i'm just wondering about some of the specific behavior of this inverter and thought someone else must have the same unit.
like i said, i thought it would behave similar to the prosine 3.0 i had when it was in float mode.
i can try calling xantrex, but i thought i'd try here first.

 

[SteveK]

Have you got the SCP to program. I have the same unit. Mine floats at 13.9 but it does jump up/down when fridge or something draws. May be normal. What are you seeing

 

[Bmarler]

Have you got the SCP to program. I have the same unit. Mine floats at 13.9 but it does jump up/down when fridge or something draws. May be normal. What are you seeing

yes, i have the scp. you can watch the mode change from float back to absorb or sometimes bulk. either of those modes put the volts back up to 14.7. it will stay there for quite some time before it goes back to float. and then as soon as the fridge cycles on again, or i turn on some lights, or cycle the head, the charger kicks in again.
is that what yours does?

 

[SteveK]

I also have remote monitoring of systems which has up to 7 day graph. No, when not there it does not go to 14.7. overnight due to winds power went out for 4 hours and battery dropped to 12.7 (stand by level). power back on it resumed 13.9 float as I have it programmed not to recharge until volts drop to 11.5. Maybe check that setting.

When you see it changing modes, what draws power from battery besides the charger. What is house bank batteries.

 

[Bmarler]

I also have remote monitoring of systems which has up to 7 day graph. No, when not there it does not go to 14.7. overnight due to winds power went out for 4 hours and battery dropped to 12.7 (stand by level). power back on it resumed 13.9 float as I have it programmed not to recharge until volts drop to 11.5. Maybe check that setting.

When you see it changing modes, what draws power from battery besides the charger. What is house bank batteries.

i'll check the recharge setting when i get back to the boat, it's on my list of things to look at. i was thinking it was at 12.5 but don't remember for sure. i was thinking i'd set it at 12.2.
i have the inverter disabled right now, so only normal house loads on the batteries. fridge, lights, pumps.
there's always a small draw on the bank, propane sniffer, co monitor, stereo sleeping still draws a tiny amount. about an amp and a half all together. fridge pulls another 5 or so when it kicks on. add a couple more for some lights and my normal draw is between 5 and 20, depending.
it doesn't seem to take much to drop it out of float mode though. i thought maybe i was having issues with the house bank, but i isolated it overnight and it shows 12.72 in the morning. the house bank is 10 trojan t-105's. 1100 amp hours or thereabouts.
thanks by the way, nice to get some feedback on this.

 

[SteveK]

If you are set at 12.5, even 12.2 for recharge, for sure it will act as you have described.
12.7~ is battery at rest. A load can quickly drop battery to 12.5 and then 12.2. and then it kicks in to recharge.
The factory setting is 12.5 and you can set it 11-13.5, I chose 11.5

You either have a load causing this or a bad cell in battery.
Try 11.5 to see if it calms down.

 

[Bmarler]

i'll try it. it seemed unlikely to me that this would be the problem, float volts are 13.8 or so, i have 4/0 cable from the house bank to the buss bars so volt drop should be minimal. but it is possible so i guess i should rule it out.
my other thought was to set for two stage charging and eliminate the float.

 

[SteveK]

You were worried about overcharging, unless there is a constant load on batteries stay with 3 stage or you will be charging more. JMO

 

[Bmarler]

the recharge voltage was indeed the culprit. i fell a little stupid about not noticing how high it was set. i think the po was trying to solve some issue and set it way too high, maybe thinking it was a cut off voltage or something.
anyway, it floats properly now, and finally my amp hour meter is registering properly as well. i'm trying a 12.3 setpoint and will re-adjust if needed.
thanks for the help on this, always nice to bounce ideas around.