Changing Bulk Charge value on XW-MPPT60-150

muirhouse · June 2011

I am trying to maximize my 4 hours of sun here in new hampshire. Can't seem to get into the menu where I can change the bulk setting from 57.4 up to 60.

Am considering Solar Guppy's advice on going to 2 stage also from 3 (skipping float).

What I am doing now in the meantime is running a 64v (is the default) EQ charge.

muirhouse · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

To add info to my post: Interestingly enough my 15kw generator never gets the batteries up to 60 even on an EQ, but the PV does.

Even though we have halved our generator run time with our PV, the generator still runs an average of 2.5 hours per day. So, it is coming on at 4am, just prior to when the sun comes out, and wasting the pv during the day. I am therefore trying to reset things, both on the gen (inverter settings) side, and on the PV side to keep the generator from coming on at all if possible.

We are not sure why our 700 amp hour battery setup won't hold a charge overnight - it almost is, but not quite. We are a pretty normal household, flat screen TV, dishwasher, washing machine, computers, summertime fans, wintertime radiant floor heat pumping, etc. So, something somewhere isn't right.

The array is 2.7kw, 12 schott. So, the question still is: how to get into the XW-MPPT60 menu where I can change the Bulk setting. I can get into advanced, but the battery options there don't address the charge settings, just the absorb time.

BB. · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Do you have a battery monitor?

-Bill

Dave Angelini · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

You have to select the custom battery menu. Do you have a manual???

muirhouse · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Yes, Bill just had one installed, but haven't configured it to tell me anything serious. It just reads 102 when charging, and goes down from there, around 92 seems to be close to when the generator comes on. Its on my list of things to do.

The Xantrex inverters tell me the charge, and of course the charge controller tells me the charge. The goal tonight after PV is finished is to turn off the AC and look at the battery reading on the inverters, and charge controller.

I tried setting the genstart timer to come on if the battery charge is less than 47.6 for 2 hours to see if that made any difference in whether or not the gen came on at 4am. It didn't make a diff, still came on. I think I will set it back to 48, as that is still right about 50% charge, a little less.

RCinFLA · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Running the bulk voltage from 57.4v to 60v is not likely to make much difference.

The 700 AH lasting overnight depends on how much you are drawing and when you start from (like 5 pm).

I cannot imagine that the inverter/charger (assume you have something like a XW6048 ) on generator is not able to hit equalize voltage but PV can. Check your settings on XW inverter.

As to generator setup, assume you are using autostart, you can set 'quiet time' to prevent startup until later in morning if you want PV to get a first chance at charging. You of course need enough left in batteries to make it through. You might want to run gen to makeup any short fall later on in evening. This will give you enough battery left in the morning to wait for PV power to have a chance before generator kicks on.

muirhouse · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Dave,

Do you mean the custom battery menu on the charge controller itself? I have a manual for the XW itself, but can't seem to find how to get at battery settings.

I will go get the manual for the monitor that I have installed in the house, this is the one I was referring to when I said, yes I have a battery monitor.

Vic · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Hi muirhouse,

OK, in reviewing your past posts, note that you have: SW 4048, XW CC, Surrette S460 (?) and 2-ish KW PV (from memory ... may have errors).
This info is very helpful to those trying to give advice on your actual system ...

YES, please find or download the XW SCC-150 manual. Getting the settings correct for both the SCC and the SW inverter is very important. Especially if you are unable to have inverter power all night. Very important.

Until you get the settings correct, you might want to elinimate heavier loads, things that heat, A/C, dishwasher, and so on. You might have additional battery problems, until this is done correctly for your system.

You should study your power loads, so you will know what you are using, and what things may need to be elinimated to stay within your budget.

If you could perhaps create a signature which details your exact Solar hardware, it would save you a lotta typing, and help target the advice that you do get to your exact setup.

Good Luck, Vic

RCinFLA · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Vic wrote: »

OK, in reviewing your past posts, note that you have: SW 4048, XW CC, Surrette S460 (?) and 2-ish KW PV (from memory ... may have errors).

Response to Bill's question of battery monitor, "The Xantrex inverters tell me the charge"

Doesn't sound like a SW inverter. Unless he is talking only about battery voltage.

Vic · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Hi RC,

Yea, a bit ambiguous to me, did find a statement from Oct, 2010 that muir was running stacked SW4048 with SW+4048. This was from a thread regarding intermattant dropout of XW 4048 IIRC ... dunno.

More later, am sure. Good Luck, Vic

muirhouse · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

RC,

Right, we are going to run the gen tonight during our heavy dinner TV time to do just as you suggest.

Turning the PV charge controller to 2 stage, just cut off the charge completely after the EQ was done, so I set it back to 3 stage as the sun was still out, and it went back to charging, even though in float. I did set absorption to 480 minutes, so on next regular bulk, that should be in effect. If I leave it in 3 stage, will it bulk then absorb for 4 hours, then go to float (which by then shouldn't matter, since we only have about 4 good hours of sun here anyway) - or should I set it back to 2 stage tomorrow.

I have always know something was not right with the gen charging, but none of us can figure out what. There are two inverters a SW4048 and a 4048plus, each 120. Often the gen controlling inverter, the SW will still be in bulk but the plus is in float. I have spent huge amounts of time on that to no avail, but when the PV charge started showing a charge of 60 on both of these inverters, as well as on the XW controller - when the gen never gets it that high, maybe I have a new clue? But beats me what it is.

muirhouse · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Vic,

Yes, did the signature. I do have the manual for the XW. When I go into the battery menu in advanced mode, accessing custom gives me a blank, instead of a value I can reset. This is my first summer with the PV.

So. Starting over - I will run gen tonight to get us into the am, so PV can take over. We have a 95 year old here, and 3 women, so we may be off grid, but we are dishwasher, washer and dryer, night time: lots of TV, lots of lights, hairdryer, 220 water pump but gas stove, and minimal microwave use. We have dimmable switches everywhere so are just now getting the new fluor dimmables to cut down wattage. Summer we run 3 fans all night, two in barn, 1 in house.

Do want to be tackle the odd behavior of the inverters under generator run. And yes, I was talking about voltage when I said the inverter read out told me the charge.

Thanks for everyone's attention, thanks for the signature suggestion. And I am a gal, not a guy!

Vic · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Hello again, muirhoust,

Your signature looks great, thanks!

OK on your power demands. All that you can do is what you can do. You probably need to check the inverter's charger and AC in settings. Make certain that EACH charging source has its own temperature sensor attached midway down the case of the SAME battery for the SW inverters, and on a terminal of that battery for the XW SCC, ideally at the center of the battery bank.

i did not know that one could stack an SW with an SW+ inverter. But that is probably not your issue. RC will know about this.

Sounds like you have a full hours there, and you now have PV, so some generator run time must be better than it was last year.

Good Luck, Vic

muirhouse · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Yes! Life would be much simpler with one 220V inverter. You are probably right a 4048 and a plus were never meant to stack together, (xantrex even says so) but that is a brain child from someone long gone, and when I get another loose K or two, replacing it will be the final correction in a long list. It is probably why the plus goes to float early.

But, in seeking advice to try anything that might fix it last winter, it may have been RC that said temperature sensors when working with two inverters cause weird swapping, fluctuations and to remove it, so I did from the inverters. The XW must have a temp sensing on board, because the monitor does read out a temp.

So waiting for more input, thanks for yours, esp. the you can only do what you can do part!

muirhouse · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Aha! When I turned on the generator tonight, I did a check of the AC inputs as you suggested, and for some reason they were indeed off, the gen amps was set to 30 on the SW and to 60 on the plus. AND, the plus was in float, while the SW was still in bulk. Could it be that easy. So I reset SW to 60 turned gen on again; the input amps on the SW read 34, on the plus 19, then 8, then went to float within a minute. SW stayed in bulk. If the logic holds, then SW should catch up and on the next run, both should stay in bulk same amounts of time.

RCinFLA · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

You are going to get different absorb to bulk switchover between plus and regular SW. I have two SW4048's with different rev software and they have different switch over times, even with absorb time set the same. Absorb timer starts when each unit thinks it has reached its bulk voltage setting. There is likely some calibation difference between units. You can 'tweak' the absorb voltage up or down on one of the units to try and match their actual voltage trip points.

When they are both in absorb voltage charge regulation (bulk voltage setting), you can tweak the bulk voltage on one unit to match the pushed DC charge current, as measured with clip on DC amp meter, between units. In lew of not having a DC clip on amp meter, you can look at the inverter/charger AC current and match that, but it is a pain to go back and forth between SW meters.

Your SW+ has an additional bulk abort criteria that regular SW does not. Plus has a current level abort when absorb current drops to set value. You can put it to zero to disable this and rely solely on absorb period timer. Stacked with a regular SW you pretty much have to run both units with absorb timer mode.

If you don't have a battery monitor, like a Trimetric, you should get one. It will give you an accurate readout of AH's going in and out of battery.

muirhouse · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

Thank You RC, finally an answer to this. Immensely appreciated. I have the Trace TM500A battery status monitor, but so far I haven't been able to program it so that it tells me anything useful. I will look into Trimetric. thanks again.

Joe_B · June 2011

Re: Changing Bulk Charge value on XW-MPPT60-150

RCinFLA wrote: »

You are going to get different absorb to bulk switchover between plus and regular SW. I have two SW4048's with different rev software and they have different switch over times, even with absorb time set the same. Absorb timer starts when each unit thinks it has reached its bulk voltage setting. There is likely some calibation difference between units. You can 'tweak' the absorb voltage up or down on one of the units to try and match their actual voltage trip points.

When they are both in absorb voltage charge regulation (bulk voltage setting), you can tweak the bulk voltage on one unit to match the pushed DC charge current, as measured with clip on DC amp meter, between units. In lew of not having a DC clip on amp meter, you can look at the inverter/charger AC current and match that, but it is a pain to go back and forth between SW meters.

Your SW+ has an additional bulk abort criteria that regular SW does not. Plus has a current level abort when absorb current drops to set value. You can put it to zero to disable this and rely solely on absorb period timer. Stacked with a regular SW you pretty much have to run both units with absorb timer mode.

If you don't have a battery monitor, like a Trimetric, you should get one. It will give you an accurate readout of AH's going in and out of battery.

RC, Can you use this trick in a system with two XW-SCC's? I have noticed that one of my SCC's reads 0.2 volts higher than the other one for battery voltage. The one that reads higher is always throttling back before the one that reads the lower voltage. When they are in bulk, they both share equally but once I get into absorb, one always puts out less than the other. I am thinking that this is because absorb mode is constant voltage and if they are reading differently, then the higher reading one will always throttle back sooner.

So the question is if I disable cascading and set the lower reading SCC 0.2 volts higher on my absorb and float values, will both SCC's play nicer together?

Changing Bulk Charge value on XW-MPPT60-150

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