Outback Lack of Bulk Charge integration -- anniversary rant
vtmaps
Solar Expert Posts: 3,741 ✭✭✭✭
Today is the first anniversary of my joining this forum, so I've decided to treat myself to a rant and bring up an old issue again. (Discussed here, here, and here)
The issue is that during bulk stage charging, Outback's charge controller and inverter/charger do not regulate the maximum DC current going into the batteries. Either unit alone can be programmed to limit its DC output to the batteries, but when both are charging at the same time, the current to the batteries is the sum of the two limits.
In a discussion some months ago, Stephendv indicated SMA's Sunny Island system does not have this problem. In a more recent discussion, Cariboocoot said he would look into the situation.... nothing so far.
My battery bank is about 370 ah. I do not wish to charge the batteries with more than 40 amps DC. My array typically pushes about 25 amps into the battery, but in cool weather I often see 35 amps. My inverter/charger is (usually) programmed to use only 9 AC amps for battery charging, which is about 35-40 DC amps (depends on battery voltage during bulk).
We've had a lot of overcast weather lately. Yesterday I was at 60% SOC and hadn't been to 100% in a few days, so decided to run the generator in the morning.
The weather was mostly overcast with 'breaks of sun'. Before I started the generator I noticed that the array was pushing about 5 amps into the battery so I dialed down the inverter/charger power to 8 amps AC (about 30-35 DC amps). With the generator running, the battery was taking about 40 amps, 35 from the generator and 5 from the solar array.
About 30 minutes later we had a 'break of sun' and my array was exceeding its 940 watt rating and I had 68 amps going into the batteries. I disabled the charger mode on the inverter/charger (a mere four button pushes on the Mate). I knew the sun wouldn't last long so I left the generator on. Ten minutes later it was overcast again and I re-enabled the charger function on the inverter.
This whole cycle repeated itself two more times before I reached the absorb voltage (when it is no longer an issue). This is not the way multiple charging sources should work!
This problem comes up on sunny days also. I run the generator anytime I need a lot of prolonged power in my workshop. If I want to use the generator in the morning on a sunny day (while still in solar bulk charge) I have to remember to disable the charger in the inverter before I start the generator.
I don't have Outback's battery monitor, the Flexnet DC. I would buy one if it would solve this bulk charge issue, but it won't. As far as I know, there is no practical off-the-shelf solution to the problem (other than replacing the whole system with a Sunny Island).
What do you folks with both wind and solar do about this issue? I imagine that on a windy sunny morning you could have some very high bulk charging currents.
--vtMaps
The issue is that during bulk stage charging, Outback's charge controller and inverter/charger do not regulate the maximum DC current going into the batteries. Either unit alone can be programmed to limit its DC output to the batteries, but when both are charging at the same time, the current to the batteries is the sum of the two limits.
In a discussion some months ago, Stephendv indicated SMA's Sunny Island system does not have this problem. In a more recent discussion, Cariboocoot said he would look into the situation.... nothing so far.
My battery bank is about 370 ah. I do not wish to charge the batteries with more than 40 amps DC. My array typically pushes about 25 amps into the battery, but in cool weather I often see 35 amps. My inverter/charger is (usually) programmed to use only 9 AC amps for battery charging, which is about 35-40 DC amps (depends on battery voltage during bulk).
We've had a lot of overcast weather lately. Yesterday I was at 60% SOC and hadn't been to 100% in a few days, so decided to run the generator in the morning.
The weather was mostly overcast with 'breaks of sun'. Before I started the generator I noticed that the array was pushing about 5 amps into the battery so I dialed down the inverter/charger power to 8 amps AC (about 30-35 DC amps). With the generator running, the battery was taking about 40 amps, 35 from the generator and 5 from the solar array.
About 30 minutes later we had a 'break of sun' and my array was exceeding its 940 watt rating and I had 68 amps going into the batteries. I disabled the charger mode on the inverter/charger (a mere four button pushes on the Mate). I knew the sun wouldn't last long so I left the generator on. Ten minutes later it was overcast again and I re-enabled the charger function on the inverter.
This whole cycle repeated itself two more times before I reached the absorb voltage (when it is no longer an issue). This is not the way multiple charging sources should work!
This problem comes up on sunny days also. I run the generator anytime I need a lot of prolonged power in my workshop. If I want to use the generator in the morning on a sunny day (while still in solar bulk charge) I have to remember to disable the charger in the inverter before I start the generator.
I don't have Outback's battery monitor, the Flexnet DC. I would buy one if it would solve this bulk charge issue, but it won't. As far as I know, there is no practical off-the-shelf solution to the problem (other than replacing the whole system with a Sunny Island).
What do you folks with both wind and solar do about this issue? I imagine that on a windy sunny morning you could have some very high bulk charging currents.
--vtMaps
4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
Comments
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Re: Outback Lack of Bulk Charge integration -- anniversary rant
vtMaps;
On the last day I was there I found I could make it do it (had just re-installed the panels). This is indeed a problem of non-integration and could be encountered on any system with multiple charge sources. Most of the time it will not occur. I had to trick my system into doing it by leaving off both panels and gen until midday and then energizing both. They came up so quickly that the current wasn't an issue (especially as this won't happen 99% of the time with my system) but the shortness of the Bulk stage then does become one.
Let's face it: the industry is without a tool that it needs which is a battery monitor that can measure and regulate charging from all sources. In theory this could be as simple as something that would detect current going in to the battery and then disconnect one or more charge sources if it exceeded a certain amount.
I have a smaller battery bank than you do as well as a smaller array. So my settings for 232 Amp hours is 5 AAC on the inverter which equates to approximately 25 Amps maximum. But I only use the gen for Bulk if there doesn't look like much opportunity for sun that day. Since there's a good two hour window on my system before full sun occurs, I can Bulk with the gen before the panels reach full potential. I also do not use the gen connected to the inverter if I need it to power other equipment.
If anyone has wind and solar or multiple solar charging sources it has to be balanced to be within that maximum charge current limit.
Now I'm going to suggest the simplest work-around I could figure out for your situation: relay connected to AC IN that will disconnect the charge controller if the gen is active. Yes, less than perfect but it would prevent your battery being zapped by high current from dual sources.
There are a lot of problems with solar related to relying on Voltage (which is easiest to measure and deal with) when you in fact need to be looking at current. -
Re: Outback Lack of Bulk Charge integration -- anniversary rantToday is the first anniversary of my joining this forum
congratulations, happy brithday to you! ...;-)I don't have Outback's battery monitor, the Flexnet DC. I would buy one if it would solve this bulk charge issue, but it won't. As far as I know, there is no practical off-the-shelf solution to the problem (other than replacing the whole system with a Sunny Island).
What do you folks with both wind and solar do about this issue? I imagine that on a windy sunny morning you could have some very high bulk charging currents.
i think that with FlexNet dc, the outback system synchronizes all chargers to put in the battery only amps you've set, and also has the intelligence to take all you can from the sun, reducing generator fuel costs ... also in absorption makes the same criteria ...
anyway let me confirm, that so far with the size of my battery never wasted nor an amp than I have when I use the genset and also I have sun ...
I'll look and I'll tell you, okay? ... -
Re: Outback Lack of Bulk Charge integration -- anniversary rant
if you set the controller to limit to 8a and it did not then it's not operating properly. i can't say with specifics on the outback as i don't have one, but when a cc has programability on the output current then it should go to what you programmed it to. you indicate the cc was outputting 33a which is 25a higher than you set it for.
it's bad enough you are having difficulty with managing different charge sources, but to have one not do what it was programmed to do is a big problem. babysitting a charge is a royal pain and i feel for you on this. if you can't trust the output of the cc to limit where you set it to then i'd pop a breaker inline to cut it off should such an incident occur and i'd be on the phone with outback asking why. -
Re: Outback Lack of Bulk Charge integration -- anniversary rantif you set the controller to limit to 8a and it did not then it's not operating properly.
I read his post to say that he set his inverter/charger output limit to 8 amps AC (30-35 amps DC) - not the controller.
Do the Outback Flexmax CCs allow you to limit the output amps? If so I would think that would be a solution.
The Midnite Classic CCs do allow this and it works well.
Unicornio - I don't think the FNDC will help in this case - at least as far as I can tell. The FNDC can terminate absorb based on return amp parameters but I do not think it can limit amps during bulk as vtmaps would like to do - at least I don't think so - I could be wrong..
i stand corrected on which was set back, but it would still indicate something's not right. maybe he should've limited the solar and left the inverter wide open? niel -
Re: Outback Lack of Bulk Charge integration -- anniversary rant
What batteries are you using ? Not all batteries care about this.
Maybe you have small wire and/or smaller circuit breakers ??
boB -
Re: Outback Lack of Bulk Charge integration -- anniversary rant
Yes, that is correct. The inverter/charger can be programed to limit its charger function to 8 amps AC. I also program the inverter/charger to never draw more than 13 amps from the generator. If, while charging, I run an AC load of 10 amps, the charger will cut back on the battery charging so that the total load on the generator does not exceed the 13 amps I have programmed.I read his post to say that he set his inverter/charger output limit to 8 amps AC (30-35 amps DC) - not the controller.Do the Outback Flexmax CCs allow you to limit the output amps? If so I would think that would be a solution.
Yes, I can limit the output amps of the flexmax controller, but in my case there is no need to do so. My array (only 940 watts) cannot push more than 35 amps into my batteries.
The problem is that two chargers, each with their own limits, do not coordinate and together they may exceed a reasonable charge rate for my batteries.
--vtMaps4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i -
Re: Outback Lack of Bulk Charge integration -- anniversary rantDo the Outback Flexmax CCs allow you to limit the output amps? If so I would think that would be a solution.
The Midnite Classic CCs do allow this and it works well.
Yeah they can limit amps, but that's not a solution, because vtmaps doesn't want the current limited when only the flexmax is charging. The current should only be limited when both inverter/charger and flexmax are charging at the same time. And if this feature is eventually added, it should of course be the inverter/charger that limit's it's charging current and not the flexmax. Fuel costs money, sunlight doesn't
Another related issue I've been wondering about is why don't any charge controllers limit the current during EQ? Many of the battery spec sheets say that current above 2.4V should be limited to 5A/100Ah, yet all charge controllers will output full capacity during EQ. -
Re: Outback Lack of Bulk Charge integration -- anniversary rantWhat batteries are you using ? Not all batteries care about this.
Maybe you have small wire and/or smaller circuit breakers ??
boB, the batteries are 370 ah flooded L16. I have read here that C/10 is a good charge rate for the batteries, and that a C/5 charge rate (75 DC amps) is too high. Some folks have written that no charge rate is too high as long as the batteries don't overheat.
My equipment is installed on a Midnite E-panel with appropriate sized breakers, #0000 battery cables, and low resistance connections. I use a DVM each month to look for voltage drops across the battery interconnections. At 30 amps charge or discharge I seem to be losing about 30-40 millivolts total on all battery connections.
I believe the equipment and connections are all working properly. My problem is that I am looking for a feature that has not been implemented on my equipment (and most other RE equipment). Or maybe I don't have a problem.... do you think it is OK to push 70 amps into a 370 ah bank of L16 batteries?
Please keep these issues in mind when you design the controls and communication for your Midnite inverters. :cool:
--vtMaps4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i -
Re: Outback Lack of Bulk Charge integration -- anniversary rantYes, I can limit the output amps of the flexmax controller, but in my case there is no need to do so. My array (only 940 watts) cannot push more than 35 amps into my batteries.
The problem is that two chargers, each with their own limits, do not coordinate and together they may exceed a reasonable charge rate for my batteries.
--vtMaps
Yes, I can see how it would be nice if there was a way to set a global limit for charging amps with use of available PV amps prioritized. At least for now wouldn't temporarily setting the amp output limit low on the CC when using the generator to charge at least avoid the scenario in your OP? Not a real solution I know...
OK, Happy Anniversary. Rant on. -
Re: Outback Lack of Bulk Charge integration -- anniversary rantAnother related issue I've been wondering about is why don't any charge controllers limit the current during EQ? Many of the battery spec sheets say that current above 2.4V should be limited to 5A/100Ah, yet all charge controllers will output full capacity during EQ.
This is another non-issue.
The batteries should be fully charged before equalizing, and loads are supposed to be turned off. Even if loads are not turned off it will make little difference to the current actually going in to the batteries. Under EQ conditions the batteries should never be demanding full current as they are already fully charged. If they do, something is wrong with the system. -
Re: Outback Lack of Bulk Charge integration -- anniversary rantCariboocoot wrote: »This is another non-issue.
The batteries should be fully charged before equalizing
Yet there's only 1 obscure charge controller on the market that will actually perform an EQ after absorb. Every other charge controller will attempt to go straight from bulk to EQ, skipping absorb.Cariboocoot wrote: », and loads are supposed to be turned off. Even if loads are not turned off it will make little difference to the current actually going in to the batteries. Under EQ conditions the batteries should never be demanding full current as they are already fully charged. If they do, something is wrong with the system.
The system should operate automatically, walking down to my solar installation do to an EQ every month is not something I want or should have to do. The charge controller has all the information it needs to be able to regulate the EQ charging current. Don't see why I would have to do this manually. -
Re: Outback Lack of Bulk Charge integration -- anniversary rant
Stephen;
I don't see a charge controller listed in your sig. What one are you using?
Normally a battery set would have to go through Absorb in order to get up to EQ Voltage, which is only a couple of Volts higher than Absorb at most. By this time the current level should be well below maximum because it has to complete Bulk in order for the Voltage to be that high.
The loads could become an issue if they draw a lot of current at this time, but again that is not current going to the battery. If the inverter can run at EQ Voltage (all good ones can) then the amount of current is irrelevant. It should also be lower for any given Wattage output because the Voltage is higher.
Another fine argument against automatic EQ in my opinion.
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Re: Outback Lack of Bulk Charge integration -- anniversary rantCariboocoot wrote: »Stephen;
I don't see a charge controller listed in your sig. What one are you using?
I'm using a midnite classic, but it don't matter as all the popular MPPT do this the same way: straight to EQ.Cariboocoot wrote: »Normally a battery set would have to go through Absorb in order to get up to EQ Voltage, which is only a couple of Volts higher than Absorb at most. By this time the current level should be well below maximum because it has to complete Bulk in order for the Voltage to be that high.
Although it goes through the absorb voltage, it doesn't sit around during the absorb stage. The current stays at max current until it hits the EQ voltage. That can take some time between leaving absorb voltage at 2.4V and heading up toward EQ at 2.65V. For all of that time, the batteries are being subject to currents that manufacturer says should not be there. During my last EQ the battery spent 1.5 hours above absorb voltage as it was heading towards EQ. Not insubstantial.Cariboocoot wrote: »Another fine argument against automatic EQ in my opinion.
Pah! I'd say it's a fine argument for the chargers to start implementing current limiting above absorb voltage
Out of interest Victron offers this on their inverter/chargers, they call it "batterysafe (tm)(copyright)(yo mama)" and it sounds quite clever because unless you have a shunt installed none of the chargers or charge controllers will know how much current is going to the battery. So what they do is monitor the rate of change of the battery voltage. If it's rising too fast then there's too much current, and they back off. -
Re: Outback Lack of Bulk Charge integration -- anniversary rantI'm using a midnite classic, but it don't matter as all the popular MPPT do this the same way: straight to EQ.
No, it is not possible to go "straight to EQ" as the Voltage has to be brought up to EQ level before the EQ clock starts counting down. Sub-EQ level Voltage does not count as equalization; it is just ordinary charging even if it doesn't say "Bulk" or "Absorb" while doing it. It will zoom past the Absorb stage right on up to EQ Voltage, but this is also not a problem. You do not EQ every day, so it is logical the batteries got their Absorb cycle yesterday and will get it tomorrow. Missing one Absorb cycle a month will not have any significant affect on the batteries.Although it goes through the absorb voltage, it doesn't sit around during the absorb stage. The current stays at max current until it hits the EQ voltage. That can take some time between leaving absorb voltage at 2.4V and heading up toward EQ at 2.65V. For all of that time, the batteries are being subject to currents that manufacturer says should not be there. During my last EQ the battery spent 1.5 hours above absorb voltage as it was heading towards EQ. Not insubstantial.
Here's something I noticed from your sig: 2800 Watts of panels on a 48 Volt system with 900 Amp hours of battery? Looks like <5% peak charge current to me. That is problem #1. If you had enough charge current available to begin with it wouldn't be demanding full current all the way up through Absorb/EQ. If you are using a secondary source to supplement the solar for charging (such as that generator) then your whole charge regime as far as the MidNite is concerned will be messed up. Precisely what we are discussing in this thread. What are these current levels you are experiencing? Frankly that battery should have no trouble handling the MidNite's full output capacity (80 Amps) and then some (like 135).Pah! I'd say it's a fine argument for the chargers to start implementing current limiting above absorb voltage
I totally agree that consolidated charging regulation is needed in the industry and so far absent. But since EQ is more of a "monthly maintenance" item rather than daily occurrence I don't see any reason why you don't do it manually when you check the water level and SG of the battery (which you must do). If you truly want a "set and forget" system you go for AGM's and forget about EQ.Out of interest Victron offers this on their inverter/chargers, they call it "batterysafe (tm)(copyright)(yo mama)" and it sounds quite clever because unless you have a shunt installed none of the chargers or charge controllers will know how much current is going to the battery. So what they do is monitor the rate of change of the battery voltage. If it's rising too fast then there's too much current, and they back off.
Yup. Been nagging boB about the controller with built-in battery monitor for ages now. Since it would read all the current going in/out it would not only have a better idea of SOC but also could limit current even if it only backed off one charge source. For multiple units of the same, a bit of communication between them would solve the issue entirely. Heck such function could be a stand-alone after-market regulator that could integrate with any system and slack off certain sources as needed.
But *sniff* nobody ever listens to us! -
Re: Outback Lack of Bulk Charge integration -- anniversary rantCariboocoot wrote: »No, it is not possible to go "straight to EQ" as the Voltage has to be brought up to EQ level before the EQ clock starts counting down. Sub-EQ level Voltage does not count as equalization
I'm not talking about the time spent at the EQ voltage. I'm talking about the time spent above the absorb voltage while in the process of doing an EQ charge. My battery manufacturer (and many others) don't care about the current at EQ voltage. They care about any current spent above absorb voltage.
No matter what sized array I have, there will be some time spent above absorb and below EQ.Cariboocoot wrote: »Looks like <5% peak charge current to me. That is problem #1.
Is that 5% for Canada or 5% for SpainCariboocoot wrote: »What are these current levels you are experiencing? Frankly that battery should have no trouble handling the MidNite's full output capacity (80 Amps) and then some (like 135).
Sure, below 2.4V/cell it'll accept any amount of current, but above 2.4V / cell the current must be limited to 5A/100Ah (C5). It's a 700Ah(C5) battery, so need to limit to 35A, I'm seeing 45A above 2.4V during EQ... and am planning on more panels. -
Re: Outback Lack of Bulk Charge integration -- anniversary rant
Calculating using "typical" numbers:
2800 Watts @ 77% efficiency / 48 Volts = 45 Amps, and that's what you are getting. I was basing the percentage on the 900 Amp hours in your sig line:
45 * 100 / 900 = 5%
Up here it would be worse, or better depending on your POV:
2800 Watts @ 82% efficiency / 48 Volts = 47.8 Amps or just above 5%
With a 700 Amp hour battery the calculated peak rate improves to 6.4%
I'm surprised your panels aren't less efficient in Spain's famous warm climate.
Maybe you could put the new panels on a separate controller and orient them more Easterly so that they give you more charge current early on, before EQ is triggered. If you can push the Voltage up to Absorb level with the current falling below 5% before EQ starts then the rise to EQ Voltage should be rapid and of no concern.
I think I'd have about 4.4kW of panels on that 700 Amp hour 48 Volt bank. It's unfortunate there's no computer model that can check such speculation and see for certain how it would behave under varying conditions of insolation and charge sequence. -
Re: Outback Lack of Bulk Charge integration -- anniversary rantCariboocoot wrote: »
But *sniff* nobody ever listens to us!
Oh believe me ! We listen ! Otherwise I wouldn't be reading this forum and thread
As for Trojan L16s, I think they say 20% C max for charging current for longest life which in the case of
a 370 A-hour battery would be almost 75 amps. If you get more than that once in a while, it's probably fine too.
Do you limit your discharge current when starting a big load ?
This is not a problem I would say. BUT if you really want to limit the charging current when you are running your generator,
you could add a relay powered by the AC output of the genny to turn off the PV at that time.
I think we can probably accommodate a global current limit eventually but I would wait until our battery monitor is done.
boB -
Re: Outback Lack of Bulk Charge integration -- anniversary rant
Another thing related to all of this is that either over charging OR over discharging is basically a problem because of
battery resistance and if too much current flows either way, it will heat up more and damage the battery prematurely.
SO, the way to stop that would be to use the battery temperature sensor to also limit the battery charge current
as well as well as charge voltage.
boB -
Re: Outback Lack of Bulk Charge integration -- anniversary rant
I think we can probably accommodate a global current limit eventually but I would wait until our battery monitor is done.
boB
Now there is a glimmer of hope in everyone's hearts!
That is also a point I've tried to make before, that most batteries can take 20% charge every now and then for not too much time. If you were hitting them with that kind of current every charge cycle or for a couple hours they would no doubt suffer.
But we've got too different current problems in this thread: vtMaps' occasional double-burst and stephendv's high current prior to EQ starting. -
Re: Outback Lack of Bulk Charge integration -- anniversary rant
I noticed something at the Outback forum that I didn't know... The Mate3 has a Global Charger Output Control:The global charger control allows the MATE3 to limit the DC current delivered to the batteries by all FLEXmax charge controllers in the system. (This function cannot limit charge current from inverters of any kind.)
This function requires the system to have a FLEXnet DC battery monitor installed in the system. The FLEXmax charge controllers must be set to GT Mode in order to establish priority for this function. (However, the inverters in the system cannot use grid-interactive functions, if any.)
This would solve the problem of additive currents during Bulk charging, but it solves the problem the wrong way: Obviously it would be better to reduce the generator charging rather than the solar charging when the sun unexpectedly comes out, but at least this method will prevent excessive currents during bulk charging.
No way I will trade my Mate for a Mate3, buy a Hub, and buy a FlexnetDC for this feature. It will be interesting to see what Midnite comes up with when they release their battery current monitor in a few months. It may be possible to duplicate this current limiting function in the classic... what say you boB?
--vtMaps4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i -
Re: Outback Lack of Bulk Charge integration -- anniversary rantThis would solve the problem of additive currents during Bulk charging, but it solves the problem the wrong way: Obviously it would be better to reduce the generator charging rather than the solar charging when the sun unexpectedly comes out, but at least this method will prevent excessive currents during bulk charging.
vtmaps - we can have this problem big time if the wind and blowing and the sun comes out. It's not unusual here to see 180 amps into our 1200ah bank. I use a feature in the Classic controllers called "Waste Not Hi" that drives a SSR with PWM and turns on inverter power to 240V water heater elements. This effectively reduces the amount of charging amps by sending the excess directly to the inverter to power the water heater elements.
I believe the FM controllers have this too? Maybe called "Opportunity Diversion" or something like that? It works if you can set up a load to use it. And even if your generator is running it's not a bad deal because it helps keep the gen at full load during the run time, where you get the most kWh possible from a gallon of fuel.
--
Chris -
Re: Outback Lack of Bulk Charge integration -- anniversary rantChrisOlson wrote: »I use a feature in the Classic controllers called "Waste Not Hi" that drives a SSR with PWM and turns on inverter power to 240V water heater elements. This effectively reduces the amount of charging amps by sending the excess directly to the inverter to power the water heater elements.
I believe the FM controllers have this too? Maybe called "Opportunity Diversion" or something like that?
I don't see how that would work for me... when I'm running the generator my inverter is being a charger.
I thought that 'opportunity diversion' and 'waste not hi' was a way to use 'potential solar power' during absorb or float stage charging. My problem is that during bulk stage each of my chargers has no idea what the other is doing. As I mentioned, if I upgrade to Mate3 and hub and FlexmaxDC, the FM60 could throttle back (if the generator is on) when the sun comes out.
As far as getting the most kwh per gallon of fuel, my eu2000 does a reasonable job... certainly not as efficient as your setup, but the scale of our systems is so different that my annual fuel use is a drop in your bucket.
Finally, the problem I have occurs mostly when I need to use shop tools on a cloudy day with low SOC. I don't need generator support because all of my tools can be run (one at a time) by the generator alone. Most shop tool use is intermittent, so when my finger is not on the trigger of the saw, my generator is charging my batteries. Works great until the sun unexpectedly comes out while still in bulk stage. Of course, there is no problem once absorb stage is reached.
Occasionally if I have prolonged heavy loads (shop vac) I will run the generator on a sunny day. In that case I just manually turn off the flexmax or dial down the charging amps on the inverter. Its not an automatic, but the best I can do (sort of like when you have to manually turn on your generator before welding).
--vtMaps4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i -
Re: Outback Lack of Bulk Charge integration -- anniversary rantI thought that 'opportunity diversion' and 'waste not hi' was a way to use 'potential solar power' during absorb or float stage charging. My problem is that during bulk stage each of my chargers has no idea what the other is doing.
Ah - sorry about that. It didn't register that we're bulk charging and then the Opportunity thing isn't going to work anyway.
It's probably like boB said, though. It probably don't hurt to charge at C/5 for brief periods as long as the batteries don't start warming up excessively.
Now I'm curious as to how the XW system handles something like this? I wonder if when the generator is running, and you got solar coming in with a XW-MPPT60, if the two coordinate with one another? We had a XW-MPPT60 for our new solar array and it didn't play nice with the Classics. The Classics are networked so they all follow the same charge stage. The XW-MPPT60 got into an argument with them about who's boss over when to switch to absorb and float. So I traded the XW-MPPT60 back in to the dealer and got a Classic Lite instead.
So, yes, I do realize how important this charging coordination is between different devices.
--
Chris
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