Conext SW4024 Tips

stmar

My SW4024 and SCP should be here soon so if there are any tips about install I would appreciate it. I think I will go with 240 volt grid tie, old unit was 120 volt.  I have a Honda EU2000I that I can use during an emergency and had the inverter wired so that I could plug the generator in easily, used a 12/3 cable and limited the gen to 12 amps charge so as not to overtax. Is there any cautions/concerns when grid tie is 240 volts and the generator charges at 120 volts? Tips about the settings would help and order of steps and maybe even deficiencies in the install manual.

And I must compliment NAWS, the forum sponsor. My order was shipped Tuesday the same day I ordered and is scheduled to be here Friday, Very fast and the prices were good.

MrM1

Do u have a transfer switch between the grid on and generator in?

Will u b charging batteries?

Do u plan to use the inverter in an off-grid style set up or in its AC support mode?

stmar

No xfer switch, I do it manually, the grid breaker is close to the unit.
Charging 4 X 6 volt Lifeline AGMS total 400ah.
AC support mode, use it as a UPS.

stmar

I do have a transfer switch for grid, I am running my well pump on it, and a T-220 120v to 240v step up xformer for when the grid goes down. If I run 240 volt with the inverter then I have eliminated the need for the T-220, can save it for the Apocalypse. I can move the transfer switch to grid and inverter. The generator has never been used in an emergency, just testing, so manually plugging it in and disconnecting the grid are no big deal, a transfer switch for that operation would be overkill. The ability to have 240 volts has opened up a whole new avenue of things I can do better with my system and every comment brings on more brainstorming so thanks.

MrM1

Have you looked at the wiring diagram for the SW?

MrM1

I am asking How Will You Use the SW? 

- AC Support with Grid In

- Or totally off Grid

- Will it be used to charge batteries

- As a 240v split phase or 120v single phase

stmar

AC support with Grid in

Charge battery bank

Thinking I will go 240v split phase

I think I see where you are coming from for the xfer switch on gen and grid, looks like this unit does not have AC1 and AC2 terminals like the old SW. May just leave the gen out since it is hardly ever used, plus it is 120 volt so may not be compatible with this setup.

mcgivor

stmar said:

AC support with Grid in

Charge battery bank

Thinking I will go 240v split phase

I think I see where you are coming from for the xfer switch on gen and grid, looks like this unit does not have AC1 and AC2 terminals like the old SW. May just leave the gen out since it is hardly ever used, plus it is 120 volt so may not be compatible with this setup.

Read this thread, has some interesting info regarding ballance and AC support.
http://forum.solar-electric.com/discussion/353094/balancing-the-loads-of-my-conext-sw-with-an-autotransformer#latest

MrM1

Yes you are correct.  There are only L1 and L2 Input,  so only a single AC in.    

As Mcgivor pointed out,  Load balancing is important with the Conext SW.   If you load one side of the split phase way more than the other there is some derating in the output.   

There are several install / operation Tips in these threads:

http://forum.solar-electric.com/discussion/353294/conext-sw4024-ac-support-performance/p1

https://www.solarpaneltalk.com/forum/off-grid-solar/off-grid-solar-panel-systems/380237-off-grid-inverter-charger-shopping

mcgivor

It is ironic that the split phase is cheaper than the single phase, using the host store as reference, perhaps a supply demand thing in the US, I was going to suggest a single phase using an external transformer, but the split phase is less expensive, go figure, they are probably identical except the output transformer. But it would appear using an external transformer would avoid the ballance issues.  

stmar

Thanks for all the input, new item learning curve, helps a lot. I will balance the loads, we are fairly frugal with our power and have just regular household loads. What is the disadvantage of unbalanced L1 L2? Reason I ask is that wife has hair dryer and curling iron going in the mornings on one circuit and there won't be much load anywhere else. If it is just more grid energy use then no problem, I don't think there would be a way to split those two appliances.

The old T-220 auto transformer I have puts out 2800 watts so I may find a use for it in the future. I will get my system installed and play with it for a while to see what is best for my situation. 

mcgivor

That's a good plan, generally hair dryer and curling irons are short duration loads so wouldn't make that much difference on the grand scale. 

MrM1

mcgivor said:

It is ironic that the split phase is cheaper than the single phase, using the host store as reference, perhaps a supply demand thing in the US, I was going to suggest a single phase using an external transformer, but the split phase is less expensive, go figure, they are probably identical except the output transformer. But it would appear using an external transformer would avoid the ballance issues.  

That is what drove me to the SW in the first place,  cost per output watt. 

MrM1

stmar said:

 What is the disadvantage of unbalanced L1 L2? Reason I ask is that wife has hair dryer and curling iron going in the mornings on one circuit and there won't be much load anywhere else. If it is just more grid energy use then no problem, I don't think there would be a way to split those two appliances.

The old T-220 auto transformer I have puts out 2800 watts so I may find a use for it in the future. I will get my system installed and play with it for a while to see what is best for my situation. 

The issue is the derating of the inverter.  It is really only rated for about 1700 watts per side - L1 and L2.  But as Mcgivor said,  it would be fine for short duration.

Also,  the inverters AC Support Mode really does not work well at all if the loads are inbalanced.  But it would work flawlessly with an Auto Transformer after the output of the inverter to balance the L1 / L2 loads.    When I use a single 240v L1/L2 load like a pump that is perfectly balanced,  AC support mode works as adversitised.  Let those loads got off by an amp or 2 and it starts drawing more from the Grid than from the battery. 

mcgivor

The Conext SW series of inverter chargers are actually pretty good  considering the price, way more features than a non integrated system of similar cost, the System Control Panel or better yet Combox make it a very versatile unit. 

Horsefly

We have the SW4024 as well. I was originally trying to figure out how to balance the loads, but we really can't. Our main load is a 120VAC well pump that pulls around 12A-13A (~1500W), but it runs for 2 min 40 seconds each time, maybe 3-4 times per day. The other big load we have is a microwave, which pulls about 1000W for no more than 5 minutes, 2 times per day. Those two are not on the same leg, which is about all I can do.  It's all worked fine when running off the solar / batteries.

My brother has reported some strange behavior from the SW4024 when he's running the generator and the well pump turns on.  He's actually reported different types of strange behavior, and I haven't actually seen it at all myself. I was speculating that it might be due to the imbalance between the legs, but I'm not sure.

MrM1

@Horsefly,  have you considered an Auto Transformer as we discussed here?  I am hoping someone actually tries this, as  I actually think it will work very well and cause the SW in North America to do what it is suppose to do.   Schneider told me it would work and was a very good idea,  but I have not had the resources to try it yet.

As to strange behaviors,  I have seen  a few.  What are they looking like on your end?

MrM1

To the OP and Install Tips.  IMHO, AC support mode is a great feature if it worked as advertised.   In North America with 120v split phase circuits,  it does not due to load imbalances.     It works  when the loads are balanced,  and it works sometimes when the loads are pretty balanced.  And the higher the loads get the better it works if there is inbalance.  You can see the disadvantage of unbalance issues discussed here. 

But if you really wanted to have AC  support mode work well,  I would say to plan into your install an Auto Transformer like the FW-X240 or PSX-240 would work.   While I have not tested this,  I have been told it should work. 

mike95490

Or skip the add on transformer and get the XW+ series, but that's more $$

stmar

> @mike95490 said:
> Or skip the add on transformer and get the XW+ series, but that's more $$

When I was looking it said the 24 volt model was being discontinued and the XW was going to 48 volt or did I miss something? And like you said it was twice as much $$$ as the SW if you could find one.

stmar

What temperature range is your mechanical room where your system is located, summer winter?