A Forum run by Enthusiasts of MidNite Solar

Rag Chew => Off Topic Discussions => Topic started by: toothy on January 29, 2015, 05:07:39 PM

Title: Fun and games off grid!
Post by: toothy on January 29, 2015, 05:07:39 PM
I have an ongoing problem.

I have 2 Outback VFX3648’s and an x-240 connected to a 1350Ah fla bank and a 10Kw Northern lights generator.

When charging at 20A per inverter my lights flicker and my fire alarm goes off, sometimes, backing off the charge rate doesn’t seem to help and adding resistance loads for generator health also makes no difference.

So, my buddy was selling 2 Trace SW5548tes inverters with AC and DC disconnects and stacking data cable. I figured I could use these as a better, separate means of charging and keep the Outbacks as inverters only.

Hooked them up and they function. However, I set the AC input at 20A and they start bulking at about that, in 2-3 minutes the master starts backing off and the slave rises slightly. At 4-5 minutes the master is around 8A and the slave is around 22A.  That to me is an unacceptable imbalance. Bulk voltage set at 59V and when it starts backing off the battery is at 53V.


How do I balance these legs? I don’t want to change the gen to 120v as I need it for welding sometimes. Or is it Craigslist time?

Thanks for any input
Wade

Title: Re: Fun and games off grid!
Post by: toothy on January 29, 2015, 06:03:01 PM
I may have just found my answer. Do away with the stacking cable and let them do their own thing, since I'm not using the 240 AC output.

Thanks
Wade
Title: Re: Fun and games off grid!
Post by: toothy on January 31, 2015, 05:15:32 PM
New thought, yes I know how scary that is!

I didn't unhook the stacking cable because I figured the 2 inverters could still unbalance the gen legs based on time, temp, voltage and stuff.

I have a Hevi-Duty shielded general purpose transformer model #S5H15S that I think I could use to balance the legs no mater what the chargers decide to do. Now I just need to figure out how to wire it in without blowing anything up.

I'm pretty sure I hook one hot leg to H1 and one to H2. The tap wires came connected as you see them below.

I am also pretty sure I put the ground to the lug on the side of the case.

Here is where I get lost, although I could be lost in the thoughts above, I want 120v to 2 inverters where do I get it and how does the neutral become involved?

Thanks for any help.
Wade



Title: Re: Fun and games off grid!
Post by: toothy on February 03, 2015, 03:18:04 PM
If anybody's curious, the balancing transformer works great.

The SW5548's still have the same issue of backing off on the master but now the gen is in balance so I don't care.

Now I'm thinking of running the Outbacks through the transformer also, to balance pass through loads when welding and such. I don't think the X-240 in the outback balances the pass through but I'll check before the change.

Wade
Title: Re: Fun and games off grid!
Post by: TomW on February 03, 2015, 03:32:11 PM
Quote from: toothy on February 03, 2015, 03:18:04 PM
If anybody's curious, the balancing transformer works great.

The SW5548's still have the same issue of backing off on the master but now the gen is in balance so I don't care.

Now I'm thinking of running the Outbacks through the transformer also, to balance pass through loads when welding and such. I don't think the X-240 in the outback balances the pass through but I'll check before the change.

Wade

My (now decommissioned)twin Outback system had an X-240 on the output and would try to balance the grid if I left it in circuit while "bypassing" the Outback's with grid.

Not sure if that is what you are thinking about?

Just an FYI.

Tom