Wellsee MPPT

**BB.** · October 18th, 2010, 19:13 PDT

You can only parallel Charge Controllers on the output... For various reasons, you cannot parallel two chargers on the same solar array charging the same battery bank.

Adding diodes on the array or at the battery bank will not help, and with the battery bank will mess-up the charging voltage readings by the charge controllers (diode drop) and may cause the controllers to not work at all (controllers usually need to sense battery voltage and use a small amount of power to even startup).

-Bill

**moorsb** · October 19th, 2010, 5:52 PDT

I am feeding a 2nd array to the battery bank. I am trying to get 120amps into the battery bank.

**BB.** · October 19th, 2010, 7:26 PDT

Two separate arrays, two solar charge controllers, both connected with short heavy leads directly to the same battery bank--Should work fine.

-Bill

**dwh** · October 19th, 2010, 11:24 PDT

Originally Posted by moorsb

I am feeding a 2nd array to the battery bank. I am trying to get 120amps into the battery bank.

How full is the battery bank? Perhaps one unit has raised the voltage to the point where the second unit thinks the battery is charged.

Test them separately when the battery is down a bit.

**moorsb** · October 20th, 2010, 16:52 PDT

I have added a TM2020 to the system. I am not sure at all if I have it programmed correctly. That is the worst manual and instruction for setup that I have ever seen. It is like someone translated the step by step and left out things like, why am I doing this what effect does this have on the system. To enter the mode where you enter the bank capacity I had to turn off loads to get its attention seemed like it was too busy calculating things to catch the keyboard strokes. At this point I the volt were set 14.3 amps 99 is that as high as it will go I have over 100a from pv.
I will have to play with this before I believe any data. It shows the battery fully charged the MPPT is still charging. and the MPPT show the battery not fully charged. I am not sure what number to plug in for the bank capcity it say to enter half if you do not want to discharge them very much so I entered 600 amps

**moorsb** · October 27th, 2010, 20:03 PDT

They seem to be working. I have a 1.5 kva transformer on the output of the inverter. If I leave the inverter on over nite my tri metric tells me the battery is down to 85% full in the morning and it is full at night. I tried a 5 kva transformer on over nite and the battery is down to 50%
I guess I should rewire the pump to 120 vac and kill the transformer.

**moorsb** · November 18th, 2010, 13:27 PST

The TM 2020 looks like I need to reconfigure. It says it has met charge criteria yet it shows 10 amps going into the system with little load. The MPPT controllers one says the battery is full the other one says it is not so I guess just one is charging the bank once it gets to this level. I have rewired the pump to 120vac and taken out the transformers. I am setting up to run my xmas lights outside too. The lights are drawing 50 amps out of the battery. I have them on a timer for 4 hours. This morning the TM2020 showed down 210 amps. The solar panels were pumping 50 amps back in this morning and by 11:30 I was back at 100 percent according to TM2020 but I noticed 10 amps still be pumped into the bank with minimal load. So I guess I need to reprogram the TM2020?

**mikeo** · November 18th, 2010, 15:08 PST

I noticed 10 amps still be pumped into the bank with minimal load. So I guess I need to reprogram the TM2020?

I haven't followed this thread closely, but depending on your battery bank, it could draw 2 to 10 amps just to float it. I have forklift batteries, 940 amp hours and it takes 2 to 3 amps to float.

**Gulch** · January 21st, 2011, 22:22 PST

Hi Gang.

I have one of the 24Vin 12Vout, 20 AMP ones, purchased direct from Welsee in China.

First, the good news: Service was good, only took a week to get here.

Had it in service for two days now, feeding a 400AH bank off of two Kyocera 205 watt 24V panels in parallel.

Just using it to keep the batteries that run my lights and furnace blower in the RV topped off.

It charges the batteries OK, but it is NOT MPPT (at least as far as my limited understanding of the concept goes), just as earlier posters have surmised. Amps out is slightly less than amps in, but since the voltage is just about halved, I'm losing about half the wattage that the panels put out.

Here is a photo of two Watts Up meters showing what is going into and out of the Welsee controller. The top meter shows what is coming off the solar panel, the bottom shows what is going into the battery bank;

(I have photos of the inside of the controller as well, if anyone is interested.)

**Gulch** · January 22nd, 2011, 9:01 PST

By the way, even when the batteries are down to 12.0 volts the controller still puts out a fraction less than 1/2 the watts that are going into it. The batteries haven't gone below 12.0V since I got the controller, so I can't say definitively that there won't be a better efficiency throughput if the batteries are deeply discharged.