Solar Charger Recommendations

[questingvagabond]

Having some issues with the MakeSkyBlue controller I am using on my new setup.

I was using the MakeSkyBlue about two years, and was on lead acid battery bank. 2 months ago I assembled a 8 cell, LIFEPO4 bank, for 24 volts, 272 amp cells. It seems to work fine, and I noticed many times during the day I was getting about 450 watts, on my 630 available, and was hitting 28.8 volts on bank usually in a few hours in the morning.

A few days ago, I installed a second bank, a 8 cell 310 amps bank, which was tested to be about 291 amp cells, in parallel. I noticed the controller would not go above about 120 watts on this setup. If I take out the fuse to the panel, it will jump for about 30 seconds to 400 watts, and then work it way down to about 120.

So today, I took charger off the banks in parallel, and patched a wire to the total positive individually, one at a time, and it made no difference, still 120 watts no matter which bank.

Then I took them out of parallel, by disconnecting them at the common terminal, and then tried to charge one bank with them connected at common only. No change.

So I suspect this controller does not like the negative load in its programming. So I am looking for any recommendations, on a good solar charger, that would have no problem handling two LifePO4 banks, totaling 560 amps, 24V.

For panels I have two on my roof of my camper, 2 x 315, for 630 watts on one string incoming feed in parallel, and a third 315 on the front of the truck that I bring in separate, so having two PV inputs would be a plus since the front panel can get shaded time to time.

I use two daly BMS's and I did this on purpose so I had redundancy in case of failure, where I could revert to on bank in an emergency, etc.

A video walk through if interested is here. As said, if any of you are using a controller on more than one bank, of high capacity, would love to hear the model.

 

[snoobler]

Are you being limited by absorption?

If your batteries are at 28.8, and that's the SCC's absorption voltage, it doesn't matter if you have 10,000W on on it, it won't take more than the battery can handle.

If you're trying to test your array performance, it helps to ensure the battery is below absorption voltage AND add loads.

 

[questingvagabond]

Are you being limited by absorption?

If your batteries are at 28.8, and that's the SCC's absorption voltage, it doesn't matter if you have 10,000W on on it, it won't take more than the battery can handle.

If you're trying to test your array performance, it helps to ensure the battery is below absorption voltage AND add loads.

No, they are very slowly charging, I am right now, 26.5 volts on the 290 amp bank, and .002 cell voltage difference, and 26.5 on the other 272 bank with .002 cell difference, and it seems to be self balancing nicely in that it seems to be moving the current from one bms to the other on charging.

My solar charge has now dropped to only 26 watt, but then just as I looked it went up to 250 for a minute, and then back down, I am hoving right now as we speak at 150 - 200 watts.

 

[snoobler]

There's no reason a second bank in parallel should cause this. Either the controller has failed/is failing, or something else is wrong.

Any of the SCC that Will recommends that can handle your array should be fine. Battery capacity doesn't play into it with LFP.

I'll always vote for Victron.

 

[questingvagabond]

There's no reason a second bank in parallel should cause this. Either the controller has failed/is failing, or something else is wrong.

Any of the SCC that Will recommends that can handle your array should be fine. Battery capacity doesn't play into it with LFP.

I'll always vote for Victron.

Thanks, so I am looking at them right now, would you go with two separate controllers, so the max my panels could ever put out at 35.4 volts is under 30 amps, so if I put two 15 amp chargers, or even say two 20 amps etc, one on each bank would that make more sense than one larger one?, and jsut have them share the panel voltage coming in?

The thing is two controllers would thrown off my bms reporting I think, or since it is on the ground of the pack, would it sill see the right charge rate?

 

[snoobler]

Thanks, so I am looking at them right now, would you go with two separate controllers, so the max my panels could ever put out at 35.4 volts is under 30 amps, so if I put two 15 amp chargers, or even say two 20 amps etc, one on each bank would that make more sense than one larger one?, and jsut have them share the panel voltage coming in?

If your bank is in parallel, it's essentially one big battery. No value and issues with connecting SCC separately. You should only have ONE negative terminal at the shunt ONE positive terminal on the other pack.. Otherwise, you will load/charge them unevenly.

Charge controller:
945W/24V = 39A

If the panels are ~47Voc/36Vmp, why not just wire the panels all in parallel? Shading becomes a non-issue, and you maximize your production.

 

[questingvagabond]

If your bank is in parallel, it's essentially one big battery. No value and issues with connecting SCC separately. You should only have ONE negative terminal at the shunt ONE positive terminal on the other pack.. Otherwise, you will load/charge them unevenly.

Charge controller:
945W/24V = 39A

If the panels are ~47Voc/36Vmp, why not just wire the panels all in parallel? Shading becomes a non-issue, and you maximize your production.

Ok, so a singular 40 amp scc, of course Victron is best , and just parallel the panels into one input.

 

[questingvagabond]

Thanks everyone, I decided to go with the Renogy Rover 40 amp with Bluetooth, they had one at Amazon Warehouse deals, so thought I would try it, pretty sure it is this controller does not like the load or something.

 

[snoobler]

Many of the Renogy products force you to use canned programs. Make sure you can customize your battery parameters.

 

[questingvagabond]

Many of the Renogy products force you to use canned programs. Make sure you can customize your battery parameters.

Thanks, yes, I see a user custom profile for it there, which can override certain features of the LI profile, I was just going to search for a thread of those paramaeters, but price wise as a Canadian, we are paying quite a bit for the Victron.

 

[meaCulpa]

Thanks everyone, I decided to go with the Renogy Rover 40 amp with Bluetooth, they had one at Amazon Warehouse deals, so thought I would try it, pretty sure it is this controller does not like the load or something.

do u want to sell ur MakeSkyBlue CCs???