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Charge controller compatibility with lifepo4

066logger

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Hello everyone, been lurking here awhile after seeing Will’s diy lifepo4 battery videos on YouTube while researching battleborn batteries. Thank you for the wealth of knowledge, I’d never consider buying from alibaba and especially not batteries but here I am, patiently waiting for 8 EVE 280ah batteries from Amy lol.

A little background, I have been off grid for about 4 years now. 8- Trojan L-16 e-ac batteries, aimes 24v 6000w inverter, 2-250 watt 24v panels 4-260 watt 24v panels, 1-2000w (supposedly, I haven’t ever seen close to that) mwands freedom 9 blade turbine on a 70’ tower. 2 panels paralleled per wire and then into a combiner box. I definitely am no electrical expert, but I absolutely love being off grid and I love to learn so here we are!

Now, for the hard part. My lead acid is dying, 4 years of hard cycling and some abuse from me definitely hasn’t helped. I had just finished up my wind turbine project, along with a new charge controller and dump load when I decided that now I felt confident I wouldn’t be abusing batteries as much so I could upgrade to a better set. Call battle born at first they say yes my system is a perfect candidate for lifepo4 and all is well. Then I talk to the guys at Missouri wind and solar and they say my charge controller is incompatible with lifepo4 and I need to spend $3000+ on 2 midnight 150’s and a clipper for the wind turbine. Ugh. Took the wind right out of my sails, literally.

So I regroup. Look at all available options, go down all other battery chemistry’s and because of my weight limit 1,200lbs and wanting at least 500ah of storage capacity pretty much everything is out the window except lifepo4. Find the diy batteries and figure heck if I can save several thousand that will sure help me afford all these crazy expensive charge controllers.

now, if you’re still with me. Thank you. My question is, with the Diy batteries and bms systems do I really need a different charge controller? The controller I have is pretty barbaric lol. It’s basically a 440amp relay with an adjustable voltage set point at which it opens and connects to a dump load. Basically just 4 giant resistors. I have been using versions of this controller for the last 4 years. Besides a few $12 relays it’s worked without a hitch. But, is it trash for lifepo4? It’s called the sky max 440 and it’s made by Missouri wind and solar. From what I’m understanding posting links is okay as long as I’m not benefiting from them hopefully ?. But here’s a link, for some reason I always have trouble finding this controller on their website. https://mwands.com/skymax-440-diversion-controller

what do you think? Trash? If so that’s okay. I can lay the turbine down and keep it offline for awhile while I save my pennies and just run a single midnight 150 on my solar if need be. I definitely don’t want to kill my new battery’s or bms. Thanks in advance!
 
I have to believe we could come up with a solution that is a lot less than $3000 for the controllers alone. That seems insanely high.

I am trying to understand your current system.

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I need to understand the SkyMax better, but I am guessing the Turbine, Solar and Battery are all in parallel and the SkyMax controls the voltage by turning the dump load on and off through the relay. I am also guessing it does not have a charge profile. Instead it just holds the voltage at a pre-set level. That is a pretty old-school system and not what you want for a lithium battery.

If you are going to keep the turbine, you are going to need a diversion controller, and dump load so we may be able to use the Skymax, but if my guesses are correct, it *can not* be the primary controller. There will need to be something else between the Skymax and battery.

Do you have a link to the manual of the skymax?
Do you have the model or specs for the solar panels?
What do you have for breaking the turbine? Just the diversion controller or do you have something extra for high winds?
What wattage are you getting from the turbine?
 
Wow, that is an incredibly detailed response and honestly I think you spent more time understanding my system than anyone I have ever talked to. Thank you.

So now on to the questions, the manual for this controller is not on their website anywhere, and the link they sent to me is dead. So I’m waiting on them to send me a new link.

The brand is helios and model of two of my solar panels is hse250-60p, the other 4 of my panels are Canadian solar and I believe the model is cs6p-260p. That i am not sure of because I can’t find that particular receipt. Your diagram of the solar is wired how I have them exactly except it’s the 2-250’s on one string and then two strings of 260’s but they are wired just as you show them.

On the turbine braking I do have dual brake switches if a big storm was coming I can flip them. The way I understand they work is it just shorts the 3 legs in each core together and doesn’t let the turbine spin. But the turbine cannot be spinning when they are engaged. Your wiring on the turbine is how I have it except it’s dual core so 6- 10ga wires coming in. And they go through my brake switches and then into the dual rectifiers.

As for the wattage coming in, that’s been quite a disappointment to watch for the last few months and another reason why I’m not opposed to laying the turbine down. It’s a whole new rabbit hole to climb down. When I was planning for the turbine and designing my tower I spoke at great lengths to the salesman about wire runs and exactly what I was planning to do. I honestly do not know what happened and am still trying to understand currently. But as one can imagine 70’ tower and into the second story of my house eats up 100’ of wire and then I’m a little over 200’ from the house to get up on the hill so my turbine would be over the trees. I’m completely surrounded by trees and the house is on a hillside. I have fair solar with the few trees I cleared but that was the closest I could get the turbine. But long story short, my wire run is 350’ of 10-6 fine stranded copper wire. And I feel personally I have too much voltage drop. The turbine spins a fair bit the time, but it has to really get to singing to see anything above battery voltage. The highest I have ever seen was about 600 watts of output in a roughly 35-40 mph wind. Since October the turbine has produced 15kwh of power... while my solar is sitting at 269kwh, lots of snow here in Missouri this year.

Anyway, let’s just suffice to say the turbine is in the works and I would like to make provisions for it if possible at some point if nothing more than to make myself feel better about blowing $4000 and a fair bit of my time for a yard decoration. Supposedly the tech guy for Missouri wind and solar is working on creating a higher voltage output turbine to combat my voltage drop issues but I’m not going to hold my breath.

hopefully these pictures help you on the wiring, the black wires coming into the white breaker are wind, red wire coming into the black breaker is solar. The charger as I understand it literally just lets power come in and once the sense leads see the batteries are at my set point (28.8) currently they open the relay to the dump load.
 

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So is this more correct? (Notice I put in a conceptual model of the skymax)

1613757224531.png

Are there any fuses on the series strings of panels?

But long story short, my wire run is 350’ of 10-6 fine stranded copper wire. And I feel personally I have too much voltage drop.
I think you hit it on the head. At 2000W You are going to have ~50A per phase. At 350' that is going to be a huge voltage drop even for doubled up 10 gauge. Even 1/0 AWG would see a substantial voltage drop.
 
BTW: For 3 phase you can calculate the current with this formula

I = P/(1.732*V)
I just did a back-of-the-envelope calculation and you would need ~2/0 AWG on each leg to get the voltage drop down to 3%. For a 10% drop you could go as small as 4AWG. (This is a first approximation. You would want to validate this before you spent any money on new wires)

You either need a lot higher voltage coming out of the turbine or a lot larger wires (or some combination). Till that problem is solved, I don't think you will get much out of the wind turbine.
 
BTW: For 3 phase you can calculate the current with this formula

I = P/(1.732*V)
I just did a back-of-the-envelope calculation and you would need ~2/0 AWG on each leg to get the voltage drop down to 3%. For a 10% drop you could go as small as 4AWG. (This is a first approximation. You would want to validate this before you spent any money on new wires)

You either need a lot higher voltage coming out of the turbine or a lot larger wires (or some combination). Till that problem is solved, I don't think you will get much out of the wind turbine.
From what I can see on your diagram that looks pretty much exactly correct for everything I have currently. If you don’t mind I might save that just to have a breakdown if I ever need it?

I do not have any fuses on my series strings of panels, other than the 63A breaker that I have when they enter the charge controller. Do I need them?

As for the wind turbine, that makes perfect sense to me. You confirmed what my suspicions were, but I wasn’t able to do the math to confirm. I’m not opposed to running some more wire up there if that’s what it would take to actually get some power out of the thing. The mwands tech guy had me buy a boost module, supposedly it can take the lower voltage and get it up above battery voltage. It was $40 and so I have that coming to experiment with. But even if it can take the 15v I get all the time and bump it to 28.8 I’m sure there’s a trade off somewhere...

I was trying to find an answer to my thought before asking you but I’m only confusing myself lol. If I were to run a second 10-6 fine stranded copper wire up to the turbine, and then use 2 of the 10awg wires per output lead from the turbine would that effectively double my awg size? Do 2-10awg wires make a 5awg or is it not that simple?
 
I was trying to find an answer to my thought before asking you but I’m only confusing myself lol. If I were to run a second 10-6 fine stranded copper wire up to the turbine, and then use 2 of the 10awg wires per output lead from the turbine would that effectively double my awg size? Do 2-10awg wires make a 5awg or is it not that simple?
I found a 3phase voltage drop calculator here: http://www.nooutage.com/vdrop.htm

When I plug in 4 parallel 10AWG lines per phase I get a 36% voltage drop.

1613764187154.png
If I plug in 1 2/0 line per phase I get a 13% drop
1613764461161.png

The mwands tech guy had me buy a boost module, supposedly it can take the lower voltage and get it up above battery voltage.
Is this something that goes up at the turbine? Do you have a link to the product?
 
I do not have any fuses on my series strings of panels, other than the 63A breaker that I have when they enter the charge controller. Do I need them?
The short answer is Yes. If you have more than two strings in parallel, there should be fuses on each string. You may want to review this:


Also, it is a bit unusual to have miss-matched panels like that. I now understand why they wanted to sell you two solar controllers. I just don't know why they wanted to sell you such high end controllers. (If you had two controllers, you would not have 3 strings in parallel and therefor would not need fuses)
 
Hmm, 350’ of 2/0 x 6 ugh. That’s a real bummer.

https://www.amazon.com/Voltage-Converter-DROK-Regulator-Transformer/dp/B076TTBKFG here’s a link to the boost module. And the way he explained it to me I would put it in directly after my rectifiers.

As for the fuses that’s definitely something I need to look at. I will read that link you sent me now.

The miss matched panels are because I was buying things as I could afford them, unfortunately building a new house and paying for a small farm and all the related equipment had my budget stretched to the limit. I bought the original 250 watt panels and survived on them for a year, of course when I was able to go get more they had sold all their stock and only the 260 watt panels or a 305 watt were available. So I tried to get what would most closely match what I already had.

as for the 2 charge controllers, the way I understood it, one would be for the solar side, a midnight 150. And then another midnight 150 with the clipper for the wind turbine. I guess the midnights can only have one type of input each. This is the clipper https://mwands.com/midnite-clipper-mnclip4kac16
 
Hmmmm..... It will be interesting to see how much that helps. It seems to me that by the time it gets to the rectifier, the losses have already occurred.
I agree with you, to be honest should I even wire it up or just send it back? Probably $40 wasted.
 
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