RiccoS

I hope someone can shed some light on what I'm going to try and explain. I know the MPPT is a very clever piece of kit that gets the maximum from your solar array but there is this bit that I do not understand or maybe I do but did not know temps can play such a big role. So on a normal busy day in my house like on a Saturday with washing and cleaning, essentials and non-essentials running, basically using everything the sun can throw at me on a bright sunny day I get in the region of 4500W from my two strings of 8x 370W JA Solar panels, this is now in winter time. They are not pointing in the perfect direction but that is irrelevant in my question. Why would if I only get the above 4500W max on a sunny day if on a cloudy day when the sun peaks out from behind a cloud for a short while it would shoot up to around 5500W. Is this because the panels run cooler, if this is the case surely the temp difference cannot be that great. Or is it the MPPT that takes a while to recalculate what is happening? On a sunny day each string is running around 260V and 8-9A current, on a cloudy day scenario they are running around 270V and current 9-11A

Step 0: Gas, good move, solar geyser uuuhmm, ask yourself do you use most of your hot water during the day. See Step 1 Step 1: Good choices, there is however more to it than just battery disconnect, think splitting your DB into 2, essential and non-essential side. Extra earth leakage, breakers, cable, etc. Cable is getting ridiculously expensive these days. See Step 0 on the geyser comment, Sunsynk inverter is bi-directional and if you have enough panels it can supply the non-essential side of your DB with excess solar aka geyser, unless you use a lot of hot water during the daytime. If not I would use the solar geyser money towards more panels. Step 2: Again good choice just keep in mind your first battery would have cycled a few times by now. Step 3: You will need more panels for this inverter, 4 will barely get you into the voltage range of the MPPT. On the solar geyser, my parents have one and every time we go and visit they need to manually override the element or change the settings. You see my kids bath/shower after the sun set and we usually take a shower around 5 in the morning so from the time the kids had a bath until we took a shower in the morning you do not have sun and therefor you are using the element and Eskom to warm the water. Then during the day when nobody is using hot water I've seen it going up to as high as 77 degrees, surely that amount of heat and pressure cannot be good for a geyser. I'm also running a Sunsynk 5kW inverter and 2x 4.8kWh batteries, the past weekend we had a 41 hour outage my 2 batteries was good for 18 hours and the dishwasher also ran at some point because I set it to start after load shedding during the night and then the power never came back on. I'm in the process of installing 16x 370W JA Solar panels and will be able to start giving you real life stats in the next two weeks or so. First string to be switched on hopefully today.

50% DOD is not really advisable, even though they say you can do it at 16A draw you are really hurting them and may have caused damage already. I was running 4x 200Ah Leoch batteries for a few years until upgrading and on the Leoch batteries spec sheet the difference on cycles vs DOD is huge. At a 0.25C at 25 degrees 30% DOD will give you 1500-1700 cycles, that same draw and same battery will at 50% DOD only be able to cycle 600-700 times. I'm sure when you draw camping fridge type of current from that battery it will be fine on a 50% DOD but at 16A when you are hitting that 50% mark you are really hurting those batteries and may have already caused unreversible damage. Maybe run them on a recovery charge cycle with a decent charger and see if you can put some life back in them.

Inverter sold

I would set Shutdown to 20%, leave Restart at 40% and put Low warning at 30% maybe even 35%. Restart is if the battery shut off because of the Shutdown percentage then it will only restart once it hit the Restart percentage, you obviously want to stay away from shutdown percentage but if it happens. This is the way I understand it, I might be wrong.

On my previous Axpert type setup I ran 4x 200Ah batteries and setup was straight forward, charge at 20A and draw what the inverter can give 🙂 I've installed a Sunsynk 5.5kW inverter and running to lithium batteries in parallel, my question is; max charge and discharge current. The batteries are rated at 0.5C and being a 100Ah batteries that is 50A charge and discharge but because I'm sharing the load across two batteries I can actually draw and charge at 100A because I've doubled my capacity. I obviously don't want to charge at 100A but what I want to know is if I set the charge current to 40A does that mean I'm charging each battery at 20A or due to the BMS do the inverter know that I'm running 2 batteries and if the setting is 40A it will charge each at 40A. Now that I type it I think I answered myself 🙂 If I measured the current on one of the leads with a clamp on multimeter I'm sure I will see 40A so if that goes into the bank then it will be divided by the number of batteries (2) and that will be 20A. This brings me to my next question, even though the batteries can take a charge of 50A each being 0.5C what is a good current to charge a lithium battery at? You obviously don't want to hammer it at 0.5C the whole time but charging it at to low current can also not be good? Help will be appreciated.

As far as I know they are 95% DOD batteries so 20% should be fine.

Add updated, batteries sold.

Item: The Sun Pays 5kVA Axpert Type Inverter Age: 2 years and a few months Price: SOLD Payment Method Accepted: FNB Geo Payment, Cash or EFT from FNB Warranty: No Packaging: No Condition: Inverter great only had batteries connected never PV Location: Krugersdorp/Rangeview Ext 4 Reason: Upgraded Shipping: No Collection: Yes

Datasheet on Solar Advice website, but this is good to know.

According to the datasheet not the UP5000’s only the US2000/3000C Pylontech’s

I will definitely be going for 2 or more batteries, my main concern is what batteries is most compatible with Sunsynk for the money I have available. The Shoto’s is a good price for 90% DOD vs 80% on the UP5000.

Both are 0.5C discharge but the actual amperage is different because the capacity is different.

Hi guys I'm in need of around 7kWh + battery that will be hooked up to a SunSynk 5.5kW. I'm currently looking at 2x 3.5kWh PylonTech US3000C batteries for around R38k but see I can get 2x Shoto 5.12kWh batteries for around R46k or PylonTech UP5000's for about the same price as the Shoto's. So for about R8k more I can get quite a bit of extra capacity. My question really is what is the biggest capacity I can get for around R45k and successful communication to a Sunsynk invertert without issues, it must just work, good reliable batteries?

I'm back 🙂 So something happened and partly my own doing, Krugersdorp for 2 years in Covid did not have load shedding and I never cycled my 200Ah batteries and nor did I put an equalizer on. I used to get really really good hours out of my batteries but about a week ago 1.5 hours into the scheduled 2.5 hours everything goes off, turns out I must have destroyed a battery with it just sitting on float for 2 years. It was actually 2 batteries but one I could save with running a recon cycle on a proper charger on all my batteries. Fast forward a few days and found out my old Axpert type inverter cannot talk to a lithium so lithium not being an option I decided to start researching for a complete new setup, and not wanting to pay school fees again in 2 years I've decided on the bigger names out there and also full on hybrid, Sunsynk, Deye, Fusion etc. Me being the DIY type I'm again planning on doing it myself and seeing that I already have a setup most is done in any case and I got a COC for it, but I have some questions. With the above inverters and using the CT it seem like I need to worry about things like earth to neutral bonding etc when utility goes off and I'm feeding back into the DB, not feeding back into utility just DB. Is this correct, if so does this mean I cannot feed back into the DB while I do not have utility if I do not add some sort of relay to do this? To be honest I know nothing about earth to neutral bonding, I just know generators and inverters do it inside. I also did not have solar on the Axpert and planning on adding as part of the new installation to make it well worth the cost of the inverter and not just use it as a UPS setup. Adding panels I obviously need to stay under the 11A + 11A current draw limit, within the voltage range of 125-425V and the 6500W limit. Solar advice recommend 455W Canadian Solar panels but in perfect conditions (STC) they are capable of 11.02A which is already higher than recommended. I know perfect condition is out of the question as this is lab figures but I also heard they are under rated because of the 80% claim over x number of years due to the warranty. What size panels do I go for and how many, I can fit around 10 on my garage roof but that is not perfectly North so I was thinking of putting 8 on the garage on one MPPT and another 6 on the lounge facing very West on the other MPPT. BTW the garage still get sun around 16:00 in winter just not at the optimal angle. Except for the solar, battery, inverter and all the normal compliance and fitment stuff what else do I need to really make it worth it, like monitoring software etc? Comments and help would be appreciated.