February 24, 20224 yr Hi guys I have an existing 5 kVA inverter with 3x US3000C Pylontechs. It's an Axpert type inverter and although it has performed without problems for 2 years, I would like to replace it with 2 Sunsynk 5kVAs and add 3 more batteries. My question is, the manuals say that only 3 batteries can be connected using the standard cable (25mm^2), so how do you connect 6 batteries? My 3 are currently connected as per standard in parallel with the positive coming off the master and the negative off the 3rd battery, with the standard interlink cables between the 3. Thanks Greg
February 25, 20224 yr Edit* You need a busbar and connect the batteries to that and then from inverters to busbars. Edited February 25, 20224 yr by Nexuss
February 25, 20224 yr 9 hours ago, greghayter said: Hi guys I have an existing 5 kVA inverter with 3x US3000C Pylontechs. It's an Axpert type inverter and although it has performed without problems for 2 years, I would like to replace it with 2 Sunsynk 5kVAs and add 3 more batteries. My question is, the manuals say that only 3 batteries can be connected using the standard cable (25mm^2), so how do you connect 6 batteries? My 3 are currently connected as per standard in parallel with the positive coming off the master and the negative off the 3rd battery, with the standard interlink cables between the 3. Thanks Greg For US3000C, you can have as much as 16 x Batteries in one bank. The standard battery cable for pylontec is capable of carrying 120A, doubling the cable will increase that to 240A. BTW, This information is there in the manual😀
February 25, 20224 yr Hi greghayter You can have 16 us3000c in a parallel config. Current draw limit to 100A per cable. So a good config for you would be 2 packs of 3 batteries each on 2 pairs of cable. Edited February 25, 20224 yr by Piper
February 25, 20224 yr @greghayter, assume you will be paralleling the two inverters, if so, I believe you have to run them off one bus bar, don't know too much about paralleling, but please confirm.
February 25, 20224 yr 3 hours ago, Piper said: Hi greghayter You can have 16 us3000c in a parallel config. Current draw limit to 100A per cable. So a good config for you would be 2 packs of 3 batteries each on 2 pairs of cable. Please share,... where do you get the 100A per cable from? the documentation say 120A
February 25, 20224 yr Just now, hoohloc said: Please share,... where do you get the 100A per cable from? the documentation say 120A It further say you can get up to 240A if you double up
February 25, 20224 yr Nice , i was just thinking another option to avoid a expensive busbar solution would be to make two packs of 3 batteries wire them to the inverters and then just parallel the 2 packs of 3 with the leftover ports on the batteries(with say 2 one meter cables),so then all 6 batteries will function as one pack as required and each inverter can do 100/120 amps easily.
February 25, 20224 yr 1 hour ago, hoohloc said: Please share,... where do you get the 100A per cable from? the documentation say 120A Have a look see . Maybe they updated the cable specs as this is what my manual shows.They changed the constant to a 100A. This must be what I was thinking about.But yes the cables are good for 120A under normal ops. My Bad.. Edited February 25, 20224 yr by Piper
February 25, 20224 yr Regarding the Parallel topic. I just made 2 short cables and connected them to the bottom of the fuse holders.(Needed 2 fuse holders because the one I Had was only rated to 160A) If you have one of those 250A fuse holders you should be able to connect both cables to it no problem. Edited February 25, 20224 yr by Piper
February 25, 20224 yr 24 minutes ago, Piper said: Regarding the Parallel topic. I just made 2 short cables and connected them to the bottom of the fuse holders. Can you post a photo? How thick is the short cables?
February 25, 20224 yr 10 minutes ago, hoohloc said: Can you post a photo? How thick is the short cables? I used Pylontech battery Cable. Cant really see much. Edited February 25, 20224 yr by Piper
February 25, 20224 yr 10 minutes ago, Piper said: I used Pylontech battery Cable. Cant really see much. ok, I thought you had bridged the two fuse holders at the bottom.
February 25, 20224 yr 14 minutes ago, hoohloc said: ok, I thought you had bridged the two fuse holders at the bottom. I did Look closely and you will see there is 2 cables in each port If you look closely at the Orange cable you will see that I used white heat shrink on the link cable. On the black link I used black heat shrink so cant really see it. Edited February 25, 20224 yr by Piper
February 25, 20224 yr And the cable size from the fuse to the inverter? Surely you would require a 200A compliant cable to be fitted there?
February 25, 20224 yr 35 minutes ago, FixAMess said: And the cable size from the fuse to the inverter? Surely you would require a 200A compliant cable to be fitted there? Used 2 pairs.One for each inverter. And 100 amp fuses.
February 28, 20224 yr I am also looking to add 2x more US3000C batteries to my system. Will let you know what my electrician ends up doing.
February 28, 20224 yr Author Hi Everyone Thanks for all the responses. So some follow up questions and some comments. As per the image posted by Piper, the interconnect cables are 180mm in length - I have a 4 battery cabinet and plan to get another identical cabinet to put on top or alongside to house the additional batteries, with the aim of getting to 8 batteries eventually. Any suggestions on where to get a cable long enough to parallel all the batteries - the jump between cabinets will be longer than the standard cable? The full story behind my change in inverter is that we installed it 2 years ago as a load shedding solution in our house under a stairwell, and then decided to build a cottage for my parents who have just moved in. So they are on grid power at the moment - I have installed a main DB in the new garage which then feeds the house and cottage so I plan to install the bank of inverters and batteries in the garage to feed both house and cottage. So after that long winded explanation, the issue is I want to parallel the new inverters and my understanding is that running them off a common bus on the DC side is the best solution so the charging duty is split between between inverters, and on the AC side the idea is to also feed a common AC DB which will feed the main DB. I just think that it is a much more flexible approach. I want to install 2 inverters initially, but with 2 households there is the possibility of needing a third. Are there any thoughts on the pros/cons of running 2x 8 kVAs vs 3x 5 kVAs? The one limit is that Sunsynk only allow 3 single phase in parallel, so using the 8 kVA allows for expansion to 24 kVA at a later point, whereas 3x 5s is already maxed out. However 3x 5s are a lot more cost effective than 2x 8s. As a note, my geysers and oven are still on Eskom, but the plan going forward is to either: a) connect them to the inverter system, probably necessitating at least 15 kVA capacity b) go to either vacuum tube or c) go the DC element route with its own panels Any comments on these options? Thanks again for all the feedback Edited February 28, 20224 yr by greghayter
February 28, 20224 yr You will always end up with a spare set of those 180 mm link cables.Nothing prevents you from chopping them in half and extending them with the same type cable.Proper ferrules and a hydraulic crimper would be required though , OR buy an additional set of cables. The other thing is that KVA is is apparent power. So 8kva at a power factor of 1.0 is 8000 watt but at a power factor of 0.8 it will only be 6400 watt. My 10kva system is only good for 8000 watt. Keep this in mind when you shop for inverters.
March 1, 20224 yr I have two very lightly used US2000 B plusses going for a steal of you're interested (and close to Pretoria).
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