greghayter Posted February 24, 2022 Share Posted February 24, 2022 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 Quote Link to comment Share on other sites More sharing options...
Nexuss Posted February 25, 2022 Share Posted February 25, 2022 (edited) Edit* You need a busbar and connect the batteries to that and then from inverters to busbars. Edited February 25, 2022 by Nexuss Quote Link to comment Share on other sites More sharing options...
hoohloc Posted February 25, 2022 Share Posted February 25, 2022 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 Quote Link to comment Share on other sites More sharing options...
Piper Posted February 25, 2022 Share Posted February 25, 2022 (edited) 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, 2022 by Piper Gareth_ZA 1 Quote Link to comment Share on other sites More sharing options...
Tariq Posted February 25, 2022 Share Posted February 25, 2022 @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. hoohloc and Nexuss 2 Quote Link to comment Share on other sites More sharing options...
hoohloc Posted February 25, 2022 Share Posted February 25, 2022 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 Quote Link to comment Share on other sites More sharing options...
hoohloc Posted February 25, 2022 Share Posted February 25, 2022 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 Nexuss 1 Quote Link to comment Share on other sites More sharing options...
Nexuss Posted February 25, 2022 Share Posted February 25, 2022 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. Piper and hoohloc 2 Quote Link to comment Share on other sites More sharing options...
Piper Posted February 25, 2022 Share Posted February 25, 2022 (edited) 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, 2022 by Piper hoohloc 1 Quote Link to comment Share on other sites More sharing options...
Piper Posted February 25, 2022 Share Posted February 25, 2022 (edited) 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, 2022 by Piper Quote Link to comment Share on other sites More sharing options...
hoohloc Posted February 25, 2022 Share Posted February 25, 2022 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? Quote Link to comment Share on other sites More sharing options...
Piper Posted February 25, 2022 Share Posted February 25, 2022 (edited) 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, 2022 by Piper Quote Link to comment Share on other sites More sharing options...
hoohloc Posted February 25, 2022 Share Posted February 25, 2022 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. Quote Link to comment Share on other sites More sharing options...
Piper Posted February 25, 2022 Share Posted February 25, 2022 (edited) 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, 2022 by Piper hoohloc 1 Quote Link to comment Share on other sites More sharing options...
FixAMess Posted February 25, 2022 Share Posted February 25, 2022 And the cable size from the fuse to the inverter? Surely you would require a 200A compliant cable to be fitted there? Quote Link to comment Share on other sites More sharing options...
Piper Posted February 25, 2022 Share Posted February 25, 2022 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. Quote Link to comment Share on other sites More sharing options...
Gareth_ZA Posted February 28, 2022 Share Posted February 28, 2022 I am also looking to add 2x more US3000C batteries to my system. Will let you know what my electrician ends up doing. Quote Link to comment Share on other sites More sharing options...
greghayter Posted February 28, 2022 Author Share Posted February 28, 2022 (edited) 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, 2022 by greghayter Quote Link to comment Share on other sites More sharing options...
Piper Posted February 28, 2022 Share Posted February 28, 2022 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. Quote Link to comment Share on other sites More sharing options...
Speedster Posted March 1, 2022 Share Posted March 1, 2022 I have two very lightly used US2000 B plusses going for a steal of you're interested (and close to Pretoria). Quote Link to comment Share on other sites More sharing options...
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