24 to 48 volt upgrade

I've had four Rolls S530 6 volt batteries in series for about 2.5 years,
and am planning to upgrade to a 48 volt system. Some seem to think I
can add four new S530s to the string without impacting their health or
lifespan, while others think it's a mistake, meaning I'd need to
purchase (gulp) eight new batteries. Thoughts? Thanks.
Comments
Your new batteries will degrade to match the old set within 4-6 months. If the old set is barely degraded then not so bad but if the old batteries have been heavily used then you're paying for new batteries that will only last as long as your old batteries.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
For what it's worth, I'm doing this very same thing... May it be a long wait and perhaps a good learning experience shifting loads as best we can to run off the array.
- Number and depth of cycles on existing. A deeply discharged daily year-round bank may be well into middle age. A lightly cycled bank in a weekend cabin may still be fine.
- It follows that you're going to 48v because loads have grown. If you have tons of pv and run only when sunny but would like capacity to run without sun, and/or use a generator to run and want to use less, that's different than if the bank has been used heavily for the growing loads.
Before making a decision, I would check SGs on all cells, EQ fully to get all cells up to spec as needed, then do a carefully measured load test.
If the EQing finds weak cells, or the load test finds much capacity reduction, I would bite the bullet and buy 8 new. At least then I could have the 4 old ones in reserve (and charged regularly). I would use that along with the gear made redundant by the voltage upgrade for backup to new 48v system if an inverter etc failed. When the 48v bank starts to fail, odds are some batteries will go before others, at which point you may be able to use some of the stronger "old" batteries to keep the bank going for a while.
If I did add 4 to the existing bank, I would swap out the old for the new and keep running 24v for at least 60 cycles or so on the new to get the new bank broken in, and do SG check and EQ on old and new battery strings individually before putting them into use as a single string. I would also want to be sure I had lots of charging capacity for the combined string as mixed life batteries + undercharging will likely end badly.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
I am available for custom hardware/firmware development
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
When I looked at the B-17 video, I was really impressed by the technology that was apparently behind it all. By aiming the front-facing stuff at nerdy and WWII buffs, I think they missed the point. Maybe it's just me.....
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Sometimes marketing gimmicks work out, like the computer company named after a fruit that made some real dud products and nearly went under, then made an mp3 player and later phones which featured design as the main differentiator.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
I am available for custom hardware/firmware development
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada
I find this very interesting. To the point that Apple made great 'ready to use' product in computers and 'nerds' hated them! Where they found a market is in graphics, because they did the job so much better end to end. And in education again simply worked.
They were always a creative company, did lots of interesting design work, but the Mp3 player was truly a 'Creative' design! How creative? It wasn't really their design, but a design by a company by the name Creative. What they did so well was promote and sell the 'cool factor'.
https://www.cnet.com/news/apple-settles-with-creative-for-100-million-1/
I think the brothers Gudgel want to be on the cutting edge, and do some one time cast case design. Similar to what Apple did, but they, also were on the cutting edge of the electronics design.
He finally admitted defeat and Microslopped it as those neat graphics machines can not handle heavy data crunching... I'm still not an Android fan yet, may be a long time too...
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada
Oddly enough my brother was one of those who never thought much of Apples/Mac's, He worked for IBM while getting his EE and went on to get a Masters in AI from Michigan, His family is down to 1 Windoz machine (out of many) and after years or being a software engineer, he writes I-Phone Apps!
http://www.zcage.com/
I use to be a Photoshop professional, He shared a seminar he went to where part of the presentation was a demonstration of electronic architecture, back when the apples 'pipe' was quite a bit higher than Windoz. They come in and talk about comparing speed in processing an image, they have a top end Mac and Windoz and start a process on the Windows machine, and the start the mac up and load the image and start the same process on the 'slower' Mac machine and of course it finishes just ahead of the windows machine. Of course Photoshop was written for Mac's originally, so there might be an advantage in the translation, this was a while back, I think in the days of PS 5.5.
PS 5.5 yup still got the CD..
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada