So earlier this year I replaced my old 6v 2P2S battery bank in my RV with 2 - 100 amp SOK 12v batteries. I now realise I would like more storage so I need to decide whether to spend about $1200+ on two more 100 Ahr 12v batteries or build two 280 AHr 12v DIY batteries for about the same or a bit more investment. With the latter option I would either resell the SOKs or use them in a different application. I realize that components for building 2 - 280AHr 12v batteries may cost more but I am thinking the added amp will off set the cost. Your thoughts?
Add more SOK or switch to DIY build?
- Thread starter 1holaguy
- Start date
I guess its sorta a personal preference. Most of the vocal people here skew towards the DIY option, but I think both are very valid approaches. And many of the people encouraging DIY don't price everything in (price as in $$ and price as in non-monetary tradeoffs). The tools/equipment/odds and ends/enclosures/fasteners needed to properly take the DIY route are usually not factored in, for a big build its not a huge cost relative to the cells, for a small build its definitely something to account for. Its also worth considering, what is the warranty worth to you? what is your risk tolerance? On average buying raw cells tends to carry more risk, and limit your recourse if there are issues. It also gives you more places to potentially screw up, which could be costly, has a higher learning curve which has a 'cost' in time and maybe stress.
On the other hand, the DIY route can potentially have considerable cost savings--particularly for larger builds. It can be fun and interesting if you are DIY inclinced, and like building or designing things. And it can give you greater flexibility and control to build what you want, how you want it (so long as its within your capabilities). And eventually lead to greater experience and awareness and understanding of your system, but also greater responsibility over it.
On the other hand, the DIY route can potentially have considerable cost savings--particularly for larger builds. It can be fun and interesting if you are DIY inclinced, and like building or designing things. And it can give you greater flexibility and control to build what you want, how you want it (so long as its within your capabilities). And eventually lead to greater experience and awareness and understanding of your system, but also greater responsibility over it.
I have been giving this more thought since writing and am now also considering server style batteries like the EG4. That would require a DC-DC converter to step down from 24 or 48v to 12v, in my application, but cost wise this may be the way to go. You note the extra costs and that is true. In retrofitting from 6v to 12 v I ended up replacing the cables at a cost of almost $200.
Depending on your scenario, a lot of things can be powered direct from 24V (in fact many--but certainly not most--"12V" devices are 12-24V if you look at the specs). Its possible that you could run some or most of your DC loads direct rom 24V battery, and use a smaller 12V converter for the rest. Of course whether its possible and whether its practical or worthwhile for your situation are different questions.
Victron makes some good DC-DC converters, up to about 70A I believe. There are many other cheaper options as well.
Well, it seems that since my I/C is 3k watts I would need a 300 amp DC to DC converter for that and the cost sort of makes that direction not practical. CG4 is made in 400 amp 12v. In fact they advised the 12v, 24v and 48v units are all made with 100 amp cells (16S, 8s2P and 4S4P configurations) Because of the configuration of the 12v 400 amp version I believe I can place it in series with my existing 2 - 100 amp cells for a total of 600 amps at 12v. Now I just need to make sure it fits in the space planned.
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