House battery bank

daddysgirl · April 09, 2019, 08:07:31 AM

I want to build a smaller version of this:
https://www.thepowerstore.com/24v-2070ah-c100-energycell-re-high-capacity-vrla-battery-bank.html

With this battery (or one like it):
https://www.thepowerstore.com/simpliphi-phi-3-2-kwh-high-power-lfp-battery-24v.html

Thoughts? Pitfalls? Alternatives?

Fred Mc · April 09, 2019, 08:34:41 AM

http://www.beginningfromthismorning.com/
Follow this guy.He's already done it with batteries from a Nissan Leaf.

buswarrior · April 09, 2019, 08:48:40 AM

I love the ingenuity of developing new ways of using these new technologies.

BUT...

The SAFETY message doesn't often get included in DIY pursuits.

How can these technologies harm you, or your neighbours?

Unfortunately, that knowledge is often buried in scholarly sources, not out in the common media.

Everyone needs to gauge for themselves what risks any particular technology poses, and whether they want to take those risks.

Don't just follow someone else!

One wonders if Madame Curie had known what she was really messing with, would she have continued, miscarriage, cancer, et al?

Expand the experience, go where none other has dared to go, but DO IT WITH KNOWLEDGE OF THE DANGERS!!!

A safe busnut continues to be:

Happy coaching!
Buswarrior

Dave5Cs · April 09, 2019, 10:14:02 AM

Lots of knowledge here also for years with them.

https://www.technomadia.com/lithium/

bevans6 · April 09, 2019, 02:55:56 PM

There are a ton of unique and different battery choices these days. Those are VRLA - valve regulated lead acid - AGM lead acid batteries, a well known and mature technology developed in the 1960's for military aircraft use, but nothing particularly new. You can build your own house bank of commercially available deep cycle AGM batteries in a variety of sizes. Sean, a highly technical old-timer around here that now plays with quite large boat, built a very large house bank out of 8D sized AGM batteries with tremendous success. The point being that you don't need to buy a high end UPS or building battery system designed for large solar systems for your bus - the technology and effectiveness can be equalled with more accessible batteries and inverters. You don't say how large you want to go, I'd venture a guess that a 1,000 AH 24 volt system could be built for around $6,000. Figure $6.40 per 24 volt AH for high quality AGM batteries.

Lithium or similar, including taking Chevy Volt batteries apart, are places I don't go yet. AGM's I've used and abused for many years...

You no doubt know this well, but you design based on known load, time, and recharge capability. Figure what you need to do, for how long, and how long it takes to get back to ground zero, and you can design a system. VRLA AGM lead acid is a very good battery choice if you can afford it or need it's particularly attractive qualities - an 80% depth of discharge, and a very fast recharge rate with the correct voltage regulated charger.

Jim Blackwood · April 09, 2019, 05:35:38 PM

Also do not fail to consider the inherent fire/explosion risks of lithium batteries. Inadequate safety measures can mean that one simple puncture can result in a conflagration of astounding proportions. Life threatening doesn't begin to do it justice. Obviously the risk can be minimized if you know what you are doing but it's not to be taken lightly.

Jim

buswarrior · April 09, 2019, 05:54:13 PM

Quote from: Jim Blackwood on April 09, 2019, 05:35:38 PM
... a conflagration of astounding proportions...

I bet that the smoke tastes really yummy too? Once...

Happy coaching!
Buswarrior

MagnoliaBus · April 09, 2019, 06:53:00 PM

Lithium batteries need thermal management. You need to cool them in hot wheather and warm them if cold (they cannot be charge when it's freezing temperature).
Even a coach converter like Millennium luxury coach won't go for lithium right now, maybe in 2 to 5 years...(look on You Tube).
For now, AGM is the way to go.

windtrader · April 09, 2019, 07:08:05 PM

Agree on need for thermal mgt but virtually every electric car manages this on lithium packs.

RichardEntrekin · April 10, 2019, 05:33:05 AM

Howdy,

I have had LiFePo batteries in my coach for five years. First, educate yourself about Lithium before you even begin. Lithium is not lithium, there are many different technologies out there. Some are more inherently dangerous than others.

LiFePo can be quite friendly in an RV environment. It does require knowledge of how to charge them without killing them, some sort of battery management system to provide a safeguard against over or undercharging, and a completer understanding that they do not behave like lead acid batteries.

Suggest you take a look at the Battleborn site as a starting place. I have no stock or connection with them, just they have an excellent starting place for learning about what you are getting into. Also, keep in mind that sailors and cruisers have been using Lithium based systems for some time now.

There is also a strong connection between the complexity of the system and what you want to do. If you just want to have a lighter, longer lasting version of the standard 12/24V house system, then the install isn't too tricky. If you want to go all in and run a roof top AC or two, then get ready for complication and big $$$$

chessie4905 · April 10, 2019, 07:20:22 AM

Hopefully, anyone that goes down this road, will make accurate records of expenditures to implement this type of system. Then others can compare the cost vs. Gen run time vs actual use or need of systems.

daddysgirl · April 10, 2019, 01:26:55 PM

I'll need to consider all of your points before I actually start building a system. I am lucky to have my PD 4590, and I'll want 1000-1200 AH in a system without spending $3,000 on one battery. I like to build my own when possible and the electrical system is the system I'm most familiar with, but if i get new appliances, I'll need to recalculate everything anyway.
I noticed the LFP batteries getting more attention lately and I can use them safely...but I wanted the various points of view. Thanks so much.

Jim Blackwood · April 10, 2019, 09:46:49 PM

Here's another thought. With these batteries we are beginning to get large enough that making your own begins to look like it might be feasible. It's basic technology, a couple of lead plates, a separator, and some acid in a plastic box. By now some of our folks are proficient enough in making plastic boxes (holding tanks) to give it a go. Modern battery plates are stamped with a waffle pattern that increases surface area while lightening the plate but battery capacity is entirely dependent on plate surface area while life is dependent on plate thickness so that's a trade-off. I suspect you could buy a quantity of 1/16" thick lead plate and some glass mat for separators. Optima did it by the simple expedient of rolling it all up in a cylinder but plenty of other approaches are possible, and then you have to stick the plates in a puddle of lead to terminate the cell. Drop it in your case and add acid. Wouldn't surprise me any if the original optima prototypes were dropped into sections of PVC pipe, but overall a plate stack is probably easier to manage and the trimming scrap can be melted down to make the bus bars and terminals. You could make it as large as you want, the issue probably being handling the weight. You could certainly make it longer lasting. And you could add to it rather easily once you made the first one or two.

Jim

richard5933 · April 11, 2019, 03:21:30 AM

Jim - That may be taking the DIY concept just a little bit further than most.In the early years of automobile development though, I'm sure that many did just as you describe using glass jars.
I've read through this, and if the end result is 1K to 1.2K of Ah capacity, the biggest bang for the buck is going to be flooded cell 6v batteries. six Trojan L16H-AC batteries will easily get you over 13K of Ah capacity and probably cost less than half that capacity with other types of batteries. Of course the trade-off would be maintenance and venting requirements.
Black box in the photo is our battery box with four of the L16 batteries. Could easily have added two more to the enclosure with just a little more material. I used PVC board for the material - it's lightweight and easy to work with. Seams are held together with 1" aluminum angle.

daddysgirl · April 11, 2019, 08:58:32 AM

While I am one of those people who will build just about anything, I spent enough time (and sacrificed a few pair of jeans) filling batterys with acid to know building them is something I'll forego in favor of buying them. I do however really appreciate the out of-the-box thinking. The ideas and thoughtful evaluation you all provide helps me more than I can express, and I have no doubt when finished, my system will be engineered just as well as a Mastervolt system.
Thus far, I'm leaning towards those Trojan 6 volt batteries that Richard mentioned, but I'm keeping LFP drop ins in the idea folder. I am also thinking of where I will put them, especially given that I haven't finalized a location of the power center, and just about everything is connected to that.

So, under the bus in a bay, or inside the bus? If I go with the L16H-AC batteries they'll need to go in a bay. The LFP can go in the bus, but is that convenience worth it?