Battery pack lithium

[mojoman]

Just ordered my battery pack, 900AH 12v
250lbs with fuse,Contactor,cable, BMS, bus bars etc... $5100
http://www.electriccarpartscompany.com Good folks there.

[markopolo]

$5.70 per ah for a complete lifepo4 system is really good compared to other pricing I've seen.

More details please. I don't see that kind of pricing on the site

[mojoman]

There is a section for RV marine, the prices are listed, some of them include a large battery charger which I didn't need so it was deducted. They will put together any size kit for you. I picked out the cells that would fit in the area I want. Give them a call, they can provide most anything you want at a reasonable price. I'm picking up my cells in their warehouse in Pomona,ca to save on shipping. They are located in Utah

[Boxster1971]

How are planning to avoid the freezing temp limitation on charging lithium batteries?


- - Mike
2013 AS Interstate on 2012 MB Sprinter 3500 Long & Tall

[mojoman]

The battery pack is going to be installed inside the van, Were I live in ca, it seldom freezes in my area, a small 12v heated blanket could be used for those who live in cold areas. The battery warms itself during use so if you could put a load on it for a while before charging. Maybe I'll install a 12v seat heater under the pack, but I doubt if I'll ever need it.

[Boxster1971]

Good ideas on using 12v heater pads if needed. Thanks.


- - Mike
2013 AS Interstate on 2012 MB Sprinter 3500 Long & Tall

[booster]

Is a low temperature cutoff included in the battery management system that comes with them, or are you on your own for that.

[mojoman]

I have an audio alarm, my wife, she gets cold, complains till temperature comes up.

[markopolo]

Are you combining the 900 ah lifepo4 battery battery with a traditional RV generator? ( link: http://www.classbforum.com/phpBB2/vi...art=165#p25005 )

Can you share or elaborate a bit more about your design ideas re: the batteries & charging etc?

[mojoman]

All the equipment I ordered is lithium programmable, MPPT solar controller, 400watts of solar, 2800 magnum2800 pure sine inverter/charger,Sterling120 amp battery to battery charger,220amp van alternator and the onan 2800 generator. I'll be able to feed the Magnum with the generator or shore power to charge the lithium batteries correctly at 120 amps. I probably won't use all the available capacity of the batteries but they will last a few years longer not cycling them at their full potential capacity.

[markopolo]

Nice well known name brand components.

Gas or diesel van?

I kind of like the idea of running it all off the genset or all off the batteries option. Doing both has been kind of pricy but as you've shown the price is dropping.

We parked right in the middle of a bunch of tent sites at one campground last year and I knew I would not run the van engine or a generator in that situation. A large battery bank like yours would be great for an extended stay there.

[booster]

When you are on generator or shore power, are you doing the 110v from them to the Magnum charger, output of the inverter section of the charger to run the van 110v? The rest of the power to go to the charge the batteries until they are full as 12v or to 12v uses in the van.

I have to assume that the Magnum does not need a battery in the circuit to operate correctly, as the lithium BMS will have the batteries out of the circuit sometimes. Some chargers have trouble when they don't have the battery for voltage stability.

[mojoman]

I will be quite knowledgable in the programming and operation of all the equipment, after I figure it out I will have to assemble and wire the battery pack. I'm ordering a 3v lithium charger to top balance the cells. I learned "top balancing" maximizes the capacity. "Bottom balancing" consists of connecting all the batteries together for a couple of days so they all are at the same charge level. Top balancing insures every cell is at its maximum capacity before assembled so you have a true "full" in the BMS/controller when programing. It will take days to do this and its something I think some battery providers may not have the time to do so they "bottom balance". there are BMS systems that will do this but they are too expensive and complicated for a small bank like this.

[stanw909]

What are you putting them in?

[mojoman]

2500 long tall promoter

[rtz]

Top balancing is risky and not worth it as there is not that much to gain at the very top. The charge curve at some point goes vertical and fast. Not worth it up there.

Bottom balancing is superior and safer. Bleed down each cell individually down to a certain amount. All of them. Now they are set. Now you can charge them up to a safe level. Never under discharge them(below your chosen bottom balance amount), and never, ever overcharge them.

Read up on it in depth. These aren't at all like the flooded lead acid batteries people have been using and abusing for decades.

http://media3.ev-tv.me/cellcare.pdf

[mojoman]

Now my head hurts, link failed, the EV supply vender I'm buying the cells and BMS contradict your view. More research on my part needed I guess. Thanks for the info

[stanw909]

Are you DIYing a Promaster? I think many here would find that very interesting.

[mojoman]

Yes, I'm building a Promaster, all electric except for the Espar gas heater, I'll be propane free.

[stanw909]

Gas or diesel? Full bath? porta potti or black tank marine toilet? Floorplan?