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LiFePo4: how to get shore power?

11K views 38 replies 15 participants last post by  nebulight 
#1 ·
I have a 600Ah 12V LiFePo4 battery bank. I can't figure out what I need in order to charge via shore power. Everything I've found has been for AGM.

What do I need to buy in order to charge my system via shore power?
 
#5 · (Edited)
>:D Trade them in and get AGM? >:D Then it is simple and cheap and works fine.

You’ve got a BIG battery set and must have an impressive electrical plan. The charger is available.
 
#8 ·
The "world" is designed for lead-acid/AGM batteries. The concepts of "bulk", "absorption" and "float" are all related to lead-acid and AGM. Yet, most all of the chargers and solar controllers can be configured for LiPO4.

The starting point, though, is to know what you have . . . meaning, whose 600AH of lithium do you have, what is their configuration (meaning: Parallel-Series or Series-Parallel) and, more importantly, what Battery Management System do you have. Provide more information and we can help.
 
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#10 ·
Let this be another warning to lithium battery prospective purchasers. These batteries have their place in electric and hybrid autos and many other applications but might not be quite ready for prime time as RV storage as other solutions are much cheaper, the weight advantage is not so important to us and the rapid discharge and charging capabilities are not significant in this application either.
Dont get me wrong they are a great technology, I have some, and I believe they may become the way-to-go, just not now for this specific application.
 
#15 ·
Let this be another warning to lithium battery prospective purchasers. These batteries have their place in electric and hybrid autos and many other applications but might not be quite ready for prime time as RV storage
Seems to me that this particular bank is just farking huge and thus presents unique problems.
 
#14 ·
Buck
You don't specify the brand or source of your battery bank. I think the first place to check would be with the manufacturer or supplier you obtained them from. Some Lithium batteries come with a cell management system installed and others don't. It's not as simple as buying a charger for flooded or AGM but chargers are certainly available. What's important is to buy one that is suited to your particular battery bank design.

For a generic charger I would check with Progressive Dynamics as they are a major manufacturer of RV power supplies and make chargers specifically designed for Lipo batteries - their pd9100L-series.
 
#16 ·
Agreed. This is the future, for sure, but unless you are an well funded electrical engineer or serious experimenter it's still not quite ready for the average pocketbook or "prime time" in a camper van.

I remember 5 years ago, or so, when everyone was up in arms of something as simple as an incandescent light build being phased out. People were hoarding them and crying and moaning about government interference and on and on not to mention the extra cost. Today LED's have become the norm and they are as cheap as the old incandescents. I just bought an 8 pack of R30' floods at Costco for the magnificent sum of $3.99! I've actually replaced every bulb in my house (and I have well over 50 or 60) with LED's and wouldn't ever consider buying anything else in the future - until that next big advancement in technology arrives. ;)

The point is in a few years we will all most likely be using LiFePO4 batteries and look back on lead acid battery technology (and price) and laugh at how far we have come in such a short time. Thanks, in part, to the pioneers here like Winston and others.
 
#17 ·
Let's start off with a few questions?

What type of batteries are they?
Do you have a BMS?
Do you have an inverter/charger?
Will the van every be anywhere below freezing?

Most good inverter/chargers have a custom setting to allow for custom charge profiles. If you just have an inverter, then as others have said you'll need a dedicated charger. However if you don't even have an inverter yet, just bite the bullet and go with a nice inverter charger. Xantrex just released a pretty nice inverter that's a good value. It's their XC line and has an 80A charger. http://www.xantrex.com/power-products/inverter-chargers/freedom-xc.aspx. Slower charging helps with longevity, but with 600ah, slow charging isn't always an option.

My van has 400ah of lifepo4 and I've been doing research on these batteries for a while, but I'm not an expert, but feel free to ask any questions and I can help where I can or point you to the right place.
 
#18 ·
Below in bold is my response:

Let's start off with a few questions?

What type of batteries are they? They're custom made by Shen Zhen YKX Battery Energy Co. They make a lot of the LiFePO4s being rebranded in the states, I believe.
Do you have a BMS? Yes, batteries each have a built in BMS
Do you have an inverter/charger? I have a 3000W "pure sine" inverter that was $315 off eBay (PUGU is the brand) and I was using a Bioenne Power 14.6V charger model BPC-1520C
Will the van every be anywhere below freezing? Absolutely. Van is designed for four seasons, one of those being winters in Wyoming where it's regularly -20°F or colder. Van has ~R30 on the walls, R20 on the floor and ceiling. Has electric heated floors and a gasoline powered Webasto furnace. I'm not sure that will keep the batteries above freezing at all times, but the BMS is supposed to not let them charge when they're below a certain temperature.

Most good inverter/chargers have a custom setting to allow for custom charge profiles. If you just have an inverter, then as others have said you'll need a dedicated charger. However if you don't even have an inverter yet, just bite the bullet and go with a nice inverter charger. Xantrex just released a pretty nice inverter that's a good value. It's their XC line and has an 80A charger. http://www.xantrex.com/power-products/inverter-chargers/freedom-xc.aspx. Slower charging helps with longevity, but with 600ah, slow charging isn't always an option.

My solution to all of my inverter and charging issues was going to be exactly that: bight the bullet and buy a ~$700 charger/inverter combo. It's actually not nearly as pricey as I thought. When you consider that my cheap chinese "pure sine" 3000W inverter (Keep quoting that because I can prove it's always putting out a steady sine wave) was ~$315 and the 20A charger I got was $115, so $430 combined. For an extra $300 or so, I could have gotten an all-in-one solution from a reputable brand based in the USA (customer support, warranty, etc.) that would charge at four times the rate and, presumably, put out a steady sine wave at its rated wattage.

My van has 400ah of lifepo4 and I've been doing research on these batteries for a while, but I'm not an expert, but feel free to ask any questions and I can help where I can or point you to the right place.
 
#19 ·
Hey Buck,

Is this the battery you have? http://www.ykxbattery.com/Pro640/850.html

If so, I don't see a mention of any cold weather protection on the spec sheet as most do not have that feature (the only one I've seen is battle born batteries and REC-BMS for stand alone BMS for individual cell management). Just make sure that you keep them above freezing at all times if you are going to be charging. My van has an electric thermostat that turns on when it's below a certain temp that powers heating pads to warm the batteries. The problem with this is they draw a decent amount of current (15 amps) and I imagine your electric floor heating is going to draw more than that. Even with 600ah, powering an electric heater is going to drain those batteries fast. What I plan to add is a shut off switch on the solar so that when it's around freezing, I can simply turn off my solar, not plug in, and turn off my battery combiner so no charge comes from the alternator. I was even thinking about getting a 12v thermostat to trigger a relay to shut off charging manually, then turn it back on when it's back above freezing.

Remember, cold weather is only an issue at freezing temp for charging. Most batteries can discharge perfectly fine up until -4F but your spec sheet says 14F. However if it's that cold, you're probably going to be running the webasto ;)
 
#20 · (Edited)
As an FYI, we've been using a Magnum 2812 combination 2800 watt sine wave inverter and 125 amp charger. It switches flawlessly (transparently) between invert and shore power as shore power comes and goes (we lost shore power a few nights ago and the only way we knew that that had happened was the fan in the Magnum came on as the inverter was drawing nearly 150 amps to supply our AC space heater). It's pricey, but it includes flexible programming making it suitable for lithium charging (we're using a 500ah Elite/Starlight Solar pack and BMS).
 
#22 ·
That's not the battery I have. Mine was customized. They can build pretty much any LiFePO4 configuration. Mine is 12V 300Ah rated for 100A continuous discharge and 200A charge.

I'm asking the manufacturer to double check what my BMS settings are. We discussed a low temperature value to stop charging but I'm not sure if it got implemented into the BMS; I'm checking with them now.

My heated floor is 200W @ 120VAC, so with about 10% inverter loss, I'd need about 220W @ ~18A from the battery (I think that's how it works)

Eventually, I'll have two of these batteries in parallel for 12V 600Ah at 200A continuous discharge and technically 400A continuous charge (plan is to either add a second alternator or look into getting it to charge off the stock alternator - I've read you shouldn't charge with the cabin SLA battery and stock alternator because they have different voltage requirements and it's bad for the LiFePO4 after time...need to confirm this before dropping $2k on a second alternator. Forget off the top of my head, but when accounting for heat loss etc. I think a second alternator can charge these around 190A)
 
#24 ·
Yea, I'd double and triple check on that BMS.

And a second alternator will help, but check the charge capacity on the BMS. Some cheaper BMS units can only charge at lower currents.

If you haven't purchased anything yet, you might want to rethink some of this, and maybe do a little more research.
 
#26 · (Edited)
Buck,

Looks like you are at the start of an excellent adventure in house power systems using LifePO4. Its a steep learning curve that some of us find both stimulating, challenging and super fun and scary all at the same time;) As you travel along your path you may encounter many pitfalls that will threaten to dent your wallet big time! As I have traveled this path myself I urge you too stop in your tracks, grab a cup of coffee lock yourself in a quiet place, hang the do not disturb sign and read the the information at the links I have provided.

Rod Collins is the real deal!! When you talk to people in the the industry and mention his name they all know him and respect his real world experience, research, and testing. Every thing you need to know about LifePO4 house power battery systems can be learned in plain simple language from Rod's articles. In fact any one who wants to learn about any house battery bank/electrical systems weather it be lead acid, AGM or LifePO4 would benefit from Rod's articles

When I started my system I had to google how to use a volt meter!! I managed to avoid any large wallet dents do to a lot of research and a huge helping of luck! Now I'm capable of building a system from scratch from bare cells thanks to the plain language articles written by Rod. I have a 700AH Lifpo4 system, with 600 watts of solar and a second 280amp alternator with a programmable external regulator.

The main thing with charging LifePO4 battery systems is to purchase a fully programmable inverter charger with a dedicated battery voltage sensor. Xantrex, Victron, and Outback Power all make inverter/chargers that are fully programmable for LifePO4 charging profiles.

Your 20amp trickle charger is probably blowing fuses because you have a 300AHR bank that is probably overwhelming the baker. Are you plugging it into a 15Amp breaker? if so find at least a 20amp breaker. My Outback Power inverter charger has a 80amp shore power capacity and I blow 20amp breakers on occasion. Don't forget your 300 amp hr bank has a huge inrush when you first start charging that can easily over run a 15amp breaker.

Rod Collins
Compass Marine Inc.
Cumberland, ME USA

http://www.pbase.com/mainecruising/boat_projects

http://www.pbase.com/mainecruising/lifepo4_on_boats&page=1

http://www.pbase.com/mainecruising/regulator_voltage_sensing

Buck, its possible that you may have damage your cells if you let them discharge below 2.6V per cell. You may experience a loss in capacity and the only way to know this is to do a capacity test. If you have discharged an individual cell below 2.6V you need to be careful not to charge the pack back up at a high C rate. If your careful you my not loose any capacity.

Hope this is helpful,

Cheers,

Dave
 
#27 ·
Hi...I have no solar based and I realize that presents different issues, this may not work for some. Be that as it may, on the off chance that you have a two bank framework, and remotely controlled charge sources by means of dino, dealing with the LFP bank is not any more perplexing than dealing with a LA bank, with the additional advantages of LFP.
 
#29 ·
I think we see this a bit different. While perplexing is a subjective term, I would say that most people would not find that statement to be true.

Lithium batteries (of all types) have a definite learning curve and do perplex more people than lead acid chemistry batteries. Some issues that you have to deal with include low temperature cutoff, different charge profiles than the vehicle battery and alternator. The need to limit charging current (lead acid will self limit to an acceptable value due to internal resistance, Lithium is closer to a short circuit from the perspective of many alternators and wiring).

I know lithium batteries and I would say they are more perplexing for the vast majority of people. I primarily have them for the reduced weight compared to what an AGM bank to meet my needs would weight (210 pounds versus 500-600 pounds) But in return I need an inverter/charger that can handle the lithium charging profile (my old one from my other RV could not), a battery to battery charger to keep my batteries from trying to pull 300 amps from the alternator, a low temperature charge cutoff to keep the batteries from being ruined by charging below freezing, a current meter that keeps track of state of charge (because voltage is great for measuring AGM state but not for Lithium). Additionally lithium batteries don't like temperature extremes and I have an active ventilation system to keep them warm and cool depending on the need. I would say this is much more complex (and perhaps perplexing) to most people who can use a AGM with almost any inverter, a voltmeter, and a battery isolation relay.

Introduce yourself and welcome to the forum.
 
#35 ·
Not really misleading. No battery likes extreme heat and will be damaged if subjected to extreme heat lead acid or lithium. As for freezing, both chemistries have limitations. AGM and sealed lead acid batteries capacity is significantly reduced when operating in low temps. At freezing temps, depending on your discharge rate, you've got about 60% the capacity (generalization, you can have as low as 40% and as high as 80% at freezing). They also require temperature compensated charge for different temps which a lot of van users don't account for (at least the dozens I've run across). Lifepo4 CAN be damaged when charging below freezing, but if managed PROPERLY the BMS should disconnect chargers while leaving the loads intact. There is no need for temp compensated charging nor is there a noticeable capacity loss at lower temps. Lifepo4 also can't be stored at temps below -4F. Depending on your location, this, in my opinion is the biggest draw back (not the charging limitation).
 
#36 ·
Great info thanks! I did not know that Lifepo4 also can't be stored at temps below -4F, I agree that could be more limiting than the charging limitation. Lot of differences between the different battery chemistries in regard to using them at extreme temps. Id point out that the lead acid extreme temp limitations are performance limitations while the Lifepo4 limitations actually make the batteries unusable will actually destroy your expensive batteries and I just read charging while freezing can cause the batteries to short circuit and catch fire/explode. It might be unreasonable to expect the temp sensor on a battery BMS and other parts of the BMS to be reliable for the usable life of the battery. Seems like some failsafe in addition to the BMS may be necessary.
 
#38 ·
Okay, I read that here: How to Find Happiness With LiFePO4 (Lithium-Ion) Batteries

"If you really want to know, what happens when a lithium-ion battery gets charged below freezing is that metallic lithium is deposited on the negative (carbon) electrode. Not in a nice way either, it grows in sharp, needle-like structures, that eventually puncture the membrane and short out the battery (leading to a spectacular Rapid Unscheduled Disassembly Event as NASA calls it, involving smoke, extreme heat, and quite possibly flames as well). Lucky for us, this is something the BMS prevents from happening. "

It seems to refer to Lifepo4 and is a "pro-Li" battery article. I dont believe everything I read on the web and you seem like you may know more about the subject than the authors, in any case bottom line is dont charge your Lifepo4 batteries while freezing!
 
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