100Ah 12v LiFePo4 Battery charger

[thepartyhound]

I am looking at getting a 100Ah LiPo battery for an RV. I'd like to take advantage of its ability to take a charge quickly, but most chargers out there do not supply anywhere near enough current to do this. I found this on amazon, and it looks promising, but they almost (but not quite) come right out and tell you the thing is going to break in the description! Im looking for recommendations.

60A 12v Charger

C60A 12V High Power Lifepo4 Charger Smart Battery Charger Maintainer with 0-15V Adjustable Current and Voltage, 12.6V Portable Power Adapter for 14.6V LiFePO4 Lithium Iron Rechargeable Battery(60A) https://a.co/d/aXzJRiL

 

[mikefitz]

Only 30 amps but recomended,

https://www.amazon.com/Victron-Energy-12-Volt-Battery-Bluetooth/dp/B08NY23BKF?th=1

 

[thepartyhound]

I do like the blue equipment! However, this battery will be used between a couple of different locations and will mostly be charged via generator. The less time the generator has to run, the better! @ 30A the generator would only be pushing out what...380ish watts. I'd really like to find a charger that can push a little more than that.

 

[MiSh]

Progressive Dynamics has been around forever and has a nice line of RV lithium chargers/converters. They are recommended by several battery manufacturers. I own a 60amp version and it works fine - Around $250ish. They are designed to be mounted in an RV, but I use mine as a benchtop charger.

 

[thepartyhound]

Progressive Dynamics has been around forever and has a nice line of RV lithium chargers/converters. They are recommended by several battery manufacturers. I own a 60amp version and it works fine - Around $250ish. They are designed to be mounted in an RV, but I use mine as a benchtop charger.

Hey MiSh, thank you for this. I found one available through etrailer.com...possibly the same one you have?
The one I found is:
Progressive Dynamics PD9100L Series Battery Converter Charger w/ BMS - Lithium - 12 Volts - 60 Amps

I was really hoping for an option maybe a hundred bucks less than this, but in the end I think I will be glad I ponied up a little extra now rather than having to do this all over again down the line.

So, with all that said, is 60A enough? It looks like I have an option of going even bigger. 75A is available, as well as 100A...although that might not be ideal for a 100Ah battery.

 

[thepartyhound]

There is also an 80A version available. Is charging a an LFP battery at .8C on a regular basis ok? I think my generator would run this, but it would be on the outer limits of ideal. My 2kw harbor freight inverter generator has a max continious output of 1600 watts. This charger would pull 1300 watts, or about 85% of the max continious rating. I think I have read somewhere that 75% of this rating is more ideal.

 

[thepartyhound]

Ok, I just did some digging around the forum and it turns out that charging at 0.8C is NOT ok! That idea is scrapped! Sounds like 0.6C is not ideal either, and 0.5C will heat the batteries, cause a shorter than advertised life span, but will overall work. From what I have read, when manufacturers give a cycle life estimate for LFP batteries, the results are obtained using 0.2C charge. Other opinions state that 0.4C will still provide for an acceptable lifespan.

 

[OrthoMechanical]

Ok, I just did some digging around the forum and it turns out that charging at 0.8C is NOT ok! That idea is scrapped! Sounds like 0.6C is not ideal either, and 0.5C will heat the batteries, cause a shorter than advertised life span, but will overall work. From what I have read, when manufacturers give a cycle life estimate for LFP batteries, the results are obtained using 0.2C charge. Other opinions state that 0.4C will still provide for an acceptable lifespan.

I have the progressive dynamics 80amp charger. PD says a 20 amp circuit is needed, so I had to run 12ga for a 20 amp outlet as my camper has only 15 amp outlets. I charge two batteries with it, so it is a reasonable charge rate. I have been very happy with this charger. It has sat out in 130+ temps in my camper in the Arizona desert for a few years now and there have been no problems. I typically see 960 watts out of this charger. I think paying the higher price for quality components makes sense in high current devices like this. And yes, .8C is too high, .4 C or lower is more reasonable, but most battery mfgs will provide recommended charge rates. I don't live in my camper, so I will never see 3000+ charge cycles, they will time expire before they charge expire.

 

[thepartyhound]

I have the progressive dynamics 80amp charger. PD says a 20 amp circuit is needed, so I had to run 12ga for a 20 amp outlet as my camper has only 15 amp outlets. I charge two batteries with it, so it is a reasonable charge rate. I have been very happy with this charger. It has sat out in 130+ temps in my camper in the Arizona desert for a few years now and there have been no problems. I typically see 960 watts out of this charger. I think paying the higher price for quality components makes sense in high current devices like this. And yes, .8C is too high, .4 C or lower is more reasonable, but most battery mfgs will provide recommended charge rates. I don't live in my camper, so I will never see 3000+ charge cycles, they will time expire before they charge expire.

I keep getting pulled in different directions on this! I was just reading this page of Will's, where he discusses several different types of 100Ah 12v LFP batteries. Down toward the bottom under the SOK batteries I found the spec sheet for their batteries. This spec sheet seems to show, if I'm reading it right, a full 1C charge and discharge cycle lifespan of their batteries. Even at this severely abusive discharge/charge cycle the battery lasted almost 3600 cycles before the test results stopped at 83% of the original capacity!
So, if I understand this correctly, they put a 100A draw on the battery for about an hour or until the battery was at 0% SOC (2.5v/cell) then recharged it at 100A until it reached 3.65v/cell. They repeated this cycle nearly 3600 times! Am I correct in this understanding?
If that's the case, I am definately going the 80A charger route! My discharge rate will be very low and, like Ortho mentioned above, I too will not likely put 3k+ cycles on this battery I use only occasionally. Is there any good reason NOT to recharge these at 0.8C besides a faster degradation of the battery?

How long before these batteries "time expire"? I didn't know that was a thing!

 

[OrthoMechanical]

I keep getting pulled in different directions on this! I was just reading this page of Will's, where he discusses several different types of 100Ah 12v LFP batteries. Down toward the bottom under the SOK batteries I found the spec sheet for their batteries. This spec sheet seems to show, if I'm reading it right, a full 1C charge and discharge cycle lifespan of their batteries. Even at this severely abusive discharge/charge cycle the battery lasted almost 3600 cycles before the test results stopped at 83% of the original capacity!
So, if I understand this correctly, they put a 100A draw on the battery for about an hour or until the battery was at 0% SOC (2.5v/cell) then recharged it at 100A until it reached 3.65v/cell. They repeated this cycle nearly 3600 times! Am I correct in this understanding?
If that's the case, I am definately going the 80A charger route! My discharge rate will be very low and, like Ortho mentioned above, I too will not likely put 3k+ cycles on this battery I use only occasionally.

How long before these batteries "time expire"? I didn't know that was a thing!

Each cell is different, so they can have different charge rates, discharge rates. So, there is a range. Just look at the specs on the battery per the manufacturer, and that will give you the answer. It can get confusing and overwhelming. It is just best to define what you want your system to do and what your requirements are and design around that. Do you really need a 1C charge rate, etc? If you need fast recharge rate, then SOK might be the way to go. If you are on a budget buy a cheaper battery and charge it slower.

I am not sure if there is a universal definition of what a "cycle" is. Some may define a cycle as 80% to 20% cycling. They are always going to publish the best-case scenario. Would be an interesting video to see how many 100 to 0 to 100% cycles these batteries actually can handle. By "time expire" I mean the cell chemistry degrades over time to a point where you are not happy with the capacity, or one of the cells or components(say in the BMS) goes bad. Electronics, battery cells do not last forever. Capacitors tend to be some of the earlier components to go bad. There is even "designed obsolescence" where the product is designed to quit after a certain timeframe. I am not saying the mfgs do this, but you never know.

 

[thepartyhound]

I am not sure if there is a universal definition of what a "cycle" is. Some may define a cycle as 80% to 20% cycling. They are always going to publish the best-case scenario. Would be an interesting video to see how many 100 to 0 to 100% cycles these batteries actually can handle.

If you look at the spec sheet I linked, it detailed the top and bottom voltages I listed.
As I continued looking at the SOK battery, it appears that the ones sold by current connected are BMS limited to 0.5C charge rate, and 1C discharge. It also appears they have their own BMS on the battery, and along with that offer a total of 10 years of warranty instead of SOKs normal 7.

It is just best to define what you want your system to do and what your requirements are and design around that. Do you really need a 1C charge rate, etc? If you need fast recharge rate, then SOK might be the way to go. If you are on a budget buy a cheaper battery and charge it slower.

I may not NEED a 1C charge rate, but it would sure be nice! The faster the battery recharges, the shorter a period of time I have to run the generator!

 

[OrthoMechanical]

Ah, Good point, depends on what you need for your application. If you have a one or two hour generator window at a campground, then I get you on the need for fast charging. That is why defining what your specific application is helps in deciding what you need. Battery charging rate is like horsepower in a car: the more the better.

 

[Tomthumb62]

So, with all that said, is 60A enough? It looks like I have an option of going even bigger. 75A is available, as well as 100A...although that might not be ideal for a 100Ah battery.

It’s not recommended to charge a 12v 100Ah lifepo4 more than 30A for longest life. 50A maybe occasionally, but at 60A+ on a regular basis, you’ll be shortening the lifespan of your expensive lifepo4. But perhaps you’re okay with that.

 

[Tomthumb62]

I keep getting pulled in different directions on this! I was just reading this page of Will's, where he discusses several different types of 100Ah 12v LFP batteries. Down toward the bottom under the SOK batteries I found the spec sheet for their batteries. This spec sheet seems to show, if I'm reading it right, a full 1C charge and discharge cycle lifespan of their batteries. Even at this severely abusive discharge/charge cycle the battery lasted almost 3600 cycles before the test results stopped at 83% of the original capacity!
So, if I understand this correctly, they put a 100A draw on the battery for about an hour or until the battery was at 0% SOC (2.5v/cell) then recharged it at 100A until it reached 3.65v/cell. They repeated this cycle nearly 3600 times! Am I correct in this understanding?
If that's the case, I am definately going the 80A charger route! My discharge rate will be very low and, like Ortho mentioned above, I too will not likely put 3k+ cycles on this battery I use only occasionally. Is there any good reason NOT to recharge these at 0.8C besides a faster degradation of the battery?

How long before these batteries "time expire"? I didn't know that was a thing!

Yes but. This was with an SOK battery, which is better built than your cheap $250-350 lifepo4. But you could try it and see how long it lasts.

I like my Powerurus battery because the Bluetooth app shows cycle counts. Up to 33 cycles so far.

 

[thepartyhound]

It’s not recommended to charge a 12v 100Ah lifepo4 more than 30A for longest life. 50A maybe occasionally, but at 60A+ on a regular basis, you’ll be shortening the lifespan of your expensive lifepo4. But perhaps you’re okay with that.

According to that report I linked to, the SOK got nearly 3600 cycles while charging and discharging at 100A! Hell, if I can get 1000 cycles when charging at 60A it would last me 10+ years! I mean, honestly, does anyone thats not living in their camper spend more than a few weeks a year in it? So, lets say, just for arguments sake, I cycle the battery 60x a year while out camping. How many years does that get me even if I'm "abusing" the battery? The extra $119 for the base model SOK seems like it might be worth it to be able to have 10 years of quick charging!

I'm gonna try to speak with someone at SOK on Monday. Im pretty sure their battery says right on it to charge at 50A max...and a paltry 20A is recommended.

 

[HarryN]

According to that report I linked to, the SOK got nearly 3600 cycles while charging and discharging at 100A! Hell, if I can get 1000 cycles when charging at 60A it would last me 10+ years! I mean, honestly, does anyone thats not living in their camper spend more than a few weeks a year in it? So, lets say, just for arguments sake, I cycle the battery 60x a year while out camping. How many years does that get me even if I'm "abusing" the battery? The extra $119 for the base model SOK seems like it might be worth it to be able to have 10 years of quick charging!

I'm gonna try to speak with someone at SOK on Monday. Im pretty sure their battery says right on it to charge at 50A max...and a paltry 20A is recommended.

If you want to charge a 100 amp-hr LiFe battery at 50 amps, then the SOK is not designed to do that.

It is in the data sheet. Sorry - that is the wrong battery for what you are wanting to do.

What you can do is to buy a combo inverter / charger unit such as a Victron 3000 and set the "charge rate" to match the spec of the battery.

When plugged into shore power, it will pass through the excess available.

If you want to charge faster, there are other batteries for this or buy two.

 

[Pierre]

Ok, I just did some digging around the forum and it turns out that charging at 0.8C is NOT ok! That idea is scrapped! Sounds like 0.6C is not ideal either, and 0.5C will heat the batteries, cause a shorter than advertised life span, but will overall work. From what I have read, when manufacturers give a cycle life estimate for LFP batteries, the results are obtained using 0.2C charge. Other opinions state that 0.4C will still provide for an acceptable lifespan.

That is why the Victron 30A is ideal and is what I use.

 

[thepartyhound]

If you want to charge a 100 amp-hr LiFe battery at 50 amps, then the SOK is not designed to do that.

It is in the data sheet. Sorry - that is the wrong battery for what you are wanting to do.

What you can do is to buy a combo inverter / charger unit such as a Victron 3000 and set the "charge rate" to match the spec of the battery.

When plugged into shore power, it will pass through the excess available.

If you want to charge faster, there are other batteries for this or buy two.

Hmm, it says right on every SOK battery that Max charging current is 50A.

 

[Tomthumb62]

According to that report I linked to, the SOK got nearly 3600 cycles while charging and discharging at 100A! Hell, if I can get 1000 cycles when charging at 60A it would last me 10+ years! I mean, honestly, does anyone thats not living in their camper spend more than a few weeks a year in it? So, lets say, just for arguments sake, I cycle the battery 60x a year while out camping. How many years does that get me even if I'm "abusing" the battery? The extra $119 for the base model SOK seems like it might be worth it to be able to have 10 years of quick charging!

I'm gonna try to speak with someone at SOK on Monday. Im pretty sure their battery says right on it to charge at 50A max...and a paltry 20A is recommended.

Yes there is a thing called calendar aging, but as @HarryN points out, what you intend to do will damage the battery. I would be leery of a single report that SOK themselves produced that suggests that charging at 1C is okay. I would want to know of more reports by reputable third parties that show what the expected life cycles might be.

A big consideration of that report is the ambient temperature and cooling setup they used. A typical RV is used mostly during summer in warm or hot weather. And an RV battery compartment is typically a tight enclosed space with no airflow for cooling. Charging at 1C in these hot conditions is going to have a dramatic effect on the health of the battery. Very different than charging at 40F and/or with fans or heat sinks for cooling.

My point here is while an SOK is a pretty good battery for the price, it’s still hundreds of dollars. If you want to charge at 100A, at the very least, get 200Ah of 12v battery to reduce the heat build up during charging.

 

[thepartyhound]

It seems you still havent looked at the report. The temp during testing was listed as 25°C which is about 77°F.