batteies

otrfun wrote:

StirCrazy wrote:

otrfun wrote:
It's a common fallacy that a so-called "Lithium/Lifepo4 Approved" converter must be used to charge Lifepo4 batteries. Absolutely, not true. I posted this in another thread:

. . . arguably one of the better general-purpose, non-programmable charging platforms for a lifepo4 (as long as no charge/equalization mode exceeds 14.6v) is a 3-stage *lead-cell* 13.2v/13.6v/14.4v converter. It even has the advantage of a 13.2v float and more conservative 14.4v bulk vs. some of the 2-stage 13.6v/14.6v Lithium/Lifepo4 Approved converters.

. . . there will always be some debate about the best float/absorption/bulk voltages to use with a multi-stage converter to best charge a lifepo4. However, you'd be hard-pressed to find much debate about the best one, single voltage to both float and bulk charge a lifepo4. Why? Because such a voltage simply does not exist. This is why a single-stage (single/one voltage) 14.6v converter (even though Lithium/Lifepo4 Approved) is the worst possible charging platform for a lifepo4.

Claims that a given converter/charger is "Lithium/Lifepo4 Approved" are simply marketing ploys which tell you absolutely nothing about how well or safely it will charge and maintain your lifepo4 battery. The number of stages, and the voltage used by a converter to support each of these stages, ultimately determines how well a given converter will properly maintain (and charge) a lifepo4 battery.

I don't think it is absolutely true, in fact I agree that you can get by without one but should you... I think you can but only long enough till you can figure out exactly what you need then do the switchover. There are going to be some things you can't do properly without a constant voltage that is high enough, but here is my switch up. If you have enough solar, and your solar capacity is large enough to keep everything charged, then who cares about the charger on the converter... turn the breaker off, you don't need it. Then later when you decide you want to spend money you can change it out.

People seem to get hung up on this, but really, it's a couple hundred dollars, you're spending a couple K on batteries is it really a stretch to get a proper converter for them?

I look at this more as what do I need to get the maximum life out of that battery. I don't care if it will last for 15 years, I want 20 out of it. but when I was first looking into getting LI batteries most manufactures were saying to run your converter on a "Gell" setting as it is closest to a LI profile until you get a proper charger.

StirCrazy, you completely missed my point.

My post mentions specific "numbers" to look for when choosing the best converter to charge your lifepo4. Things like number of stages (1-3) and specific voltages (13.2v/13.6v/14.4v/14.6v).

If the goal here is to truly help someone choose the "best" converter for charging their lifepo4 battery, these "numbers" must be discussed. A "Lithium/Lifepo4 Approved" sticker or marketing claim means little to nothing. Outside of your claim that one must use a "constant voltage that is high enough", you offer nothing that would help someone choose the "best", or as you put-it, "proper" converter.

Here are voltage and stage specs for the most commonly available, off-the-shelf, RV converters:

14.6v one (single) stage converter
13.6v/14.6v two stage converter
13.2v/13.6v/14.4v three stage converter

Clearly, one of these converters has numbers that do a much better job of "pampering" a 12v lifepo4 than the other two. Care to guess which one it is?

Yup I must have missed it, I do like the numbers on the 3 stage but only because I know my BMS only needs over 13.6V to start equalizing, but having said that... EVE (manufactures of my cells) calls for a constant voltage of 14.6V at 0.5C for maximum life and proper charging, plus recommend a charging window of 10 to 90% with occasional balancing. SO I am even a bigger proponent of going by what the manufacture of the cells in your battery says to do. the problem with this is that to many "other brands" who don't make batteries but rather assemble them don't give you the actual specs in most cases and they don't tell you what all you can do with there BMS. now that more are coming out with blue tooth, most of them are just for monitoring, unlike mine, I can control the setting through my Bluetooth so I use the BMS profile to set my 10% bottom end and 90% top end when I am camping and charging via solar. I haven't tested it yet but this should work also with a single stage converter as I just set it to stop charging at 90%and I start charging again at 79% as that is just over my normal daily usage when I am running the furncace. this way every day it charges back up to 90% and the discharge stays shallow which extends the life even more.
Now I know this is specific and not everyone can do it like this, but isn't that a much better way to do it instead of relying on a converter that no matter what you pick is only going to be proper is specific situations.

so, the other issue I am having, and maybe you can explain this, is why it is such a big deal to have a second stage. When I am camping in the bush the charge isn't running, so it's no big deal. With LiFePo4 everyone is so adamant about not storing them at a full charge so we shouldn't be leaving them on charge anyways when we are not using the unit. and the final category if you camp in power sites mostly, well then why did you spend money on LFP? and if you only camp with power once and a while, just turn off the charger breaker and you don't need to worry about it

theoldwizard1 wrote:

AllegroD wrote:
Maybe. Probably. What converter do you have? If it has a lithium setting, ...

I disagree. Most "stock" converters do NOT have a a lithium setting.

Might be a good time to dump the old converter and upgrade to an inverter/charger/automatic transfer switch.

Uh! That is why I stated it as I did. The entire reply and not just a few words. I don't think we disagree on this.

I probably should have said possibly, instead of probably.

StirCrazy wrote:

Tom_M wrote:
When I'm plugged in my battery will not charge fully but that is not a problem with lithium.

be careful saying that. yes, I agree it doesn't have to be charged fully on a regular basis, but you still have to charge it full once and a while to ensure the cells stay balanced.

You can get away with this because you let your solar charge it with proper profiles and hopefully you take it up to 100% with that once and a while and let it fully balance. My BMS has a passive balancer that would take forever to balance so I added an active balancer to mine, so it only needs 2 hours or less to balance my 300AH battery. When I am camping, I do this once a week, the rest of the time I cut off at 90% but that's the BMS controlling that.

Tom_M didn't mention what voltage his converter or solar charger is using to bulk charge with. Without this information there's no way to know definitively what's going on with his system.

Also, in a number of your posts you seem to allude that you must have 14.6v to properly balance a 12v lifepo4 battery. This is not true . . . unless the BMS's threshold voltage for balancing is set too high. A 12v lifepo4 battery bulk charging at 14.4v (equivalent to a 3.600v parallel top-balance) should be more than enough voltage delta to allow a BMS to balance in a timely manner. If it's not, then you probably have bigger problems (see next paragraph). For what it's worth, Battleborn lifepo4 batteries are capable of supporting all BMS balancing functions when bulk charged at 14.2v - 14.4v (14.4v recommended). As you know, BB does not recommend long-term bulk charging at 14.6v.

Yes, an active balancer, especially a 5-10a version, will balance rather quickly. However, if you have properly top-balanced, "matched" cells, the 100-150ma passive balancer found on most BMS's should balance in a reasonable amount of time. If the 100-150ma passive balancer is not capable of doing so, then an active balancer may be compensating for, or putting a band-aid on, the true problem: moderately to badly mis-matched cells. No amount of top-balancing, passive balancing via BMS, or use of an active balancer can correct this problem. The end result, permanently reduced ah output from the battery---especially during high c discharges.

StirCrazy wrote:

otrfun wrote:
It's a common fallacy that a so-called "Lithium/Lifepo4 Approved" converter must be used to charge Lifepo4 batteries. Absolutely, not true. I posted this in another thread:

. . . arguably one of the better general-purpose, non-programmable charging platforms for a lifepo4 (as long as no charge/equalization mode exceeds 14.6v) is a 3-stage *lead-cell* 13.2v/13.6v/14.4v converter. It even has the advantage of a 13.2v float and more conservative 14.4v bulk vs. some of the 2-stage 13.6v/14.6v Lithium/Lifepo4 Approved converters.

. . . there will always be some debate about the best float/absorption/bulk voltages to use with a multi-stage converter to best charge a lifepo4. However, you'd be hard-pressed to find much debate about the best one, single voltage to both float and bulk charge a lifepo4. Why? Because such a voltage simply does not exist. This is why a single-stage (single/one voltage) 14.6v converter (even though Lithium/Lifepo4 Approved) is the worst possible charging platform for a lifepo4.

Claims that a given converter/charger is "Lithium/Lifepo4 Approved" are simply marketing ploys which tell you absolutely nothing about how well or safely it will charge and maintain your lifepo4 battery. The number of stages, and the voltage used by a converter to support each of these stages, ultimately determines how well a given converter will properly maintain (and charge) a lifepo4 battery.

I don't think it is absolutely true, in fact I agree that you can get by without one but should you... I think you can but only long enough till you can figure out exactly what you need then do the switchover. There are going to be some things you can't do properly without a constant voltage that is high enough, but here is my switch up. If you have enough solar, and your solar capacity is large enough to keep everything charged, then who cares about the charger on the converter... turn the breaker off, you don't need it. Then later when you decide you want to spend money you can change it out.

People seem to get hung up on this, but really, it's a couple hundred dollars, you're spending a couple K on batteries is it really a stretch to get a proper converter for them?

I look at this more as what do I need to get the maximum life out of that battery. I don't care if it will last for 15 years, I want 20 out of it. but when I was first looking into getting LI batteries most manufactures were saying to run your converter on a "Gell" setting as it is closest to a LI profile until you get a proper charger.

StirCrazy, you completely missed my point.

My post mentions specific "numbers" to look for when choosing the best converter to charge your lifepo4. Things like number of stages (1-3) and specific voltages (13.2v/13.6v/14.4v/14.6v).

If the goal here is to truly help someone choose the "best" converter for charging their lifepo4 battery, these "numbers" must be discussed. A "Lithium/Lifepo4 Approved" sticker or marketing claim means little to nothing. Outside of your claim that one must use a "constant voltage that is high enough", you offer nothing that would help someone choose the "best", or as you put-it, "proper" converter.

Here are voltage and stage specs for the most commonly available, off-the-shelf, RV converters:

14.6v one (single) stage converter
13.6v/14.6v two stage converter
13.2v/13.6v/14.4v three stage converter

Clearly, one of these converters has numbers that do a much better job of "pampering" a 12v lifepo4 than the other two. Care to guess which one it is?

Tom_M wrote:
When I'm plugged in my battery will not charge fully but that is not a problem with lithium.

be careful saying that. yes, I agree it doesn't have to be charged fully on a regular basis, but you still have to charge it full once and a while to ensure the cells stay balanced.

You can get away with this because you let your solar charge it with proper profiles and hopefully you take it up to 100% with that once and a while and let it fully balance. My BMS has a passive balancer that would take forever to balance so I added an active balancer to mine, so it only needs 2 hours or less to balance my 300AH battery. When I am camping, I do this once a week, the rest of the time I cut off at 90% but that's the BMS controlling that.

otrfun wrote:
It's a common fallacy that a so-called "Lithium/Lifepo4 Approved" converter must be used to charge Lifepo4 batteries. Absolutely, not true. I posted this in another thread:

. . . arguably one of the better general-purpose, non-programmable charging platforms for a lifepo4 (as long as no charge/equalization mode exceeds 14.6v) is a 3-stage *lead-cell* 13.2v/13.6v/14.4v converter. It even has the advantage of a 13.2v float and more conservative 14.4v bulk vs. some of the 2-stage 13.6v/14.6v Lithium/Lifepo4 Approved converters.

. . . there will always be some debate about the best float/absorption/bulk voltages to use with a multi-stage converter to best charge a lifepo4. However, you'd be hard-pressed to find much debate about the best one, single voltage to both float and bulk charge a lifepo4. Why? Because such a voltage simply does not exist. This is why a single-stage (single/one voltage) 14.6v converter (even though Lithium/Lifepo4 Approved) is the worst possible charging platform for a lifepo4.

Claims that a given converter/charger is "Lithium/Lifepo4 Approved" are simply marketing ploys which tell you absolutely nothing about how well or safely it will charge and maintain your lifepo4 battery. The number of stages, and the voltage used by a converter to support each of these stages, ultimately determines how well a given converter will properly maintain (and charge) a lifepo4 battery.

I don't think it is absolutely true, in fact I agree that you can get by without one but should you... I think you can but only long enough till you can figure out exactly what you need then do the switchover. There are going to be some things you can't do properly without a constant voltage that is high enough, but here is my switch up. If you have enough solar, and your solar capacity is large enough to keep everything charged, then who cares about the charger on the converter... turn the breaker off, you don't need it. Then later when you decide you want to spend money you can change it out.

People seem to get hung up on this, but really, it's a couple hundred dollars, you're spending a couple K on batteries is it really a stretch to get a proper converter for them?

I look at this more as what do I need to get the maximum life out of that battery. I don't care if it will last for 15 years, I want 20 out of it. but when I was first looking into getting LI batteries most manufactures were saying to run your converter on a "Gell" setting as it is closest to a LI profile until you get a proper charger.

fj12ryder wrote:
That sure looks authoritative, but what are the credentials behind whoever wrote that up? Anybody can write anything, but that doesn't really mean it's strictly factual. I don't care personally, but any cut-and-paste without crediting the source is sometimes questionable.

Here's the source. You will note that he quoted himself so it must be true.

https://forums.goodsamclub.com/index.cfm/fuseaction/thread/tid/30385436/gotomsg/30387192.cfm#30387192

I upgraded to a Renogy lithium battery and did not upgrade my converter. I'm hardly ever plugged in to a 120 volt source relying on solar most of the time. When I'm plugged in my battery will not charge fully but that is not a problem with lithium.

AllegroD wrote:
Maybe. Probably. What converter do you have? If it has a lithium setting, ...

I disagree. Most "stock" converters do NOT have a lithium setting.

Might be a good time to dump the old converter and upgrade to an inverter/charger/automatic transfer switch.

otrfun wrote:

Grit dog wrote:
^No, say it ain’t so….lol.

Don't blame you for lol. For folks like yourself that visit here often, yeah, replies like this get redundant. However, it's a simple theme---numbers trump words and stickers. Bears repeating because it comes up often. If I can save one person $200, it's worth it.

The “lol” came from the inevitable responses to follow by the “experts” here who pretend like they’re tuning their camper batteries like a top fuel dragster.

That sure looks authoritative, but what are the credentials behind whoever wrote that up? Anybody can write anything, but that doesn't really mean it's strictly factual. I don't care personally, but any cut-and-paste without crediting the source is sometimes questionable.