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 > New 2 stage PD lithium Converter charger yet?

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BFL13

Victoria, BC

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Posted: 06/16/22 02:49pm Link  |  Quote  |  Print  |  Notify Moderator

One of the complaints about the older PowerMax PM3 converter was that the Bulk Stage was too short. Like the Iota, it had a 15 minute time after it got the battery to 14.6v and then dropped its voltage.

In the new LK version, the standard 3 stage mode extended the Bulk time to 30 minutes, still way too short for many scenarios. But they fixed that by including the single stage mode that will hold Bulk voltage forever until you change it.

I am trying to find out what the new Li LK has, where it says there is a new Load Sensing system that extends Bulk if needed.

Meanwhile, it might be that the old PM3 with its 15 min after reaching Vabs or the 30 min in the new one, would be what the LFP guys are now looking for as an automatic timer to keep Bulk short. That still leaves the question of whether it could drop to a desired voltage if you don't like 13.6.

This all only applies to being on shore power using the converter. On generator you don't leave it running long enough to matter. On solar it might matter depending how early in the day you get to Full.

If you want to stop the solar at a certain SOC like 90% automatically and not wait till dark happens (automatically every day!), then you would have to invent something if the Load Controls of the solar controller can't be made to do that. Maybe use the Load terminals to control a switch on the PV input?

Maybe get an old Shunt type solar controller that stopped at the high set point and restarted when the batt got low again?


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3 tons

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Posted: 06/16/22 05:43pm Link  |  Quote  |  Print  |  Notify Moderator

Per BFL, “This all only applies to being on shore power using the converter. On generator you don't leave it running long enough to matter. On solar it might matter depending how early in the day you get to Full.”

***********
Fair enough,

I’d only point out (unless I’m misunderstanding…) that this charging scenario seems to assume a practice of keeping a charged battery on an active converter-charger - but other than for ‘occasional’ cell-balancing (an activity requiring 100% SOC…) why do so with a LFP??

I would counter that this apparent consternation (possibly a FWC thingy?) mainly applies to ‘unattended set and forget’ shore power charging (as is typical with lead batts)…But even if using a ‘less that ideal’ charging device for LFP, one need ask how realistic of a scenario is this??

And, to arrive at the dreaded ‘the slide-out won’t work’ gottcha, it suggest that once ‘shore power’ charging has been completed (to whatever level?), for protection, an LFP battery needs to be sequestered….Why is this??

I’d counter that one can merely shutoff the onboard converter-charger (at it’s breaker…), at which time 12v power will come from the now charged, still active battery (minor loads only, and possibly with some solar assist?), while leaving shore power connected for 120v heavy appliances (e.g. air cond, etc)…

Regardless of the charging source (and, charged to whatever desired SOC?? - definitely NOT a lead acid thingy!!), one can simply opt to discontinue charging and just live for a considerable time off the battery’s deep reserves…This is exactly what I do, and with 400a/hr LFP and 660w of solar, seldom the need for shore or genny power - the last time I ran the genny was about 11 mos ago (and have since circumvented America…), and if in a park, ONLY use shore power where shading prevents harvest or when using air conditioner…In most other scenarios, the pass-thru inverter (concurrent with harvest) does the job…Just Saying [emoticon]

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BFL13

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Posted: 06/16/22 06:08pm Link  |  Quote  |  Print  |  Notify Moderator

Note that I am not advocating for leaving the LFP connected while on shore power with an active converter.

I am commenting on how the converter makers see the problem, where they assume the converter will be on during shore power time ( nearly all the time for most RVers AFAIK), and they have to be sure a connected LFP won't be ruined during that time. (They do not imagine the RVer disconnecting the LFP)

So their various attempts to make the converter "compatible".

Guys on Tech Issues are not like most RVers? which means they are more likely to be willing to do a few things instead of being totally automatic and hands free?

Just saying that so far IMO it seems the converter makers have not solved their problem of making their converters totally "compatible" with LFP (something of a moving goal post itself for what is needed?)

I did say their converters are not totally compatible with FLA and AGM either, but the penalty in dollars for the RVer who treats them as such is low compared with the penalty cost of doing that with LFPs.

The OP is trying to get as close as he can to hands free by maybe swapping out his converter, but it seems like he is as good as it gets now with his OEM converter, unless he wants to do more manually himself.

otrfun

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Posted: 06/17/22 09:41am Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

Note that I am not advocating for leaving the LFP connected while on shore power with an active converter.

I am commenting on how the converter makers see the problem, where they assume the converter will be on during shore power time ( nearly all the time for most RVers AFAIK), and they have to be sure a connected LFP won't be ruined during that time. (They do not imagine the RVer disconnecting the LFP)

So their various attempts to make the converter "compatible".

Guys on Tech Issues are not like most RVers? which means they are more likely to be willing to do a few things instead of being totally automatic and hands free?

Just saying that so far IMO it seems the converter makers have not solved their problem of making their converters totally "compatible" with LFP (something of a moving goal post itself for what is needed?)

I did say their converters are not totally compatible with FLA and AGM either, but the penalty in dollars for the RVer who treats them as such is low compared with the penalty cost of doing that with LFPs.

The OP is trying to get as close as he can to hands free by maybe swapping out his converter, but it seems like he is as good as it gets now with his OEM converter, unless he wants to do more manually himself.
Excellent questions!

My take: The vast majority of converter/charger sales are to regular folks who generally have a set-it/forget-it mentality. There are always going to be folks who will leave their converter on 24/7/365 while connected to a lifepo4---for better or worse.

Back in the day, it took manufacturers some time before they offered 3-stage units for lead-cell batteries to address long-term float needs. I believe manufacturers are going through the same learning process with lifepo4. Many of the lifepo4 converter/chargers currently on the market are single-stage 14.6v units---a less than ideal charge profile. Manufacturers are now transitioning to 2-stage units to address the potential overcharging risk posed by single-stage units.

Lastly, lifepo4 cell/battery manufacturers ship their units with a 30-50% SOC for a reason. It's the ideal SOC for a lifepo4---for the short and long-term. I think it's just a matter of time before manufacturers eventually transition to 3-stage units to address this unique lifepo4 storage/float requirement. Until then, those set-it & forget-it folks (who may be striving for maximum lifepo4 cycle life) will just have to remember to turn-off their 1 and 2-stage lifepo4 converter/chargers when they're not camping.

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Posted: 06/17/22 12:34pm Link  |  Quote  |  Print  |  Notify Moderator

Agreed, but recall the saying, “we go to war with the Army we have, rather than the one we want”, and learned newbees with a bit of *awareness will likely have success when using most conventional chargers…

* Best General LFP Practices: Avoid unattended final-stage ‘extended’ (beyond cell-balancing) charging, storing batt at about 50% SOC (isolating), no charging at or below 32dF…

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StirCrazy

Kamloops, BC, Canada

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Posted: 06/18/22 06:42pm Link  |  Quote  |  Print  |  Notify Moderator

otrfun wrote:



Lastly, lifepo4 cell/battery manufacturers ship their units with a 30-50% SOC for a reason. It's the ideal SOC for a lifepo4---for the short and long-term. I think it's just a matter of time before manufacturers eventually transition to 3-stage units to address this unique lifepo4 storage/float requirement. Until then, those set-it & forget-it folks (who may be striving for maximum lifepo4 cycle life) will just have to remember to turn-off their 1 and 2-stage lifepo4 converter/chargers when they're not camping.


Since I put my cells in the Camper I created a second profile for my solar charger and I don't use the house charger at all when at home except for the day before I leave for camping to top it off and ballance the cells. for conventance I picked 3 days as the max I leave it at full charge with out any use. I havent been able to find any numbers on what the manufactures concider storage but they ship at a middleish level as it could be a year with shipping and sitting in a where house and retailers shelf.


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SFVdave

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Posted: 06/18/22 08:22pm Link  |  Quote  |  Print  |  Notify Moderator

Thanks for all the replies. I am sticking with what I have for now. Not a problem hitting the charge wizard if I need extra charge. Usually in the morning after running the microwave at dinner, furnace and TV satellite the night before. It’s down 80 to 100 amps and my 300 watts of solar won’t come close to recharging to 200amps full charge..

3 tons

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Posted: 06/19/22 08:21am Link  |  Quote  |  Print  |  Notify Moderator

I believe a far better investment would be in having a LFP compatible shunt based SOC meter (like Victron or equivalent.) so that you can accurately determine SOC and be able to monitor the occasional end of cell balancing activity…

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Microlite Mike

NW Washington State

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Posted: 06/19/22 11:05am Link  |  Quote  |  Print  |  Notify Moderator

otrfun wrote:


Lastly, lifepo4 cell/battery manufacturers ship their units with a 30-50% SOC for a reason. It's the ideal SOC for a lifepo4---for the short and long-term.


Yes, 30%-50% may be an ideal SOC for long term storage but since April 1 2016 international regulations regarding air shipments of Lithium batteries restricts the SOC to 30% or less.


FWIW, my solution to the storage issue is to just go camping regularly and since I primarily boondock, batteries are constantly being cycled. I just follow Battleborn's recommendation when I return from a trip. "Charge to 100%, disconnect, and just charge again after 6 months of inactivity" (which has yet to occur).

With 200 ah of storage and a daily average consumption ~50 ah, I will complete a full charge cycle every 4 days. If I were to "Full Time Boondock that would amount to 91.25 full cycles per year. Battleborn advertises 3,000 to 5,000 cycles from their batteries. This amounts to 32 to 55 YEARS of battery life based on cycles alone.

Most LiFePo4 batteries in RV's will most likely outlive their owners and possibly those who inherit the RV and batteries.

Reality Check, LiFePo4 batteries are also subject to internal chemical degradation like Lead/Acid chemistry batteries. Even with the most careful charging practices they will most likely age out somewhere after 10-12 years which is why the best warranties max out in that range.


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otrfun

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Posted: 06/19/22 11:58am Link  |  Quote  |  Print  |  Notify Moderator

Microlite Mike wrote:

otrfun wrote:


Lastly, lifepo4 cell/battery manufacturers ship their units with a 30-50% SOC for a reason. It's the ideal SOC for a lifepo4---for the short and long-term.
Yes, 30%-50% may be an ideal SOC for long term storage but since April 1 2016 international regulations regarding air shipments of Lithium batteries restricts the SOC to 30% or less.

FWIW, my solution to the storage issue is to just go camping regularly and since I primarily boondock, batteries are constantly being cycled. I just follow Battleborn's recommendation when I return from a trip. "Charge to 100%, disconnect, and just charge again after 6 months of inactivity" (which has yet to occur).

With 200 ah of storage and a daily average consumption ~50 ah, I will complete a full charge cycle every 4 days. If I were to "Full Time Boondock that would amount to 91.25 full cycles per year. Battleborn advertises 3,000 to 5,000 cycles from their batteries. This amounts to 32 to 55 YEARS of battery life based on cycles alone.

Most LiFePo4 batteries in RV's will most likely outlive their owners and possibly those who inherit the RV and batteries.

Reality Check, LiFePo4 batteries are also subject to internal chemical degradation like Lead/Acid chemistry batteries. Even with the most careful charging practices they will most likely age out somewhere after 10-12 years which is why the best warranties max out in that range.
Some of the discussion here is a somewhat, in-the-weeds debate about ways to maximize cycle life. Some of the SOC and charge voltage monitoring required to implement some of the charge profiles (for only a nominal increase in cycle life) is probably overkill for the average user. Only someone who places a higher priority on cycle life vs. usability would find it worth their time.

I only mentioned the 30-50 cycle as an extreme example of how to maximize lifepo4 cycle life--just to make a point. Rather doubt it's worth anybody's time to actually implement it because it would reduce the ah capacity of the battery to a ridiculously low level.

As for your comment about air shipment of lifepo4's at 30% or less SOC, I'm not sure how this fits into the current discussion. Maybe you can clarify.

Bottom line, as I mentioned in an earlier post (and as you also somewhat alluded to), the average user can get by without having to resort to any special charge profile and still obtain many, many years of use from their lifepo4.

* This post was edited 06/19/22 08:06pm by otrfun *

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