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lem55

Santa Maria,Ca USA

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Posted: 05/14/22 04:05pm Link  |  Quote  |  Print  |  Notify Moderator

Let me add a little more info on the equipment in question. My house converter/charger is a WF-9845 which has 3 step charging Bulk/quick charge 14.4
Normal charge/13.6, then a trickle or float charge 13.2 volt, but nothing in the manual does it mention anything about "Lithium". The battery is a 200 AH with a
2560 WH. If this helps. Thanks for the good info,

time2roll

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Posted: 05/14/22 04:44pm Link  |  Quote  |  Print  |  Notify Moderator

lem55 wrote:

Let me add a little more info on the equipment in question. My house converter/charger is a WF-9845 which has 3 step charging Bulk/quick charge 14.4
Normal charge/13.6, then a trickle or float charge 13.2 volt, but nothing in the manual does it mention anything about "Lithium". The battery is a 200 AH with a
2560 WH. If this helps. Thanks for the good info,
That WFCO is fine. Not sure if it will ever see 14.4 volts but is fine if it does. There is no metric or lithium electricity. It is just about voltage and the WFCO falls well within range of the battery specifications.

Connect the battery and enjoy some camping. Nothing is immediately needed to change.


2001 F150 SuperCrew
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3 tons

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Posted: 05/14/22 04:51pm Link  |  Quote  |  Print  |  Notify Moderator

I can’t attest to the WFCO, but first you should have a charge strategy, meaning since you have a dedicated LFP charger, do you plan on also using the WFCO??… Either way, an AGM battery algorithm will likely work fine, but no need to routinely ‘fully charge’ the battery…

However, LFP is a considerable investment, thus it’s Uber wise to know what is happening with your SOC, particularly when charging, this is why a Lithium SOC monitor is a critical component in my view - flying blind is a very poor $$ strategy…

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lem55

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Posted: 05/14/22 05:13pm Link  |  Quote  |  Print  |  Notify Moderator

Yes I have a stand a lone lithium charger (portable unit) not install yet. This is what I am trying to find out where I can use the house charger, or only use the Lithium one.

time2roll

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Posted: 05/14/22 05:18pm Link  |  Quote  |  Print  |  Notify Moderator

lem55 wrote:

Yes I have a stand a lone lithium charger (portable unit) not install yet. This is what I am trying to find out where I can use the house charger, or only use the Lithium one.
Either or both is fine.

otrfun

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Posted: 05/15/22 07:30am Link  |  Quote  |  Print  |  Notify Moderator

theoldwizard1 wrote:

otrfun wrote:

theoldwizard1 wrote:

You will never get a 100% charge without a DC-DC charger.
Why would you need or want a 100% charge (14.6v) to begin with? Unlike lead-cell batteries, lifepo4's subjected to 100% SOC (14.6v) on a constant, short-term basis experience reduced cycle life. 13.6v will still net 99% SOC (and a higher cycle life), although at a slower charge rate.

Long-term float at =>14.6v can permanently damage a lifepo4.
I never said anything about long term float at that voltage. The point of a DC-DC charger is to give the correct voltage at the correct time during the charging cycle.
No, you didn't. I mentioned it because it's one of the potential consequences of charging a lifepo4 to 100% SOC with a single-stage converter. Something you failed to mention.

In your previous post, you stated 1) "You will never get a 100% charge without a DC-DC charger. Above you state 2) the primary point (or mission) of a dc2dc charger is to provide the "correct voltage at the correct time during the charge cycle".

1) Ref charging a lifepo4 to 100% SOC, many folks make the false assumption that a lifepo4 must/should be charged to 100% SOC (14.6v) like a lead-cell battery. The fact is, a lifepo4 experiences a reduction in cycle life the longer it sits at 100% SOC (14.6v). If it floats at 14.6v long enough it can be permanently damaged.

2) Ref your comment about "correct voltage", the correct voltage is ultimately up to the user---as it should be. Renogy dc2dc chargers are one of the most widely used dc2dc chargers because of their low-cost. It allows the user to choose various absorption/float charge voltages ranging from 12.6 to 14.7v. Surprisingly, if you choose the "lithium" mode, it will only operate as a single-stage charger. As a single-stage charger set to charge to 14.6v (100% SOC), it will charge at 14.6v indefinitely---the worst possible way to charge a lifepo4. This is why I mentioned the dangers of long-term float at 14.6v while a lifepo4 is at 100% SOC. This is precisely what may occur if you leave it up to the Renogy dc2dc charger to provide the "correct voltage at the correct time during the charge cycle" while charging in lithium mode.

Fortunately, Renogy provides a 2-stage absorption/float mode in their dc2dc chargers which can be used to charge a lifepo4, safely and fully. I find it ironic it's a recommended setting for lead-cell batteries. Progressive Dynamic's first generation of lithium converter/chargers were/are single-stage units. It's telling that they are now transitioning to multi-stage lithium converters.

I also find it ironic (and sad), that so many folks spend their hard-earned money upgrading to so-called "lithium approved" converter/chargers when in many cases their existing 3-stage lead-cell converter/charger will actually do a safer and better job of charging their lifepo4.

3 tons

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Posted: 05/15/22 08:37am Link  |  Quote  |  Print  |  Notify Moderator

otrfun, while I don’t use a dc2dc charger, thanks for expanding on this topic, and for the worthy additional in site - also I agree with your statement on LFP charging voltage (e.g. not to exceed 14.6v) being up to the user - Great points!

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steveh27

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Posted: 05/15/22 08:57am Link  |  Quote  |  Print  |  Notify Moderator

theoldwizard1 wrote:

steveh27 wrote:

While driving the alternator charges it just fine also shutting down when full.

I question that statement !

Modern vehicle charging system do not supply adequate voltage to properly charge LiFePO4 batteries. That is why DC-DC chargers exist !


My Class B Xplorer 230XL has a battery isolater with 40 amp breakers.

It charges the batteries to 14.7 volts and then shuts down, I think due to the BMS.

otrfun

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Posted: 05/15/22 09:27am Link  |  Quote  |  Print  |  Notify Moderator

3 tons wrote:

otrfun, while I don’t use a dc2dc charger, thanks for expanding on this topic, and for the worthy additional in site - also I agree with your statement on LFP charging voltage (e.g. not to exceed 14.6v) being up to the user - Great points!

3 tons
You're welcome, thanks!

philh

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Posted: 05/15/22 05:39pm Link  |  Quote  |  Print  |  Notify Moderator

Get the Lithium charger. WFCO will never go into bulk with LiFePO4 batteries and will diminish the life of the battery. Little better with progressive, but the same issue exists.

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