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Microlite Mike

NW Washington State

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Posted: 05/05/22 09:02am Link  |  Quote  |  Print  |  Notify Moderator

Here's a clip from the WFCO site on their 8900 series (including the 8955) converters:

Automatic three-stage charging extends the life of your battery with output voltage modes of 13.2 VDC range “float” mode, 13.6 VDC range “absorption” mode, and a 14.4 VDC range “bulk” charge mode.The WF-8955 model provides 55 Amps and a clean, constant 13.6 VDC nominal output, for reliable operation of electronics and appliances. Automatic three-stage charging extends the life of your battery with output voltage modes of 13.2 VDC range “float” mode, 13.6 VDC range “absorption” mode, and a 14.4 VDC range “bulk” charge mode. Automatic three-stage charging extends the life of your battery with output voltage modes of 13.2 VDC range “float” mode, 13.6 VDC range “absorption” mode, and a 14.4 VDC range “bulk” charge mode.

The WFCO 8955 converter is NOT a single stage converter. While many claim it never goes into boost mode, my experience with that is that batteries are often mounted far from the converter and the voltage drop across the wire from battery to converter causes a false sense that the battery is fully charged. Nothing wrong with the converter that either relocation of batteries closer, or upgrading the battery to converter wire (to min #4 awg from standard #8 awg) won't solve.

That said, my old WFCO 8955 converter section now sits on a shelf in my shop and a Progressive Dynamic's deck mount converter is located within about a foot of my batteries (both LiFePo4).


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Microlite Mike

NW Washington State

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Posted: 05/05/22 07:29pm Link  |  Quote  |  Print  |  Notify Moderator

SirBenji wrote:


Looks like you mount the remote pendant somewhere more accessible which gives you more control. It claims to be a true, smart 4 stage charger, which would beat the **** out of my single stage. Anyone have any experience with these???


I used to use one with the pendant.

It allows one to switch to the different charge modes manually.

A good feature if one wants to "Boost" charge a battery where the charger is forced into a 14.4 volt charge setting where it will remain until current drops as full charge is approached and then the charger drops to he Absorption phase (~13.8 volt).

I found it also works pretty good to force a conventional converter to charge LiFePo4 batteries at 14.4 volts and accomplish cell balancing.

I eventually just replaced it with a "Lithium" (Progressive Dynamic's) converter. Since I boondock almost exclusively I want my Battleborn batteries to charge as quick as possible while running my generator without having to remember to use the pendant.

BFL13

Victoria, BC

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Posted: 05/05/22 07:52pm Link  |  Quote  |  Print  |  Notify Moderator

SirBenji wrote:

bestconverter finally got back to me and confirmed that there is no auto desulfation or manual control with the BD 1255 MBA 55 Amp 4-Stage Main Board Replacement. The price is great on these, but I want a smart charger and something with more control.

Instead they recommended the wildkat powered by progressive dynamics.

Looks like you mount the remote pendant somewhere more accessible which gives you more control. It claims to be a true, smart 4 stage charger, which would beat the **** out of my single stage. Anyone have any experience with these???


Since you continue to insist that "desulfation" is somehow the same as "destratification", and somehow think that your WFCO is single stage, and that you want more "control", but don't want an adjustable voltage charger, I don't see how you can be helped any.

Perhaps you are not making yourself clear? We all can help once you are clear what you want.


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time2roll

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Posted: 05/05/22 07:55pm Link  |  Quote  |  Print  |  Notify Moderator

Microlite Mike wrote:

Here's a clip from the WFCO site on their 8900 series (including the 8955) converters:

Automatic three-stage charging extends the life of your battery with output voltage modes of 13.2 VDC range “float” mode, 13.6 VDC range “absorption” mode, and a 14.4 VDC range “bulk” charge mode.The WF-8955 model provides 55 Amps and a clean, constant 13.6 VDC nominal output, for reliable operation of electronics and appliances. Automatic three-stage charging extends the life of your battery with output voltage modes of 13.2 VDC range “float” mode, 13.6 VDC range “absorption” mode, and a 14.4 VDC range “bulk” charge mode. Automatic three-stage charging extends the life of your battery with output voltage modes of 13.2 VDC range “float” mode, 13.6 VDC range “absorption” mode, and a 14.4 VDC range “bulk” charge mode.

The WFCO 8955 converter is NOT a single stage converter. While many claim it never goes into boost mode, my experience with that is that batteries are often mounted far from the converter and the voltage drop across the wire from battery to converter causes a false sense that the battery is fully charged. Nothing wrong with the converter that either relocation of batteries closer, or upgrading the battery to converter wire (to min #4 awg from standard #8 awg) won't solve.

That said, my old WFCO 8955 converter section now sits on a shelf in my shop and a Progressive Dynamic's deck mount converter is located within about a foot of my batteries (both LiFePo4).
The defect is that WFCO requires the voltage to sag below 13.2 volts during initial charge to trigger boost voltage. This is a nearly impossible task no matter how it is wired. In most cases it simply does not work.


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BFL13

Victoria, BC

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Posted: 05/05/22 08:17pm Link  |  Quote  |  Print  |  Notify Moderator

"The defect is that WFCO requires the voltage to sag below 13.2 volts during initial charge to trigger boost voltage. This is a nearly impossible task no matter how it is wired. In most cases it simply does not work."

It would better explain this to say the WFCO needs to see less than 13.2 as the "spike" when first turned on rather than a "sag".

If your set-up is such that there will be a spike of 1 volt when WFCO is turned on, then you have to start with the batt at 12.1 to see 13.1 at start, so it will go into Boost.

Problem is with long thin wires (higher R) and not so much of a bank in AH (hence higher R) your spike is higher, so it might even be 1.5v so now the WFCO needs to start with battery resting at 11.6 to see 13.1 after the spike.

time2roll

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Posted: 05/05/22 08:41pm Link  |  Quote  |  Print  |  Notify Moderator

Ok and as the lead-acid battery gets to 11.6 volts the internal resistance is high enough that the battery cannot even accept the 55 amps and again voltage will remain well above the 13.2 threshold with no boost mode. Complete failure.

The only way to consistently get boost is to load down the system with a large additional load. I have found running the microwave for 15 seconds using the inverter during initial charging works every time. How can this be a reasonable design to claim three stage charging?

BFL13

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Posted: 05/05/22 08:55pm Link  |  Quote  |  Print  |  Notify Moderator

time2roll wrote:

Ok and as the lead-acid battery gets to 11.6 volts the internal resistance is high enough that the battery cannot even accept the 55 amps and again voltage will remain well above the 13.2 threshold with no boost mode. Complete failure.


Not defending WFCO.

Yes except it is the total R of the wiring and battery that determines the size of the spike.

At a lower SOC a battery will accept higher amps until the curve goes vertical as seen in my ugly graph [emoticon]

StirCrazy

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Posted: 05/06/22 08:22am Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

When off grid using generator recharge, you do 50-80s or maybe 50-90s with FLA. So it can be that there is little time advantage with LFP---very scenario dependent.

My ugly graph has 55 amps on a 220 AH bank doing a 50-80 reach 72% SOC before amps taper. So most of the 50-80 is at constant 55 amps anyway and would take the same time with LFP--except a small diff in time where the LFP does not take as much heat loss. That heat loss only gets going with the FLA above 80% SOC as noted in the Trimetric's manual wrt charging efficiency assumptions for that monitor's AH counter.

The LFP advantage in time for the same amps is in the zone above 75% say, but the gen will not be running by then anyway. Itinerant1 does more like 35-75s with his LFPs so not much time saving there over FLA times, but he uses his LFPs for other advantages mainly.

3tons hates it when I doubt he saves much time on solar recharging like he claims he gets from no heat loss on recharging. Since solar is such a low charging rate in amps per battery bank capacity, that means the FLA will get to 90% or so before amps taper and gassing starts. If the LFPs are only going to 90% too on solar as is common it seems, they have almost the same times on low amp solar as FLAs

The LFPs can be charged way faster, but "they" forget to mention that means using way more amps and that means you need more of a generator to run the bigger amps charger--not always possible to carry in an RV.

Lots of good reasons for some to choose LFPs but recharging times are not made clear how that works in different scenarios


actualy the LFP advantage is throughout the entire range. its the fact that LFP batteries have less internal resistance than flooded batteries that makes the difference, well there is more to it than just that but that keeps it simple. it may make more difference the fuller the batteries get or the warmer they get but it does make a difference everywhere in the range. I have already noticed a faster charging time from 40% to 70-80% by a significant amount.


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BFL13

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Posted: 05/06/22 09:44am Link  |  Quote  |  Print  |  Notify Moderator

We are comparing charging efficiencies for generator time saved.

How many minutes is "significant", and how did the side by side comparison testing get measured for equal AH restored in each case? What is the heat loss allowance in the particular monitors used?

Trimetric uses 94% for FLA charging efficiency but notes some batts are better than that so they say the 94% could under-measure AH restored a bit. Also says once the batt is gassing it is crazy.

Taking a possible case where the FLA and LFP are in Bulk constant amps and charging at 60 amps for two hours using a gen to run the charger, and measuring with Trimetric for the FLA and just timing the LFP, we get:

FLA: 120AH plus 6% for heat loss = 127 minutes
LFP: 120AH minus no loss for heat = 120 minutes

I would not say the 7 minutes is significant in my scenario but it might be to somebody else's.

Of course once you try to do a side by side test that includes the gassing stage for the FLA it would be hard to show how much time difference is from earlier tapering with the FLA and how much is from heat loss. Now the time saved could be "significant" mostly from the longer time in Bulk for the LFP to a particular high SOC amount.

The Renogy monitor I am getting has something called "battery attenuation", value not given, which might be their charging efficiency built in, don't know. Your monitor might have a default for charging efficiency.

"Battery attenuation ratio: After the battery Capacity cumulatively once per cycle,The capacity value is automatically changed according to this ratio" (not well translated!)

* This post was edited 05/06/22 10:02am by BFL13 *

StirCrazy

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Posted: 05/07/22 06:46am Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

We are comparing charging efficiencies for generator time saved.

How many minutes is "significant", and how did the side by side comparison testing get measured for equal AH restored in each case? What is the heat loss allowance in the particular monitors used?

Trimetric uses 94% for FLA charging efficiency but notes some batts are better than that so they say the 94% could under-measure AH restored a bit. Also says once the batt is gassing it is crazy.

Taking a possible case where the FLA and LFP are in Bulk constant amps and charging at 60 amps for two hours using a gen to run the charger, and measuring with Trimetric for the FLA and just timing the LFP, we get:

FLA: 120AH plus 6% for heat loss = 127 minutes
LFP: 120AH minus no loss for heat = 120 minutes

I would not say the 7 minutes is significant in my scenario but it might be to somebody else's.

Of course once you try to do a side by side test that includes the gassing stage for the FLA it would be hard to show how much time difference is from earlier tapering with the FLA and how much is from heat loss. Now the time saved could be "significant" mostly from the longer time in Bulk for the LFP to a particular high SOC amount.

The Renogy monitor I am getting has something called "battery attenuation", value not given, which might be their charging efficiency built in, don't know. Your monitor might have a default for charging efficiency.

"Battery attenuation ratio: After the battery Capacity cumulatively once per cycle,The capacity value is automatically changed according to this ratio" (not well translated!)


I see what your saying. I guess if we stay in that area that skews the numbers the advantage will be on the smaller side but what if we are looking at using the genny from 65-100% how much differentce is there then. this is more where I lived with my GC batteries and solar instead of a genny. I would be at tht 60 to 70% mark in the morning and recharged by 1 to 2 pm to 100% I did drain down my new battery pack by about 45AH in the drive way an did a simulation and it was recharged by 11:38am. hardly scientific but a simular amount that needed to be recharged and a significantly faster time.

I guess I just have a hard time understanding with how cheep solar has gotten why we are still talking generators unless you have to run an AC.

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