Stop shore power from charging battery?

[airborne_spoon]

I have a 2022 bushwhacker 10HD and I did a LiFePO4 upgrade ages ago 200Ah from Ampertime and I have 200w solar to charge it off a victron 100/20 and it works perfectly stopping at 14.00v to 14.20v when it's charging.

However when I plug into shore power the converter wants to charge the battery to 14.5v and I don't like that.
I have a Wfco WF-8735P and one of the fuses is labeled as reverse battery protection fuse 40A and if I pull it the battery doesn't charge.

Is it fine to do this and just leave that thing pulled out always? Seems like a bad idea. How to I stop shore power from charging my battery?

I need shore power to run my AC, be it my generator in the woods or a plug at a campground I need AC it's gonna be hot soon.

 

[Gary RV_Wizard]

I suspect that pulling the reverse polarity fuse might also prevent the converter from pulling power from the battery when there is no shore power available. Remember, the 8735 is your AC/DC power panel as well as battery charger. See what happens with no shore power connection and the polarity fuses removed.

Is there a breaker on the panel labeled something like "charger" or "converter"? If so, just flip that off to prevent shore power charging. You would also lose the converter function that provides 12v power instead of the battery, but you have solar to compensate for that.

The real solution is to upgrade the 8735 to one of WFCO's newer models that supports lithium battery charge profiles.

 

[airborne_spoon]

I suspect that pulling the reverse polarity fuse might also prevent the converter from pulling power from the battery when there is no shore power available. Remember, the 8735 is your AC/DC power panel as well as battery charger. See what happens with no shore power connection and the polarity fuses removed.

Is there a breaker on the panel labeled something like "charger" or "converter"? If so, just flip that off to prevent shore power charging. You would also lose the converter function that provides 12v power instead of the battery, but you have solar to compensate for that.

The real solution is to upgrade the 8735 to one of WFCO's newer models that supports lithium battery charge profiles.

Well that was a good idea in though at least lol.
I plugged it in and it was charging the battery then I pulled the fuse labeled battery and it stopped charging but I also lost power once I was off shore power.

So that means I'd have to keep insertion and remove a fuse and that isn't good for the contacts to constantly insert and remove.

What about if I installed a battery kill switch on the main POS side at the battery itself? If I cut that would the current have nowhere to go and just not charge?

Also the newer wfco controller is no better because you can't adjust the charge stop voltage level so it would still charge to I think the manual says 14.6v before going to float.

 

[Lou Schneider]

Why are you afraid of charging your battery to 14.5 volts? Converters with a lithium profile put out a constant 14.6 volts in lithium mode so 14.5 volts from your present converter won't harm your battery.

 

[airborne_spoon]

Why are you afraid of charging your battery to 14.5 volts? Converters with a lithium profile put out a constant 14.6 volts so 14.5 volts from the converter won't harm your battery.

The manufacturer recommends 14.2v to be the 100% mark.
Also I know that 14.6v is acceptable but it's going to a true 100% which is unnecessary because I don't draw enough juice during the night or cloudy days to drain even below 70%. And that would make my battery sit at over full for extended time and that's just not healthy for the longevity of the pack.

 

[Gary RV_Wizard]

So that means I'd have to keep insertion and remove a fuse and that isn't good for the contacts to constantly insert and remove.

How about a simple knife switch at the battery + terminal?

I'm no Lithium guru, but everything I see agrees with Lou - 14.5v is fine for those batteries. I suspect that 14.2v is just the desirable float (maintenance) voltage once the battery reaches 100%. And you can be confident the battery BMS on a Battleborn product isn't going to let any damage occur.

 

[Mark_K5LXP]

I have a 2022 bushwhacker 10HD and I did a LiFePO4 upgrade ages ago

2022 only goes back so far...

The data sheets I could find for this converter don't specify the mode duration but typically multistage converters will switch out of absorb mode after some period of time. So you would not see 14.5V or whatever indefinitely, it should switch to a trickle or float mode until reset.

Mark B.
Albuquerque, NM

 

[touchracing]

Have you verified that your converter is actually pushing 14.5 volts to your battery? I would bet between the minimally adequate wire size and the wire length between the converter and battery your battery probably won’t see higher than 14.2 volts.

 

[airborne_spoon]

Have you verified that your converter is actually pushing 14.5 volts to your battery? I would bet between the minimally adequate wire size and the wire length between the converter and battery your battery probably won’t see higher than 14.2 volts.

Well it's currently plugged in as an experiment so we'll see what it gets to when it stops. Last time I did a few months ago it stopped at 14.55v which is why I've not done so since. But next week is supposed to be hot and I'll need my AC, I'm using the heater right now so I don't need shore power for that, it just happens to be cold right now.

 

[John From Detroit]

If you can't easily find the breaker do this. Turn on interior lights while connected to shore power. Disable solar (or do this at night) lift a battery wire.. Now one at a time turn breakers off. wait 10 seconds and turn on .. You will quite likely know which breaker it is.. Now if re-connect battery and again turn this breakjer off Check EVERYTHING (including outlets) and see if there is anything else that breaker posers.. IF more than one wire is connected to that breaker.. One of them will likely be the converter and the other the rest of what it powers (or look for a point where wire becomes two often a few inches (Wire path) away)

 

[Ex-Calif]

Over/Under voltage relay might be the answer here.

I was looking for one where the "make" voltage was adjustable too. That way you could "break" the converter/charger connection at, say, 14V. You'd then set the make voltage at something like 11V. This way if the solar can't keep up the converter/charger kicks in.

The pictured unit is a break/break device.

 

[SuwanneeDave]

On my cargo trailer conversion, I installed a marine battery cutoff switch on the positive cable going to the + bus bar. That way I can turn off charging when on shore power if needed but the converter is still powering all other 12V things.

 

[Zulu Kono]

I have a 2022 bushwhacker 10HD and I did a LiFePO4 upgrade ages ago 200Ah from Ampertime and I have 200w solar to charge it off a victron 100/20 and it works perfectly stopping at 14.00v to 14.20v when it's charging.

However when I plug into shore power the converter wants to charge the battery to 14.5v and I don't like that.
I have a Wfco WF-8735P and one of the fuses is labeled as reverse battery protection fuse 40A and if I pull it the battery doesn't charge.

Is it fine to do this and just leave that thing pulled out always? Seems like a bad idea. How to I stop shore power from charging my battery?

I need shore power to run my AC, be it my generator in the woods or a plug at a campground I need AC it's gonna be hot soon.

I'd be inclined to install a battery disconnect switch if I needed the battery not to charge, however the converter sounds like it's charging at the correct voltage for LiFePO4, so maybe you don't need to.

 

[WME]

Two possible answers...
12V 20A DC to DC On-Board Battery Charger
Same answer, but different...a 12v adjustable buck/boost. 4-32v input and 1.2-32v output.
DC/DC 15A Buck Adjustable 4-32V 12V to 1.2-32V 5V Converter Step Down Module DT | eBay

 

[Ray-IN]

Well it's currently plugged in as an experiment so we'll see what it gets to when it stops. Last time I did a few months ago it stopped at 14.55v which is why I've not done so since. But next week is supposed to be hot and I'll need my AC, I'm using the heater right now so I don't need shore power for that, it just happens to be cold right now.

That sounds like my inverter/charger settings for my AGM battery bank. Most better quality LiPo batteries say that is acceptable, but some of the cheaper ones have narrow charge rates.
example: Battery Charging | Guide to Battery Charging | LithiumHub