Convertor question

[tech740]

Okay this will be long but I think the background info is important.
My RV went in for repairs and the dealer flipped the battery switch to kill power and didn’t restore it. I picked it up and took the RV home after repair. Plugged it into shore power and it sat for 4 days before we were planning to leave. After 4 days when I went to operate the slides, it was attached to the truck when it was opened after repair, the batteries were dead. I found the battery switch and turned it on. I waited overnight to close the slides and I got them closed. Now we have been plugged into shore power for 36 hours at our site and I am still only showing 12.7 volts. With a meter at the batteries plugged in I still only show 12.7. Shouldn’t I be seeing 13+ because it is in shore power? I am not sure if I have a converter issue or not.

Sorry for all words and thanks for the insight.

[JRTJH]

Several things you need to consider.

1. When a battery is "fully discharged" (which is probably what happened when it sat for weeks at the dealership) most batteries will never again accept a full charge. You'll probably need to buy replacement batteries.

2. When a battery is discharged, using the converter or the truck connection to operate "high amp draw" items (slides, leveling systems, etc) can damage either the truck connection and/or the converter since the battery is unable to "help provide the amp surge"....

3. To check your converter output for proper voltage (13.6 VDC) the battery must be completely disconnected from the cables. Then use the voltmeter to check the voltage present at the cable terminal ends. It should be 13.6-13.8 VDC. If the battery (good, bad, fully charged or completely discharged) is connected to the battery cables, the converter circuitry will not produce "full output" but will produce only the "adjusted voltage per the charge regimen programmed into the converter"... So, it might read 12.1 VDC or it might read 14.2 VDC. That's the "biased voltage caused by the battery"... Remove the battery and check the cable ends for proper voltage.

[sourdough]

RJ, first, did you make the dealership aware of the fact they left the batteries disconnected all that time? Were they aware that they were dead when you picked it up? If not, did you let them know right away? How did you raise/lower it to get it on the hitch on pickup?

The reason I ask is that a similar thing happened to me. When I picked up my trailer they had let 2 new Interstate batteries completely die. I could not make the tongue jack work so immediately let them know sitting there in the yard. At that time I told them the batteries were destroyed and I wanted new ones. They responded that they would charge them and they would be OK. I provided them with the discharge chart from Interstate to show them that the batteries had lost 88% of their recharge capability and I would not be taking the trailer home without new batteries. They did and I took it home. You may want to address this situation similarly if you are holding all the cards.

[travelin texans]

Even though the dealer may have used the factory disconnect that WILL NOT prevent the batteries from totally discharging, too many parasitic draws that bypass that disconnect. The only sure way to totally disconnect battery drains during storage is to disconnect the battery cables.
I'd guess if it sat at the dealer for several weeks waiting on repairs the batteries are toast, replacement is your best bet.

[Pigman~1]

Rechargeable batteries are rechargeable batteries (https://www.allicdata.com/product/battery-products/batteries-non-rechargeable/1477.html)with a limited number of recharges. They are used with chargers. No. 5 and No. 7 are generally sold in the market, but there is also No. 1. The advantages of rechargeable batteries are economic, environmental protection, sufficient power, suitable for high-power, long-term use of electrical appliances (such as Walkman, electric toys, etc.). The voltage of the rechargeable battery is lower than that of the same type of disposable battery. The AA battery (Charge 5) is 1.2 volts, and the 9V rechargeable battery is actually 8.4 volts. Now the general charging times can be around 1000 times. As of February 2012, there are only five types: nickel cadmium, nickel metal hydride, lithium ion, lead storage, and iron lithium.

[tech740]

So I let the dealer know and there response was that there responsibility is to flip the switch when it is dropped off. They did that. They never did any other time they had it. I guess they don't have to put it back or inform the customer. I didn't look because they hadn't done it in the past. I pulled my leads and tested the voltage at the leads with no batteries hooked up and it was 13.2 which I expected from the converter. I cleaned all the battery connections and the batteries are up to 13.0. My goal is to unplug it at home for a night when I go to work so I can see if they make it through the night. If not new batteries it is.
If I go the new battery route I am considering 6V. I know I have to hook them in series not parallel. My question is do I need to do anything with the converter or will it charge them appropriately?
I am also changing the wiring on the disconnect to make it a true disconnect.

[tech740]

So if you measure with a volt meter and get 13.2 and the one control display inside the RV says 12.7, I assume you trust the meter? Or am I missing something?

[chuckster57]

I have dealt with Lippert and the voltage display on the One Control panel. Been a while but I think there was a fix. Call LCI and ask for tech support, very friendly and extremely knowledgeable about their products.

[tech740]

When I flip the disconnect why do I have power in both lugs still?

[flybouy]

When I flip the disconnect why do I have power in both lugs still?

What disconnect and where are you measuring the "power"?

[tech740]

What disconnect and where are you measuring the "power"?


I was trying to find which side of the battery disconnect was “hot”. One side was 12.7 and one side was 13.6 with the switch off. We figured out the 12.7 is the battery side. We were plugged into shore power. When we unplugged that and checked it we had no power on one side and the 12.7 remained.

All this make my factory disconnect an actual disconnect. I am going to put what is now my positive lead on the switches side of the disconnect and tuna 6awg wire from the positive to the hot side of the switch. That way when I turn it off it isolated all power from the batteries.

What I learned is that if plugged into shore power even with the battery switch off you have power on both sides of the switch.

As I said earlier my plan is to be able to have the trailer sit 12-13 hours at work in the lot so I can leave right after work. Tonight I am leaving it unplugged from shore power to see if the refrigerator is still running in the morning. I am guessing I will be putting two new deep cycle batteries in it after the test because when I turn off the switch I drop to 12.7 volts from 13ish right away.

[flybouy]

With shore power active you should have the voltage from the converter on the load side of the switch and you should have voltage on the line side (from the batteries). When shore power is disconnected the converter is not energized and the load side will drop to zero if the switch is in the off or disconnected position.

The reason the factory switch does not completely disconnect the batteries completely is because some items such as landing gear or tongue jack , slides, CO monitor, and radio memory wires are not connected to the switch. Those circuits are connected inbetween the batter positive lead and the switch.

[tech740]

With shore power active you should have the voltage from the converter on the load side of the switch and you should have voltage on the line side (from the batteries). When shore power is disconnected the converter is not energized and the load side will drop to zero if the switch is in the off or disconnected position.

The reason the factory switch does not completely disconnect the batteries completely is because some items such as landing gear or tongue jack , slides, CO monitor, and radio memory wires are not connected to the switch. Those circuits are connected inbetween the batter positive lead and the switch.


Yup I understand that now. I knew about the parasitic drains that is why I am adding the new positive cable and moving the old to the old side. That way when I leave it at the dealer it is actually disconnected and I don’t have the same issue again.

[sourdough]

So I let the dealer know and there response was that there responsibility is to flip the switch when it is dropped off. They did that. They never did any other time they had it. I guess they don't have to put it back or inform the customer. I didn't look because they hadn't done it in the past. I pulled my leads and tested the voltage at the leads with no batteries hooked up and it was 13.2 which I expected from the converter. I cleaned all the battery connections and the batteries are up to 13.0. My goal is to unplug it at home for a night when I go to work so I can see if they make it through the night. If not new batteries it is.
If I go the new battery route I am considering 6V. I know I have to hook them in series not parallel. My question is do I need to do anything with the converter or will it charge them appropriately?
I am also changing the wiring on the disconnect to make it a true disconnect.


That response would be inadequate for me. If the trailer is not returned to you just as you left it with them it is incumbent on them to inform you of any changes that were made; particularly if they require your intervention to correct. An owner should not have to go through an RV looking for anything/everything that might have been done by the dealership that they need to correct (but we do). They knowingly put your trailer in a non operative condition leaving you to figure it out resulting in dead batteries....nada.

[tech740]

That response would be inadequate for me. If the trailer is not returned to you just as you left it with them it is incumbent on them to inform you of any changes that were made; particularly if they require your intervention to correct. An owner should not have to go through an RV looking for anything/everything that might have been done by the dealership that they need to correct (but we do). They knowingly put your trailer in a non operative condition leaving you to figure it out resulting in dead batteries....nada.

I completely agree! I have argued that with the dealer and Forest River. Neither will budge because I am a week outside warranty. So now I am moving onto making sure it cant happen again. This RV has been by far the biggest pain I have ever dealt with. It has been back to Elkhart twice, the dealer twice, a home repair by Lippert, and a flooring repair company. I know its not Keystone but this forum is so active and helpful I will always come here first. They are all the same parts just built in a different plant.

Thanks again

[tech740]

I have never kept an RV long enough to need new batteries. I am leaning towards two of these.
https://www.walmart.com/ip/EverStart-Lead-Acid-Marine-RV-Battery-Group-Size-24DC-12V-690-MCA/180350522
I am thinking I will need new ones, at 6:00PM I was at 13.0V at 7:15 it was 12.42V. Only draws are the detectors and the residential fridge on the invertor. I think its 8 amps total

[sourdough]

I understand your frustration. When I forced them to replace both my batteries due to a similar dealership error my trailer was almost 6 years old. Had nothing to do with warranty, it was a dealership failure. Good luck.

[tech740]

Well after 6 hours the batteries were at 12v. I got two new deep cycles today and put them in. Rewired the shut off to be a true disconnect. Batteries were both 12.6 when I picked them up. Letting them balance and acclimate for 24 hours. (Not sure that needed but makes me feel better) Then I will redo the test tomorrow. Gotta turn off the antenna booster and I think I will have everything isolated except the inverter for the fridge and the detectors.

[LERD]

Having been a previous boat owner, I still had an old Perko 2 battery disconnect switch laying around. All battery power goes through that first. This switch is very heavy duty. It takes effort to turn the dial from battery 1 to battery 2 to both batteries or Off. It has a very noticeable detent and a very loud and solid clunking noise when you turn it. There's no mistaking that you rotated that knob. I have had my battery last 4 weeks with no drain whatsoever. I was more disappointed in the fact that it took four weeks to get back on the road. But sometimes that's life for you

[flybouy]

Having been a previous boat owner, I still had an old Perko 2 battery disconnect switch laying around. All battery power goes through that first. This switch is very heavy duty. It takes effort to turn the dial from battery 1 to battery 2 to both batteries or Off. It has a very noticeable detent and a very loud and solid clunking noise when you turn it. There's no mistaking that you rotated that knob. I have had my battery last 4 weeks with no drain whatsoever. I was more disappointed in the fact that it took four weeks to get back on the road. But sometimes that's life for you

It's frustrating but it's also a learning experience is it not? Being a several decades boater myself if I were going to install 2 12 volt batteries I would use the POerco switch you described as well.

My reasoning for the use of the Perco 1,2,1+2 & off switch is the isolation ability. If you have one battery go south it's easily taken out of the equation by selecting the other battery. If you have say a solar charger that you want to quickly charge 1 battery you can do that. It also gives you the option to run run 1 battery down to the max 50% while keeping a second battery "in reserve" instead of running both batteries down and then being forced to recharge or be powerless. JMHO

[sonofcy]

That is NOT a deep cycle battery. Look at the MCA on the side of the battery, it's a Hybrid start/deep cycle. A true deep cycle has no spec for Cranking. Get a pair of GC's by Trojan (T105) or others, 6V 225AH. If you have a residential fridge do NOT boondock with 2, get at least 4 plus 400 to 600 watts of solar.

[tech740]

No interest in boon docking. My only interest is making it through up to 13 hours in a parking lot while I am at work until I start the truck and head off into the sunset. I just got a amp clamp meter that reads DC current. I was surprised to see that when the fridge runs it shows I have 8 amp draw on the battery by the investor shows only 0.5 amps. 8 amps on a 202 amp system for 13 hours is just over 50% discharge. Unless I am not understanding something. Luckily I can check on the voltage throughout the night and will flip the switch at 40% if I get there. I will trying this tomorrow when I leave for work.

[sonofcy]

No interest in boon docking. My only interest is making it through up to 13 hours in a parking lot while I am at work until I start the truck and head off into the sunset. I just got a amp clamp meter that reads DC current. I was surprised to see that when the fridge runs it shows I have 8 amp draw on the battery by the investor shows only 0.5 amps. 8 amps on a 202 amp system for 13 hours is just over 50% discharge. Unless I am not understanding something. Luckily I can check on the voltage throughout the night and will flip the switch at 40% if I get there. I will trying this tomorrow when I leave for work.

A residential fridge will draw 3 to 4 amps max. That will be roughly 30 to 40 coming out of the batteries. I did a multi day killawatt test and my Samsug uses 1.5kWh per day. Working backwards from there, a standard Trojan T105 pair has 1.5kWh usable (50%discharge). That means the fridge alone will drain the battery in 24 hrs. If that's all you are running then you are good to go for 13 hours.

[tech740]

I rewired my disconnect to be a true master. I think I am going to add the investor to the battery side and run that from just its switch. That way I know that is all that is getting power. No detector or antenna booster draw

[tech740]

Okay, to report back the batteries made it through the night with no issues. I rearranged the wiring so that the inverter is the only thing on the battery side of the kill switch. Everything else is on the load side. After 12.5 hours, I was at 12.2 volts. Only thing I don't under stand is the amp readings I had. My inverter takes 2.5 amps to sit idle. It also has a display that tells the amperage it is putting out. It would show about 0.5amps. When I used the DC current clamp I would show that the batteries had about a 7-8 amp draw. I feel like I am missing something but I know that the battery positive and the positive to the circuit breaker to the inverter are the only things on that side of the switch. Anyways just wanted to report back how it went for future readers to base decisions from.

[gearhead]

Assuming your 2019 Ram is the same as my 2018, the 12volt hot pin in the truck bed is hot all the time. Be careful about letting the trailer pulling the truck batteries down. I would unplug it from the truck if left any amount of time.
I just got back from a 2,000 mile round trip. The first day at a refueling stop I heard a beeping from the front of the 5th. It was the residential fridge inverter beeping that my battery was low. It was 11.6 volts. I discovered I had somewhat loose cables on the battery posts. I run stainless steel nylock nuts on my boat batteries and will replace the 5th battery nuts soon.

[CedarCreekWoody]

That is NOT a deep cycle battery. Look at the MCA on the side of the battery, it's a Hybrid start/deep cycle. A true deep cycle has no spec for Cranking. Get a pair of GC's by Trojan (T105) or others, 6V 225AH. If you have a residential fridge do NOT boondock with 2, get at least 4 plus 400 to 600 watts of solar.

Sonofcy is correct, the batteries you bought are not true deep cycle batteries. Wal-Mart does sell deep cycle batteries. You might want to look at getting them to swap them out.

[tech740]

Assuming your 2019 Ram is the same as my 2018, the 12volt hot pin in the truck bed is hot all the time. Be careful about letting the trailer pulling the truck batteries down. I would unplug it from the truck if left any amount of time.
I just got back from a 2,000 mile round trip. The first day at a refueling stop I heard a beeping from the front of the 5th. It was the residential fridge inverter beeping that my battery was low. It was 11.6 volts. I discovered I had somewhat loose cables on the battery posts. I run stainless steel nylock nuts on my boat batteries and will replace the 5th battery nuts soon.


It is the same. I unplug it and turn off the battery disconnect. Then leave a sticky note in my steering wheel to plug it back in and turn the disconnect back on.

[sonofcy]

It is the same. I unplug it and turn off the battery disconnect. Then leave a sticky note in my steering wheel to plug it back in and turn the disconnect back on.

I think most modern trucks cut the power to the 7 pin when the truck is turned off. I know for sure my 2018 Ford does. IIRC it will not turn on again until you turn truck on AND either put in gear or apply brakes, I don't remember which. Once it comes on it will stay however until turned off again.

[tech740]

Good to know about Ford. I tested my Ram after about an hour of sitting and it was still live. There is a post above that says a new Chevy is the same way.

[SummitPond]

Okay, to report back the batteries made it through the night with no issues. I rearranged the wiring so that the inverter is the only thing on the battery side of the kill switch. Everything else is on the load side. After 12.5 hours, I was at 12.2 volts. Only thing I don't under stand is the amp readings I had. My inverter takes 2.5 amps to sit idle. It also has a display that tells the amperage it is putting out. It would show about 0.5amps. When I used the DC current clamp I would show that the batteries had about a 7-8 amp draw. I feel like I am missing something but I know that the battery positive and the positive to the circuit breaker to the inverter are the only things on that side of the switch. Anyways just wanted to report back how it went for future readers to base decisions from.

Unless I'm interpreting this all wrong ... your current numbers almost balance, and maybe even do counting for efficiency issues. Remember current time voltage is (essentially) a constant, and the "essentially" is in there to accommodate efficiency issues. So:

8A X 12V = 96W
96W / 120V = 0.8A

Of that 0.8A, roughly 0.25A is inverter use/loss (as you stated 2.5A @ 12V) which leaves you about 0.55A which is close to your stated 0.5A value.

[tech740]

Unless I'm interpreting this all wrong ... your current numbers almost balance, and maybe even do counting for efficiency issues. Remember current time voltage is (essentially) a constant, and the "essentially" is in there to accommodate efficiency issues. So:

8A X 12V = 96W
96W / 120V = 0.8A

Of that 0.8A, roughly 0.25A is inverter use/loss (as you stated 2.5A @ 12V) which leaves you about 0.55A which is close to your stated 0.5A value.


That makes sense. I was forgetting that 12v amps isn’t the same as 110 amps. Thanks

[sourdough]

That makes sense. I was forgetting that 12v amps isn’t the same as 110 amps. Thanks


Amps are amps as far as I've ever studied:

"DC Amps and AC amps are the exact same thing, they are the measurement of electrons past a given point, the difference is that the electrons of AC go back and forth (alternating) and DC go only in one direction".

I will tell you when you want to get "astraddle of them" DC is almost like a hot burn, AC feels like it will blow your heart up (when "astraddle" of it; btdt) and pulse every fiber of your being.

[SummitPond]

That makes sense. I was forgetting that 12v amps isn’t the same as 110 amps. Thanks

Amps are amps as far as I've ever studied:

"DC Amps and AC amps are the exact same thing, they are the measurement of electrons past a given point, the difference is that the electrons of AC go back and forth (alternating) and DC go only in one direction".

I will tell you when you want to get "astraddle of them" DC is almost like a hot burn, AC feels like it will blow your heart up (when "astraddle" of it; btdt) and pulse every fiber of your being.

Danny is right - an ampere (or shortened, amp) is literally a measure of the number of electrons that pass a given point in one second; it is independent of the type of electromotive driving force, voltage.

My comment came from the principle of conservation of energy, in this instance a watt (which is energy per second). The energy output has to equal the energy input. As no device is 100% efficient, some of the energy that passes through it will be "lost" to heat, thus the input side has a greater power consumption than the output side can deliver. The difference between the input energy and output energy is heat energy, so:

input energy = output energy + heat energy

[moparmad]

FYI check all the fuses for the converter internal and external, the converter can show you a voltage charge but put out no actual amperage and that is almost always a blown fuse in the converter... just in case... Sometimes when you use high amperage systems and a completely dead battery it can overload the converter, some have regular bus fuses some have slow blow fuses.

[JRTJH]

Also remember that most inverters use a step up transformer to increase the voltage from 12 VDC to 120 VAC, then the "inverter" puts the "cycles" in the solid voltage waveform....

Any time the inverter is plugged in, the 10:1 step up transformer primary winding is energized and is "flowing DC power through the winding". That causes a "heat loss" and is the "parasitic loss" or the 1/4 amp load shown on a DC ammeter connected to the power input on the inverter. Then, to add "wasted energy" if the CONverter is still powered on by the INverter, the CONverter will try to charge the batteries, which creates an "energy consuming circuit that goes nowhere fast"... In other words, you use battery power to make AC and use that AC to make DC to charge the battery that's providing DC to the AC producer....

There is an enormous amount of "wasted energy if that is happening.

THEN, to "add insult to injury" remember the posts about "120 volts at .8 amps is the same as 12 volts at 8 amps. The "DC side of the equation "loses power" much faster than the AC side uses it... So, depending on the battery system, the inverter can "suck down a battery charge" at phenomenal speed, even when everything is turned off on the 120 VAC side (through that primary winding) especially if the CONverter is left on.

This link may explain it a bit better than I can: https://www.guaranty.com/blog/whats-the-difference-between-an-inverter-and-converter/