No 12 VDC Power in 2005 Ambassador - 120 VAC OK

[Dr4Film]

Tom,

The Amp-L-Start is still in production and is definitely a good choice as I installed one in my Windsor when the Lambert Battery Maintainer failed. Lambert is out of business.

However, I much better device to install s the Blue Seas ML-ACR than either of the Lambert or Amp-L-Start.

Ed, you should also consider getting rid of those BEP Battery Shut-Off Switches and replace them with Blue Seas, Perko or Guest switches. The BEP just can't handle the high amperage needed.

[MyronTruex]

Since I suggested not using continuity way way back I'm not going to try to absorb all of the information in between. Sorry. It should take about two or three voltage measurement to get out of that front run bay if the fault is not there.

I looked at the schematic for his unit before posting my previous suggestion and his picture confirms the schematic is good.

Look at the bottom right of the circuit board where there is a pile of white wires. Move the black covered wiring over so you can read the circuit board. It may say chassis negative or something like that. 

Meter negative goes there. Use your positive probe to touch "house 12 volt non-switched". This will tell you if your meter is connected correctly and that there is power there. If no power, keep touching large round binding posts until you see the meter is functioning correctly. 

If you find power on that terminal mentioned, move down to the silver 12 volt breaker right below and check both posts. If no voltage, go ahead and touch each side of the large solenoid. Keep the negative terminal where it is at all times. 

A solenoid can show continuity and still not hold up under load. 

 

[WayneC]

2 hours ago, Dr4Film said:

Tom,

The Amp-L-Start is still in production and is definitely a good choice as I installed one in my Windsor when the Lambert Battery Maintainer failed. Lambert is out of business.

However, I much better device to install s the Blue Seas ML-ACR than either of the Lambert or Amp-L-Start.

Ed, you should also consider getting rid of those BEP Battery Shut-Off Switches and replace them with Blue Seas, Perko or Guest switches. The BEP just can't handle the high amperage needed.

Richard 

I still have the original 2 battery shut offs,one for house, one for starting batteries,they are located in the same compartment as the batteries, are those the one's that you suggest replacing ? If so are those the brands your suggesting in the post? Doing a whole bunch off maintenance/upgrades in couple months,just Starting to order parts

Thanks 

Wayne 

1999 Signature ceaser 

[Tom Cherry]

2 hours ago, Dr4Film said:

Tom,

The Amp-L-Start is still in production and is definitely a good choice as I installed one in my Windsor when the Lambert Battery Maintainer failed. Lambert is out of business.

However, I much better device to install s the Blue Seas ML-ACR than either of the Lambert or Amp-L-Start.

Ed, you should also consider getting rid of those BEP Battery Shut-Off Switches and replace them with Blue Seas, Perko or Guest switches. The BEP just can't handle the high amperage needed.

Richard,

I never had one of these and there has been so much posted about them in the past 13 years, I guess that my "brands" have run together.  I did have a long conversation many years ago with the folks at Lambert.  They were in hard times and the Lambert was very expensive.  I THOUGHT it was out of business....but maybe not.  The Amp-L-Start is still there and was a much lower priced competitor.  

However, the comments and the explanation of the how they work still stand.  I used the same language and explanation that I got about how they worked from Lambert.  They do "STEAL" Power and left unchecked or uncontrolled, they will eventually drain down, I think the system.

In the OP's case, he as very expensive Li Batteries that will not take well to total Discharge.

As to the Blue Seas ML-ACR, that is a great system.  Van Williams did extensive research and has a great article here on it.  It is more expensive and require more knowledge and also more labor to install.  There is some heavy duty cabling that has to be created.  However, the main problem, to get full benefit from it is the multiple wire NEW harness that must be run from wherever the OLD Boost solenoid is to the Cabin and then rewiring of the Boost Switch (or perhaps replacing).  The existing Monaco circuitry, at least on the ones that I have looked at, do not have enough "leads or conductors", so you run a new harness.

Myself and some savvy Dynasty owners have evaluated and decided NOT to change it out.  BUT we already have BIRD charging.

That is the Caveat that must be stated.....it works great on old systems.....and is obviously better than what was installed.

BUT....the CONCERN (Danger?) is that with the Lithiums that the OP has, it might not functrion or prevent damage.

THAT is why I suggested a 120 VAC powered pulsing maintainer.  Then the Low Voltage Cut Off can be set to keep the Inverter from draining down the Lithiums and damaging them

Thanks for the correction on the "branding" of Lambert and Amp-L-Start

 

[Dr4Film]

3 minutes ago, WayneC said:

Richard 

I still have the original 2 battery shut offs,one for house, one for starting batteries,they are located in the same compartment as the batteries, are those the one's that you suggest replacing ? If so are those the brands your suggesting in the post? Doing a whole bunch off maintenance/upgrades in couple months,just Starting to order parts

Thanks 

Wayne 

1999 Signature ceaser 

Wayne, are they BEP switches or some other brand?

Photos of failed BEP switches included.

[MyronTruex]

Great pictures Richard. That is a great example of how an ohmeter/continuity testor can read what appears to be a good set of contacts. But the poor mating surfaces will not carry a real load and the voltage can drop to zero when under a load. 

Even a voltage test on a battery switch in an RV can fool you IF the battery banks are mostly charge and there is little demand for current to flow across poor contacts. 

Your meter may show full voltage on both sides of that switch until one bank gets run down a bit. Kind of tricky if you do not have a good grasp on how the individual RV is setup. I can think of a couple of ways to isolate it but often a simple replacement is the best way.

I rarely ever suggest throwing parts at a problem but substitution is a valid test of course. Getting voltage measurement before and after is an absoute must to verfy the solution is good. 

[WayneC]

3 hours ago, Dr4Film said:

Wayne, are they BEP switches or some other brand?

Photos of failed BEP switches included.

Not sure from that view,I believe the ones I have are Afurkvot high current battery disconnect switch, 12v - 48V.

$ 24.00 each on Amazon.  I am flying back home from the coach, I was following along reading the posts but was unfortunately at the airport already. I did not have a chance to change the second solenoid and still had no 12volt in the coach when I locked her up yesterday.

Thanks 

Wayne 

1999 Signature ceaser 

[Ivan K]

Wayne, if you only replaced the left one of the two solenoids, it only sends power to FRB. The one to the right is for interior. As far as the switches, I suppose you also have the ones with metal handle and casing and connections are made outside of the battery box wall. I never had a problem with those and used them in other battery disconnect applications too. That upper 'house' switch also disconnects inverter/charger power so if that worked, the switch is good. I would expect our wirings to be identical.

[WayneC]

Thanks Ivan

You are correct, I did change the right side one ,and the shut offs work fine.going to have to do some more digging around to why no 12 volt in the coach,120 is good.

Thanks

Wayne 

1999 Signature ceaser 

[MyronTruex]

8 hours ago, myrontruex said:

Since I suggested not using continuity way way back I'm not going to try to absorb all of the information in between. Sorry. It should take about two or three voltage measurement to get out of that front run bay if the fault is not there.

I looked at the schematic for his unit before posting my previous suggestion and his picture confirms the schematic is good.

Look at the bottom right of the circuit board where there is a pile of white wires. Move the black covered wiring over so you can read the circuit board. It may say chassis negative or something like that. 

Meter negative goes there. Use your positive probe to touch "house 12 volt non-switched". This will tell you if your meter is connected correctly and that there is power there. If no power, keep touching large round binding posts until you see the meter is functioning correctly. 

If you find power on that terminal mentioned, move down to the silver 12 volt breaker right below and check both posts. If no voltage, go ahead and touch each side of the large solenoid. Keep the negative terminal where it is at all times. 

A solenoid can show continuity and still not hold up under load. 

 

My apologies, I have been quite ill for several days and just could not read all of the last threads before posting this. However it would have taken you to the battery compartment in just a couple of readings. Good information to save for the future. My first impression was it was going to be the breaker in the bottom of the front run bay. The silver one. Mine is actually just like the one you have in the battery compartment. There is a chance your system was modified and that breaker moved to that location. 

We have almost identical systems and layout for future reference. They made few changes between your model and mine. 

[saflyer]

On 2/21/2023 at 9:45 AM, Tom Cherry said:

Richard,

I never had one of these and there has been so much posted about them in the past 13 years, I guess that my "brands" have run together.  I did have a long conversation many years ago with the folks at Lambert.  They were in hard times and the Lambert was very expensive.  I THOUGHT it was out of business....but maybe not.  The Amp-L-Start is still there and was a much lower priced competitor.  

However, the comments and the explanation of the how they work still stand.  I used the same language and explanation that I got about how they worked from Lambert.  They do "STEAL" Power and left unchecked or uncontrolled, they will eventually drain down, I think the system.

In the OP's case, he as very expensive Li Batteries that will not take well to total Discharge.

As to the Blue Seas ML-ACR, that is a great system.  Van Williams did extensive research and has a great article here on it.  It is more expensive and require more knowledge and also more labor to install.  There is some heavy duty cabling that has to be created.  However, the main problem, to get full benefit from it is the multiple wire NEW harness that must be run from wherever the OLD Boost solenoid is to the Cabin and then rewiring of the Boost Switch (or perhaps replacing).  The existing Monaco circuitry, at least on the ones that I have looked at, do not have enough "leads or conductors", so you run a new harness.

Myself and some savvy Dynasty owners have evaluated and decided NOT to change it out.  BUT we already have BIRD charging.

That is the Caveat that must be stated.....it works great on old systems.....and is obviously better than what was installed.

BUT....the CONCERN (Danger?) is that with the Lithiums that the OP has, it might not functrion or prevent damage.

THAT is why I suggested a 120 VAC powered pulsing maintainer.  Then the Low Voltage Cut Off can be set to keep the Inverter from draining down the Lithiums and damaging them

Thanks for the correction on the "branding" of Lambert and Amp-L-Start

 

You say a battery maintainer for the chassis battery needs to be at least a 1.75-2 amp one. Why is that. I have a 1 aml Battery Minder that I was thinking of using. Would that not work?

Ed

[Tom Cherry]

39 minutes ago, saflyer said:

You say a battery maintainer for the chassis battery needs to be at least a 1.75-2 amp one. Why is that. I have a 1 aml Battery Minder that I was thinking of using. Would that not work?

Ed

If you have an accurate clamp on ammeter, you can measure the parasitic load for your particular MH….and it w8ll vary.  Sometimes the type of IRD or whether you leave several phone chargers in the plugs or the minute amount of resistance in a cable connection or the gauge and length of the cables…..it all depends.  Those of us that have done such confirm that the parasitic load is around  1.75 A.  We also know that most are barely rated for 1.0A….and that is often overstated.  So, to get full reliability, purchase one with a minimum of 1.75.  Actually 2 amps would be better.  Don’t buy a cheap 2-6 A as it has no electronics to control Amps and Volts like the MH inverters have.  They will overcharge and toast (dry out) your battery as most starting batteries are sealed.

read the specs and get one that desulfonates.  

Pulse Tech is a brand that many use here to desulfonate.  They are trusted like Trojan.  They make an XC400.  Amazon sometimes has it.  Not today. 

https://www.pulsetech.net/xc400-xtreme-charge-4-amp-12v-battery-charger-desulfator.html

two of the smaller import brands that might not be reliable or deliver at least a combined (2 maintainers hooked will be additive) 2 amps MIGHT work, but I would buy the Pulse Tech as I trust their specs.

[saflyer]

39 minutes ago, Tom Cherry said:

If you have an accurate clamp on ammeter, you can measure the parasitic load for your particular MH….and it w8ll vary.  Sometimes the type of IRD or whether you leave several phone chargers in the plugs or the minute amount of resistance in a cable connection or the gauge and length of the cables…..it all depends.  Those of us that have done such confirm that the parasitic load is around  1.75 A.  We also know that most are barely rated for 1.0A….and that is often overstated.  So, to get full reliability, purchase one with a minimum of 1.75.  Actually 2 amps would be better.  Don’t buy a cheap 2-6 A as it has no electronics to control Amps and Volts like the MH inverters have.  They will overcharge and toast (dry out) your battery as most starting batteries are sealed.

read the specs and get one that desulfonates.  

Pulse Tech is a brand that many use here to desulfonate.  They are trusted like Trojan.  They make an XC400.  Amazon sometimes has it.  Not today. 

https://www.pulsetech.net/xc400-xtreme-charge-4-amp-12v-battery-charger-desulfator.html

two of the smaller import brands that might not be reliable or deliver at least a combined (2 maintainers hooked will be additive) 2 amps MIGHT work, but I would buy the Pulse Tech as I trust their specs.

Those are the details I needed.

Thanks

[saflyer]

On 3/6/2023 at 1:13 PM, saflyer said:

Those are the details I needed.

Thanks

 

On 3/6/2023 at 12:33 PM, Tom Cherry said:

If you have an accurate clamp on ammeter, you can measure the parasitic load for your particular MH….and it w8ll vary.  Sometimes the type of IRD or whether you leave several phone chargers in the plugs or the minute amount of resistance in a cable connection or the gauge and length of the cables…..it all depends.  Those of us that have done such confirm that the parasitic load is around  1.75 A.  We also know that most are barely rated for 1.0A….and that is often overstated.  So, to get full reliability, purchase one with a minimum of 1.75.  Actually 2 amps would be better.  Don’t buy a cheap 2-6 A as it has no electronics to control Amps and Volts like the MH inverters have.  They will overcharge and toast (dry out) your battery as most starting batteries are sealed.

read the specs and get one that desulfonates.  

Pulse Tech is a brand that many use here to desulfonate.  They are trusted like Trojan.  They make an XC400.  Amazon sometimes has it.  Not today. 

https://www.pulsetech.net/xc400-xtreme-charge-4-amp-12v-battery-charger-desulfator.html

two of the smaller import brands that might not be reliable or deliver at least a combined (2 maintainers hooked will be additive) 2 amps MIGHT work, but I would buy the Pulse Tech as I trust their specs.

Looking at a couple or three chargers, Schumacher 10a and 8a units that say they are maintainers and a Noco Genius 5. They all say they are set and forget chargers/maintainers but the Noco also says it has an onboard temperature sensor and a desulphanator which the Schumacher units don’t mention. I’m hoping a charger such as one of these can serve my purposes for general use in the motorhome. What are thoughts on these or are there better alternatives?

Ed             
‘05 HR Ambassador