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Topic: "True Ignition Source" for Battery Isolator and Relay (Read 17 times) previous topic - next topic
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"True Ignition Source" for Battery Isolator and Relay
Yahoo Message Number: 99190
Hello all,

I am going to get rid of the stock battery isolator in my 82 LD.
Although it's  working reliably, I just can't stand its inefficiency.  When the alternator is running, the voltage at the chassis battery is 14.5V, but only 13.5V at the coach battery.  No wonder my 75AH house battery does not get fully charged after 3 - 4 hours driving.
 Thanks to Larry for Msg #14572, I learned about the 3 different types of isolator/combiner and decided to go with a Relay System.  It's cheaper ($25 on Ebay) than the more sofisticated Hellroaring unit.
 http://www.sonicelectronix.com/item_16885_Stinger+SGP38.html

Looking at the installation process, I got stuck at "True ignition source".
 http://www.discountcarstereo.com/pdf/sr200.pdf

What is a "True ignition source"?  Help!  How do I make that connection?

Thanks,

Sam
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #1 –
Yahoo Message Number: 99192
"Looking at the installation process, I got stuck at "True ignition source".
http://www.discountcarstereo.com/pdf/sr200.pdf What is a "True ignition source"? Help! How do I make that connection?"

Sam
 To activate the relay, you need to find a power source, under the dash or hood, that is switched on or off by the ignition switch.
Its been a while but I seem to remember that when I wired our 1983 LD, I spliced into a switched 'accessory' hot wire coming down the steering column from the ignition switch.
I used the accessory wire so the relay would not be powered when the engine was cranking but would energize as soon as the engine started and the starter was disengaged.
The down side of using a 'dumb' relay is that the batteries can be tied together even if the engine is not running.
'Smart' relays sense when the alternator is charging and then connect the batteries. This prevents the accidental discharging of both batteries
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #2 –
Yahoo Message Number: 99194
Quote
I am going to get rid of the stock battery isolator in my 82 LD.
Although it's  working reliably, I just can't stand its inefficiency.  When the alternator is running, the voltage at the chassis battery is 14.5V, but only 13.5V at the coach battery.  No wonder my 75AH house battery does not get fully charged after 3 - 4 hours driving.
Let me point out that with the voltage readings you are getting, you don't have an inefficient isolator, you have a problem. The isolator is simply a pair of diodes, with a maximum voltage drop of about a volt in the forward conduction direction, at high current. Two possibilities:

1)Your coach battery has a shorted cell, drawing a heavy charge  current. This would also mean that the chassis battery is charging  very little, and is essentially fully charged, and the isolator is  working as it should.

2)The isolator has an open diode to the coach battery, or shorted  diode to the chassis battery. With engine running, check the voltage  on the isolator input, as well as the outputs. If the input is the  same as the chassis battery output, then disconnect the coach battery  from the isolator terminal (don't let it short!), and recheck  voltages. If the isolator input voltage rises, the chassis battery  diode is ok. Then check the coach battery voltage. If it is lower,  then the coach battery diode is good, and you probably need a new  battery. Let the coach battery rest a few hours and recheck its  voltage. If below 11.9 volts, it is definitely bad.

Note that a diode isolator, while it does dissipate some power, is  nearly perfect at distributing current requirements to the battery  banks, and it won't 'wear out', as relay contacts will. There are also  several other charging system factors you should be aware of:  
1)The alternator on that vintage Chevy is driven by a poorly-routed  v-belt. It is vital the belt be in top shape and belt tension be set  with a gauge to the proper range. Slippage under load is very common,  and often hard to detect, but the resultant heating will destroy your  alternator.

2)The standard LD supplied alternator is only rated at 45 Amps. If it  has not already been upgraded, you may want to consider it. If you do,  and elect to stay with the diode isolator, it may need to be upgraded  as well. You can find them at Pep Boys, etc.

3)The LD supplied converter, if a battery-charging model, will
 overcharge and destroy your coach battery if left plugged in for extended periods.

Steve
2004 FL
2013 Honda Fit
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #3 –
Yahoo Message Number: 99195
I forgot to mention:
 If your coach battery is 75 A-hr, it is likely a group 24. Although it is a squeeze maneuvering it in, there is room for a group 27, with ratings in the range of 105-125 A-hrs.

Steve
2004 FL
2013 Honda Fit
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #4 –
Yahoo Message Number: 99196
Thank you, Larry.  I appreciate it.

Sam
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #5 –
Yahoo Message Number: 99197
Wow!  Thank you, Steve.

You're probably right that my coach battery is bad.  I'll check it out.

Yes my current 75AH is a group 24.  Thanks for bringing up the 27.
That's the one I've been looking at, and wondering if it would fit.

Sam
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #6 –
Yahoo Message Number: 99198
"Slippage under load is very common, and often hard to detect, but the resultant heating will destroy your alternator."
 And/or your belt--take it from a former 1985 LD owner who knows! :-)

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #7 –
Yahoo Message Number: 99199
Quote
Let me point out that with the voltage readings you are getting, you don't have an inefficient isolator, you have a problem.
Steve,

Don't you mean:

Quote
Let me point out that with the voltage readings you are getting, you HAVE an inefficient isolator AND a problem.
1 volt drop is very inefficient, correct?  Of course it does not mean that my isolator is bad.  It's just the way it's designed.

So after replacing my bad coach battery, I would still benefit more from a relay than the current isolator when charging with the alternator, right?

Thanks,

Sam
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #8 –
Yahoo Message Number: 99201
Quote
1 volt drop is very inefficient, correct?  Of course it does not mean that my isolator is bad.  It's just the way it's designed.

So after replacing my bad coach battery, I would still benefit more from a relay than the current isolator when charging with the alternator, right?
If the isolator has not been damaged, then the 1V drop means you are charging with a high current. Since the battery charge is Amps X Hours, the high charge current is all that really matters. Likewise your alternator is rated by current output, so it will simply 'seek' an input voltage to the isolator to produce the required output current. For example, with a 1V drop across the isolator and 45A charge current, the isolator will be dissipating 45W as heat. The alternator will be supplying 45A X 13.6V = 612 Watts of charging to the battery. You won't notice any change in gas mileage from the 45W dissipated by the isolator, and it will add an insignificant demand to the alternator. Bottom line is you will get no additional charge current from a relay, so it will not reduce your charge time. However, the relay may increase the time it takes to fully recharge your chassis battery, since its charge voltage will be reduced. The isolator allows the ideal charge voltage to be produced across each battery to maximize charge current to each.

Steve
2004 FL
2013 Honda Fit
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #9 –
Yahoo Message Number: 99202
"When the alternator is running, the voltage at the chassis battery is 14.5V, but only 13.5V at the coach battery. No wonder my 75AH house battery does not get fully charged after 3 - 4 hours driving.
Sam

In addition to Steve's advice, you should check for voltage drop across all of the connections and wires in the charging circuits.
I found a couple crimped connections in our 1983 LD that were bad.
Chopping the old leads off and installed new cured the problem. If possible, solder the high-current connections.
Where connections screw or push together, butter everything with a little dielectric grease to help seal out moisture and prevent corrosion. http://tinyurl.com/ah9ggg>
 Steve mentioned the small 45-amp alternator. Ours originally had a 60- amp and it was way too small.
Replacing it with a larger alternator was one of the first major improvements made in our 83 LD.
Our old LD's 3-way refrigerator would ran on 12-volts, to be used while driving. The refrigerator used around 24-amps on 12-volt power.
The stock alternator did not have enough output to run the engine, dash A/C and the refrigerator at the same time. The battery would discharge while driving. We had to run the refrigerator on propane while on the road.
I found a 150-amp marine alternator that fit with a little modification of the mounting bracket. After upgrading of the wires from the alternator to the battery and isolator relay, we had no other charging problems.
 I would look for as large a self-regulated, one-wire Delco alternator as will fit in your LD. They are super-simple to wire.  You cannot have too powerful an alternator.

Steve also mentioned the fan belt. He is 100% correct. The belt driving the alternator is small and under a lot of stress. They wear out quickly and can jump if not keep correctly tensioned, not to mention burning the alternator's front bearing.
Always carry a full set of spare belts. If one jumps, (and they do jump) it will usually take the rest of the belts with it and produces a terrible mess that sometimes needs to be cut out.  A very pleasant job to do on the side of the road. Do your maintenance at home to prevent this.
 Buy yourself a Krikit I V-belt tension gauge and learn how to use it.
Napa carries them.  Make sure to get the Krikit 1 V-belt model.
The more commonly available Krikit 2 is made for flat and serpentine belts, the type of belts used in late-model cars and light trucks.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #10 –
Yahoo Message Number: 99207
"1 volt drop is very inefficient, correct? Of course it does not mean that my isolator is bad. It's just the way it's designed."
 A silicon diode drops 0.6V, so that's the minimum voltage drop you can expect from a diode-type isolator. While that might sound inefficient, in the grand scheme of things it makes very little difference. If your alternator is doing its job and your batteries are able to accept a charge, you'll never notice a drop that small. And diode isolators, which have no moving parts and no contacts to corrode, are much more reliable than the old relay type. That's why most modern RVs use them.
 I agree with Steve: your isolator probably isn't at fault. Check your wiring, and if necessary, put in a new battery. Chances are that will solve your problems.

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #11 –
Yahoo Message Number: 99208
Thank you, Steve, Larry, and Andy.

You have given me a lot to think about.  I appreciate your help.

Sam
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #12 –
Yahoo Message Number: 99210
Quote
Steve mentioned the small 45-amp alternator. Ours originally had a 60-amp and it was way too small.
....

Quote
You cannot have too powerful an alternator.
OK, two dumb questions:

1) How do I know which alternator I have?  Is the amperage written  somewhere on the alternator itself? 
2) I plan to replace the battery (if indeed bad) with a group 27
 125AH deep cycle battery.  How high a charge can such battery accept?  Isn't there a limit to how many amp it can take per hour? I looked at the battery spec but could not find it (or may be I don't know what to look for.)

Thanks,

Sam
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #13 –
Yahoo Message Number: 99211
Quote
1) How do I know which alternator I have?  Is the amperage written somewhere on the alternator itself?

2) I plan to replace the battery (if indeed bad) with a group 27  125AH deep cycle battery.  How high a charge can such battery  accept?  Isn't there a limit to how many amp it can take per hour?  I looked at the battery spec but could not find it (or may be I  don't know what to look for.)

1)I checked one I have in the garage, and the specs are stamped into  the casting, just behind the upper mounting lug. On the engine, will  be hard to read. It lists system voltage and output current, etc.

2)The higher the charge current, the more voltage drop across the
 wiring. As a practical matter, it will be self-limiting. My alternator is now 85A, and I doubt it ever puts close to that into battery charging. However, the LD stock isolator in our '83 was rated at 65A, so I had to upgrade that. The isolator not only handles charging current, but also fridge, headlights, and all other electrical functions for both coach and chassis while enroute.

Steve
2004 FL
2013 Honda Fit
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #14 –
Yahoo Message Number: 99214
Hello Group..This question is along the lines of electrical upgrades, but I was wondering if there is an upgrade to the 85 square headlites on our Chevy LD. They are about as usefull as two candles in the wind. Sounds like a song i heard once.
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #15 –
Yahoo Message Number: 99215
" I was wondering if there is an upgrade to the 85 square headlites on our Chevy LD."

John

A few ideas Make sure the alternator is putting out 13+ volts. Check at the battery when the engine is running.

Older vehicles develop electrical problem.
Check the voltage reaching the headlight plugs.
Ground wires often develop resistance, especially where they attach to the frame.

Do you have halogen headlight or the original lamps? Halogens are brighter.
 You could spend some bucks and buy new housings that use replaceable halogen bulbs. You could install much higher wattage bulbs. This could require upgrading of the headlight wires and/or adding a relay.

You could add auxiliary-driving lights to supplement the existing lights.

Hope this helps Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #16 –
Yahoo Message Number: 99216
Quote
Hello Group..This question is along the lines of electrical
upgrades, but I was wondering if there is an upgrade to the 85 square headlites on our Chevy LD. They are about as usefull as two candles in the wind. Sounds like a song i heard once.

I installed halogen replacement sealed units, which are a little better. You are limited in that the wiring is insufficient to handle much more current.

Steve
2004 FL
2013 Honda Fit
Re: "True Ignition Source" for Battery Isolator and Relay - Headligh
Reply #17 –
Yahoo Message Number: 99218
"I installed halogen replacement sealed units, which are a little better. You are limited in that the wiring is insufficient to handle much more current"

Steve
 When I measured our Cherokee's headlight voltage, it was 2 volts less than what was available at the battery, way too much voltage drop.
Rewiring the headlights, using 10-gauge wire and relays, made a big difference in the brightness of the stock headlights and enabled using more powerful bulbs.
 The auto manufacturers have been under sizing wires for years to save on the cost of copper. Our 2003 LD's taillights and toad lights suffered from low-voltage problems until they were rewired.

I changed our 2003 LD's headlights to Silver-Star bulbs but I'm not sure if they are really brighter or just have a blue tint. I should go ahead and upgrade the head light wiring and add a couple extra driving lights for dark roads.
My night vision is not getting any better.
 Today, the most lumens for the dollar are probably the 4" and 7" HID driving lights, sold for less than a $100 each, at Kragen (Parts- America).  I have seen a lot of them in use by the off-road crowd.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #18 –
Yahoo Message Number: 99224
Quote

2) I plan to replace the battery (if indeed bad)...
A new datapoint: I took my LD to Walmart for a battery test (with the expectation to replace the coach battery).  They used the expensive EXP800 tester and concluded that mine was in good health.  Here's the printed result:

Voltage 12.47V Measured:  489CCA Rated:  500 CCA Temperature:  81F "Battery meets or exceeds required standards".
Test code: 20N6201J9AG (I have no idea what that means)
 After test, the technician told me that I might want to clean up all the connections as they look somewhat corroded.  I will do that soon.

I wonder if deep cycle battery should be tested differently than normal starting battery?  I did not ask the tech at the time.  But it looked like he was testing mine as he would a starting battery (using the rated CCA as the standard test parmameter.

Sam
Driving Lights Standards
Reply #19 –
Yahoo Message Number: 99225
"...I should go ahead and upgrade the head light wiring and add a couple extra driving lights for dark roads.

Quote
My night vision is not getting any better..."

Larry
I wish there were consistent, enforceable standards for "driving lights" - aftermarket and original equipment.  It seems like so many newer vehicles not only blind oncoming drivers with high intensity headlamps but exacerbate the situation with unnecessary driving lights.  If indeed newer vehicles have state-of-the-art headlamps, why are driving lights needed except for the "cool" factor and the occasional bad weather event?  Auxiliary lighting for older headlamps assemblies is understandable.  Larry is right; unfortunately as we age, night vision deteriorates.  Hyper-lighted vehicles are an annoyance.

Chris Horst
2002 30' IB
Arvada, CO
Formerly: 2002 30' IB
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #20 –
Yahoo Message Number: 99226
Quote
After test, the technician told me that I might want to clean up all the connections as they look somewhat corroded.  I will do that soon.

I wonder if deep cycle battery should be tested differently than normal starting battery?  I did not ask the tech at the time.  But it looked like he was testing mine as he would a starting battery (using the rated CCA as the standard test parmameter.
Was it disconnected from the vehicle at the time? If not, was the engine running? I would do the voltage tests I mentioned previously, and bear in mind that your system may be working normally if you had simply let the coach battery become heavily discharged. It will have a short life if regularly discharged below 80%, which will be common with a single coach battery and no high-quality external source of charging while your LD is idle.
 Also, it would be a good idea to replace any connectors where there is corrosion, and check all crimps for signs of looseness. Clean binding posts with a wire brush, with all batteries disconnected. (Always pull the ground cable first.)

Steve
2004 FL
2013 Honda Fit
Re: Driving Lights Standards
Reply #21 –
Yahoo Message Number: 99230
I wish there were consistent, enforceable standards for "driving lights

Chris

Europe has more comprehensive regulation pertaining to headlights.
Their headlights (e-code) have better light patterns with very shape cutoffs, similar to better HID headlights, Our headlights, along with our cell phones, are behind the times when compared to Europe and Japan.
Years ago, I remember Jonna ranting about being blinded by HID headlight. The situation today is even worse with more folks installing the dazzling hyper-blue bulbs.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Driving Lights Standards
Reply #22 –
Yahoo Message Number: 99231
Great info as usual from the group...I have two questions on headlights...First one is if and when I replace the "original" 1985 headlites to more modern halogen if memory serves me right the three adjustment screws on the lamps will remain in place, Yes? And if not what are your ideas on *aiming* the beam so as to be most useful? Next question is...if I add highway lamps onto the bumber should they be wired separately with 2 toggle switches and inline fuses or does that matter?  Chevy chassis 1985 oldy but a goody.
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #23 –
Yahoo Message Number: 99232
Quote
Was it disconnected from the vehicle at the time? If not, was the engine running?
No, it was not disconnected from the vehicle, and the engine was not running.

Quote
... and bear in mind that your system may be working normally if
you had
 
Quote
simply let the coach battery become heavily discharged. It will
have a
 
Quote
short life if regularly discharged below 80%, which will be common with a single coach battery and no high-quality external source of charging while your LD is idle.
Can you elaborate on this?  FWIW, I do let the coach battery heavily discharged, sometimes down to 10V.

Sam
Re: "True Ignition Source" for Battery Isolator and Relay
Reply #24 –
Yahoo Message Number: 99233
"I wonder if deep cycle battery should be tested differently than normal starting battery? I did not ask the tech at the time. But it looked like he was testing mine as he would a starting battery (using the rated CCA as the standard test parameter."

Sam

In my previous life (before retirement), I performed and then supervised the maintenance of dozens of battery power vehicles and equipment at LAX. I bought T-105 Trojan batteries by the pallet.
We never found a tester that would quickly and accurately indicate a deep-cycle battery's condition.
What did work was following Trojan's testing recommendations and using a hydrometer to measure specific gravity of each cell. Periodically logging the information gave us a way of watching the gradual decline of the battery packs.
http://www.trojanbattery.com/BatteryMaintenance/Testing.aspx>
 A T-105 battery, heavily discharged daily (60%+) has a life of two or maybe three years. Life span in MH can be as short if excessively discharged regularly.
With lower discharge rates, proper maintenance and intelligent charging, a T-107 can last 5-7 years.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze