No 12V To Ignition: Alternator Problem?

[NoviceKnomad]

2003 Holiday Rambler Traveler having problem with 12v side (chassis) House side good.

It started when battery swelled and spilled acid. I replaced battery and now chassis is completely dead.

My question is could the alternator cause this ignition to have no power at all?? 

[wolfe10]

NoviceKnomad,

Welcome to the FMCA Forum.

No, an alternator is very unlikely to cause this, unless your chassis battery is so discharged while driving that the battery is dead.

What is voltage at the chassis battery?

I have no schematics on your particular coach, but most motorhomes use an IGNITION SOLENOID. The ignition switch/key turns on the ignition solenoid when then powers all those things that are on when and only when the ignition is on.

 

[abyrd]

Most likely you alternator is not causing the problem.  Starting at the battery, check the voltage to ground at each connection unit you read (0) volt.  Then trace backwards until you find the problem.

Jim

[NoviceKnomad]

but i have gone thru 3 batters because they overcharged but this time when hooking new battery i have no ignition but can get ignition from boost switch?

03 traveler 12v.pdf

[kaypsmith]

Your alternator may very well have a problem, or actually the voltage relay, which can and will allow the battery to overcharge and possibly explode. But the alternator probably is not why there is no ignition voltage. The relay that Brett refers to is the most likely culprit for no ignition voltage. The last explosion may have caused the relay to go bad. If you are overcharging you certainly must track down the reason for this happening. I don't know about your unit, the schematic is too small for me to read without downloading at this time, but many alternator systems have the charge relay built in and some have an external relay for this function, so you will need to verify which one and get this corrected. Sometimes a bad ground will cause the overcharging to happen, and a dead cell in a battery/battery bank can also cause same to happen. If I were troubleshooting, I would make attempts to locate the source that is causing no voltage on the ignition system first, then go after the reason for the battery overcharging very aggressively. Good luck finding it, and as stated by Brett, Welcome to the forum.

[rsbilledwards]

What trans is in the coach, Allison, then possibly a fuse in the VIM below the key pad. All the above suggestions are valid. You have to trace it down. It does make a difference which cable is attached first.  Ask me how I know. Please post the solution or resolution to help us all.

Thanks,

B

[NoviceKnomad]

Thanks to all i did find the breaker popped right after the battery cut off and ignition is on again now to check for the overcharge problem

THANKS AGAIN JDF aka NoviceKnowmad

[abyrd]

Glad you were able to find a problem. Thanks for the update.  Trouble shooting the alternator should not be as difficult.  I would start by monitoring your battery voltage when you start you engine,  the correct voltage should range between 13.2v to 13.8v depending how you voltage regulator is set.

 

Jim

[wolfe10]

And, when first started and at 1000 RPM or higher, even 14.0.  If higher, next question is what alternator do you have/what battery isolator do you have.

If a diode-based isolator, there will be an EXTERNAL SENSE WIRE on the chassis battery side of the battery isolator. It is a small gauge wire (just a signal wire), and even a little corrosion or loose connection at either end can cause excessive voltage.

[rsbilledwards]

With Brett bringing up the isolator, that brings up another point. It seems that they have a life span and when they reach that point they create all kinds of havoc in the electrical system primarily between the alternator and itself. Many of us in the Safari coach crowd have experienced this issue. I suggest you preform a preemptive strike and pitch the original and replace it with a new one. They are very inexpensive on Amazon. Stay with the old one  and remember this suggestion cause it will be a real head ache, ask me how I know.

Good luck

B

 

[xdieselbob]

On ‎10‎/‎24‎/‎2017 at 8:31 AM, RSBILLEDWARDS said:

With Brett bringing up the isolator, that brings up another point. It seems that they have a life span and when they reach that point they create all kinds of havoc in the electrical system primarily between the alternator and itself. Many of us in the Safari coach crowd have experienced this issue. I suggest you preform a preemptive strike and pitch the original and replace it with a new one. They are very inexpensive on Amazon. Stay with the old one  and remember this suggestion cause it will be a real head ache, ask me how I know.

Good luck

B

 

Bill: I own a 2001 Safari Zanzibar and have replaced the original alternator with a single wire 180 amp Delco. If you understand the purpose of the isolator it really is not necessary. The isolator is used to direct alt charge to either house or coach batteries as needed. The inverter has a battery charged built in to keep house batteries charged. We have been on the road full time for three years and have not had a problem without the isolator. You just need to hook battery wire from alternator to coach side of bus bar to keep chassis batteries charged. 

[rsbilledwards]

Yes BOB you are quite right. I too have a 2001 Zanzibar but for sale. I also have a 1999 Panther and the alt is hooked straight to the chassis batteries. I added another tray in the engine compartment for the chassis bats and added a pair of sixes to the house tray. It has a full solar, 6 panels at 960 watts and that is hooked to the house through Bogart's Trimetric stuff. When home and this time of year it is plugged in and all is well through the echo charger. We are headed out January one for sunny Arizona and the Safari Party in Quartzsite.

There was no way for me to know your background and many have no clue to the problems the isolator can create. The same for you and my coach history/experience let alone it being with Safari coaches learned over the last 8 or so years. One must start somewhere to find out what comes next. Glad to have you aboard the forum. If you have not, look into safarifriends@yahoogroups.com, huge files section on Safari and a great group.

 

[wolfe10]

Indeed there are a number of viable alternatives to battery isolators and even two distinctly different types of battery isolators-- diode-based and solenoid-based.

One of the simplest that still allows battery bank separation (so discharging the house bank will not take down the chassis bank) is a simple marine ON-OFF switch.  Alternator B+ and chassis battery to one lug and coach battery to the other.  Switch OFF and chassis battery will be charged.  ON and both banks will be charged.  With a DP, pretty easy to mount at foot of bed where easily switched from inside the coach.  Been there, done that.

 

BUT (read that a BIG BUT) one needs a complete understanding of their charging system to successfully modify it.  Does the alternator have an external sense wire?  Does the alternator have an ign hot excite wire.  What type of battery isolator is used? Questions like these MUST be understood before it is reasonable to modify  factory wiring.