Battery charging issue - see below!

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Bannister2014
Posts: 11
Joined: Sun Nov 04, 2018 2:28 pm

Battery charging issue - see below!

Post by Bannister2014 »

My coach is a 2003 26RSB with the Ford V-10.
I recently had a problem with the vehicle battery and replaced it wit a new one.
Next, I had issues with the coach batteries losing power and replaced both of them.
Shortly thereafter, I found that the vehicle battery was not being charged.
I replaced the alternator and checked all wiring - all OK, except now the vehicle battery is still not charging and the coach batteries are being charged at 18+ volts when the engine is running, with the resultant smell of sulfuric acid in the battery compartment.

I suspect the isolator is to blame, but am looking for advice from anyone who has had a similar issue.

HELP!!!

Bannister
Bannister2014
2003 26RSB Casual Elegance
2008 Smart cabrio TOAD
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whemme
Posts: 2110
Joined: Mon Aug 15, 2005 8:05 pm

Re: Battery charging issue - see below!

Post by whemme »

Bannister,

Well you have already thrown a lot of parts at trying to fix the problem. I do believe that your battery isolator has probably failed. The battery isolator in your born Free is most likely a Sure Power P/N 1602. You will find it attached to the inside of the E450's frame rail around the area under the driver's seat. You will have to slide under your coach in order to see it attached with 8 screws. It is a 3 terminal device. Most likely the Battery 1 terminal output has failed. How this works is that the E450's alternator output is connected to center A terminal. Then the isolator's terminal 1 is connected back to your chassis battery and also your alternator's voltage regulator. The isolator's terminal 2 is connected to your house batteries. In normal operation when your chassis engine is started, the alternator output connected to terminal A gets feed back to the chassis battery and the alternator's voltage regulator via terminal 1. Since the chassis battery voltage is feeding the alternator's voltage regulator, the voltage regulator will typically set the alternator's charge voltage output to the +14.0 vdc range. This same charge voltage is feed to your house batteries via terminal 2.

Now if the isolator's terminal 1 output fails, no charging voltage gets to the chassis battery but worse the alternator's voltage regulator seeing no charge voltage cranks up the alternator voltage to the maximum +18.0 vdc available thus causing your house batteries to start boiling acid - this will destruct your house batteries quickly.

A test you can do to verify the isolator failure is to climb under the coach with a volt meter and with the chassis engine running, check the voltage on terminal A - it will probably be about +18.0 vdc. Then check the voltage on terminal 1, it will probably be zero verifying the isolator failure.

You can buy a new Sure Power 1602 from several sources on the internet. The least expensive I found was $67.05 from the following source by clicking on the link below.

https://allbatterysalesandservice.com/s ... utput-1602
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Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
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Bannister2014
Posts: 11
Joined: Sun Nov 04, 2018 2:28 pm

Re: Battery charging issue - see below!

Post by Bannister2014 »

Bill,

Thanks so much for the detailed reply.
I have tested the isolator and found it is, in fact, defective.
A new 1602 is on its way.
FYI, the alternator was making a squealing noise, so by replacing it, I prevented a future failure, due to bad bearings.
Have a Blessed Thanksgiving.

Bannister
Bannister2014
2003 26RSB Casual Elegance
2008 Smart cabrio TOAD
User avatar
Bannister2014
Posts: 11
Joined: Sun Nov 04, 2018 2:28 pm

Re: Battery charging issue - see below!

Post by Bannister2014 »

Well, the saga continued, even after I installed the new isolator. . . no power to the battery.

So, I started tracing circuits and found a fault between the cable coming from the isolator to the connector and the one going from the connector to the battery.

Apparently, the connector had corroded so badly that it was not allowing current to pass from the isolator cable to the battery.

After cutting the cables and reconnecting, using an aluminum connector I had on hand, the battery is again being charged at 14.3V.

So, I still don't know what the failure sequence was (alternator, isolator or vice versa), but all is well now.

Bannister
Bannister2014
2003 26RSB Casual Elegance
2008 Smart cabrio TOAD
User avatar
whemme
Posts: 2110
Joined: Mon Aug 15, 2005 8:05 pm

Re: Battery charging issue - see below!

Post by whemme »

I had suggested that you use a voltmeter to measure the voltage on both terminals A and 1 on the isolator with the chassis engine running. If you had +18 vdc on terminal A and 0 vdc on terminal 1, then the isolator would be defective. If however there was +18 vdc on terminal 1 but still no charging voltage getting to your chassis battery, then the isolator would not be faulty but somehow the connection between terminal 1 to your chassis battery would then be open circuit for some reason.

Did you ever measure those terminal A and 1 voltages?
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
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