Community Forums

glsponchos · 04-18-2018, 02:39 PM

I have a 2010 Tiffin Allegro Bus 43QRP. I’ve noticed that my coach batteries do not appear to be charging from the alternator when traveling. I talked to Tiffin just now and they claim that none of their coaches charge house batteries from the alternator. Does that match everyone’s understanding ? I thought they did charge while traveling

**NLOVNIT** · 04-18-2018, 02:53 PM

House batteries can charge from an alternator but I think it's mostly the chassis battery that gets charged that way. House batteries are charged via the converter when plugged into shore power or through the generator being on.

Lori-

This is a good video about the system:

https://www.youtube.com/watch?v=v6s9yeT1Hd0

awol50 · 04-18-2018, 03:11 PM

My Winnebago Forza keeps the house batteries charged. Not sure exactly how. Maybe by some sort of equalization from the chassis batteries

**NLOVNIT** · 04-18-2018, 03:15 PM

House batteries can also be charged by solar panels. Unfortunately the little panels that come stock on most coaches are just for topping off. Those little things won't fully charge house batteries unless you had much bigger, & muliple, ones on the roof.

Lori-

**Lt Dan** · 04-18-2018, 03:31 PM

Quote:

Originally Posted by glsponchos

I have a 2010 Tiffin Allegro Bus 43QRP. I’ve noticed that my coach batteries do not appear to be charging from the alternator when traveling. I talked to Tiffin just now and they claim that none of their coaches charge house batteries from the alternator. Does that match everyone’s understanding ? I thought they did charge while traveling

I don't know who you talked to at Tiffin, but that's not true for any Tiffin I am aware of and I've owned two. Normally, the engine alternator charges the house batteries by connecting the battery banks together with the boost/merge solenoid. In the models prior to the addition of the Spyder multiplex controls, the battery merge solenoid was engaged any time the engine was running. With the new system, there is a logic controller that determines when the batteries charge. You should have two large solenoids near the battery bank. One of them is the latching solenoid for the 12v house supply and the other engages when the engine is running. It is very common for the boost/merge solenoid to have burned contacts and not allow charging.

Crasher · 04-18-2018, 03:43 PM

The house batteries on my Tiffin are definitely getting charged when the engine starts. After dry camping, the house battery SOC might be 60% or about 12.3-12.4 volts. As soon as the engine is started, the voltage will increase to 13.6 volts. That voltage will not completely charge deep cycle batteries, as they need a three stage smart charger that can bring the voltage up to approximately 15.2 volts. However, at the end of a days drive, the house batteries will be up to 12.7, approx 90% SOC.

**NLOVNIT** · 04-18-2018, 03:47 PM

Is that solenoid what allows me to use the house batteries to jump the chassis battery (& visa versa) with that aux start switch on my dash?

If so, I learned something today.

Lori-

awol50 · 04-18-2018, 03:48 PM

I think so

**Lt Dan** · 04-18-2018, 03:52 PM

Quote:

Originally Posted by NLOVNIT

Is that solenoid what allows me to use the house batteries to jump the chassis battery (& visa versa) with that aux start switch on my dash?

If so, I learned something today.

Lori-

That is exactly correct Lori. The merge/boost solenoid serves double duty as a charge solenoid for the house batteries when the engine is running and a boost when one of the battery banks is low.

twinboat · 04-18-2018, 04:14 PM

Quote:

Originally Posted by Lt Dan

That is exactly correct Lori. The merge/boost solenoid serves double duty as a charge solenoid for the house batteries when the engine is running and a boost when one of the battery banks is low.

That is common with practically every brand of MH.

Names like
Isolation Solenoid.
BIRD, bi directional relay with delay.
BIM, battery isolation management.
BCC, Battery Control Center.

That's a shame that Tiffin gave you that poor information.

vsheetz · 04-18-2018, 04:35 PM

Quote:

Originally Posted by Lt Dan

I don't know who you talked to at Tiffin, but that's not true for any Tiffin I am aware of and I've owned two. Normally, the engine alternator charges the house batteries by connecting the battery banks together with the boost/merge solenoid. In the models prior to the addition of the Spyder multiplex controls, the battery merge solenoid was engaged any time the engine was running. With the new system, there is a logic controller that determines when the batteries charge. You should have two large solenoids near the battery bank. One of them is the latching solenoid for the 12v house supply and the other engages when the engine is running. It is very common for the boost/merge solenoid to have burned contacts and not allow charging.

This is correct. I have 2011 Phaeton and have had the charge/boost solenoid fail causing house batteries not to charge via the alternator.

You can check it with a meter - the two large terminals of the soliniod should read slightly differing voltage as one connects to the house batteries and the other the chassis batteries. Now turn on the key or press the aux switch - the voltage should now be the same on each terminal as they are tied together.

glsponchos · 05-07-2018, 09:52 AM

Saga continues Tiffin acknowledges that coach batteries should be charging. I’ve taken a lot of voltage reading and have arrived at the isolation solenoid (picture attached). One side has voltage that matches coach batteries. The other matches chassis. I can tell by turning chargers off and on. I’m told one of the white or yellow wires ties back to the Aux switch the other to the ignition. I’m not getting voltage to either wire. When I jump voltage to either connection the solenoid won’t fire. When I detach the wires from the solenoid still no voltage on wires. I’ve checked every fuse I can find Id feel better about replacing the solenoid if voltage was present on yellow and/or white wire. Any thoughts ?

Click image for larger version

Name: IMG_2761.JPG
Views: 583
Size: 294.5 KB
ID: 201880

twinboat · 05-07-2018, 10:34 AM

Quote:

Originally Posted by glsponchos

Saga continues Tiffin acknowledges that coach batteries should be charging. I’ve taken a lot of voltage reading and have arrived at the isolation solenoid (picture attached). One side has voltage that matches coach batteries. The other matches chassis. I can tell by turning chargers off and on. I’m told one of the white or yellow wires ties back to the Aux switch the other to the ignition. I’m not getting voltage to either wire. When I jump voltage to either connection the solenoid won’t fire. When I detach the wires from the solenoid still no voltage on wires. I’ve checked every fuse I can find Id feel better about replacing the solenoid if voltage was present on yellow and/or white wire. Any thoughts ?

Attachment 201880

That is NOT the correct solenoid.

That is a latching relay, probably the coach disconnect. The switch for that would be near the coach door.

The isolation solenoid wouldn't have that extended section on the bottom. It would be a continuous duty type. A steel can looking thing or a much larger Big Boy solenoid.

It would also have large, battery size cables on both sides.

Gary RVRoamer · 05-07-2018, 11:07 AM

The solenoid in the photo does have "large battery size cables on both sides", but the label on the bottom says "BD Relay", so I suspect twinboat is right.

Shouldn't be too hard to verify if its the right one, though. If one of those cables runs to the chassis side (Alternator/battery), it's the right solenoid. If not, it's the disconnect solenoid.