Sure Power 1315-200 question....

[94-Newmar]

I know the 1315-200 senses both the coach and chassis battery sides and connects the two sides together automatically if it sees 13.2V or higher on either sides since it believes a charge is being applied. I also know the 1315-200 will disconnect the two sides if the voltage drops below 12.8v or so on either side so as to protect from draining the chassis batteries.

My question is what does the 1315-200 do if it sees charge from both sides? For example.. what if Im driving down the road using the generator to run the A/C's which is also powering my 45amp converter which is already charging the coach batteries. I don't think I want the alternator and the converter both charging both sets of batteries.

My current isolator has gone bad. The relay pulls in when you start the engine and it sees 12v from the alternator but it's not passing the voltage through to the coach side, Im assuming the contact points inside have gone bad. I purchased a 1315-200 to replace it.

[RJay]

On my coach the BIRD isolates the chassis and coach batteries when both alternator and generator are running and prevents a conflict where it's possible to cause 120 volt breakers to trip. You can test if the batteries are isolated on your coach by running the generator and the engine and measuring the voltage on the chassis battery and the coach batteries, if the batteries are isolated there will be different voltage readings on the batteries since the alternator output voltage is higher, approx 14.5 volts verses 13.8 volts for the chassis batteries if in float charge mode.

[94-Newmar]

Not sure what you mean by a BIRD... however with a bit more investigation...

(1) It appears nothing but the alternator charges the chassis batteries. There is electrically no way possible for the converter to energize the big solenoid tieing both the coach and chassis sides together since the big solenoid is powered solely from the ignition ON position OR the battery boost switch up front. I started the generator and waited until the time delay on the transfer switch engaged and there is no difference in voltage on the chassis batteries.

(2) The voltage regulator is used to drop the voltage from the Chassis side to 5v and thus energize the big solenoid and is working properly, I see 13.7 or so being fed and only 5v being fed to the solenoid. If the engine is running and I disconnect either of the wires I can hear the big solenoid clunk open. The solenoid is not a continuous duty, so Im assuming they're dropping the voltage to prevent it from burning itself up.

(3) When the engine is running I will see 13.8-14.0 volts on the left (chassis batteries) side of the big solenoid, and 12.7 or so on the right, so nothing is being passed to the coach batteries as the contacts are most likely bad.

(4) I'm not sure what the unknown relay is pictured bottom right. The one lead is connected to a 20amp fuse in the 12v panel and the other goes into mystery land. The relay is energized from the same 12v feed from the ignition that powers the voltage regulator when the key is in the ON position. This prevents the 12v from passing from one side to the other. When the key is off, the 12v is allowed to pass to the other side.

So it appears that the Chassis and coach batteries are isolated due to wiring and no other devices in between. The alternator will charge both the chassis and coach batteries (when the big gold solenoid contacts are repaired or replaced or the entire unit replaced) however neither the converter or the generator will charge the Chassis batteries.

So Im assuming that this 1315-200 will not work in replacement of the big gold solenoid since it will automatically tie chassis and coach batteries together when it sees (either?) or one side or the other charging. Seems to me I'd have a charging conflict if Im running the generator or plugged into shore power at the same time and could boil some batteries? Unless the sure power unit will see charge on both sides and elect to NOT tie the two sides together?

(click image for a larger pic)

[94-Newmar]

Just wanted to update this thread after more investigation, trial and tribulation.

In the picture above, what I have listed as a "regulator" is indeed an older style BIRD. It would manage the connection between the solenoid on the left (chassis batts) and the solenoid on the right (coach batts). The solenoid on the left has aged and the contacts inside were arc'd and damaged beyond repair so I purchased the Sure Power 1315-200 as a replacement. As it turns out I was able to replace both the left solenoid and the original BIRD with the new Sure Power unit. The new unit has provisions for the existing Emergency Start (boost) wire and indicator light up on the dash, which all work just fine!

The Sure Power 1315-200 Bi-directional relay is a BIRD but with it's own solenoid to use in place of an existing one. Worked out for me and I was able to clean up a LOT of wiring in the compartment. Great alternative for those of us with older coaches - especially those of us who use the same regular automotive type flooded batteries for both Chassis and Coach.

1315-200 Info here: http://www.surepower.com/pdf/separatorinterconnect.pdf