Battery Boost not working

Just because you can here the boost solenoid energize or thunk does not mean it will boost the chassis batteries. Ours would energize but the contacts were so corroded that they would not conduct. Trombetta makes a relay with silver contacts instead of copper and will last much longer. This relay is also used in a lot of Monacos to charge the house batteries with the engine running, only energizes after the chassis batteries are up to charge.
Blessings;KDK

Mr.Mark wrote:
Moffittclan, I had that happen once on our previous coach. It was in the storage garage and when I went to start it, dead dead dead!

I held the boost switch and tried to start and 'no go'.

So, I held the switch for a while, about 5 min., that was enough to get it to turn over and start.

The next time, same issue, so I had the batteries replaced as it was about time anyway.

MM.

X2
I've never had the pleasure using the switch yet :W but I heard that on another board. Some will wedge a credit card on the switch to hold it there. It can take a few minutes to equalize the two banks.

This is what I have for an Intellitic BCC-

Service Manual

Troubleshooting Support

Never used Google Drive to share documents so I don't know if the links will work or not.

wilanddij wrote:
An easy way to determine if the Aux Start and Charging Circuit Relay is working is to have someone listen to it when you hit the aux start button. They should be able to hear it pull in. If it doesn't pull in, it could be a bad relay or a problem with the BCC board getting power to it.

There is a PDF Troubleshooting Guide for the Intellitec BCC. I have a PDF copy of the guide and can send it if you PM me and include your email address.

Awesome! I sent you a PM. Thanks!

My chassis batteries only charged from engine as wired from Monaco. Took a few times of dead batteries to discover and add trickle charger. Twice my boost failed to start coach. First time the fuse in the switch/solenoid circuit was gone, second time solenoid failed.

An easy way to determine if the Aux Start and Charging Circuit Relay is working is to have someone listen to it when you hit the aux start button. They should be able to hear it pull in. If it doesn't pull in, it could be a bad relay or a problem with the BCC board getting power to it.

There is a PDF Troubleshooting Guide for the Intellitec BCC. I have a PDF copy of the guide and can send it if you PM me and include your email address.

Dale.Traveling wrote:

Moffittclan wrote:

Dale.Traveling wrote:
Easy to check the AUX Start/Boost circuit. Two ways to do but which works depends on how you coach is wired.

Turn on a convent 12VDC light. Trip the house battery disconnect. Light should go out. Hit the AUX Start/Boost switch and light will come back on.

-or-

Turn on a convent 12VDC light. Disconnect the ground terminal from the house battery bank. Light should go out. Hit the AUX Start/Boost switch and light will come back on.

The AUX Start/Boost circuit works both directions not just to send extra power to start the engine but will also feed power back to the house.

Perfect! I know what I'm doing tonight while I'm installing the new chassis batteries! Thanks for the help!

Forgot one additional step. Either shut off your AC to DC convertor/charger or unplug shore power. If the converter is on the light will never go out or it might. Again depends on how your coach is wired.

You can take the test one step further. With the convenient DC light out start the engine. If the light comes back on after a short time period then the engine alternator is feeding the house DC circuit via the AUX Start/Boost circuit and will help keep a ...

Okay, tried all of this and none of them seemed to work. Here's what I THINK is happening:
With motor running: Chassis batteries charging but now house batteries
plugged into shore: Chassis batteries not charging but house batteries are charging

Here's the battery readings using a meter:

Chassis running/no shore power
12v= 14.01
6v=6.49
2x 6v=12.96

Chassis not runing/no shore power
12v= 12.8
6v=6.45
2x 6v=12.9

Chassis not running/with shore power (120v)
12v= 12.74
6v=6.8
2x 6v=13.7

Manual says that the BCC should charge house batteries while driving down the road off of the alternator but it doesn't do that within the first 10 minutes of just sitting there running...not sure if there is a certain point that is starts charging them.

Generally house bats charge from the Gennie and start it as well. If I run my inverter too long it will drain the house Batts to the point the Gennie will not start. If I then use the batt boost switch it will use the chassis battery to start the gennie

it sounds like you may not have enough voltage to energize the relay to connect the house and chassis batterys together. grt the voltmeter out and check both sets of batterys

Moffittclan wrote:

Dale.Traveling wrote:
Easy to check the AUX Start/Boost circuit. Two ways to do but which works depends on how you coach is wired.

Turn on a convent 12VDC light. Trip the house battery disconnect. Light should go out. Hit the AUX Start/Boost switch and light will come back on.

-or-

Turn on a convent 12VDC light. Disconnect the ground terminal from the house battery bank. Light should go out. Hit the AUX Start/Boost switch and light will come back on.

The AUX Start/Boost circuit works both directions not just to send extra power to start the engine but will also feed power back to the house.

Perfect! I know what I'm doing tonight while I'm installing the new chassis batteries! Thanks for the help!

Forgot one additional step. Either shut off your AC to DC convertor/charger or unplug shore power. If the converter is on the light will never go out or it might. Again depends on how your coach is wired.

You can take the test one step further. With the convenient DC light out start the engine. If the light comes back on after a short time period then the engine alternator is feeding the house DC circuit via the AUX Start/Boost circuit and will help keep a charge on the house batteries when going down the road. This may also confirm that the convertor will also keep the chassis batteries charged when plugged in to shore power. If the test works you could use the generator to recharge the chassis batteries but it will take time depending on how depleted they are. At 9VDC that could be all day if they even recover at all. The whole process is a little more complicated with voltage levels, priority charging and such.

But, and it's a big one, it all depends on how your coach is wired. Add in an every deeper darker problem of former owner undocumented alterations (used to call the Sailor-Alts during my Navy days) and there's no telling how you system might behave.