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Topic: Battery boost switch solenoid location & testing  (Read 1004 times) previous topic - next topic

Battery boost switch solenoid location & testing

Our (GV 295/03) Engine battery booster switch is suspect. I looked but could not locate if there was a previous discussion about how to test the booster switch solenoid. Right next to battery isolator forward of engine compartment there is solenoid that looks like this Cole Hersee 24213 12V 200A Continuous Solenoid  ( I have this as a spare part). Is that the battery booster solenoid?
How can I test it without removing it?
Thank you,
AL

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Former 2003 GV U295 (6230) (2015 - 2025)
Former 94 GV U225 (2013-2016)

Re: Battery boost switch solenoid location & testing

Reply #1 –
Yes that is it.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Battery boost switch solenoid location & testing

Reply #2 –
Quote from: propman –
I looked but could not locate if there was a previous discussion about how to test the booster switch solenoid.
How can I test it without removing it?
AL,

It looks like your solenoid has two small posts, and two large posts.  One small post should be connected to a good ground - the other small post is connected to your dash boost switch.  Doesn't matter which is which.  To check the BOOST solenoid:

With the boost switch OFF, neither of the small posts on the solenoid should show any voltage, and you should read start battery voltage on one large post, and coach battery voltage on the other large post.  Under most conditions, they will be at least slightly different.  If they are very close to equal, turn your headlights on for a few minutes, then turn them back off.  Check voltages on the large solenoid posts again.

With the boost switch turned ON, one of the small posts will show 12 volts and both large posts on the BOOST solenoid should read the exact same voltage.  If they don't, the solenoid is not closing/functioning correctly.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Battery boost switch solenoid location & testing

Reply #3 –
The REAL way to test a boost switch/solenoid:
Put a cheap digital cigarette lighter voltmeter  into the cigarette lighter socket.  This is the only accessory that runs off the START battery. If you  have 2 cigarette sockets, you need to determine which is house and which is start. Be plugged in to shore power. The meter should read around 12.6 volts or so, this is start battery voltage. Flip ON the boost switch and if the solenoid works, the voltmeter will gradually start to go up. If it does not go up you have a problem.
1994 U280, Build 4490
Deming, NM.

Re: Battery boost switch solenoid location & testing

Reply #4 –
Quote from: Twig –
The REAL way to test a boost switch/solenoid...
"There are more ways than one to skin a cat".
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Battery boost switch solenoid location & testing

Reply #5 –
Chuck, I followed your instructions last night and determined that I would install a new solenoid in the morning. However out of further curiosity I left the boost switch on overnight while she was connected to a shore power. In the morning I tested it again and found the voltage to be equalized by +/- 0.3, where last night it was about 1.5. For whatever reason when I use to use the booster switch the house batteries and coach batteries would come close to each other almost instantaneously.  Both batteries banks are charged and healthy.

Twig, I use to have a "cigarette lighter voltmeter  into the cigarette lighter socket" it quit working. I will get another one. But In the meantime I was using my voltmeter, dash gauge, audit and VMS.

Thank you,
AL
Former 2003 GV U295 (6230) (2015 - 2025)
Former 94 GV U225 (2013-2016)

Re: Battery boost switch solenoid location & testing

Reply #6 –
Al,

Do you have a Trik-L-Start or another "passive" means of maintaining the start batteries?  If you do, then after a night on shore power both battery banks would probably be very close to the same voltage, even if the boost solenoid was inoperative.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Battery boost switch solenoid location & testing

Reply #7 –
I had an Amp-L-Start and although it said it was charging no amps were going through. What I don't like about them is they only charge when the house batteries are near fully charged, didn't know that when I bought it. The most important battery to have charged is the chassis battery so I bought two forty amp diodes and a piece of two inch aluminum angle for a heat sinc. I don't know if I needed two diodes but I didn't want to burn out the diode when starting as I use my generator when starting in the cold.

It sound like you booster switch is working. The easiest way to check it is when plugged into shore power or generator is running
put a good load on you chassis battery and if it is working the voltage for both battery banks should be the same
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport
 

Re: Battery boost switch solenoid location & testing

Reply #8 –
I think I have no problem :-) but it is ok, still learned something, thanks to you all.
I have BEP DVSR (Digital Voltage Sense Relay) Picture attached. It was/is temporarily disconnected. 
Former 2003 GV U295 (6230) (2015 - 2025)
Former 94 GV U225 (2013-2016)