Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 10, 2025 ...

Stuck in st. Augustine

April 27, 2018, 01:46:20 pm

I may have tried to start coach while plugged in. Now the coach wont start. Took off battery terminals and cleaned then. Jumped the coach with my car battery and it started. Voltage at coach engine batteries under 10 volts. Plugged in a tricklecharger and hope it helps. Couldnt check voltage at alternator no meter. Any thoughts?

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Re: Stuck in st. Augustine

Reply #1 – April 27, 2018, 01:49:26 pm

Voltage under 10 means that the chassis batteries were stone dead. 

Do you have some "add on" device to charge the chassis batteries?

Did you try using the boost switch (adding the house batteries to the chassis batteries)?  That can be done to allow the inverter/charger to charge the chassis batteries and/or to start the coach when the chassis batteries are discharged.

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Re: Stuck in st. Augustine

Reply #2 – April 27, 2018, 01:51:51 pm

Do you have a boost switch?  Do you get 12+v after combining your battery banks?

I've seen it mentioned that starting while plugged in should be avoided.  I've never avoided starting while plugged in and never had a problem.  What's the reason for that concern?

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Re: Stuck in st. Augustine

Reply #3 – April 27, 2018, 01:56:12 pm

Momentary max amps through the charge system if the Start battery is in the trickle charge system. Should not be a problem if the start battery is isolated.

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Re: Stuck in st. Augustine

Reply #4 – April 27, 2018, 02:01:51 pm

I have a boost sw, and will turn it on and see if voltage goes to 12v. Can i leave boost sw on to charge. Coach started this morning. Three red tops are brand new. One year old.

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Re: Stuck in st. Augustine

Reply #5 – April 27, 2018, 02:06:41 pm

If the boost switch is engaged while starting, the house electrical systems may have the following problems:

- voltage will vary wildly from 9 to 14 VDC
- current could surge massively in the house battery charger on both AC and DC sides
- possibly cause lockup in the house 12VDC systems: Fridge, hot water heater, furnace, AC
  Anecdotally speaking, scalding hot water once spewed from my U270 because the propane hot water heater Dinosaur Electronics board stuck in the On mode.
- Could cause spikes in the inverter, causing damage to electronics

I would recommend turning off AC power, all appliances and inverter until the engine is started.

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Re: Stuck in st. Augustine

Reply #6 – April 27, 2018, 02:20:54 pm

If you don't have an added way to charge the chassis batteries, yes, use the boost switch to allow shore power/generator to charge them using the inverter/charger.

You should be able to look at your inverter/charger remote panel for both voltage (both batteries if boost switch is on) and more importantly, the amps.

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Re: Stuck in st. Augustine

Reply #7 – April 27, 2018, 02:29:52 pm

Brett  i am plugged in with boost sw. on. Roof ac is running along with frig. And hot water heater. Voltage at panel is 13.18 . Amps are fluctuating around 6.9

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Re: Stuck in st. Augustine

Reply #8 – April 27, 2018, 02:37:56 pm

IF, repeat IF the boost switch is working and the chassis batteries are indeed, deeply discharged, the inverter/charger would go into bulk mode (14+ VDC) and amps would be high-- likely over 100.

Go check voltage at the chassis batteries.  Let us know what you find.

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