Jumper Cables

SJones · 06-19-2021, 10:13 PM

I have a class A motorhome. If it sits for a few days I have to get it jump started. Instead of always having to call for assistance I would like to purchase a set of jumper cables to do myself. Wondering what gauge of cables should I get. Thanks in advance for your help.
Susan

DavidM · 06-20-2021, 05:24 AM

I would first try to find out why your chassis battery is running down.

But for jumper cables, get the biggest you can find, 4 gauge minimum, preferably #2.

David

**creativepart** · 06-20-2021, 10:15 AM

Do you not have a momentary switch on your dashboard to tie your house batteries into your starting battery to provide a boost to start your RV? I don't know of a Class A (or other) motorhome that doesn't have this item.

WAIT... in your first post you made here 3-days ago you said you have a 2015 Voyage 5th Wheel travel trailer. What Class A motorhome do you have and we'll help you find that switch on your dashboard.

SJones · 06-20-2021, 10:30 AM

I do have a button but there are times I still have to jump start. I'm trying to find someone that is able to diagnose what is draining the batteries but no success thus far.

As for type of motorhome it is a class A Voyage motorhome, error was made with the year it's an 05 not 15, guess I need to proofread better.

**creativepart** · 06-20-2021, 01:38 PM

When you put your RV in storage do you use the battery disconnect switches to turn off ALL power - chassis and house disconnects?

Leaving these on will drain your batteries.

But if you are turning off the disconnects, the likely thing is that your batteries are damaged, ruined, shot, worn out, sulfated and not holding a charge even when you turn off all the disconnects.

Also, even if they are newer batteries you would need to run the engine or generator or connect to shore power for many hours (5 to 6 hrs???) to charge them back up... if they haven't already been ruined by spending so much time discharged.

SJones · 06-21-2021, 05:09 AM

I'm not really sure where a turn off switch is located. There is s switch next to the steps that I do turn off but not sure if that's the only one.

**creativepart** · 06-21-2021, 09:37 AM

This is covered in your Operator's Manual. If you don't have yours or it's not handy here's a link to a PDF version of it online:

https://www.winnebago.com/Files/File...5/05Voyage.pdf

Assuming you are turning off the Aux Batt switch then you must assume it's a battery problem - they are either damaged or worn out. And, it could be both the Chassis (starting) battery and the House batteries, both.

Also, I've attached a photo of the switch that you should be turning off when you store the RV. When off nothing but your stairs and one or two other things will remain powered. Turn it off and try turning on a light. If the light comes on with that switch off then you have a bad solenoid or a bad switch.

4x4van · 06-23-2021, 04:50 PM

Keep in mind also that in order for the "boost" button to work, you must actually hold it. Best to press and hold for a few seconds, then (while still holding) try to start the rig.

1237dmctlc · 06-27-2021, 05:00 PM

So a couple of question if you don't mind. First are they FLA or AGM batteries? Second, how old are they? Third, have you cleaned they terminal post and cables lately and checked to make sure they're tight on the post? If you're saying that the coach batteries aren't providing boost enough to start it are they trying or are they dead or almost as well. Like cars, RV with Batteries needs to have the terminal posts and cables cleaned at least once a year to assure good contact, IMHO. As previously mentioned a 4 gauge jumper set should be sufficient as long as the car or truck your using is running it should start it up.

BSchulz · 06-27-2021, 05:58 PM

Best thing I have ever had is a set made from 2-0 welding cable. Clamps can also be obtained as well from welding supply house, or Amazon. Mine are 20+ years old and are about 15 feet long.
If you get the cables from a welding shop you can make them any length you like. Make them as long as you might think you will ever need then add 5 feet.

NeilV · 06-27-2021, 07:05 PM

Be mindful that if the engine battery is extremely low then there may not be enough current to flip the solenoid from the house battery storage/disconnect position to the operating position at which point the boost switch on the dash won't be able to tie both sets of batteries together.

I find a good portable jump start pack that is large enough to deal with the needs of the V10 or Diesel is a bit handier than jumper cables especially on an F53 based Class A coach with a center entry door and the batteries under the step well. You need an extra-long set of jumper cables to reach the batteries when in the storage lot.

I sometimes find it easier to get the generator started to top off the house batteries and then use the boost button when the engine battery and the house batteries are both a bit low. On a 2005 like my 2001 this will more likely only charge the house batteries however getting the house batteries topped off will usually allow the boost to work for getting the engine started.

Note of caution though that when the engine battery is failing it can get to the point where even after you have jump started it that once you start driving getting to over 5/10 MPH and the alternators charging system tries to go into high charge mode due to the higher engine RPMs that it will cut out faulting the ECU and cause the engine to buck severely enough to cause drive train damage. If this occurs when the torque converter is locked it can pitch you into the steering wheel especially if you don't have your shoulder belt cinched tight enough or may knock an un-belted passenger to the floor or perish the thought, cause your morning cup of Java to get knocked over and wasted.

Yes if the batteries are not capable of fully charging up and holding a resting voltage of around 12.5 volts then its time to replace the batteries.

jerichorick · 06-28-2021, 04:01 AM

Quote:

Originally Posted by SJones

I have a class A motorhome. If it sits for a few days I have to get it jump started. Instead of always having to call for assistance I would like to purchase a set of jumper cables to do myself. Wondering what gauge of cables should I get. Thanks in advance for your help.
Susan

To answer your question about cables... Any good quality set of jumpers will do. When jumping any vehicle the first thing you do is use the remote charging/start source to charge the dead battery a bit. The amount of loss between the two connected batteries through the cables is determined by the security of the connections and the size of the wire.

As others have suggested, test your start batteries. No matter how new, early failures do happen. If the battery tests good you then need to look for the foreign parasitic drain.

Rick 99037 · 06-28-2021, 06:50 AM

I agree that your Deep Cycle batteries sound like they are bad, because they are going down to quickly. But understand that at least on my rig, when you turn off the switch by the door, your gas detector is still running off the batteries, so the batteries will still be drawn down. When I park my rig for a while, I flip the door switch, and pull the gas detection fuse in the panel. That keeps my batteries from being killed. Just be sure to have that fuse in place when you start being in it again. Do something obvious to remind you.

Elkman · 06-28-2021, 04:21 PM

The coach batteries can also be drained by the cab equipment if there is no BIM or battery isolation manager installed. With a battery to start the engine a quick check is to use a voltmeter and see how much the voltage level drops while the starter is operating.

For $30 one can buy a decent battery charger and insure that the batteries are being fully recharged. If for any reason a battery in the loop is not getting sufficient current to recharge or has a single bad cell it will cause problems for the other batteries.