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Jump start from house batteries
I'm on my first trip with my Lazy Daze and in general everything is going well and I'm quite happy. Right now I'm staying for a week in the boondock area of the (55+) Jojoba Hills RV Resort in Aguanga, CA which is a coop and a truly amazing and welcoming place. Their "boondocking" includes large, level lots and a bathroom. From my living room I have a great view onto Palomar Mountain (I'm sitting there now). It's a small paradise.

The only thing that went wrong was that I forgot to turn the headlights off when I was parking for the day at the place where I am attending a retreat. The battery was completely dead when I returned to the vehicle late in the evening. I was quite in panic but got in the end saved by another retreat attendee who used a jumper cable and his running car to charge my battery for 15 minutes. After that the combination of a jumpstart and the power in my battery did the job (the jumpstart attempts without charging my battery for a bit first failed).

I hope this will never happen again but when it does I'm wondering whether I could use my house batteries (two 6 volts batteries) to give myself a jumpstart. Is this possible and if so how would I have to do this?
2001 26.5 Mid-Bath
Re: Jump start from house batteries
Reply #1 –
You can if your jumper cables are long enough.  A better solution is a small lithium jumper battery. They are available from Amazon, Costco and other places.  About the size and weight of a old hardbound dictionary they take up less room than a set of jumper cables and will even charge your cellphone and rechargeable flashlights.  Larry recommended one. I’m not at home now but will look at my amazon history to see if I can get the name of the one I have.
Previously: 2007 Mid Bath
Re: Jump start from house batteries
Reply #2 –
desertman,

While in Yosemite a few weeks ago, I suffered from the dreaded dead battery syndrome myself. For different reasons but with the same result.

My jumpers were too short and the generator will NOT charge the chassis battery (drat!).

My bacon was saved by a gentleman with a “DBPOWER” lithium ion Jumper battery pack. As John says, they are small compact units that fit in the palm of your hand.

It got me up and running in seconds. I purchased one on Amazon for about $80. When I got home I ordered the “Antigravity Litiuim Ion jumper that Larry recommended. To be on the “safer” side, I purchased the Schumacker Battery Charger as well. All three reside in our RB.

As a precaution, if camping for a week, I start the e450 about midway through the week and run it for about 30 minutes to charge the chassis battery.

Here’s a pic of what I now carry, besides my relic Cobra jumper cables.

Kent
2015 27' RB "MissB.Haven"
Re: Jump start from house batteries
Reply #3 –
Quote from: John DaCrema  - 
You can if your jumper cables are long enough.  A better solution is a small lithium jumper battery. They are available from Amazon, Costco and other places.  About the size and weight of a old hardbound dictionary they take up less room than a set of jumper cables and will even charge your cellphone and rechargeable flashlights.  Larry recommended one. I’m not at home now but will look at my amazon history to see if I can get the name of the one I have.
I can not recommend the one I got off Amazon as it is sized for up to a 6L gas engine, I got it for the car.  It might start our MB but it might not.  The ford V10 is 6.8 L or so.   A quick view of similar jump starters showed the nearest size to be 8L.  
Previously: 2007 Mid Bath
Re: Jump start from house batteries
Reply #4 –
The DBPOWER I purchased is rated for a 6.5 liter gas engine not much less than the 6.8 Ford engine.

 DBPOWER states a cautionary note about the unit I purchased being used on anything larger than 6.5 liter, however it is the same unit that got my rig started in Yosemite.

The Antigravity XP-10 is rated far above our beloved 6.8 liter Ford’s. At nearly twice the cost of the DBPOWER unit I would hope it would be.

Works for me. Though I hope I never have to use it.

Kent
2015 27' RB "MissB.Haven"
Re: Jump start from house batteries
Reply #5 –
I always carry jumper cables to jump from the coach batteries..just in case I forget the lithium jump starter battery.

I bought some 20 foot  professional jumper cable. 4 or 2 GA.
Rodney
1988 Mid Bath
Re: Jump start from house batteries
Reply #6 –

Yes, I was dubious at first, but I bought a DBPower 600A jump starter through Amazon from this LDO affiliate program after a discussion with Kent. I especially like the digital battery charge gauge on it. I don't know why they list a limit of 6.5 liters on the engine size. The marketing person maybe was unaware that there are a lot of bigger engines out there, (maybe only in the U.S.) Perhaps they didn't have one to try it on. Three tenths of a liter is immaterial. (18 cubic inches!) Ambient temperature of the engine and battery, degree of discharge of the existing connected battery and compression ratio of the engine have a lot more influence on whether the DBPower is able to start it.  Amazon.com: DBPOWER 600A 18000mAh Portable Car Jump Starter (up to 6.5L Gas,...
   I do carry a 20' #2 jumper cable, mostly to start my towed vehicle, but I've never needed it (yet). I have used it to start other people's motorhomes at caravan club meetings.
    My house batteries on the E350 TK are just aft of the coach door and are on the same side as the chassis battery, so just 8 feet apart. As far as using two 6 Volt  house batteries, just pretend that that single jumper wire in the center (or disconnect switch) connecting the two batteries isn't there. From the ground connection of one battery, connected to the chassis, and the positive of the other battery, connected to the bundle of red wires, that is House 12 Volts.
   I have installed a Trik-L-Start to keep my chassis battery charged while parked, it wouldn't help in the headlight 'on' situation. Terry Tanner did have a 'Bell" sounder that could be installed to alert you. (still on my list of To-Do's)  RonB
  

As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Jump start from house batteries
Reply #7 –
Ron B,
Sorry, I take great issue with this statement," Just a reminder though, if you are jumping your own battery, then you only need to hook up the positive lead.", in reply #6.
Only use it the charge a dead chassis battery.
In my 1988 MB,the ground wire fire risk is too great for jumper engine starting with only the positive lead.
Use BOTH jumper leads betwen the chassis and coach battery for direct engine starting.

For the technical types, the coach ground leads on My 1988  are too small (#6)  and route 6 feet through the floor,midbath dinette bench, then the floor,  to the frame to handle the needed starting current of the V8 Engines.  The power center ground wire(#6) routes 12 feet through the power center fuse circuit board to the opposite frame rail.  On my 1988 MB both positive and negative Jumper leads must be used to Start the Ford Engine from the Coach Battery!  The ground wire fire risk is too great to Not use both jumper leads betwen the chassis and coach battery for engine starting.  Not to mention the #12 fusable joining wire between the two 6 volt batteries.
Rodney
1988 Mid Bath
Re: Jump start from house batteries
Reply #8 –
Thanks for the info Rodney, I stand corrected. I edited my previous comment to reflect that there is no 'high current' path from the house batteries to ground, so those batteries still need the ground (black jumper cable wire) to carry the current needed to start the engine.  RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Jump start from house batteries
Reply #9 –
My preferred way of jumping is to use a lithium battery booster, having seen too many damaged vehicle electrical systems caused by reversing the jumper cables polarity. The lithium jumper has automatic protection that prevents this from happening.
In our LD, the battery wiring has been reconfigured to include a marine battery switch that allows connecting to the starting battery, jumping the starting battery in case it is low or dead.
Old battery and tray removed | New battery switch with jumpe… | Flickr
Completed electrical/propane compartment | Compartment now h… | Flickr

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Jump start from house batteries
Reply #10 –
There are many options available to jumping a dead battery. Like Larry, I resist the use of jumper cables as my Avalon Owners Manual warns of damage to the cars electronics if the cables are used incorrectly.

The recent topic of Lithium Ion Jump Starters had me very interested in their usefulness. Yesterday I came across a YouTube video on “Ultracapacitor Jumpers”...https://youtu.be/cq3ihYJ4rbE

A quick look on amazon revealed three such Ultracapacitor Jump Starters. Now our options have increased a little bit more. Super capacitor technology has finally made it to our own front doors.

Super cool.

Kent
2015 27' RB "MissB.Haven"
Re: Jump start from house batteries
Reply #11 –
I carry a small  battery charger. Just fire up the generator, run an extension cord to your battery from an inside socket and hook up the charger. In an hour or two you can start your motor.
Discuss anything with anyone and disagree agreeably. Always be polite and respectful.
Re: Jump start from house batteries
Reply #13 –
^^^
Have this. It is a powerhouse. Get the 12V dongle too and you can take your 12V things outside and use them.
Ruby, the red 2004 26' RK hauling Dave and Kristine hither and yon
Re: Jump start from house batteries
Reply #14 –
I’ve reserved our Antigravity Jumper for the chassis battery (hope I never need it) and I have used our DBPOWER Lithium ion jumper for charging my cell.

One thing I’ve noticed, however, is that the DBPOWER doesn’t charge my phone more than once or twice despite its claims to the contrary and it takes quite a while to charge it back up using the coach 12 volt system.

I’ve found that the small cell phone (pocket sized) charger can do as well as the DB and takes far less time to recharge in the LD 12 volt outlet.

Well at least now I have two jump starters to use in case there is a black out in camp.

Kent
2015 27' RB "MissB.Haven"