Portable 12v Jump Starter

[wa8yxm]

Have had a number of Jump Packs, I suggest 900 Amps Peak or better for Jump starting best one I ever had was 1000. The 600 amp jobs MIGHT start a generator.. Don't know, used a Garden Tractor battery when I had to jump mine

But I have owned a lot of those portable batteries in assorted sizes and it was eitehr 700 or 900 minimum that worked, I'm thinking 900.

(I use the smaller ones for other tasks and they do that well)

The Emergencyh Start button needs a good battery proviging power.. IF the HOUSE is down.. depending on the design, it may refuse to work.... Mine did. but I think all batteries were down that Sunday.... I Jumped with the battery from my wife's scooter and got the ONAN cranked up, and the converter, converted, and all was good once more.

[mauricedorri]

Originally Posted by Racklefrack

Len, thank you! This is exactly what I have planned... jump start the engine from my car, 20-30 minutes running the engine on fast idle, then start the genny and charge up everything else.
Thanks!

Interesting advice that you are getting here. Way too many times have I been caught with dead chassis and house batteries. It takes hours to get everything right.

In my opinion, you have the right approach here. Get the engine going first. No question there. After about 20 mins, you will hopefully have a decent charge on the chassis battery and at the same time, the alternator will be charging the house batteries.

When the chassis battery gets enough voltage, the battery isolator will divert more and more of the alternator voltage to the house battery and will help to charge them. This alternator voltage, along with a little bit stored in the house batteries, will definitely start the generator even when the house batteries are not up the task on their own.

So... start the engine, run for 20 mins, then start the generator

Originally Posted by Racklefrack

I'll also be checking to see if the genny charges the chassis batts. I always assumed it did, but now we're not so sure.

Unless your motorhome is different from all the rest, the generator will not charge the chassis battery. But the alternator absolutely will charge both the house and chassis batteries.


The best way to charge a completely dead house battery is by plugging it in. Its a deep cycle and needs a long slow charge. You should be using the engine and/or alternator to top it off, not to charge it from empty. Deep cycle batteries can be tricky at time.s

[Racklefrack]

Originally Posted by mauricedorri

Interesting advice that you are getting here. Way too many times have I been caught with dead chassis and house batteries. It takes hours to get everything right.

In my opinion, you have the right approach here. Get the engine going first. No question there. After about 20 mins, you will hopefully have a decent charge on the chassis battery and at the same time, the alternator will be charging the house batteries.

When the chassis battery gets enough voltage, the battery isolator will divert more and more of the alternator voltage to the house battery and will help to charge them. This alternator voltage, along with a little bit stored in the house batteries, will definitely start the generator even when the house batteries are not up the task on their own.

So... start the engine, run for 20 mins, then start the generator



Unless your motorhome is different from all the rest, the generator will not charge the chassis battery. But the alternator absolutely will charge both the house and chassis batteries.


The best way to charge a completely dead house battery is by plugging it in. Its a deep cycle and needs a long slow charge. You should be using the engine and/or alternator to top it off, not to charge it from empty. Deep cycle batteries can be tricky at time.s

Thanks for the encouragement - I think you're right. Once I get the engine started I still have to deal with a coolant hose leak, so it'll be trickier than you think I'll limp her to my local Spartan shop next week and while they're working on it I'll have them put it all on a charger.

I still don't know what drained the batteries, but it's not the first time it's happened. I'm certain I'm doing something wrong but I have no idea what it is.

No, I don't start the generator often enough to kill the chassis batteries.
Yes, everything was fully charged when I parked it.
Yes, the batteries are all well-maintained with proper water levels.
No, I haven't custom-wired anything... everything is stock.

The coolant leak is priority one, then I have a couple seals that need to be replaced (probably replace them all while they're at it) and THEN I can concentrate on the electrical.

I really appreciate everyone's help on this. Couldn't have done it without you.