Can jumping the chassis battery ruin anything?

[ponytail_mom]

Hello RVers,

My apologies for the newbie question. I just inherited an RV, a 2009 Simba Safari. When I went to start the beauty, the engine would not turn over. I jumped it with my portable charger. It started instantly.

But then I noticed the electric car seat and the radio were not getting power. They didn't work, although everything else (lights, turn signals, etc) I drove it for gas and on the way back the turn signals stopped working.

Could I have damaged anything by jumping the chassis battery??

Any and all comments are appreciated. (And I'm enrolled in a class to understand my electrical systems better through good Sam!!)

Cristina

[Gjac]

My guess is that you're starting battery is not fully charged that's why you're having problems with the power seat. When you check the batteries they should read around 12.6 12.7 volts if they are fully charged. To check the alternator start the engine and you should read about 14 V at the positive and negative terminals on the battery if the alternator is working properly. Good luck with your new MH.

[MEXICOWANDERER]

I was hoping the other forum participants would add their comments to my recipes for electronic protection devices but they didn't. sorry for being so technical, but my comments are many times aimed at the general forum participants and one person may ask a question and many others have that question in mind plus others and I try and address everything in my answers. just about everything I write needs elaboration and I hope that others will jump in and help out and do some elaboration which includes questions and how to do things so if that isn't present then my contribution can be rather elaborate and confusing.

[j-d]

Auto Supply Store? Yes you absolutely can. Walmart, Ace Hardware, Harbor Freight. You shouldn't need to spend more than about $10 for one and Harbor Freight has them on sale for $5.99. Or free with any purchase right now. At least with a coupon. They look like this

They're called DVOM which stands for Digital Volt Ohm Meter. Measures voltage in AC and DC circuits plus resistance of components. If you have a switch in your hand that you want to test, you use the DVOM in Resistance and you can watch the digits change as you turn that switch on and off. ON will display as a very low reading, close to Zero, and Off will look like you turned the meter on and haven't connect the it to anything yet.

[ponytail_mom]

Goodness, thank you all for your suggestions!

Harvey I had no idea I should unplug for at least 8 hours to get an accurate reading! The RAv is quite the distance from me. In storage. I'll head out and hang out this weekend.

MW, your technical advice, although far beyond my understanding, is surely appreciated! You sure would be an asset to any RVer!

I have more questions (this time about slide-outs). Time for a new topic!!

I will come back and update after I know more about my batteries. And I'm sure I can buy a voltmeter at the local auto parts store?

Cristina

[MEXICOWANDERER]

A vehicle doing the boosting (engine running) can profit from the following:
1) 10, 000 uf electrolytic cap connected to the battery.
(1) 2.2 uf cap connected to ignition 1
One avalanche diode across each cap. Of course reverse biased.
eBay MR-2535 and see what you come up with.

And I certainly invite techhies with oscilloscopes to do a before and after visual while jump starting another vehicle.

Diode note: the band on the diode goes closest to the positive connection of the capacitor. But both the battery and the ignition-1 get the MR-2535 diodes. Ignition-1 stays "hot" even when the ignition key id turned to the cranking start position.

[Harvey51]

Ponytail Mom, note that the voltmeter method of measuring the state of charge only works 8 hours or more after charging has been stopped. While charging, the meter just measures the charging voltage. When the charging is stopped, the voltage on the battery takes hours to fall to a stable value as the chemical reactions in the battery finish. Fully charged = 12.6 volts, 12.0 is as low as you go without damage.

Starting a vehicle with a dead battery by charging it will take a few hours. Would connecting the booster cables while the engines are stopped help? Might there be a way to eliminate the transient currents - perhaps a coil in the booster cable wire? Or a big capacitor across the target battery?

Current drawn by RV fridge on propane - this source says a quarter of an amp or 6 amp hours per day unless equipped with auto defrost. Much less than that for the detectors I think. One battery should last a week.
http://www.rvnetwork.com/index.php?showtopic=103161
This has been my experience, too.

[MEXICOWANDERER]

Exactly according to the rules ladies & gents. It's a sad thing to play good samaritan then get bit in the butt for it.

Jumping from coach to house batteries does not involve eight pounds of copper windings the inductor.

When I built alternators for towtrucks I connected 3-mica .01 uf caps 1-2, 2-3, 1-3, across the stator leads. A 10, 000 uf electrolytic via a short as possible 10-gauge pigtail. Ganged atop the top of the cap was a 100 uf electrolytic, and a reverse biased Motorola MR2535 avalanche rectifier. Then a 2nd MR2535 across the alternator field connection
Ambulance companies and the city of LA purchased more than 200 sets. Then I ran out of higher voltage electrolytic caps. One Fire Chief called the suppressor "A miracle". All due to one horrified glance at an oscilloscope screen. I miss my scopemeter. An MR2535 clamps voltages at 28-32. The caps did the rest.

[wa8yxm]

I have jump started dozens of vehicles...

Using a Jump Pack so long as you hook up properly (Positive to positive)odds of damage approach ZERO

Using a portable battery.. Likewise

Using the BOOST switch on your dash (may be labeled AUX start or Emergency Start)

likewise

Using a battery charger/booster..Likewise

Always making sure to hook up properly

Hook up backawards YOU WILL KNOW IT INSTANTLY

Now...Jumpstarting off another vehicle

I have ruined a few alternators that way.. Always on the donor vehicle, Never on the stranded.

This is the primary reason I have a jump pack battery.

[jplante4]

BTW, most Safari coaches have a built-in battery jumper. There should be a switch on the dash that cross-connects the house batteries to the chassis battery. This allows you run run the starter with all batteries.

[j-d]

I think Mex, a professional alternator rebuilder by trade, tried to say to use the vehicle donating the jump to Charge the recipient and not actually Crank it. I've been taught, and probably not adequately, to let the donating vehicle run awhile before attempting to start the recipient. Then let them run "together" before disconnecting the jumper cables. Mex is saying Charge, Disconnect, Start. That's the safer approach. I personally have not seen a problem, meaning damage, unless the jumper cables got shorted (including grounding the positive) or reversed.

[ponytail_mom]

Hello Everyone,

Thanks for the messages! And thanks MW although I confess, even after reading your post multiple times, I still don't fully understand all of the technical stuff.

How does one know if the alternator is bad?? The RV is starting up instantly now.

Cristina

[MEXICOWANDERER]

Can jump starting hurt. Not only yes but heck yes. When an alternator is charging hard and you have an inductive reactive discharge is introduced into the system from a second motor vehicles starter motor that alternator is vulnerable to transient voltage damage to the voltage regulator and also to the engine ECU unit. This is not theory or conjecture it is reality and here is how you should start a car by jump starting.

Use the car doing the jumping to recharge the battery in the other car. Disconnect the cables then start the disabled car. This stops the sending of a transient voltage spike from the disabled car after it starts into the electrical assembly of the car doing the jumping. To be specific the transient voltage spike entering the jumping cars circuit amplifies and the alternator and then resonates through the jumping cars electrical circuit. You can see this on an Ocilloscope if you are technically oriented or if you wish you could read it in your car's owner manual it's plenty clear and specific. This phenomenon is less pronounced with today's switching power supplies chargers.

Don't do this if you have a bad heart but if you hold your finger on the terminal of the starter solenoid that connects to the starter motor crank the engine then release the key you're going to get a 100 volt + shock.the starter motors solenoid interrupts the positive transient but it does nothing to interrupt the negative oriented transient. The proof of this is in the shock so if you are brave try it. Rectifiers and regularors don't like it much either. Neither do intregrated circuits. The effect acts much like an electronic term called a "tank circuit" and can "ring" the charging car's alternator like The Bells of Saint Mary's. The effect is ugly enough on an oscilloscope never mind your wallet or purse.

The automobile industry tried to counter the effects of transient voltage damage by installing special diodes actually rectifiers in alternators. Those rectifiers are referred to as avalanche rectifiers. And finally, yes, using the starter on an onboard generator eventually takes its toll on house electrical electronics such as refrigerator boards hot water heater boards and anything else that has integrated circuits or transistors in it. This is much of the reason why RV 12volt electrical equipment in the house seems to be so fragile. The very newest motor vehicles contain avalanche rectifiers in the ECU computers and sometimes in the charging circuit the alternator circuit.

Ah yes those little fluorescent stickers with the el cheapo rebuilders stuck on their alternators. the stickers bond both halves of the alternator Shell together to detect whether or not the customer had broken the seal and rotated the rear of the alternator to fit different applications. The stickers that said warranty void if battery not fully recharged before using is a mark of a garbage alternator. We in the rebuilding industry used to laugh and laugh about people that would use these particular stickers. To claim the production of 60 or 70 amps would damage the alternator then your alternator could not recharge a 40 amp maximum charge rate battery + vehicle load and survive is ludicrous. Motorhome alternators frequently start and max their charge rate for hours on end. Motorhome alternators frequently arrived with worn out brushes or blown voltage regulator. 100% were rebuilt with 150 amp rectifier bridges special voltage regulators and St Mary"s Carbon copper graphite brushes. I was forced to discard useless 12-SI Delco "turbine fans" with the old 13-blade fan on the earliest Delco 10-DN alternator. I ENCOURAGED my customers to install my alternators then load them 100% into discharged batter banks
My one-year warranty yielded .6% failure rate note the decimal with 10,000+ remans made with my own two hands. I spent a lot of time with "Big Al" the owner of Renard Rectifier and Frank Oropeza of Transpo Electronics.

Concludes the novel of the month. Any errors are the products of psychotic voice recognition and or clumsy fingers.

But in those long long response time should be taken to clarify that jump starting using a solid-state meaning light weight charger to jump started engine is an entirely different procedure then jump starting from another motor vehicle when its running. The battery charger is far less damaging.

[westend]

Check the vehicle's fuse panel. Some of your electrical issues may be caused by a blown fuse/s.

[ponytail_mom]

Hello everyone,

Thank you for even more information. The RV has and is plugged in (inside a storage unit, 50-amp).

What I seem to be hearing you say is that the house batteries might be fine (because they were being kept charged by being plugged in), but not the chassis. Thus the chassis battery could have died just because of the time it sat.

I can test the batteries with a Voltometer and the chassis battery can be kept up trik-l-start unit.

Also that even though plugged in, the CO meter and other things continue to need about 35 amps a day, which is (probably) drawing from both chassis and coach batteries. Which means the chassis battery can die even if plugged in.

I will get a voltometer and check both house and chassis batteries. If all checks out, the. I will try to find out what is wrong with car seat, radio, and turn signals.

Cristina

I can't believe it is so fun to learn about something so complicated!