Battery Charging while driving?

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Seattle Paul
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Battery Charging while driving?

I should be picking up my 13' Scamp in September.  At some point I will add solar, but for the drive back to Seattle I'm wondering how long you have to drive in order to recharge the battery.

Greg A
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Battery Charging

No real good way to give an answer to that as each situation is going to be different. It is dependent on how much you've used of the battery (hopefully, not below 50%) while camping off-grid. Also, dependent on the alternator rating on your tow vehicle, gauge of wire going back on charge line, whether your tow battery needs any charge when leaving.

If you've only used 10% of battery and you have a fairly robust charging setup on your tow, it won't take long. If you are 40-50% discharge it will take longer, etc.  Once you start towing from various states of discharge you'll start to see how long your particular vehicle will take to bring it back up.

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Seattle Paul
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The tow vehicle is a RAV4, so

The tow vehicle is a RAV4, so I'm guessing the charging system is pretty standard.  So, to give a specific: Lets say I used 30 amp hours.  Would it take from 1 to 2 hours, or from 7 to 8 hours.  You brought up another important question: is there a reliable way to tell how much charge your battery has.

Thanks

ac0gv
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Battery charge state

There are several good metering systems out there, but I use the chart on the right side of this photo along with a free Harbor Freight meter. 

salukispeed
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SOC -State of Charge

Battery State of charge is a fickle thing to read and gauge. If using a quality Digital voltmeter. ( I have had decent readings with a HF meter too ) But back it up with my name brand once in a while.  But full to very low is only around .5-.6 volts at the battery terminal with absolutely no load and after some stabilizing time 1-12 hours. So Technically it is very subjective reading.  With 10ga wire and 30amp breaker to the trailer along with very good ground and good clean connections several travel hours is usually enough to bring the battery near 80-90% . And when possible peaking the battery with the converter or large enough solar system is very important to battery life. Properly charged battery can last for several years and one left a 50%or less can be junk in a season. Sorry for the gibberish but there is no simple answer. 

2019 Scamp 13 standard

ac0gv
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HF meters

Hergertp
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gas mileage-

Wow! 1st time towing our brand new 13’ and our mileage is down 10mpg!!! Ouch!  Tow car is a 6cyl RAV4 - any suggestions??? 

ac0gv
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gas mileage-

May be normal, but remember that mpg will depend on how you drive, wind, and hills. Also note that Scamps come with 60 MPH max tires. I get my best MPG going as slow as I can and still keep the transmission in the highest gear. (about 60 MPH on my F150 w/six speed.)

salukispeed
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HF meter accuracy

I too find there can be a difference between the HF meters   I had three and picked the closest one to My Fluke also.   With our 13 on the back of my Subaru Crosstrek We dropped from almost 30 MPG using paper and pencil and not the optimistic Read out.  down to 20 and even 19 This was expected since most cars and light trucks are tuned with light load and moderate speeds to get good mileage and when you actually make them work hard the mileage can really drop. As a side note we could only get 14-16 MPg in 6th gear and got 17.5 -to almost 20 in 5th by letting the engine run at a slightly higher RPM where it could make enough Horse power  and use and less throttle. But we are coming from a 26 foot motorhome that got 7-8 MPG so we are way ahead.  

2019 Scamp 13 standard