road trip charging using a lead acid RV battery

[parajared]

I am planning on an e-bike road trip and I am planning on using my car as the charge station for my lipos. I was thinking of strapping a deep cycle RV battery to the floor of the car and running the charger off of that.
1) The RV battery I am looking at is rated in "reserve capacity". How do I calculate for the losses of the charger and determine how much reserve capacity I would need to fully charge a 900 watt hour battery assuming I don't want to over-deplete the battery and likely won't be driving the car while I charge?
2) I am looking to re-charge said RV battery using the car's battery while I drive aroud. I was thinking I would just run a wire and a couple of power poles from car bat to RV bat. Is this a viable way to charge, or do I need an actual charger to do the job? Will a 10 gauger get all melty on me if I do this?


Update: I just alligator clipped some wires to my car battery and ran the wires through the little hole in my firewall where the AC lines pass through. 10gauge was more than plenty. Raw wires worked fine, no diodes, power supplies, battery isolators, although probably not a bad idea. The battery goes flat after about 5 hours of charging without the car running but recovers nicely if the alternator has some time to put that energy back into the car batt.

When I want to charge I pop open the glove compartment and I have a little connector wire dangling there that I can plug my battery charger into.

 

[Hwy89]

Will you be using an RC charger directly from the 12 volt supply?
The common sizes of marine deep cycle batteries range from 80ah for the group 24 size to 105ah for the group 31 size. Using a ballpark figure of 100ah x 12V you can figure 1200 watt hours. Factor in 80% discharge and you get 960 watt hours. If your charger is 90% efficient you end up with 864 watt hours to feed into your bike battery. Considering that you probably won't be completely discharging the bike battery every day it should work.
You should install a battery isolator to prevent you from accidently draining your starting battery. These are available from RV supply stores and are used in motorhomes and trucks that carry campers. Using a battery isolator will moderate the current surges between the batteries caused by differing levels of charge so #10 stranded should work as long as the run is kept as short as possible. I wouldn't go any smaller than #10 and if you find it is getting warm run a second pair of wires.
If you are using a bulk charger that runs off of AC current you will need to factor in another 10% conversion loss for the Inverter.
When I travel I carry a 185W solar panel and a dedicated battery to run the RC balance charger. This has worked fine on several trips to charge two bike batteries, but I have been lucky and not had too many cloudy days.
Enjoy your trip and post about the experience.

 

[dogman dan]

I found it very difficult to get my RC charger to run very long on a deep cycle battery. Not sure what size it is, but it was cheap at Sam's club. The RC charger just wouldn't run when the voltage dropped into the bottom half of the lead discharge.

So you'll end up idling the car a lot, unless you get several of the things. But if your drive to the next ride is long, it will work fine to charge a large pack at 150-200w, taking many hours to do it. Make sure you will know it, if the charger trips off.

What I do, is charge on the road using a generator. My monster bike requires a trailer, so I put the generator on the trailer and partially charge while driving to the next leg of the ride. Then I generally have to wait, since what I tend to do is ride a 20 mile section of a long ride at a time. The drive to the next parking spot is only 40 miles or so, too short to get a full charge.

From one parking spot, I can ride each way 20 miles and back, covering 40 miles of road and riding 80. I will wait a couple hours to charge before the second run, or camp and charge during the evening. Does that make sense the way I wrote it? I drive all the road once, and ride it twice, both directions. This is how I rode all of the road, from El Paso to Santa Fe, bit by bit over several years. Having driven the road hundreds of times, I found I never really saw it till I rode it at 20 mph or less. And never really saw it all, unless I rode it both directions too.

Good generators are pricy, but the Harbor Freight cheapie should last long enough to do a few good trips. It should run 500w of charger with no problems.

Yesterday was another beautiful weather day. I rode 47 miles with 95% of it on either bike trail or very good wide bike lane. 37 miles of it was on actual trail. Not so scenic though, much of it very much urban trail, past suburban houses. But still, plenty of miles of it. The route I rode yesterday has about 12 miles that is through farms and the river, so a 24 mile ride through rural farmland is possible. The turnaround is at a state park on the bosque, or continue on a few miles of street to get to historic Mesilla and some very good eats.

This stretch of nice weather really has me eyeballing the map of southern AZ for a tour right now, before the spring wind gets cranking.

I only have 50 miles range right now, so that road system around Sierra Vista is looking nice. I'd like to just get dropped off in Lordsburg, and ride a big loop through AZ, then back to home. But I need another 20 miles of range to make some of the route. Towns all the right distance apart once in the Bisbee area, and thousands of feet lower elevation than here, at 4000'. But then I need a safe place to stash the car, or do the ride it twice routine. What I really want to do, is ride off for weeks without the car.

 

[itchynackers]

Yes, I know this is a reserve battery, but be careful about how much you deplete the lead battery. Back when I rode Pikes in 2012, I connected my charger to my Tahoe battery, just to put a little more in the bike battery before we went to the race. Well, I must have been dangerously close to running the truck battery down, since on the drive over my truck was beeping and clicking for most of the way over. I think the auto door locks and gauges must start acting up if the battery is low. Lead batteries suck balls.

 

[LockH]

Ummm... Speaking of "marine", a cruiser might "fly" a wind generator? (See also those crazy Dutch, and "wind mills") Works whether in motion or at rest (when the wind is blowing)? Also, gasoline burners might take advantage of any down hills to save gas (long hills strangely absent for the yawtee set).

Just a tought.
L

 

[dogman dan]

???

I had a Honda car I got dirt cheap at one time. It was haunted. The sway bars in the front made moaning noises, and the door locks kept going on and off by them selves. A new alternator cured the locks, I was driving around on 11v all the time, but the moaning continued.

Properly isolating the battery as AW suggested should prevent any of that. Any good RV place will have the device.

 

[FeralDog]

Lead is big and easy. :wink:

Marine (boating) guys, and RV , and towing folks deal with this issue all the time.

Get the biggest 12volt "Deep Cycle" battery you can afford. (two 6volt golf cart batteries work OK too)
Check your cars' Shop Manual to get an idea of your alternator output (I guess it should be >10amp, most are)
Then get a good charging system to charge Deep Cycles from your car ... EXAMPLE ----> http://www.jonestrollingmotor.com/chargeontherun.htm

A more Expensive, but reliable, charge system is also a Stealth 1 http://www.stealth1charging.com/
Minn Kota makes some systems. Dual Pro does http://www.dualpro.com/ So do others like StaynCharge http://www.stayncharge.com/

@dogman---- quote "I found it very difficult to get my RC charger to run very long on a deep cycle battery."
That is a weird quirk that some RC chargers (especially balance chargers) have . They seem to be very sensitive to the initial DC volts, and then they pay attention to ongoing DC input voltage to charger. I guess the charger manufacturers are assuming you are charging your batteries from your cars' starting battery and they don't want you to deplete it on the RC airplane flying field.
I normally charge Lipo's without a direct AC Power Supply Unit (PSU) to my 12s balance charger , and routinely use a Deep Cycle 12volt battery as the Power Supply for my balance charger . I do have a 15 Amp nominal. 12volt AC "Smart Charger" ready to recharge and supplement the Deep Cycle battery when the "bottom half of the lead discharge" starts to kick in :wink:


@ LockH ----- Ummm... Speaking of "marine", a cruiser might "fly" a wind generator? (See also those crazy Dutch, and "wind mills") Works whether in motion or at rest (when the wind is blowing)? Also, gasoline burners might take advantage of any down hills to save gas (long hills strangely absent for the yawtee set). Just a tought
Dude, and I say this respectfully; maybe you need to ring for the nurse ?
I have no idea what you are talking about.

 

[dogman dan]

To run long enough without the RC charger balking to charge a 700wh pack, I was having to put the battery I have on a charger. 2 amps wasn't enough, but a 10 amps charger kept er cranking fine.

It was a very cheap battery, so perhaps a better one would do a lot better.

Sounds like he will often drive plenty of distance to recharge, eliminating the issue of having to sit idling to run the charger. My use pattern, either driving only another 20 miles, or sitting in a camp, doesn't give me the drive time to run a charger from the car. So a generator worked good for me.

 

[LockH]

@ LockH ----- Ummm... Speaking of "marine", a cruiser might "fly" a wind generator? (See also those crazy Dutch, and "wind mills") Works whether in motion or at rest (when the wind is blowing)? Also, gasoline burners might take advantage of any down hills to save gas (long hills strangely absent for the yawtee set). Just a tought
Dude, and I say this respectfully; maybe you need to ring for the nurse ?
I have no idea what you are talking about.

HA! And you call yerself a sailor? Re "wind turbines" (aka "wind chargers" for batteries), see Wikipedia, here:
http://en.wikipedia.org/wiki/Wind_turbine

In part:

A wind turbine is a device that converts kinetic energy from the wind into electrical power. A wind turbine used for charging batteries may be referred to as a wind charger.

The result of over a millennium of windmill development and modern engineering, today's wind turbines are manufactured in a wide range of vertical and horizontal axis types. The smallest turbines are used for applications such as battery charging for auxiliary power for boats or caravans or to power traffic warning signs. Slightly larger turbines can be used for making small contributions to a domestic power supply whilst selling unused power back to the utility supplier via the electrical grid. Arrays of large turbines, known as wind farms, are becoming an increasingly important source of renewable energy and are used by many countries as part of a strategy to reduce their reliance on fossil fuels.

Some sailboat sailors (the hard-core cruisers, maybe NOT the yawtees, dressed in whites on the lawn playing tennis at the "Club", needing to be "disconnected" from the "grid" in odd, out-of-the-way places) routinely mount a wind genny on a pole over their "transom" (watt a landlubber might refer to as the "back" of the boat), or hang said genny on a ""cord" (line hung from eg... well, all over the boat, but the higher, the stronger the air flow usually. See also "wind aloft".)

Re "marine deep cycle" batts, the "king" (or "queen") of cruiser batt mfgrs (stolen from those witches in Salem MA. I sorta miss those naughty grrrls.)
Surrette batts aka the "Rolls" from Nova Scotia (where it is reputed some design a darn good fishing boat - see "Bluenose"), they have a pretty good FAQ on plumbum with aka "lead-acid" batts, using sulphuric acid here:
http://support.rollsbattery.com/support/solutions

CAUTION: Only for the truly "hard core". But sailors have taken lead-acid batt energy storage to a high "black art". Just mention the word "battery" to a sailor and be prepared to buy at least one round of beers. YOU HAVE BEEN WARNED!

 

[999zip999]

As Dogman has said in other threads. Just find a place to plug in your charger. Like a RV park a coffee shop ect. And easiest with a bluck charger and BMS. The balance charger and power supply can cause questions. For the unuderstanding ect. type.

 

[LockH]

BTW, re "winds aloft"... Amusing convo from the Spheroid Planet (Endless), font of all wisdom, from October, 2009:
http://endless-sphere.com/forums/viewtopic.php?f=1&t=13813&p=205409

Take that! (You landlubbers)
L

 

[TheBeastie]

Anyone have a preferred battery isolator?
I got a few of these as there pretty cheap priced.
http://www.ebay.com/itm/Car-Motorcycle-Boat-Van-Quick-Battery-Disconnect-Cut-off-Switch-Isolator-12V-24V-/271305121467?pt=Motors_Car_Truck_Parts_Accessories&hash=item3f2b0b9ebb&vxp=mtr

 

[dogman dan]

Funny how much more sense Lock's post makes now.

Yesterday, I wasn't sure if he was talking about the ol, put a wind turbine on the bike so you can charge with the apparent wind and ride forever thing. We've seen that often enough, I thought maybe it was that one again.

If he goes to the ocean, there should be an onshore breeze nearly every afternoon that would run a small turbine. Anyplace in CA that you can camp though, will have a friendly RV person with power. Not like out here with the endless empty, and you better carry your own generator. In the spring in the southwest interior, the problem would be too much wind every afternoon.

The original plan is definitely sound, very likely he will ride the coast in one spot, then be two hours of car time to the next one. In some places, two hours even if it's only 50 miles. So he won't be sitting idling the car for hours.

He got me going on touring again. I've been looking at maps for two days. Just ordered 10 more miles of range from HK. Looking at what will go in my area, on 60 miles max range, 40 miles range if it's lots of mountains. It's warm here right now! I rode 30 miles yesterday, and 50 the day before. I'd like to just ride off from the house, and be gone a week or so.

 

[LockH]

Incidently, just how big/heavy is this "RV" (recreational vehicle)? Once upon a time, I pedalled a two-wheeler from Halifax,NS to Kingston, ON. Carried my own sleeping bag and pup tent. Plenty of places to "park" off the main road overnight. But I pedalled my ass off (literally and figuratively). Was eating four (resto) meals a day and still lost weight. But I suppose I missed out on big comfy seats? Big screen TV? Surround HF sound? I guess to be "lux" I could have dragged a trailer... Probably would have been more comfy than my back pack.

 

[dogman dan]

His or mine? He seems to have a car of some kind. Not sure what his recumbent is, two wheel or three.

I have done touring so far, by driving a car to a section of road, then riding both ways. Drive 20-30 miles farther, often on another trip, ride some more. If I camp in the car, It's a Subaru Forester with a trailer for the huge bike, or a rack for carrying the dirt bike if going trail riding. With the car, I can carry a generator to charge in the woods at a remote campsite.

What I want to do is just ride off from the house on this. Like Justin did, but for just a few days, or weeks at most. 150 pounds with a full load of batteries that weighs 30 pounds or so. Then the camping gear is another 40-50 pounds at least. Call it a 200 pound bike loaded.

It remains to be seen if I can stand to camp out for more than two nights at my age. The original idea was to tour from motel to motel. No money for that now. Not enough ES fans in this area for couch surfing much either.

 

[parajared]

Thanks for the battery isolator suggestion. My alternator is a Bosch 50 amp, so I presume 50 amps x 12 volts = 600 watt hours of charge ever hour?
The prospect of fully recharging in less than two hours sounds promising.
Generators look promising too, but they look to be about $300 (for a clodger) from craigslist; the benefit of getting one is that it would be more useful for something later than just a spare deep cycle.

I will be taking the Black Bullet on the trails but the lead acid is staying in the car!

 

[LockH]

HEY! No posting naked ebikes! Is there a thread yet on Planet Spheroid (Endless) for too sexy looking electric bikes/trikes? Admin folks here might consider xferring that pic (overhead) to the thread for folks with serious ebike addiction (maybe reformed gasoline/diseasal addicts anonymous, "AA" for short).

Anyway... Some old sailor (won't mention here any names) might suggest adding a rain, etc cover to double as a sail (full battened of course, for when the wind is off the beam, or further aft), to extend batts charge, pass more horseless carriages, etc.

L (or "R", as my Chinese friends might say)

 

[FeralDog]

@parajared --- it look like your car alternator should be sufficient for your needs. But the sticky part will be the quirkiness of your battery charger. Then, be sure to take the extra care needed to not accidently drain your car starter battery !
Test many times that charging method BEFORE you take it to the long distance road.

@dogman ---- an expeditionary system for your voyages may be one that is used by military (Romel did it) and Polar expeditions. Perhaps create hidden "fuel dumps" buried along a future route? A shovel and some old car batteries could make an interesting fuel dump?

@LockH ---- maybe go ahead and ring for the nurse. You are not parrot on a pirates' shoulder, nor are you Johnny Depp. Take a deep breath , it will be OK.

 

[LockH]

@LockH ---- maybe go ahead and ring for the nurse. You are not parrot on a pirates' shoulder, nor are you Johnny Depp. Take a deep breath , it will be OK.

You didn't say watt part of anything I said you appear to object too? I have travelled for untold thousands of miles using wind power (wind energy captured for immediate using watt is called in Engrish a "sail", or a "genoa", a "top sail", etc etc.) I once did try a trike/"land yacht" on a large parking lot. It accelerated like crazy, and it was fun to "spin out" just before reaching either end of the parking lot. (No batts - energy stored as electricity - involved).

But it is possible you are maybe a landlubber, or not too "bright" or something? I am sorry for any confusion you may be having. You perhaps already have TONS of experience in that area. My suggestion? Just ignore watt may be happening around you, or in the past. Seems to work fine for most folks. Some sort of "medication" perhaps?

L

 

[jay7264]

i would suggest a proper isolation circuit for charging your deep cycle while driving i have a optima deep cycle battery for when me and my buddies go out with the rc cars and it runs 4 chargers at once charging 6s batteries in multiple rc cars and it runs all day. my toyota solara would be used as my charger it has a 130 amp altinator that has been just fine. heres the one thats in my toyota. https://www.google.com/shopping/product/3988451645552315409?q=isolation+circuit+for+boat+battery&client=firefox-a&hs=M9J&rls=org.mozilla:en-GBfficial&channel=np&bav=on.2,or.r_cp.r_qf.&bvm=bv.61190604,d.dmQ,pv.xjs.s.en_US.OD_8LLFKFf4.O&biw=1024&bih=614&tch=1&ech=1&psi=ud78UqCnK4b20wGJ9oCwCg.1392303789735.5&ei=2d78UuqPFcS00QHbw4HYBg&ved=0CKkCEKYrMAs

 

[dogman dan]

I bet it works good with a really good battery. That one I got from Sams club all cheap was clearly a dud. It looked new, but you know how it can be with lead. Bet it was old enough to vote.

Spring touring weather is here now. I just bought 14s 10 ah of battery, so I won't have to bury any to get from town to town. Got a solid 30 ah of range. Soon as I get done with this damn swine flu, I'm outta here for some riding before it gets too hot.

 

[parajared]

I found a bonus feature of having a deep cycle marine along for the trip, not only can you charge lipos off of it, you can also lug the thing into a tent and plug a 12 volt electric blanket into it.

 

[dogman dan]

As good as a nice warm dog in the tent.

Won't need much warmth in the tent soon, 75 F out there right now. I did 50 miles this morning, working up strength for some overnighters.

 

[LockH]

Ummm... There is maybe a good reason why they are called deep cycle *marine*? (The batt makes a great boat anchor when fully consumed.)

 

[docnjoj]

Go dogman. It is good for us "older folks" to read about your strength returning. Don't forget a flu shot this year.
otherDoc