Battery charging

Electrical issues
Forum rules
Please do not start new topics here, but here: New Panhead and Flathead topics
Post Reply
beets
Posts: 114
Joined: Fri Jul 13, 2007 1:03 pm
Bikes: 56 FL, 07 Goldwing ,91 BMW K75
Been thanked: 2 times

Battery charging

#1

Post by beets » Mon Dec 29, 2008 1:33 pm

I just got a new Harley battery and am going to buy acid and charge it. The instructions with the batt. are based on specific gravity. I don't have a hydrometer. What is the voltage I should charge it to before putting it into service?
6V with 3 brush gen.



steve_wood
Posts: 947
Joined: Tue Jan 08, 2008 12:32 am
Bikes: 56 FLH, 2007 FLHRCI
Location: Belleville, Ontario, Canada
Has thanked: 48 times
Been thanked: 27 times

Re: Battery charging

#2

Post by steve_wood » Mon Dec 29, 2008 3:13 pm

Beets:

You should be able to find a battery hydrometer for about $10. Might be worth your while...

What kind of charger are you using? A good one will tell you when the battery is fully charged. Again, a good charger, as is any good tool, is an excellent long term investment.

If you're still wanting to charge ahead, then typically a 6V battery is fully charged when you hit 6.5 to 7.0V.

By the way, once you've fully charged the battery, store it at room temperature (70 degrees) for a few hours and then check the acid level and top up as required.

steve

VintageTwin
Panhead Register Member
Posts: 772
Joined: Mon Aug 16, 2010 7:18 pm
Bikes: '46 Knuck. '57 Panhead, '59 Panhead
Location: Repop Hell

Re: Battery charging

#3

Post by VintageTwin » Mon Dec 29, 2008 3:55 pm

Don't even think about charging the battery on anything but a BatteryTender. Any other battery charger will overheat your new battery and warp the separator plates.
There's a bill being pushed though congress right now that will make it a federal crime to use an automotive battery charger on a motorcycle battery. The sentence proposed is 25 to life, since the battery's can't speak for themselves, it's pre-meditated murder, since most people get warned in advance. Go here. Buy one. 6 or 12 volt.

Get the acid from a battery dealer.
I always use J.C. Whitneys cadmium battery additive. "Charge It". I've used it in my batteries and they get a year or more past the expiration date. Mother's milk for your wet cell.
http://www.jcwhitney.com/autoparts/Prod ... =Charge+it
Read the reviews. Those farmers don't have time to fool around with additives that don't work. Buy a quart, it has a long shelf life.

Cotten
Posts: 6911
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois
Has thanked: 100 times
Been thanked: 268 times

Re: Battery charging

#4

Post by Cotten » Mon Dec 29, 2008 4:06 pm

Beets!

Any ordinary "six-volt" charger should provide the proper voltage (something like 7 or 8v), but it is the amperage that is the concern.

The slower a battery is charged, the deeper the energy will be stored into the plates. Too much amperage will just saturate the surface, reducing the total load capacity.

Most modern batteries are deeply pre-charged, but some imports and reproductions must be slowly charged for over 24 hours before they will 'come to life'.
(Although, I recently had fits with a vintage NOS WISCO H-2 that seemed to never charge appropriately until I hit it with a six-amp boost!)

If your charger is not already limited to two amps or less, then you can "choke" it down by putting a headlamp bulb in series with the battery.

A battery is fully charged when it "gases freely", meaning bubbles are appearing at the surface at a constant rate.

...Cotten

john HD
Moderator
Posts: 3677
Joined: Sat Aug 20, 2005 7:24 pm
Bikes: '42 WLA X 2, '55FL, '93 Ultra Classic, '91 Fatboy, '97 883, '71 Suzuki Duster 125, '83 GPz 750.
Has thanked: 52 times
Been thanked: 77 times

Re: Battery charging

#5

Post by john HD » Mon Dec 29, 2008 5:57 pm

cotten,

i believe that should be parallel for the head lamp in the circuit.

a series circuit has the same amperage throughout. the voltage drops across each device.

a parallel circuit has the same voltage throughout. the amperage drops across each device.

john

beets,

if you use an automatic 6v battery charger that has a 6 amp maximum you will be fine. if you cannot find one a tender or the headlamp trick will work. be patient when you are charging, a 18 amp/hour battery will take (you guessed it) 18 hours to full charge at one amp!

john

VintageTwin
Panhead Register Member
Posts: 772
Joined: Mon Aug 16, 2010 7:18 pm
Bikes: '46 Knuck. '57 Panhead, '59 Panhead
Location: Repop Hell

Re: Battery charging

#6

Post by VintageTwin » Mon Dec 29, 2008 6:18 pm

if you use an automatic 6v battery charger that has a 6 amp maximum you will be fine.
If you use a battery charger like the one suggested you will kill your battery. But, it's your battery. I would suggest reading the literature on the BatteryTender® about milli-amp charging and the effects of overcharging before you shorten your H-2 batteries life.
BatteryTender is located in Deland, Florida. I'm sure that their tech dept. can enlighten you on the pertinent info before you go off on your own and do something wrong.

Trying to bleed off unnecessary amps by using a head light bulb is cheap and goofy, imo. :wink:
Last edited by Anonymous on Mon Dec 29, 2008 6:21 pm, edited 3 times in total.

FlatHeadSix
Moderator
Posts: 2685
Joined: Sun Jun 06, 2004 5:14 pm
Bikes: '31 VL, '34 VD, '45 WLA, '47 WL, '49 FL, '51 WL, '58 ST (Hummer), '71 GE (Servi)
Location: Lonoke, Arkansas
Has thanked: 5 times
Been thanked: 32 times

Re: Battery charging

#7

Post by FlatHeadSix » Mon Dec 29, 2008 6:19 pm

John,
Cotten is correct, place the bulb in series. You are not actually trying to light the bulb, you are only using it as a resistor. If you have something in the circuit to read the amps you can adjust the final charging rate by trying different size bulbs, a headlight bulb will provide more resistance (and a lower charging rate) than a tail lamp or stop lamp. You can even string several together in series if you want to drop the charging rate way down to something below 1 amp. Slower charging rate is better.

I use different sized bulbs, wired in series, for my cadmium plating setup to control amperage and plating rate. Its the same principle; lower the amperage to achieve a slow plating rate. I may have a diagram for it somewhere, I'll post it if I can find it.

mike

VintageTwin
Panhead Register Member
Posts: 772
Joined: Mon Aug 16, 2010 7:18 pm
Bikes: '46 Knuck. '57 Panhead, '59 Panhead
Location: Repop Hell

Re: Battery charging

#8

Post by VintageTwin » Mon Dec 29, 2008 6:37 pm

Here's a BatteryTender Jr. that should also do the same job, yet at an economical price. Call BatteryTender anyway and learn more than you know now.

Those Harley H-2 batteries cost about a hunnert' bucks. You going to risk it's life on a Rube Goldberg charging system? No way my friend. And, don't ever overfill the battery with acid (electrolyte) or later overfill it with distilled water. If you do....you'll ruin the battery. Get one of those eyedropper hydrometers like someone suggested. You can get them at J.C Whitney too. Peace and good charging in the days and years ahead.

john HD
Moderator
Posts: 3677
Joined: Sat Aug 20, 2005 7:24 pm
Bikes: '42 WLA X 2, '55FL, '93 Ultra Classic, '91 Fatboy, '97 883, '71 Suzuki Duster 125, '83 GPz 750.
Has thanked: 52 times
Been thanked: 77 times

Re: Battery charging

#9

Post by john HD » Mon Dec 29, 2008 7:53 pm

thud,

that is the sound of my head hitting the monitor.

mike,

try your technique and put a volt meter across a discharged battery and tell me what you get. it will not be 6 volts. plating is different than trying to induce a steady voltage on a device.

vt,

i understand what you are trying to get at. but, understand when a battery is in a bike it gets alot more than one amp. put an ammeter on it and tell me what you get when you rev it above an idle. REMEMBER i said an AUTOMATIC battery charger. that is one that automaticly reduces the current as the voltage rises just like your bike's regulator does. mine usually starts around 4 amps and drops to an amp or two in about 20 min. i usually get around 10 years out of my H-2 batteries unless i drop them like my last one.

john

VintageTwin
Panhead Register Member
Posts: 772
Joined: Mon Aug 16, 2010 7:18 pm
Bikes: '46 Knuck. '57 Panhead, '59 Panhead
Location: Repop Hell

Re: Battery charging

#10

Post by VintageTwin » Mon Dec 29, 2008 8:08 pm

REMEMBER i said an AUTOMATIC battery charger. that is one that automaticly reduces the current as the voltage rises just like your bike's regulator does. mine usually starts around 4 amps and drops to an amp or two in about 20 min.
Thanks for the civil reply 8) I believe what we have here is a failure to communicate. What you say in the quote above is 1903-1985 thinking. I thought so too until I read the BatteryTender literature. It's printed in Vol. 1 verbatim. It's new technology, improved since the days of yesteryear. Especially take note of the phrase where you said...."drops to an amp or two in about 20 min..." Capture that thought and then re-read it after you've read the BatteryTender literature and it will make your skin creep.
I don't ever feel like I've won a mechanical debate on any of this stuff. I feel like I'm cheating since I've read the material and others haven't. I think Battery Tender should publish their literature on line. I think I might just do that.
I'll be back - der plumbinator
Image
These same hi-tech chargers will charge a car or pick up truck battery. It's a necessity.

steve_wood
Posts: 947
Joined: Tue Jan 08, 2008 12:32 am
Bikes: 56 FLH, 2007 FLHRCI
Location: Belleville, Ontario, Canada
Has thanked: 48 times
Been thanked: 27 times

Re: Battery charging

#11

Post by steve_wood » Mon Dec 29, 2008 8:23 pm

Okay folks, time for some simple electrical theory from one of your resident electrical engineers.

V = I*R where V = voltage, I = current and R = resistance. Turn things around and you also get I = V/R.

Now, for the TOTAL current in a circuit, if you increase the resistance, you decrease the current. By the way, the current is the same every where in a series circuit.

So, the premise of adding resistance (like a headlight) to a circuit to decrease the current is absolutely correct. In fact, if you can measure the resistance of the headlight(s), you can calculate the predicted current.

Now, all that being said, I am also a BIG believer in using a proper battery charger (or tender). One that has an adjustable charging current. Use the lowest setting possible.

Okay. Sorry for getting technical. I'll shut up now.

john HD
Moderator
Posts: 3677
Joined: Sat Aug 20, 2005 7:24 pm
Bikes: '42 WLA X 2, '55FL, '93 Ultra Classic, '91 Fatboy, '97 883, '71 Suzuki Duster 125, '83 GPz 750.
Has thanked: 52 times
Been thanked: 77 times

Re: Battery charging

#12

Post by john HD » Mon Dec 29, 2008 10:11 pm

So, the premise of adding resistance (like a headlight) to a circuit to decrease the current is absolutely correct.
that is correct steve. i'm no engineer, just a guy who makes his living doing this sort of stuff.

what is the voltage at the battery when you do this?

john

steve_wood
Posts: 947
Joined: Tue Jan 08, 2008 12:32 am
Bikes: 56 FLH, 2007 FLHRCI
Location: Belleville, Ontario, Canada
Has thanked: 48 times
Been thanked: 27 times

Re: Battery charging

#13

Post by steve_wood » Mon Dec 29, 2008 11:17 pm

John:

I see where you're going with this... your concerned that the voltage at the battery to be charged will not be the same voltage as seen at the output of the charger. And you would be correct. The headlight (or whatever resistance you use) and the actual battery act as a voltage divider - the voltage drop across each will add up to the total voltage of the circuit.

That's why I would not use this method to charge a battery - I would use a good quality charger. All I'm saying is that adding a resistance to the circuit decrease the total current. The headlight method may work, perhaps because it's the current that does all the work and the voltage is irrelevant, but I don't know for sure and that's why I wouldn't use it.

I'm just an engineer. And that means i spend a lot of time behind a desk, but I'm smart enough to know that the guys who do this for a living, like yourself, have knowledge no engineer could ever learn in school.

Peace brother.

john HD
Moderator
Posts: 3677
Joined: Sat Aug 20, 2005 7:24 pm
Bikes: '42 WLA X 2, '55FL, '93 Ultra Classic, '91 Fatboy, '97 883, '71 Suzuki Duster 125, '83 GPz 750.
Has thanked: 52 times
Been thanked: 77 times

Re: Battery charging

#14

Post by john HD » Mon Dec 29, 2008 11:25 pm

steve,

you would love to work in our office. we always have fun with the engineers!

a lot of my phone calls in the middle of a project go something like this:

what were you thinking?
were you drinking at that time?
if so, why didn't you invite me?

i shot some pics of a little experiment i just did out in the shop, i'll post them after the grand kids eat.

john :mrgreen:

FlatHeadSix
Moderator
Posts: 2685
Joined: Sun Jun 06, 2004 5:14 pm
Bikes: '31 VL, '34 VD, '45 WLA, '47 WL, '49 FL, '51 WL, '58 ST (Hummer), '71 GE (Servi)
Location: Lonoke, Arkansas
Has thanked: 5 times
Been thanked: 32 times

Re: Battery charging

#15

Post by FlatHeadSix » Tue Dec 30, 2008 12:52 am

We've been down this road several times before and I always try to simplify things by applying the "water in a hose" analogy; electricty is electrons flowing through a wire, the same thing as water molecules flowing through a pipe. Potential is the force which makes it move, in electricity its volts, for liquids its pressure. If you restrict the flow by placing a valve in the water pipe or a resistor in the wire the potential will remain constant (you will not see a pressure drop or voltage drop) as long as the source or supply of either liquid molecules or electrons is consistently high enough to maintain the flow.

Steve, voltage differential is critical to the battery charging process, the voltage coming from the charger MUST be higher than the battery voltage or nothing will happen, there will be no flow of electrons from the charger to the battery. Placing resistance in the circuit (a headlight bulb) will slow the flow (lower amps) but should not cause a voltage drop if the power supply is adequate (big heavy duty charger).

John, the reason this does not seem apparent when measuring bench circuits with the stuff we use on the bikes is because the trickle chargers and battery tenders are really puny as far as power supplies go. Small capacity chargers will definitely exhibit voltage drop when placing resistance in the circuit because they just don't have the oomph.

Back to the water analogy; think of your charger as a "pump". With water, as long as the pump is keeping up with the flow you will not have any pressure drop no matter how open or how closed the valve is. With electricity as long as the supply of electrons is greater than the demand you will not get a voltage drop no matter how much or how little resistance you place in the circuit.

did any of this make sense?, I need a beer!

mike

Post Reply

Return to “Electrical”