Total Loss Ignition charging question - what size charger

[murf99]

Hello,

What power charger should I get to ensure that my lightweight bike, with a total loss ignition system, doesn't run out of electricities?

I think my main worry would be trackdays - where the bike would run for 25 minutes, and be allowed 35 minutes to recharge.

I'm thinking that perhaps a 1.0 amp trickle charger might not be enough to recharge the battery?  Not sure...  I'm looking for some advice from some folks that have run total-loss.. before I nerd out and start doing the maths.

Thanks in advance!

[Super Dave]

I haven't done it in a long time, but, yeah, a trickle charger isn't enough.  We always carried a spare battery too.  Someone should be able to chime in.

[HAWK]

The stock battery in an  SV is about 10 Amp Hours, assuming you are running the stock battery it would take a 1 amp trickle charger 10 hours to charge this battery from dead to full. You don't mention what bike you are running so I don't know what your load is. If you have an ammeter you can measure the current draw of the bike while running and multiply it by the number of hours you will be running it between charges to get the number of amp hours you will be "removing" form it. Your charger will have to be able to put that back in the alloted time. Keep in mind that the faster you charge a battery the harder it is on the battery. As Dave mentioned is would be a good idea to have a second battery that you could swap in while the first is charging.

IF your bike draws 5 amps when running and you run it for 20 min (.333 hours) then your consumption is

5A * .333hr = 1.7 Amp Hours

assuming you have 40 min to replace that

1.7 Amp Hours / .666 hours = 2.6 Amps charge rate.

[murf99]

Thanks Dave and Paul.

The bike is a 400cc 4-cyl.

I'm assuming that the electrical load is greatest at high revs, high load (most spark plug firings per unit time, at highest resistance)?

[HAWK]

Thanks Dave and Paul.

The bike is a 400cc 4-cyl.

I'm assuming that the electrical load is greatest at high revs, high load (most spark plug firings per unit time, at highest resistance)?

Yes the load will be highest at high revs and wide open throttle so getting a full load reading will not be possible without a dyno run but if you get a reading at idle you should be seeing at least 75%.

You would probably be fine with a 5 amp charger but as I mentioned before the higher you go the shorter your battery life will be. It is also best if you start from an aux battery so that you don't load the bike battery more that necessary.

[Super Dave]

You would probably be fine with a 5 amp charger but as I mentioned before the higher you go the shorter your battery life will be. It is also best if you start from an aux battery so that you don't load the bike battery more that necessary.

+1

Common practice.

Gonna be a little hard as a track day weapon.  Make the battery changes simple so you can have an easy way out.

[murf99]

Thanks guys!

[Jeff]

Multiple batteries are definitely the trick.  I looked into this a LOT with my 600 back in the day, and ultimately it just became more pain in the ass and liability than benefit...

[Jason748]

Todd - You might want to look at upgrading to a more durable battery than the stock one (and save some more weight while your at it)... Give Josh @ Speedcell Tech a call... He's a racer from the Southwest and owns a battery company that is specializing in what you're looking for (smaller - lighter - more reserve - holds up to high amp charging - etc...)
I'll be running one of his supersport batteries next year.
http://www.speedzilla.com/forums/ducati-superbikes/51647-new-battery-installed-2.html

I have all his contact info at home... I'll PM it to you tonight

[Eric Kelcher]

Add/mount a solar battery charger.

Saw a GSXR750 with this and went down several sizes on battery, I think he ended up with a NiMH battery that was less than 2lbs.

Bike would run a full GT race with no solar gain and could go 45-60 min in full sun.

[Super Dave]

How big of a solar panel?  Solar is pretty inefficient.  And you'd need to really up the voltage to get it in a fully charged battery.  There is technology to do that, but what's the weight cost then again?  Interesting.  I looked a lot at solar for the bus for powering up my house battery, but the cost and efficiency was always a huge concern.

If solar could get less expensive and more efficient, it really should be incorporated in to every vehicle.  Nice roof there would really help out.  I would like to have solar panels running a block heater right now.   

[123user]

Do you on starting the bike on the same battery as you run?  If so, you'll need something larger.  As far as charging, plan on having one fully charged battery for each track outing until you get a good feel for the capacity consumption of your bike.

I ran a total loss hawk for a couple of years.  After lots of experimenting I landed on the Yuasa YTX5.  Its only a little bit heavier than the YTX4, but has the capacity to start the bike twice  (maybe three times if your lucky).

Its also important to keep the discharge rate in mind.  On a carb'd, bike you could probably run for over an hour on a YTX4, but you'd be way below 50% discharge.  I'd size the battery to be 2x the Amp-Hour rating you actually need.   If you take a std agm battery below 50% regularly... it will fail prematurely and you'll be pissed!

Remember, total loss is mostly about losing that 5 pound lump spinning on the end of your crank.  So, even if you had to add a pound of static weight (battery) to lose 5lbs of spinning weight its still well worth it.  Total loss bikes can be very rewarding if your willing to size and maintain your batteries religiously.  If your not up to the extra work, it'll probably be nothing but frustration.