russbost
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| posted on 23/11/12 at 07:31 PM |
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More Lithium Ion battery info
Further to questions that have been asked about these batteries, I have been gleaning some more information & have been doing some more
testing.
First I would suggest taking a look at this thread
Link
particularly the tests I've done towards the bottom of page 1
Ok so that tells us that a tiny Lithium Ion battery weighing 430g is capable of starting a mid size car engine & capable of cranking it for at
least 10 seconds!!! Something I find quite staggering!
Now, many people have asked me the Ah rating of these batteries & the manufacturer doesn't give us that info despite many questions to them,
this obviously leads me to suspect that the Ah rating is low & they don't want to advertise that fact, however, for the purposes of starting
& running a kitcar or motorcycle the Ah rating is fairly irrelevant, as soon as the engine is started everything will run from the alternator
& the battery is doing nothing more than recharging (which these batteries do in about 1/10 the time of any lead acid). For nearly all bikes &
the vast majority of kitcars the max current draw is when the lights are on main beam (in a few cases a heater fan or cooling fan might be pulling an
additional 10A or so) 2 x 60W headlights, 4 x 5W sidelights equates to around 8A, so in any normal situation you're not going to be drawing more
than 20A & even small bike alternators make at least 25A.
Hence what we should really be interested in is the CCA of the batteries (Cold current Amps) this is the starting current the battery is capable of
for 30 seconds at 0 degrees C . Now those figures we do have & they range from 70A to 380A.
As a comparison the Odyssey 625, which I believe is a commonly used kitcar battery has a CCA of 265A which is about the same as a LIP014B. The Odyssey
weighs 6Kg, the 014B weighs 1Kg & costs around 50% more, so I guess it depends how important saving 5Kg is!
Anyway, back to Ah ratings, first a brief explanation, if you take, say a 100Ah battery you would think it would deliver 1A for 100 hours or 10A for
10 hours wouldn't you? No, that's not the case! The rating is usually checked I believe as a 20 hour capacity, ie if you were checking a
100Ah battery you would draw 5A from it & it should last 20 hours, however if you draw, say, 20A from it it certainly won't last 5 hours as
the Ah rating drops as the current increases for lead acid, I don't think this is the same for the Li ion batteries, but no doubt someone will
correct me if I'm wrong.
The smallest of our batteries (the one that started the Toyota 1.6 AGE engine!) is intended to replace motorcycle batteries which are rated at between
3 & 4Ah (varies between manufacturers & standard/premium etc), so a 3ah battery for a 20 hour rating you would draw current at the rate of
0.15A (3 /20) to test it. That wasn't terribly practical for the purpose of my tests as, one, I hadn't got a bulb with sufficiently low
wattage &, two, I really didn't want to leave it overnight unattended, I wanted to be able to see what was going on. The smallest bulb I had
I could test with was a 5W sidelight bulb, I connected this up with an Ammeter in the circuit & left it sitting on the bench whilst I got on with
my work, it was drawing a little over 0.4A according to the ammeter, I started the test at 1 o'clock & at 4 o'clock was still going
strong & drawing 0.4A, by 4.30 that had dropped to .38A & by 5 had dwindled to around 0.3, by 5.30 the bulb was a dim glow & I decided to
call that the finish, so by a very rough reckoning I'd make that between 1.5Ah & 2Ah, so actually not as low as I had suspected.
I hope that at least answers to some extent the Q's I've been getting regarding Ah capacity, I would think a VERY rough guide would be to
say they are probably around 40 - 50% the capacity in Ah terms of the lead acid units they replace, so great for starting engines, not much use in
electric cars or bikes!
You also have to remember that the Lithium batteries lose hardly any charge when standing idle, however a lead acid battery loses around 5% a week
(more in colder months & as it gets older) when not in use, so leave a car standing for 6 weeks or so & the battery is down to around 2/3 of
it's original capacity & not only does it lose Ah capability it also loses CCA power.
Anyway I hope I've not bored you all to death & you've found this of interest. I am now working on putting the video together of the
test I did yesterday, bet you can hardly wait!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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zetec
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| posted on 24/11/12 at 08:29 AM |
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If they are the same as my son uses in his RC touring car they can give a massive amount of power for their size. The ones we use tend to be rated in
"C", this means that a 5A battery if rated at 60C it can supply 5x60=300A! From a 145g battery. The big concern with the batterys we use
is charging and discharging. They need to have a smart charger that will cut off at a set voltage as over charging will very quickly damage the cell,
as will over discharge, which means the battery will not recharge if run too flat. They also burn rather well if damaged, hence we us hard cased ones
and charge in a fire proof bag.
If you can sort an in car charging system that works and they dont get over discharged then they are great!
" I only registered to look at the pictures, now I'm stuck with this username for the rest of my life!"
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sebastiaan
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| posted on 24/11/12 at 08:42 AM |
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quote:
Originally posted by russbost
For nearly all bikes & the vast majority of kitcars the max current draw is when the lights are on main beam (in a few cases a heater fan or
cooling fan might be pulling an additional 10A or so) 2 x 60W headlights, 4 x 5W sidelights equates to around 8A, so in any normal situation
you're not going to be drawing more than 20A & even small bike alternators make at least 25A.
Hi,
To prevent people using this information to size alternators: whilst the above is largely correct for carb'd cars, on fuel injected card the
high pressure fuel pump needs to be taken into account as well. Current drw can easily be between 5-10 A for a decently sized pump, whilst it can be
even more for the useless "super high power, look, I've got the biggest" pumps that sometimes seem to be fitted. Bigger isn't
always better!
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russbost
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| posted on 24/11/12 at 10:21 AM |
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Fair point, & you're quite right, I'd missed that calculation, but if you have an injected car engine you'll have a car sized
alternator, probably putting out at least 45A, possibly the most marginal situation would be a fuel injected bike engine running a car high pressure
pump, which is exactly what we do on the Furore with the ZZr1400 engine, but bigg bike engines have fair sized alternators, the ZZR1400 is, I believe
around 35A, certainly seems well capable of keeping the battery charged - my point was, that if it works with a car battery it would work with one of
the Lithium batteries, it's staring that's important, running takes care of itself.
With a tin top it's a different situation, you need to have enough back up battery to run the alarm system for a couple of weeks whilst on
holiday, & have the capability of parking up, listening to the radio for a couple of hours, whilst running your laptop & phone off the cigar
lighter & playing with your electric windows/seats/mirrors etc & still having enough battery power to flash your lights at the other
doggers!!!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
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