How many Ah for my 1974 Commando?

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nomadwarmachine

nomadwarmachine

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I am nearing the finish line on the restoration of my 1974 Commando 850 (Royal Flake Blue) and I am eyeing a Shorai lithium battery to replace the 11 lbs. doorstop that sits in the battery tray now.

The bike maintains the positive ground polarity and has a Lucas 3-phase system with the Podtronics regulator/rectifier. It is running an incandescent headlight and LED taillight. I am trying to decide between the Shorai 14Ah (LFX14L2-BS12) and the Shorai 9Ah (LFX09A2-BS12).

I feel like the 9Ah should be sufficient for a kickstart 850, especially with the LED taillight. The Lucas should also keep it charged, but I wanted to check before placing an order. What do you think?
 
Be sure to check the threads on this forum on some issues with running the Lithium batts...some reports of fires, some reports of improper charging rates with standard Reg/Recs.

Note you can put in a smaller than stock lead acid battery and do fine on the non-E-start bikes, if weight is important.
 
Thanks. I feel good about going forward with the LiFe ion but I am mindful of having enough Ah irrespective of chemistry. Would the Norton hive use 9Ah or 14Ah with this setup?
 
Whatever Ah suits your fancy would work. All you need is enough to spark the EI at takeoff. The 3 phase alternator will surely
keep whatever battery is installed at the peak of performance.
 
The 9 ah lithium actually holds 3 ah of stored power, should your system be capable of charging the battery to fully charged at 14.4 volts. This info is a bit buried on the Li manufacturer websites, but it is there.
Having said that, it's amazing how little reserve one can get by with if careful and not stuck in slow traffic at night.
LEDs help.
The other thing to think about is the weight of a 3 amphour sealed lead acid battery, because that's the greatest amount of reserve you will ever get from the 9ah pbeq Lithium.
The 3 amphour lead acid has an operating voltage range more in sync with the output of your charging system.
And you can pull a full 3 amphours from it without problem
I had a 9 ah Li battery on an old bike with a fairly decent alternator.
It was a bit like running on a flashlight battery until it melted and destroyed the nice new Alton alternator and Podtronics regulator.


Glen

Found it

 
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nomadwarmachine said:
I am nearing the finish line on the restoration of my 1974 Commando 850 (Royal Flake Blue) and I am eyeing a Shorai lithium battery to replace the 11 lbs. doorstop that sits in the battery tray now.

The bike maintains the positive ground polarity and has a Lucas 3-phase system with the Podtronics regulator/rectifier. It is running an incandescent headlight and LED taillight. I am trying to decide between the Shorai 14Ah (LFX14L2-BS12) and the Shorai 9Ah (LFX09A2-BS12).

I feel like the 9Ah should be sufficient for a kickstart 850, especially with the LED taillight. The Lucas should also keep it charged, but I wanted to check before placing an order. What do you think?
Click to expand...
I use AGM batteries exclusively - not interested in fire under the seat and traditional batteries are too messy. 7 ah is plenty for a kickstart bike with regular electronics and more than enough with LEDs.

However, I use 9ah and I get them from Amazon: https://www.amazon.com/gp/product/B00XNK94LU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
 
@nomadwarmachine to answer your question - the 9ah battery is more than sufficient.


However, please consider a series-type reg/rec like the Shindengen SH775 or SH847 if you are going to pursue a Shorai LFX battery.

Also, consider wiring the reg/rec directly to the battery via it's own dedicated fuse.

You should use a charge warning light rather than the original assimilator.

Of course, remove the original zener, rectifier and capacitor.


All very minor, and easy to implement changes - but these will give you peace of mind as well as help protect the rest of your wiring should fault or failure occur.
 
Well...I have been running a Shorai for years. In the beginning it was used in the original Lucas system - rectifier/Zener, etc. Later I installed an Alton E start and changed to podtronics. The same Shorai has been in place for the entire time. No issues at all.

I am well aware of the charging/voltage characteristics of the Shorai vs a lead acid battery. All I can say is that although the differences are, of course, real, on the street they have made no difference and the Shorai has far outlasted any moto battery I have previously owned. I wouldn't put any other battery in the bike.
 
But for a kick start machine, a good quality AGM would be my choice. Lower charging voltage, no "melt down" risk. I have a Shorai as well on my e-start machine, and it's a source of anxiety for me.
 
I use a small 1.3 Ah AGM battery. Weights 520 gr.
Never felt the need for anything bigger.
For one season I used an even lighter lithium battery (Ballistic) 250 gr.
No issues, but worntorn scared me out of it..
 
The lucas 14.3 zener can hardly charge a LI battery at all??? Nor any of the electronic regulators
Why not a conventional charging system a bit "upped" for LI battery so you will not be running around always with a 1/2 charged LI battery?
1N3314B - Zener Single Diode, 15 V, 50 W, Can be had + or - ground less than $10 "R" for reverse polarity

I still would use an AGM.
 
Too much worrying about Shorai-type batteries. It's like saying you'll never fly again because there was an airline crash several months ago.

It is true that a standard charging system will not fully charge a Shorai. Basically, my charging system can maintain my Shorai 18AH at around 80-85 percent charge based on voltage checks. Yes, 100% would be better! But that 80% easily handles everything on my Commando - Alton Estart, incandescent lights, etc.

I look at it like this:

Say I need 2 gallons of water to do some job. I have a 5 gallon bucket but the water company only allows me to put 4 gallons in it. That limits the capability of the bucket but it still holds more water than I need. So the practical side of it is that it makes no functional difference.

The fact that I've had the same Shorai 18AH for 10 years demonstrates to me that there is no issue here.
 
maylar said:
The "R" version (cathode to case) for positive earth is not stocked by anyone that I have found. Still available, but the vendors want you to order a minimum of 25 pieces.
https://www.newark.com/solid-state/1n3314rb/zener-diode-50w-15v-do-5/dp/10P4824?ost=1N3314RB&ddkey=https:en-US/Element14_US/search

14.5 volts will fully charge a lithium battery.
Click to expand...

Theoretically YES...Fixed power supply?
But we are discussing a norton motorcycle with a lucas alternator that only after an extended period (at highway speed/no headllight) of running will finally reach zener control of 14.3. Now it a LI battery is 14.4 normal charge instead of 12.8 for lead/acid. If i understand batteries you must exceed the battery rated voltage to charge it unless 1/2 or low charge is acceptable?
Run the bike down the highway, leave Boston and will the battery be charged by St. Louis?

I was forced to run NO HEADLIGHT in a headlight state due to slow running engine in city driving or the bike would not run from a EI that would shut down.

MM some day you may need to cross a desert and 2 gallons is not enough no matter how big the bucket is. 15V zener helps to keep the bucket more full-quicker.
 
From Shorai's web page "Shorai Batteries require a charging system output of 13.1 Volts or higher at idle, and must not exceed 15.2 volts at maximum output."

Sparx alternator / rotor, Shindengen MOSFET regulator, LED headlight -Never see less than 13.5 -

And yup, I'm paranoid enough to mount a voltmeter.

How many Ah for my 1974 Commando?
 
RE Maylar's post re the Shorai requirement...That is exactly what I looked at 10 years ago when I needed a new battery. My charging system was able to provide that voltage so I bought the Shorai.

But as has been said many times - do what you are comfortable doing. Heck, I'm not comfortable with belt drives and wouldn't buy one. If you are uncomfortable with that battery technology, don't buy it! :)
 
MM said " The fact that I've had the same Shorai 18AH for 10 years demonstrates to me that there is no issue here."


I'm not sure this sample of one means " there is no issue here"

What about those with melted Li batteries, can we rest assured there is no issue because your battery is working?

It's like me saying " there is no issue with soft MK3 cams because my MK3 cam is fine".

If one follows the Shorai requirement of minimum 13.1 volts at idle as MM and Maylar have, then it should work fine, although now Maylar has the Sparx stuff to contend with. Search the forum to get history on Sparx stator, rotor and ignition problems.
Here's a sampler
https://www.accessnorton.com/NortonCommando/another-failed-sparx-stator.16774/
Not sure what MMs charging system is.
Most Norton charging systems do not produce 13.1 volts at idle. That is the problem.

Glen
 
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