[wrinklefree]

I'm in the market for a new HID light system and trying to decide between the Jet blast and Light Motion Arc. The L&M has bother nmh and li-ion versions. I'm wondering what is the principal difference between these batteries, and if its enough to justify the $80 premium for the ion.

Any reason why Jet only uses nmh batteries?

 

[PMC]

First - I'm no expert on lights or batteries but...

The Li-ion is much lighter than a Nmh battery so if weight is a serious concern the Li-ion may be the way to go. I've also heard that Li-ion batteries are less affected by temperatures than Nmh batteries so if you ride in cold temps Li-ion may have another advantage. I usually ride with my battery in a back jersey pocket under my jacket and have never noticed shorter run times in weather as cold as 15 degrees but it may be a different story with a frame mounted battery.

The one down side to Li-ion is they supposedly don't have as many charge cycles in there lifespan as a Nmh but it's something like 400 compared to 500 which isn't an issue for me.

I have systems with both battery types and other than the weight I've observed no differences.

 

[wrinklefree]

thanks for the explanation. I live in northern CA so cold temps aren't a factor here.

Anyone know how much of a weight difference we're talking about here? I have a feeling its pretty small.

Also if anyone has any feedback on the the 2 lights I'm considering, that would be great!

 

[Blue Shorts]

thanks for the explanation. I live in northern CA so cold temps aren't a factor here.

Anyone know how much of a weight difference we're talking about here? I have a feeling its pretty small.

Also if anyone has any feedback on the the 2 lights I'm considering, that would be great!

I've heard that Jet doesn't use Li-Ion due to safety concerns and associated lawsuits. Even though I've never heard of any problems, if you know what happens when lithium gets wet...... it ain't pretty.

I own the L&M ARC NiMH and it's a superb system. I've heard great things about the Jet lights. I have experience with their halogen systems. Quality all the way. The only downside to the Jet HID is that you have to choose either helmet OR handlebar mount systems. That's a big problem for me. I originally thought I'd prefer the HID on the helmet. it turns out that I prefer them on the bars. It's not an issue with the L&M lights since they mount either way. The main differences between NiMH and Li-Ion are:

Weight - Li-Ion is lighter
Li-Ion has far less leakage current - This means that you won't have to worry about topping off a battery that hasn't been charged in a couple of weeks and storage is easier
NiMh has a larger charge / discharge life cycle, as someone else mentioned

I just came across a couple of fabulous deals on the L&M ARC systems (both Ni-Mh and Li-ion). Shoot me a pm for details.

 

[xray]

First - I'm no expert on lights or batteries but...

The Li-ion is much lighter than a Nmh battery so if weight is a serious concern the Li-ion may be the way to go. I've also heard that Li-ion batteries are less affected by temperatures than Nmh batteries so if you ride in cold temps Li-ion may have another advantage. I usually ride with my battery in a back jersey pocket under my jacket and have never noticed shorter run times in weather as cold as 15 degrees but it may be a different story with a frame mounted battery.

The one down side to Li-ion is they supposedly don't have as many charge cycles in there lifespan as a Nmh but it's something like 400 compared to 500 which isn't an issue for me.

I have systems with both battery types and other than the weight I've observed no differences.

Maybe you're getting it mixed up, but,

Li-ion should lose voltage in the cold, much more than a NiMH cell. Li-Poly/Li-Ion put out highest voltage when warm. It would only be a problem at the start of usage, the current draw should warm it up - unless your riding in very cold conditions.

Lithium should have MANY more charge/discharge cycles than NiMH. In R/C hobbies, usually very high current (causing the cells to go bad more quickly... but its still relevant), the average NiMH cell gets 50-60 good cycles and Lithium 100+. That is at very high current... but expect similar results, just X the life by about 4 (a guess, but it should be close).

Only under very very low current and perfect charge/discharge conditions will you get the factory "Good for 1000 cycles" out of any cell.

So... generally, Lithium will be MUCH better given it is charged correctly (I don't know what charger is included) and not over-discharged or puctured.

Hope that helps,
Blake

 

[heatstroke]

energy density :
Li-ion = 130wh/kg
nimh = 65 wh/kg
So it will be about half the weight in theory. Though cell packaging would reduce that advantage slightly.

self discharge is negligible with li-on.

 

[Blue Shorts]

Lithium should have MANY more charge/discharge cycles than NiMH. In R/C hobbies, usually very high current (causing the cells to go bad more quickly... but its still relevant), the average NiMH cell gets 50-60 good cycles and Lithium 100+. That is at very high current... but expect similar results, just X the life by about 4 (a guess, but it should be close).

Hope that helps,
Blake

I don't know about R/C hobby batteries, but you will get more charge cycles out of NiMH L&M batteries than Li-Ion, per L&M

L&M specs their batteries as follows:

NiMh - BATTERY SPECIFICATIONS:
Length: 6.0" Height: 2.0" Width: 1.5"
Weight: 550g
Battery Composition: NiMH
Voltage/Capacity: 10.8v, 3.8Ah,
500 charge cycles

Li-Ion Battery:
Length: 4.0" Height: 2.0" Width: 2.0"
Weight: 300g
Battery Composition: Lithium Ion
Voltage/Capacity: 11.1v, 4.0Ah,
300 charge cycles

 

[wrinklefree]

Thanks for all the advice guys. I placed an order for a L&M Arc nimh at a fantastic price. It was almost $100 less than the Jet blast HID system.

 

[heatstroke]

Typical Li - ion cells (18650) : Cycle Performance: 80% of initial capacity > 300 cycles

Ni MH : Cycle Performance: 80% of initial capacity at 500 cycles, but drops off rapidly to about 60% at 600 cycles after that
http://www.batteryspace.com/productimages/nimh-cell/MH-AA2300A.pdf

 

[xray]

This is VERY odd.

They (L&M...or whoever) must use very low rated Lithium cells and during use the discharge current must be near the max for them to have such a short cycle life. Lithium cells will fail much faster if they are discharged at a rate nearing the max.

Heatstroke, the link you gave is not standard use - it would be a test in a perfect environment and probably done by the manufacturer - im familiar with those types of pages from Gold Peak (their cells have been, generally, superior to other brands e.g. energizer, etc) cells, each different model of cell has its own test page from the manufacturer.

Its also done at an extremely low current, 0.2C would take 5 hours to discharge at that rate. Im not familiar with lights, but they have to drain the cell much faster than that, correct?

RC Hobby cells are usually more robust than most, but they should follow the same life cycle pattern, etc, that most other cells do. Keep in mind im more familiar with Li-Poly than Li-Ion.

Given their cycle-life I'd go with the NiMH, but usually the Lithium would be far better - im suprised by the info you guys posted.

 

[Blue Shorts]

Deal at Nashbar

I'm not sure why I didn't just post this info before...... but here's the info on the deal.

Check this out.

Nashbar has the L&M Li-ION on sale for $399 (normally $499). I just received an email from Nashbar with a coupon for an additional 20% off. With the coupon, the L&M Li-Ion is only $320

They also have the Ni-MH ARC on sale for $319.99 (normally $409.99). With the coupon, it's only $256!!!

See if you can beat that price..... anywhere. I wish I had waited to buy mine.

The coupon code is:

HOLI20 and it's good through Dec. 5