DIY version of this please

[looman]

http://www.deben.com/lights_lamping/batteries/lithium_ion_battery_pack.php

Looking to go lightweight - want a Li-Ion or Li-Polymer battery option that runs to similar voltage and amperage to this please.

It will be driving this on the rotary dimmer switch as shown

http://www.deben.com/lights_lamping/tracer_gunlights/max.php

Any advise as to what battery type and where best to get them would be appreciated.

Currently use a belt mounted 12V 7Ah lead acid sealed battery which is heavy and cumbersome. Looking for the same performance but much less weight.

Thanks.

Looman

 

[rmteo]

The typical 12V, 7AH lead acid battery weighs about 5.25lb. (2.38kg.)

This LiFePO4 battery is the exact same size/configuration as the 12V/7AH SLA battery but weighs 2.1lb. (0.95kg.) - about 60% less.
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=5028

It also has much higher cycle life (2,000 cycles) than an SLA - up to 10 times as much - and other advantages as well, such as fast 1C charging.

 

[looman]

Thats the type of thing - thanks.

 

[The Dane]

I'll se Your 6.8Ah and lower the price of $100 by 33%

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7634

Much smaller and much lighter even if You use 2 in parallel

 

[looman]

I'll se Your 6.8Ah and lower the price of $100 by 33%

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7634

Much smaller and much lighter even if You use 2 in parallel

OK this is getting interesting - so this little device will run a spot light as in the 1st thread for how long ?

How do you set up batteries in parallel ?

Also, I would want to run it on a cigarette lighter socket to allow running from a vehicle power source and switching to battery as and when required.

The wires here are a little confusing - I expect the additional wires are to do with the application to hobby sports.

How would one set this up to drive the lamp as above please ?

Thanks,

Looman

 

[rmteo]

I'll se Your 6.8Ah and lower the price of $100 by 33%

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7634

Much smaller and much lighter even if You use 2 in parallel

Big difference between that and LiFePO4 cells. :thumbsdow

 

[looman]

OK Confused by your comment there ?

If 2 packs are smaller and lighter than the larger dimension unit (which is still way better than the SLA version, I dont understand why the thumbs down icon ?

Can you explain what you mean by this please.

What are the relative merits of these two batterys.

I want to make the right selection here ?

Also what about a charger - I assume the retailers linked will add this item to the wish list.

Thanks

Looman

 

[rmteo]

LiFePO4 cells are much safer in use (LiIon's can burst into flames, and sometimes explode, particularly during charging). Also LiFePO4 has a much longer cycle (up to 2,000 charge/disharge cycles) compared to about 200-300 cycles for LiIon's). Biggest concern is safety.

Most hobby chargers will correctly charge both types - pay particular attention to cell balancing for LiIon's.

 

[Benson]

OK Confused by your comment there ?

If 2 packs are smaller and lighter than the larger dimension unit (which is still way better than the SLA version, I dont understand why the thumbs down icon ?

The LiFePO4 chemistry in general has two big benefits over LiCo: they won't go up in flames from overheating (overcurrent/overcharge/etc.), and they are more resilient to charging abuse.

That particular pack also include a protection circuit that prevents egregious abuse, while I don't think those RC polymer packs normally do, so you'd have to add that. (But I haven't messed with these -- not sure what level of protection is normal...)

Also, the price comparison is not necessarily helpful, since Li-poly cells have much shorter cycle and shelf life than LiFePO4. (Although if the Li-poly will last "long enough", i.e. you expect to have moved on to a different system for other reasons before they wear out, that could be a non-issue.)

Finally, the voltage is different, making the energy comparison basically even; although the RC packs obviously have more charge capacity (8Ah vs 6.8Ah), that doesn't tell the whole story. Since the RC pack is 3x4.2V=12.6V off the charger, 3x3.7V=11.1V working, but the LiFePO4 is 4x3.8V=15.2V off the charger, 4x3.2V=12.8V working, you not only get better compatibility with SLA equipment, you also get more energy for the same charge capacity, and better. Capacity in nominal Wh (Ah * nominal working V) is only 88.8 for the Li-poly vs. 87 Wh for the LiFePO4.

As for the weight and size differences, the Li-poly definitely wins, and they'd still win after adding protection and some sort of enclosure to get equivalent mechanical protection.

 

[rmteo]

RC type LiPO battery packs normally do not have any type of protection as they are typically used at very high current rates and any type of circuitry is going to impede their performance. It is not uncommon to see them being discharged at many tens of amps - even hundreds of amps. As such, a cell balancing type charger is vital for their safe operation.

 

[looman]

OK not too keen on the Li's as the risk from fire and explosion is there.

I need something I can rely on in the field and is low maintenance.

Half the weight of the SLA's is fine by me to be honest so I will look at the larger cell.

Thank you for the input - greatly appreciated.

Looman

 

[lightforce2]

Currently use a belt mounted 12V 7Ah lead acid sealed battery which is heavy and cumbersome. Looking for the same performance but much less weight.

Been there, done that!! and with a 14 amp hour SLA too. :sweat:
Thank god for CPF, Cree emitters, Tiablo & Dereelight and 18650 Lithium cells!!


I also used to run a Lightforce 170 with a 30w globe & PWM dimmer off 3 homemade NiMh battery packs. This was much better than the old SLA setup I originaly used.

Each pack was 10 NiMh AA's totaling 6 to 7 amps. I used them for about a year but some cells started to fail so I dismantled them & gave the good cells to a friend. I since learned that the Enegizer 2500 that I had used were probably the worst cells ever made. If I were ever to go back to NiMh packs I rekon Eneloops would perform extremely well

Just one point to remember if considering using LiFeP04 is that their energy denisity is no greater than NiMh, & NiMh isnt that much heavier.

These days I have a Tiablo A9 aspheric & red cree emitter mounted to my scope, it runs off an 18650 LiFeP04 cell. Its by far the best rifle mounted light I have ever used, their's no wasted side spill, all of the light falls within the scope's field of view.

 

[looman]

Been there, done that!! and with a 14 amp hour SLA too. :sweat:
Thank god for CPF, Cree emitters, Tiablo & Dereelight and 18650 Lithium cells!!


I also used to run a Lightforce 170 with a 30w globe & PWM dimmer off 3 homemade NiMh battery packs. This was much better than the old SLA setup I originaly used.

Each pack was 10 NiMh AA's totaling 6 to 7 amps. I used them for about a year but some cells started to fail so I dismantled them & gave the good cells to a friend. I since learned that the Enegizer 2500 that I had used were probably the worst cells ever made. If I were ever to go back to NiMh packs I rekon Eneloops would perform extremely well

Just one point to remember if considering using LiFeP04 is that their energy denisity is no greater than NiMh, & NiMh isnt that much heavier.

These days I have a Tiablo A9 aspheric & red cree emitter mounted to my scope, it runs off an 18650 LiFeP04 cell. Its by far the best rifle mounted light I have ever used, their's no wasted side spill, all of the light falls within the scope's field of view.

Indeed - you know where I am coming from.

I went for the Tiablo A8 as I wanted the better regulation on rechargables rather than primaries. However, it is no longer std with a P7 emitter in it and very good run times.

I would consider the A9 with the aspheric but i see little point as I am one of the next on the list for a DEFT.

However, I still like the dedicated rifle mounted light and lightforce seems to offer what I want. the Deben dimmer is pretty good though overpriced of course. What is a PWM dimmer then ?

Looman

 

[lightforce2]

I think the deben dimmer is a PWM dimmer same as a Lightforce, PWM stands for pulse width modulated, a variable switching circuit to drop the voltage.

below are some pics of the system I'm now using

Tiablo A9/8 used as a handheld light. Mods are -
1. UCL lens
2. Cree red emitter
3. 3SD Dereelight pill (without Led) fitted as driver. hi-1100ma, med- 300ma, low-60ma
4. LiFePo4 battery used due to lower forward voltage of emitter
5. An old Lightforce scope mount used for a handle. (I;m planning on getting a better type of handle)
6. Single mode switch of higher amperage fitted

dereelight pill soldered to the brass "earth ring" in the tiablo driver housing, wires were extended
to the emitter. the led on the pill was removed.

This is the other Tiablo8/9 aspheric fitted to scope, again with red cree thats direct driven with an 18650 LiFePo4, I used about a meter of fine wire instead of a driver to add some resistance between the battery & emitter.

I've since moved the mount to an angle so I could refit the turret cap but I'm planning on changing the mounts when I can find the right components. I'll incorporate a quick detach scope mount such as a Warne QD mount and a weaver base on the top scope ring. I'd prefer the light mount fit to the scope mounts & not the scope body (recoil is pretty sharp on this rifle) and the stress should should be taked by the reciever not the scope.

 

[looman]

I like the 18650 cell. decent punch and fuel for most of the lights.

I am not keen on mounting on the scope so I have been thinking of a mounted pic rail on the fore end with an angled wedge to allow for angle adjustments.

You are clearly more adept at modding than me - it is not an area I excel in so I tend to leavi it alone if it aint broke :-(

I have also been thinking of getting some 18650's into the stocks butt pad section - they tend to be capable of being drilled out if wooden or there is usually a void there if synth anyway. Just plug and play.

I was also wondering if the std tiablo twin output tail cap could be rigged to run two tape switches - one on the lower output and one on the higher output.

The other thought was to make the head seperate from the body - a bit like the sunlite 8w with the flexible extension - only wire and longer so the battery can be brought forward and the head connected to the mod or tip of fore end so the scope is not troubled by light spill.

I am keen to see what the deft will do with the clear and diffused lens - have you seen this unit yet.

There are some good developments in the market place now with tape switch options. This seemed to be a real gap in the market till lately. Very frustrating.

There are some of the cheapo QD 25 and 30mm piccy scope rings on the bay if one wanted a cheap solution.

I am waiting for some arms rings to go with the Nightforce scope on my Howa. I am going to get all my kit rigged with piccys on top and some arms throw lever QD ring mounts so I can have a hunting and target scope all of which will fir on any of my rifles.

Two decent bits of glass tunable to several rifles is a prospect with potential so long as the things get close to zero between removal and refit.

Have you done anything down the lines of getting the batts into the stock or getting the head and the batteyr tube seperated and repositioned to a better position?

I would also be interested how you would approach 18650's mounted int0 the butt and how you would wire it up?

I think it would be a very good set up with a low weight head up front and the tube out of sight and back in the stock so weight isnt too far forward or the rifle gets top heavy.

What do you think?