MR2 Roadster Owners Club

The Workshop => Audio / Security / Electrical => Topic started by: keljon on May 9, 2016, 16:48

Title: lightweight battery
Post by: keljon on May 9, 2016, 16:48
anyone running a lightweight battery? be interested to know what you have gone for and if its moved to the frunk for better weight distribution
Title: Re: lightweight battery
Post by: lamcote on May 10, 2016, 09:38
The engine's in the back for a reason, surely moving the battery forward gives a worse weight distribution?
Title: Re: lightweight battery
Post by: Topdownman on May 10, 2016, 09:59
The only lightweight one I remember seeing is on this thread;

 l viewtopic.php?f=88&t=56416 (http://www.mr2roc.org/phpBB3/viewtopic.php?f=88&t=56416) l

My battery is in the froot but it is just a standard one.
Title: Re: lightweight battery
Post by: keljon on May 10, 2016, 10:34
Quote from: "lamcote"The engine's in the back for a reason, surely moving the battery forward gives a worse weight distribution?

well i would run without a spare wheel in the frunk so moving the battery would offset that
Title: Re: lightweight battery
Post by: M.R. on May 10, 2016, 17:16
I have 12Ah 210CCA LiFePO4 battery sitting right in front of ECU. No point placing it to front since cables would probably weight more than battery (860g).
Title: Re: lightweight battery
Post by: keljon on May 10, 2016, 18:41
Quote from: "M.R."I have 12Ah 210CCA LiFePO4 battery sitting right in front of ECU. No point placing it to front since cables would probably weight more than battery (860g).
do you have a link to the battery you have? do these need special care, increased risk of fire etc?
Title: Re: lightweight battery
Post by: lamcote on May 10, 2016, 19:09
Quote from: "keljon"
Quote from: "lamcote"The engine's in the back for a reason, surely moving the battery forward gives a worse weight distribution?

well i would run without a spare wheel in the frunk so moving the battery would offset that

Touche!!!
Title: Re: lightweight battery
Post by: M.R. on May 10, 2016, 19:50
Quote from: "keljon"do you have a link to the battery you have? do these need special care, increased risk of fire etc?

1805-ELTX12 (http://www.euroglobe.fi/en/battery-catalog/lithium-batteries/)

Some lithium batteries can be balance charged, but since this one doesn´t have that possibility only care is not to let voltage drop too much. At below ~10V its dead battery. LiFePO4 is pretty safe, so I wouldn´t worry.

https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery
Title: Re: lightweight battery
Post by: hamspeed on May 10, 2016, 19:51
(http://i60.photobucket.com/albums/h38/hamspeed/DSCF6116_zps79aaa788.jpg)

Here's my "frunk mounted" setup, the battery is a PVR22 (personally I wouldn't recommend it for a daily or regular driver.)
Title: Re: lightweight battery
Post by: shnazzle on May 10, 2016, 20:02
Quote from: "hamspeed"(http://i60.photobucket.com/albums/h38/hamspeed/DSCF6116_zps79aaa788.jpg)

Here's my "frunk mounted" setup, the battery is a PVR22 (personally I wouldn't recommend it for a daily or regular driver.)
Why not?
Title: Re: lightweight battery
Post by: hamspeed on May 10, 2016, 20:57
Quote from: "shnazzle"Why not?
Mostly due to their low capacity, parasitic loads such as an alarm system or immobiliser also drain it very quickly - this car has those systems removed and an electrical cut off switch fitted!
Title: Re: lightweight battery
Post by: shnazzle on May 10, 2016, 20:59
Quote from: "hamspeed"
Quote from: "shnazzle"Why not?
Mostly due to their low capacity, parasitic loads such as an alarm system, immobiliser etc also drain it very quickly - this car has all of that removed and an electrical cut off switch fitted!
Ah right. I suppose you could run one of these if every night you isolate the battery and store the car in garage
Title: Re: lightweight battery
Post by: hamspeed on May 10, 2016, 21:04
Quote from: "shnazzle"Ah right. I suppose you could run one of these if every night you isolate the battery and store the car in garage
In theory yes, but that would be a pain - can you imagine having to reset the clock every day?  s:lol: :lol: s:lol:  

The upside is that it's cheap, I think the battery and mount was around £35 when I purchased it.
Title: Re: lightweight battery
Post by: mr-ed_smt on May 11, 2016, 18:55
I've put my PVR22 on the left hand side of the frunk. Felt far more secure than putting it on the narrow horizontal bar.
(http://uploads.tapatalk-cdn.com/20160511/ac852386d3727ec940c0c68d05b03544.jpg)
(http://uploads.tapatalk-cdn.com/20160511/7cd45f79db9f4a1e16c2ace5147e0641.jpg)
Note the attached trickle charger!
Title: Re: lightweight battery
Post by: Nostromo on June 25, 2016, 20:58
That is ridiculously clean and shiny! Looks like a good setup. What sort of difference in weight of the battery is there? Would the trickle charger be man enough to charge the battery even with the alarm and immobilizer installed?
Title: Re: lightweight battery
Post by: mr-ed_smt on June 25, 2016, 21:45
Quote from: "Nostromo"That is ridiculously clean and shiny! Looks like a good setup. What sort of difference in weight of the battery is there? Would the trickle charger be man enough to charge the battery even with the alarm and immobilizer installed?
Thanks! It was mid-build so hadn't actually left the garage at that point so no chance to get dirty.
The race battery weights less than 7kg, whereas a standard battery is about 15kg. Even if you add a conservative 1kg for the extra cable and bracket, that's still a big weight saving - plus the weight is in a better place.
A mains powered trickle charger would probably be man enough to keep it in good nick all year round. A solar one would be useless in the winter, when it's both dark and cold.
Title: Re: lightweight battery - ETX20L
Post by: hiace82 on June 21, 2017, 21:47
Just about time for a thread resurrection and a small writeup!

In order to help my car shed a couple of grams, I had the plan to change my battery for something lighter, but without relocating it to a surely better place (i.e. frunk or near to the crossmember). I've read much good about the Odyssey lightweight batteries, namely the PC680, but after checking the alternatives, the DEKA ETX20L came up as something suited even better to my needs, being recommended as a daily driver battery in warm conditions. As you might know, DEKAs are not only popular amongst hobby racers but they are also quite expensive over here (perhaps as a consequence of import charges from the US) and can be had for no less than 189,-.

Luckily, I've come across a rebranded DEKA which is sold by the name of BANNER (well-known in Germany and Austria) Bike Bull AGM Pro ETX20L which apparently has seen use in clubsport cars given its low weight of 15.4 lbs. What sold it to me was the price of GBP 105,- which is much cheaper than the DEKA branded one. It comes pre-activated so there's no filling required. And - lucky me - the shop where it's cheapest wasn't located far from my place. Perhaps they might ship it to GB as well:

http://www.r3-batterie.at/index.php/batterien-fuer-motorraeder-rasenmaeher-atv-quads/product/view/3/79

Data sheet reads as follows:
18Ah, CCA 310A (conservatively rated)

Anyways, making the battery tray fit for the smaller battery was a bit of work. Firstly, I decided to cut the lower battery holder (plastic) a bit to shape, glueing a yellow rubber pad on it. Since the battery is also lower than the OEM one, I cut an alloy tube which i attached to the OEM bracket with two screws. Under this tube of approx. 13cm, there are two brackets (attached with rivets) that hold the battery in place quite perfectly. The custom mount ultimately got its black looks when I applied some epoxy primer and black paint. Adding some M6 to SAE(DIN) adaptors, the car was ready to be started.

Happy with the outcome so far, I'll keep you posted if something unexpected occurs   s:) :) s:)
Title: Re: lightweight battery
Post by: shnazzle on June 21, 2017, 21:54
Looks good. Every bit helps.
Title: Re: lightweight battery
Post by: hiace82 on June 21, 2017, 22:01
Ooops, something went wrong during the EUR to GBP conversion. Fixed now - happy to say it's even cheaper  s:) :) s:)
Title: Re: lightweight battery
Post by: shnazzle on June 21, 2017, 22:48
That is indeed a good price. Not far off a "normal" battery
Title: Re: lightweight battery
Post by: steveash on July 24, 2017, 17:03
My battery has given up the ghost and since I am keen to shave off weight where I can I am thinking of a Varley Red Top 25 or Odyssey PC680 which seem to be basically the same thing. It is very much a weekend car for road and very occasional track. I plan to remove the stereo so only electrical drains will be lights, windows, fan and perhaps the rear window heater. Hopefully I can get away with such a low capacity battery. As the car will only occasionaly be used I will be keeping it on a CTEK MXS trickle charger whatever battery I have. If anyone thinks this makes no sense at all please say now before I go shopping!
Title: Re: lightweight battery
Post by: m1tch on July 24, 2017, 19:08
Interested in the answer also  s:) :) s:)
Title: Re: lightweight battery
Post by: 1979scotte on July 25, 2017, 07:03
ChrisGB has an odessey for his 2GR I think.
Search what have you done to your mr2 today thread.
Him and shnazzle were discussing it recently.
Title: Re: lightweight battery
Post by: steveash on August 3, 2017, 22:30
Fitted my Vardey Red Top 25 today. Less than half the size of the old battery, it is a bit tricky to fit. I ended up buying a made-to-measure mount and then fitting this inside the original clamp. I wired up my CTEK connector while I was at it. It started straight away for the first time in about 3 months so no problems there. I think the only risk of getting stranded (from the lower capacity) is after making short runs particularly in the winter.
Title: Re: lightweight battery
Post by: keljon on August 4, 2017, 11:01
Quote from: "steveash"Fitted my Vardey Red Top 25 today. Less than half the size of the old battery, it is a bit tricky to fit. I ended up buying a made-to-measure mount and then fitting this inside the original clamp. I wired up my CTEK connector while I was at it. It started straight away for the first time in about 3 months so no problems there. I think the only risk of getting stranded (from the lower capacity) is after making short runs particularly in the winter.

can you link to the mount you used?
Title: Re: lightweight battery
Post by: steveash on August 6, 2017, 18:25
It was an aluminium racing mount. It looks very similar to the GPR4 ones on Demon Tweeks etc but they are larger so I got mine from the well known auction site for £40. Fits nicely although the phrase "remove all burrs and sharp edges" can't be often repeated in their production facility! I put a layer of 10mm foam on the original tray, inside the mount and under the original top bracket and it foitted like a glove. Vardey do recomend the foam to stop the battery being damaged by vibrations.
Title: Re: lightweight battery
Post by: steveash on August 6, 2017, 18:26
If you are searching on 'the bay' then look under "Alloy Battery Tray Suits RMD25 Red Top 20 25".