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RichardSIA
RichardSIA Dork
7/31/21 11:58 p.m.

Need a minimum size and weight replacement battery for my Lotus Europa project.

Some time ago I saw a thread on one of the forums regarding folk putting together their own Lithium batteries for normal automotive use.
Web search turns up factory versions at around $500, not interested.

Maybe for my use there is a more budget friendly version?

 

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
8/1/21 12:01 a.m.
RichardSIA said:

Some time ago I saw a thread on one of the forums regarding folk putting together their own Lithium batteries for normal automotive use.
Web search turns up factory versions at around $500, not interested.

Maybe for my use there is a more budget friendly version?

Be very careful with DIY lithium batteries, they tend to catch fire if the charging procedures are not followed exactly.  Even OEMs occasionally have problems with this (see the recent recall on Bolts).

 

Mr_Asa
Mr_Asa PowerDork
8/1/21 12:06 a.m.

Braille AGM maybe?  You'd have to double check that they can crank a V8, but if I'm reading right they should be able to.

 

Mr_Asa
Mr_Asa PowerDork
8/1/21 12:06 a.m.
codrus (Forum Supporter) said:
RichardSIA said:

Some time ago I saw a thread on one of the forums regarding folk putting together their own Lithium batteries for normal automotive use.
Web search turns up factory versions at around $500, not interested.

Maybe for my use there is a more budget friendly version?

Be very careful with DIY lithium batteries, they tend to catch fire if the charging procedures are not followed exactly.  Even OEMs occasionally have problems with this (see the recent recall on Bolts).

 

I've seen it recommended that you should wire in a capacitor to level the voltage to the battery to help protect them

RichardSIA
RichardSIA Dork
8/1/21 12:15 a.m.

Cranking 1.6 Renault I4 with high-torque starter.
I recall discussion that I4 may be harder than V8 but that seems counterintuitive.

Mr_Asa
Mr_Asa PowerDork
8/1/21 12:25 a.m.

In reply to RichardSIA :

I can never remember who has which Lotus.  V8 has twice as many firing chances as an I4?

Will
Will UberDork
8/1/21 6:46 a.m.

I had a sub 2-pound Battery Tender brand battery in my LS1 Camaro. Needed to be hooked to a tender if it sat, but not if you drove it regularly. 

DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
8/1/21 7:16 a.m.

In reply to RichardSIA :

Would a Miata battery work, or are you looking for lighter than that?

DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
8/1/21 7:18 a.m.

In reply to Will :

More info please. My Challenge car will be LM4 V8 powered and I'd like the lightest battery possible ( on a Challenge budget...laugh)

obsolete
obsolete GRM+ Memberand Reader
8/1/21 10:29 a.m.

I've been starting the L33 in my Corvette with one of these: https://www.shurikenonline.com/index.php?main_page=product_info&products_id=46 and it's been great. I've had it for 3 years, and the car was only really daily driven for one of those years. The rest of the time it's been sitting, sometimes on a maintainer, sometimes not, sometimes left outside and gotten colder than it's supposed to. I carelessly let it run down too low a time or two and had to charge it in parallel with another battery to revive it. It still works just fine.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
8/1/21 10:39 a.m.
RichardSIA said:

Cranking 1.6 Renault I4 with high-torque starter.
I recall discussion that I4 may be harder than V8 but that seems counterintuitive.

A lot of the high torque V8 starters are just 4 cylinder starters.  It's not counterintuitive if you consider torque spikes requiring instananeous starter torque, vs. the relative smoothness of more cylinders.

 

That all said, regarding batteries, I have never considered batteries to be a place to try to trim muscle weight.  Have spent too many times looking for a jump start during or after an event.  That is why the main rallycross car has a Group 34 battery: it's the highest reserve capacity that fit in the physical space.

The Group 35 in the other rallycross car paid for its weight a couple weeks ago when the alternator belt blew apart and I have to drive 30 minutes with no alternator.  There was enough charge left in the battery to easily start the engine, after I replaced the failed belt.

Cactus
Cactus HalfDork
8/1/21 10:56 a.m.

I used a lawnmower battery in my 13b powered MGB. For $25, it's not an expensive experiment to see if it works for you.

SVreX (Forum Supporter)
SVreX (Forum Supporter) MegaDork
8/1/21 11:13 a.m.

In reply to Cactus :

Me too. I used a lawn mower battery in a Miata with no issues.

stukndapast
stukndapast Reader
8/1/21 11:49 a.m.
Will said:

I had a sub 2-pound Battery Tender brand battery in my LS1 Camaro. Needed to be hooked to a tender if it sat, but not if you drove it regularly. 

I had the same in my SVO for a while.  Worked fine but I killed it by keeping it on a Battery Minder designed for lead-acid batteries.  The de-sulfation modes on those types of tenders are incompatible with Lithium-Ion and will ruin the battery over time.  You need to get a tender specifically designed for Li-Ion.  It was amazing how small and light that battery was, though.

Indy "Nub" Guy
Indy "Nub" Guy PowerDork
8/1/21 12:01 p.m.
SVreX (Forum Supporter) said:

In reply to Cactus :

Me too. I used a lawn mower battery in a Miata with no issues.

I used a lawnmower battery in my V8 Jaaaag for months (not winter time) without any issues at all.  Worked Flawlessly after modifying the battery hold down to accommodate.  Discussion about half way down this build thread page.

Mr. Peabody
Mr. Peabody UltimaDork
8/1/21 12:03 p.m.

If you search you’ll find a few good threads on lightweight batteries 

RichardSIA
RichardSIA Dork
8/1/21 12:32 p.m.

Original location for the battery was passenger side just behind the firewall.
On Euro cars that is where the second fuel tank sits.
I want to fit a second fuel tank so the battery cannot go there.
Even if it could the Webers make that space very hard to reach.
Prior owner had the battery relocated to the front, where the spare tire is supposed to be.
I need my spare. I also dislike the positive cable running alongside the shift rod.
So it looks like my available space is passenger side of the trans forward of the "Trunk box" while still clearing the shift linkage.
It's a small space. As to why of weight reduction, it's a Lotus!

The Shurikan battery looks good, I appreciate their providing dimensions.
I will look at some of the other suggestions in more detail ASAP.

pres589 (djronnebaum)
pres589 (djronnebaum) UltimaDork
8/1/21 12:51 p.m.

Second cheapest battery at Walmart is a U1 group Everstart for $40.  340CCA, weighs 17 pounds.  I'd try that.

captdownshift (Forum Supporter)
captdownshift (Forum Supporter) GRM+ Memberand UltimaDork
8/1/21 7:26 p.m.

I went the motobatt 10lb route for about $200. 550ish CCA and have had no issues dailying it including a winter of lockdown where I was driving maybe once a week. 

obsolete
obsolete GRM+ Memberand Reader
8/2/21 11:53 a.m.
RichardSIA said:

The Shurikan battery looks good, I appreciate their providing dimensions.
I will look at some of the other suggestions in more detail ASAP.

The other small/light AGM battery I saw commonly recommended when I was shopping was the Odyssey PC680 (now called the AGM-16L apparently): https://www.odysseybattery.com/products/ods-agm16l-battery-pc680/. That one was a little too small for my comfort level, though. The BTX30L is only a little larger and seems to have significantly more capacity. It's a standard battery group, if you search for TX30L battery you will find all kinds of them. There is nothing really special about the Shuriken within that group, it's near the middle of the price range, but seemed to be near the top of the performance range based on the specs.

captdownshift (Forum Supporter)
captdownshift (Forum Supporter) GRM+ Memberand UltimaDork
8/2/21 12:11 p.m.

In reply to obsolete :

At that price point and weight, I'd just pay the additional $70 for the lighter, more powerful motobatt mhtx30

fusion66
fusion66 Reader
8/2/21 12:53 p.m.

I have been pleased so far with the weight loss/size of this battery in my 06' Miata (2.0l). No plans to use it in the winter but for spring/summer/fall it is doing just fine. Being sealed allowed me to lay it down and use the existing hold down by just threading the hold down J hooks further down.

Amazon.com: Weize YTX12-BS Motorcycle Battery High Performance - Maintenance Free - Sealed YTX12 BS AGM Rechargeable ATV Batteries compatible with Honda Kawasaki Suzuki: Automotive

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/2/21 12:59 p.m.

In reply to obsolete :

PC680 is a good battery, I have a few of them and I've been using them for about 15 years. I tend to use the next size up for high compression V8s because I'm like Pete - I need my battery to be as dependable as an anvil. Dancing around the edges of sufficient capacity or dealing with difficult charging regimes is not in the cards. 

The nice things about the Odysseys is that they can be mounted in any orientation and they'll sit fully charged for months and months if you disconnect them.

obsolete
obsolete GRM+ Memberand Reader
8/2/21 1:38 p.m.

In reply to captdownshift (Forum Supporter) :

Huh? You mean the additional $195? The Shuriken BTX30L is a $150 battery, I am seeing the MHTX30 at $345. It is quite a bit lighter, though.

captdownshift (Forum Supporter)
captdownshift (Forum Supporter) GRM+ Memberand UltimaDork
8/2/21 2:13 p.m.

In reply to obsolete :

I got my MHTX30 NIB locally about a year ago for just over $200 after sales tax. Their price may have gone up significantly if there are supply chain issues. 

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