sealed gel cell batts in the boot; good? bad?

[Outffocus]

Hi,
I'm going to mount my battery in the boot of my 61 Caddy (big car! long elec travel!) and am considering going with a sealed gel cell (I think they're also referred to as dry batteries?)

Just wanting to know do they have the same strength as the acid batteries for transferring power load to the starter?

Anything else I should be aware of when using these batteries?

Cheers,
Greg

[Sudsy]

Use bigger cables when putting it in the boot. I use welding cable and have never had a problem with power loss.

[Outffocus]

Use bigger cables when putting it in the boot. I use welding cable and have never had a problem with power loss.

Thanks Sudsy! I have a good thick cable running through so that should work well as you mentioned.

[Mudgy]

Yep. heavy cross section of cable due to the length - to combat voltage drop and help the high current required flow to the starter motor.
Some batteries that have this title are still the usual wet cell unit, with blotting paper between the plates. Make sure you find the right one, plenty of Cold Cranking Amps (CCA rating) to use, ask how many plates per cell, and you may still need to put it in its own little safe house, which is vented to atmosphere.

Have you checked out Optima batteries?

Cheers, Mudgy

[woody28A]

Gel and AGM batteries are the only type that you can legally put in the boot unless you have external ventilation.

[Outffocus]

Cheers guys!
Yeah, I read on the Vehicle Standards Bulletin that I could use a dry cell battery and wouldn't need to house or vent it which is why I was interested in using them.

"With some engine substitutions the battery has to be relocated to the passenger or luggage
compartment. Unless a special kind of battery (e.g, a sealed gel cell) is used in these locations,
the battery must be fully enclosed and the enclosure vented to outside the vehicle. Electrically
insulated enclosures such as sealed marine battery boxes should be used. "

I'll look into the crank rating etc.

[Twin Spinner]

Yep, heavy welding cable is the way to go with well clamped or soldered terminals, I once used 600 amp cable because it was free

[uted]

I've got Optima batteries in both my cars and wouldn't have anything else.

[choco]

I wrote about this a while ago. Page 3 of this thread:
http://www.ozrodders.com/forum/viewtopi ... ot#p644908

but this is what I posted:
For the battery in the boot, use the thickest cable possible. For practical purposes, use 00 gauge (9mm). For the GROUND cable, you MUST anchor it to the chassis AND the body every 6 - 8 inches. Make sure all anchor points are free from paint. When you get to the engine bay, make sure you run a ground cable from the chassis and body to the engine, as close to the alternator as possible. The car's electrical system "sees" the alternator as the source of power, not the battery.
For the POSITIVE (Red) battery cable, you MUST insulate it all the way with something line convoluted plastic tubing. Avoid sharp corners, and when it goes through a panel, use a good grommet that is a tight fit. DO NOT run the cable through the chassis so you can't see it. Secure it to the chassis rail with rubber encased saddles that you can buy on eBay.
DO NOT use a battery isolation switch. It will create a high resistance link in your system and are prone to failure. If you must have one, or if you need ANDRA classification for drag racing, use a good quality one like a Redarc unit and not those crappy red plastic things with the big plastic key. They are junk.

And an extra note: Don't solder battery cable! Use a good hydraulic crimping tool.

[Mudgy]

Spot on, Choco!

AND


Don't get cheap shite "P" clamps. The rubber on them is the ONLY barrier between proper cable securement, or a flaming disaster.
Do you REALLY want to risk that?


Cheers, Mudgy

[choco]

Spot on, Choco!

AND


Don't get cheap shite "P" clamps. The rubber on them is the ONLY barrier between proper cable securement, or a flaming disaster.
Do you REALLY want to risk that?


Cheers, Mudgy

For the main battery+ cable, I only use 00 cable, not welding cable. The insulation on welding cable is thin plastic. The stuff I use is teflon. It's expensive and costs me about $200 a roll from Ingrams. I cover this cable in plastic convoluted tubing and then clamp with rubber (not plastic) P clamps every 150mm along the chassis rail.

[37willys]

Choco, when you say " you must anchor it every 6-8 inches, are you just talking about keeping it held down, not actually grounded in this spacing?
Thank you

[Mudgy]

yes, it's a positive potential cable. MUST be fully insulated. The more clamps, the better. (as long as it doesn't look silly ) - If it has to pass through sheet metal, then a decent quality and a good fitting grommet is also a MUST DO. Give yourself wriggle room !

It's easy enough to do, you just need to think about & plan its route and location, and anchor points. At the engine end, allow enough "slack" to absorb engine movement. Don't want anything to be cooked, or rubbing/chafing.

Cheers, Mudgy

[choco]

Choco, when you say " you must anchor it every 6-8 inches, are you just talking about keeping it held down, not actually grounded in this spacing?
Thank you

For the ground cable, yes to both. I use lengths of black 00 cable with eyelets crimped at both ends. Then I bolt them to body bolts that pass through both the chassis and body from the trunk to the engine bay. In most cars, there's enough body bolts to do this on one side of the car, just make sure all the connections are to bare metal. In the engine bay, I loop the last link to a good ground on the engine, then add another one to the other side of the engine. I know it sounds like overkill, but car bodies and chassis do NOT make good conductors. If you do it right, there will be no voltage drop along the ground cable.

[Sudsy]

For the main battery+ cable, I only use 00 cable, not welding cable. The insulation on welding cable is thin plastic. The stuff I use is teflon. It's expensive and costs me about $200 a roll from Ingrams. I cover this cable in plastic convoluted tubing and then clamp with rubber (not plastic) P clamps every 150mm along the chassis rail.

Choco you may be right about some welding cables that come with a welder but the stuff for heavy duty professional use is double insulated and probably twice the diameter of the copper core as it gets dragged around workshop floors and construction sites