Battery size

[fastd]

I have a 1979 C-10 with an ls1 from a 2001 corvette

My dakota digital gauges reset when i crank the engine to start it. Most annoying is the clock resets.

The previous owner recently installed an ac delco s35 battery that has 540 cca and 85 rc (whatever that means).

I was wondering if a capacitor would fix it, or do I need a bigger battery, other?

Thanks.

[gtstorey]

Have you checked voltage drop while cranking? Or is it a wiring issue that cuts the power to the accessory/gauge circuit when the ignition switch is turned to start?

[fastd]

Have you checked voltage drop while cranking? Or is it a wiring issue that cuts the power to the accessory/gauge circuit when the ignition switch is turned to start?

Just checked it. Voltage goes from 12.6 v to 9.1-9.5 v when it cranks.

Will more Battery cca fix that?

[gtstorey]

I think so. I sounds like that battery may be on it's way out anyway. Of course you also need to check all of your connections and wire sizes.

[5FDP]

Most LS batteries in late model trucks use ones with at least 750CCA, many are even 850-900+.

[Tranzman]

Make sure your battery is fully charged 12.6 or better volts with nothing on. Measure your cranking amps, your voltage shouldn't go below 10.5V while cranking. If it cranks at more than 250-300 amps while your starter is cranking the engine. (assuming that this isn't some high compression engine) Your starter probably shot or you have a ground issue. Grounds sometimes are more important than the power. Check to make sure the cables are not getting hot. That indicates corrosion at the terminals or inside the cable itself.

FYI my LS swap S10 battery is a 500CCA unit and I have the 6492N 1.4kw Starter. I cranked a little slow in the blizzard last week, but so did everything else I own. I just had to try it!

Had a lady come in to buy a battery one time. she said it just cranks real slow all the time and just barely starts. I said let's go have a look at what size battery you have. Come to find out that the negative cable looked like a Chia pet. I told her that i would like to clean that up first and see how it works after that. She say's "my son the mechanic say's that won't matter, I just need a new battery." I explained that although this is just a part's store, she just happened to get an ASE Master-tech retired. I said what i'm going to do is free and if it doesn't fix it I'll give you $20 off of the battery for your time. She smiled and said you have a deal! I cleaned it up and it cranked over like a new battery... I told her my name Is "Randy" come see me when you really need a battery. The next day she came back with a batch of Homemade Chocolate chip cookies...

[fastd]

i upgraded my 540
cca battery to a 800 cca and haven?t had the problem after about 5 starts.

thanks everyone for your comments.

[cobra30689]

i upgraded my 540cca battery to a 800 cca and haven?t had the problem after about 5 starts.

thanks everyone for your comments.

You didn't mention what you were using for cables (or whether you updated them), or how you have your alternator wired. When I swapped the 4.8 into my Jeep I went with a 600CCA, 75 series GM side terminal battery. Used a positive cable from a 1996 Fleetwood 5.7, which gave me 1 4AWG cable to the starter, 1 6AWG cable to the alternator, and 1 6AWG cable to the power distribution block. New 4AWG negative cable to the engine block with a 10AWG pigtail tied to the tub. She fired off instantaneously from day 1, and last week had one of the coldest mornings my swap has seen......+7 degrees. Might want to consider upgrading your cabling if you haven't done so.

[fastd]

You didn't mention what you were using for cables (or whether you updated them), or how you have your alternator wired. When I swapped the 4.8 into my Jeep I went with a 600CCA, 75 series GM side terminal battery. Used a positive cable from a 1996 Fleetwood 5.7, which gave me 1 4AWG cable to the starter, 1 6AWG cable to the alternator, and 1 6AWG cable to the power distribution block. New 4AWG negative cable to the engine block with a 10AWG pigtail tied to the tub. She fired off instantaneously from day 1, and last week had one of the coldest mornings my swap has seen......+7 degrees. Might want to consider upgrading your cabling if you haven't done so.

I?ve already upgraded all the wiring - I replaced 4 Awg with 1/0 awg from the from battery to starter and alternator and distribution blocks. Separate fuse panel for rewired fans relays and headlight relay harness. Also 1/0 awg to ground chassis and engine.

The old battery cranked and started the engine fine but the starter amp draw dropped the voltage low enough as to reset my clock. With the extra cca?s that issue has been resolved. I may have able to wire the car better all the way back to the DakotaDigital gauges so the voltage drop would be lower but since the stock ls1 battery had 670 cca, the 540 cca that I had previously was too low I think.

[cobaltssoverbooster]

Hopefully this helps someone because copper is expensive.

4 gauge OFC is acceptable for classic cars with 75-90 amp charging systems. Its not traditionally recommended for applications over 85 amps, especially if its continuous load.
2 gauge OFC is preffered for applications up to 180 amps. It's the go to for most aftermarket starter and alternator companies.
1/0 and 2/0 is when you start getting into multi-battery high constant current applications, most commonly SPL audio work. Usually these guys have at least 2 850-1000 CCA batteries in parrallel and a 200+ amp alternator or multiple alternators. Due to cost, weight, flexibility, and space it takes up, i personally don't install this diameter unless the application demands it.

If you installed CCA wire instead of OFC, it will deteriorate faster than OFC in the environmentally exposed engine bay or underbody chassis run. I recommend using hexagonal crimp dies and heat shrink with sealant like Raychem DR-25 to lock the environment out and extend cable life and performance.