I am at the point that I need to decide on a battery and location in my 32 Ford roadster. I could use the Odyssey PC680 or a Deka ext18 under the seat in the pan or go to a full size AGM battery in a box in the trunk. The drivetrain is a 1957 283 with a stock 30 amp generator. With the trunk location there is a nice flat spot right behind the seat, but it would be tough to get at from the trunk. The little batteries are an easy install, but am I going to regret them? The car is very basic. I see lots of guys using the PC680, the Deka has more CCA on paper, is there anything special about the PC680? Thanks
I have run Odyssey PC925 for about 12 years. The first one made it about 6 or 7 years before it failed. I found that if it ever runs completely down they don't want to hold a charge very long. If I don't plan on using the car for a few weeks I keep a Battery Tender on it. When this one fails, I will get another just like it.
Yep, I have two 925's in 2 hot rods, they are excellent batteries. I did run one flat and I brought it back using a battery charger with an AVM recovery mode. MY normal charger wouldn't touch it. the new charger also has tender mode. I hard wired it to my battery (under the seat) installed it under the seat as well in my truck in case it ever happens again and bought another one for my roadster.
The PC925 will fit behind the seat. I am going to hardwire in a plug for my cteck charger. Would the smaller PC680 get the job done? Anyone running a generator with these batteries? Thank you
Alternators on both of mine. I would think the 680 would be fine. I run a lot of power equipment and high compression engines so I opted for the bigger battery.
I’ve had excellent luck with the PC925. Cranks my old 320 Y block at 10.5:1 like it was a stock engine. I had one that died young because I forgot to turn it off for the winter. They replaced it under warranty, but kept it. Took them 2 weeks to bring it back on a big battery bank, but it’s still in my garage holding a charge 7 years later. Gave it back to me. I use it to jump the generator if I have to. Never have had a problem when keeping them on a “battery maintainer”.
I'm running PC680 equivalent in my 32-5 window. I started with the Odyssey (cost $ 250) which lasted a few years but failed due to being fully flattened so I replaced it with a Full River Chinese copy (cost$150) and it is still going and I am running a Chrysler birdcage alternator which only puts out 35 amps. Engine is a stock 318 Poly Dodge and car gets used all year round- no snow here. Battery is mounted just inside the trunk opening for easy access.
My advice, get the most cranking amps in the size battery you can fit in. Saw a guy with a Model A that was running two 350 amp lawnmower batteries. Said it always started fine…
I've never heard anyone say they regret putting a bigger battery than actually necessary in their car. Too small? That kind of regret is more common.
Dyna-Batt ! Small and light - no problem cranking my 327 https://performancedistributors.com/product/dyna-batt/
Not knocking anyone's choice for going to one of the compact batteries, but from my perspective I want something that's easy to replace if I have a problem away from home. I want to be able to walk into Walmart or any parts store and get a replacement if needed. You have to build a compartment to house the battery of choice and if the compartment is too small, a common battery won't fit in it in an emergency. While the newer batteries are pretty amazing, my 32 will have a trunk mounted AGM battery, a large one.....and I'll probably add a smart charger and an extension cord. It's just a matter of deciding what works best in your opinion for you............
I'm on my third Dyna-Bat the first two lasted over 10 years each. I changed them because of their age.
A 170cca is kinda low for an older V8 in very cold weather. My ‘28 with a semi built 327 is getting a group 51 battery on the frame rail, homemade holder and accessible with a floor cover. Group 51 is small and can be had at regular parts store on the road.
According to the info provided in the original post, I think I'd put some thought into taking a more low-tech approach. It doesn't sound like the electrical system will be put under a lot of extreme stress. I know at least some of the new high-tech wet cell and AGM batteries seem to have a higher internal resistance to charging. When in a drained condition it takes a lot more amperage to get them to even start charging back up. I'd wonder if a 30 amp generator is really up to the task, especially considering their low output at lower speeds. This might not such a big issue if the car sees enough extended highway driving though. Otherwise the cost of the high-tech battery, maybe a special maintenance charger and possibly a charging system upgrade might put a pretty good dent in your budget.
Like the idea of the smaller batteries, but I continue to use full size (AGM) ones with 800 CCA. Ease of access is also my priority, so box in the trunk is my standard solution. Here’s a pic to illustrate. Current 32 roadster project will be same (but in black/charcoal this time).
Most AGM batteries are not very forgiving to any overcharge situation. If you are familiar with A/C systems and how they work you have a change of state to absorb the heat, go from gas to liquid and back to gas again to absorb or shed the heat. Wet batteries do something similar when the wet electrolyte starts to boil it also sheds some of the heat even though it is not good to boil a battery for long periods of time. AGM batteries have very little tolerance to overcharging due to the electrolyte being in a semi solid state not a liquid. New cars that come from the factory with AGM batteries have a charging system designed to stay at a certain voltage to extend battery life. A generator charging system usually cannot provide a constant voltage to give these batteries a long life, just FYI. Mark
I like being able to buy a battery at Walmart or Costco on a Sunday if mine quits, or borrow a battery out of one of the other cars to go cruising.
Not an electrical pro, but here is what I think I know. My experience with wet cell batteries has always been that once they get discharged too far, they never seem to be as good as they were . Daily driving and attendant charging while driving and they seem to do pretty well. Let them sit and not so much. So I looked into AGM batteries which have a woven mat inside and helps prevent sulfate from forming inside the battery. Many new vehicles come with AGM batteries now. One of the key things for me is that an AGM can be fully discharged and brought back numerous times. A common Wet Cell doesn't seem to do this well. A "Smart Charger" will "repair" these AGM's pretty well. If one gets too deeply discharged though, the charger won't charge it. People often put them on a conventional battery charger at a low charge and force some lectricity into them.....then the Smart Charger can be used to bring it all the way back. With an AGM, you don't want to force too many amps in by using a conventional charger. These AGM batteries are used in mobility scooters because they can be drained down and brought back numerous times......so it seems logical that they regroup better than common wet cells. Online quotes "A standard 12 volts gel or AGM battery can carry up to 500 cycles of charge and discharge1. This is considering that it will be charged from at least 20% battery level. Replacing an AGM battery should be done after an average of 4-6 years of service life or between 200-400 full cycles, depending on the quality of the battery and how it has been taken care of." "AGM (Absorbent Glass Mat) batteries are commonly used for various applications due to their deep cycling capabilities and low internal resistance. When it comes to the depth of discharge (DoD), AGM batteries can typically be discharged up to 80% of their capacity. This means that you can use approximately 80% of the stored energy in the battery before recharging it. In comparison, standard flooded batteries usually have a recommended DoD of only 50%. Now, let’s dive into the details a bit further. The lifetime capacity of an AGM battery depends on several factors, including the DoD and the number of discharge cycles. For example, if you have a 225 Ah AGM battery: Discharging to 50% DoD: Lifetime capacity = Battery capacity × DoD × Number of discharges Lifetime capacity = 225 Ah × 0.5 × 630 (for Odyssey AGM batteries) = 71,000 Ah Discharging to 80% DoD: Lifetime capacity = 225 Ah × 0.8 × 400 (for Odyssey AGM batteries) = 72,000 Ah Interestingly, even if you discharge an Odyssey AGM battery to 100% DoD, you still get the same lifetime capacity of 72,000 Ah. So, there’s no need to worry about recharging once you reach 50% DoD; any time up to 80% is good. Just be sure not to leave the battery discharged for extended periods4." Sorry this is so long . One other thing, I would be concerned with so little margin for error with only a 30 Amp charging system. Best of Luck..........
I think you're likely on the right track here. Most of what I've learned about such matters in the last several years was from one or two of the rare dealership techs that I worked around who were truly interested in understanding some of the quirks of later model batteries. And at that time they were probably still wet cell batteries and not AGMs.
I was going to originally going to put a full size group 34 AGM in this ammo can. I was going to put it over the axle for easy access. I was not loving the location. If AGM are an issue with a gen, can I put a normal battery in this box and vent it through the floor? @RockyMtnWay how do you find the process of getting the battery in and out of the box at the front of the trunk?
The box is just a cover. Make ‘em out of plywood (if I’m going to stain it to fit in) or whatever I have handy (if I’m going to cover them). Then under the cover is a simple battery tray with stout hold downs. Lift the cover off, undo the tie downs, and just slide the battery to rear of trunk and lift out. If you use optima, keep the carry strap handy to lift out battery of trunk. Here’s a cover I just did for my current roadster project (same materials as interior/trunk upholstery). Yup, it’s wood from an old cheese box. Put a little flip access in it to have easy access to battery cutoff switch.
Anybody on hereever have a problem with a Dyna-bat? I've talked to lots of hot rodders and drag racers who use them and not a single one has had anything negative to say. The drag racers are cranking 12 to 1 engines no problem. If you think you're going to get stuck somewhere and not have a replacement, leave the battery cables extra long so you can put a standard battery back there to get you home...AND Carry a pair of jumper cables
My group 24 Farm store batteries last 6 to 8 years at a minimum, plus do not need a tender to maintain over the winter. Can be obtained Any where.
Thank you @RockyMtnWay! @SDS I did some digging, if what I read is correct. The Dyna is the same as a PC680. If you have a hotrod without a parasitic draw they seem to work, guys with newer cars that have draw have issues.
My free advice on the battery is to make it easily accessible. They all can be a problem sooner or later usually at the most inconvenient time or place. I have several cars that do not get driven enough for good battery life so I have been using Deltran battery tenders for years 30+ with no problems and long battery life, a few 10 years old, one at 15 now, curious to see when it finally dies, really surprised on that one.
They have some nice looking plastic boxes at Menards that are a little larger (twice) than the box you have. They have the same looking boxes at Harbor Freight for less. I'm considering one of them so I can put a small charger and cables right next to my battery. I like the plastic because it's less likely to get any corrosion. As for the generator harming the AGM, I can't answer that question. I just think that I would want something that has a little more amp for what you may wish to ad in the future. If you are mounting in the trunk you need larger battery cables because of the length. I bought some off Amazon that were pure copper.........most seem to be plated copper and cheaper. Guy was an American vendor with wire made in the USA and trying to get a small business going. /www.harborfreight.com/large-modular-toolbox-58511.html? I figure I can get a Ford Blue Oval logo and stick it over the Bauer logo. Or maybe a Cadillac emblem since I will have a Caddy engine............That might look almost as good as some of the ones @Bandit Billy comes up with...............nah, guess not. 10% off everything this weekend at Harbor Freight. Check this guys site on Amazon for battery cable wire TEMCo INDUSTRIAL WC0456-60' (30' Blk, 30' Red) 2 Gauge AWG Welding Lead & Car Battery Cable Copper Wire Black + RED | Made in USA Visit the TEMCo Industrial Store He has other sizes, this is just what I bought.
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