dual batteries or 16 Volt ??

Hey guys , I plan on trying to make some rounds this year and have been battling the dragging starter once up to temp for a long time. If I am going to run back to back what would you suggest ? I have a small mini starter that works fine plus heavy gauge rear battery wiring and a huge Mercedes battery with 1000 cold cranking amps . The car still hates to start once its warm. My question is should I go dual heavy batteries or go with the expensive 16 Volt battery , alternator and new charger ? I hate both options but how about your opinions before I do it.

I've used both. One 16 volt has way better cranking power than two 12 volt. 15-1 572 spins with full timing and ignition on hot or cold. Standard Dakota style starter. Mine is an XS with a 30 amp power supply to charge it. When using the two 12 volt, I had a jump box with me that plugged in under the dash. No more. The power and ground are 0 gauge. Bought a 16 volt regulator that fit my alternator.
Doug

Good wiring and good grounds/ connections. Ultra important
Good 12 v battery and a quality 1 wire alternator. Since rewiring car two years ago i have never charged the battery during race season. Even going rounds and running electric water pump and fans between rounds. I use the 95 amp mopar style powermaster 1 wire.
Car has 12.4 compression. Always starts right up like its 16 volts.

We run a single 16 volt battery. On alcohol so we don’t run fan and pump in the pits. We make a lot of rounds sometimes running two classes. No alternator only charging between rounds no problems at all. Love the 16 volt.

I run two group 24 marine RV batteries Costco brand and a 100 amp one wire alternator, no issues starting my S/P 508 C.I. 15.2 to 1 E 85 motor
high amp draw electric water pump, BG 400 electric fuel pump, fan, MSD7AL and so on.
I will charge them every now and then during the winter for several days at 3 amps and sometimes between races if I haven't race the car in the last 2 or 3 months just to make sure they are top off
They are around 6 years old so I may end up replacing them soon if they don't read at least 12.5+ volts after sitting for several months. They will read 12.65 after charging and sitting several days after using the car the last time I check them
I have a voltmeter in the car that shows the battery voltage any time the ignition is on, it will read 12. 3 + volts not running and 14+ volts when running with everything turned on and running

i switched over to a single 16 volt from two 12 volts. should have done it sooner. my car starts easier and the charge last longer i dont run a alternator. i have an xs battery and charger.

I think you have another problem. 1000CCA battery should start anything.

Study up on lithium batteries if you would consider putting everything under the hood. I ordered a 60 ah lithium cranking battery, and it is compatable with a Denso 60 amp alternater i have. At 16.5 lbs it reduces weight by at least 20 lbs, then add what ever you save by having the battery up front. A 60 ah li battery has a flatter voltage curve, so it delivers as long as a 100ah regular battery. It is also compatable with the Denso 60 amp alternater. So it looks like a great fit. The important thing is knowing the max rpm of the alternater and getting pulleys to drive the alternater at max rpm but not over. Also, setting up the charging wiring for near zero resistance is important. As for the voltage regulater wire i just looped it over to the out put terminal of the alternater. As long as you don't have huge draws on your battery, you will never need to charge it, just maintain it between races.

Exactly. I suspect he has ground/ wiring issue

Thanks for the advice and the opinions. I have chased this issue for years and it has heavy gauge wiring front to back , great connections, and great grounds. I have changed the starter from MSD to stock Dakota and made sure it don't get too warm. The car starts fine when it's cold just after running for a little while it bucks when trying to start it. Not a high compression vehicle 11.5 so that's not it. It has kicked my butt for a while. I think I may go with the 16-volt battery system and try that. What are you guys CCA for your 16Volt batteries?

I used to run dual batteries in my car as when I got into late rounds seem my battery was always dead. Alt said it was charging...after fighting the issue for many months, finally tested the alt and even though the gauge said it was charging, it actually wasn't, thus the reason the battery would be dead in the late rounds. I have since went back to 1 battery and have been problem free for years. I'm thinking that you may have another issue and by switching to 16 volt may or may not eliminate the issue. How old is the current battery? How about your coil? My dad and sister in law both had coils act up last year. My dad car would start, but was slow to fire. My sister in law coil just took a crap one morning and car wouldn't start. Sometimes its the more simple overlooked things that are the problems.

[quote=DusterKid]I used to run dual batteries in my car as when I got into late rounds seem my battery was always dead. Alt said it was charging...after fighting the issue for many months, finally tested the alt and even though the gauge said it was charging, it actually wasn't, thus the reason the battery would be dead in the late rounds. I have since went back to 1 battery and have been problem free for years. I'm thinking that you may have another issue and by switching to 16 volt may or may not eliminate the issue. How old is the current battery? How about your coil? My dad and sister in law both had coils act up last year. My dad car would start, but was slow to fire. My sister in law coil just took a crap one morning and car wouldn't start. Sometimes its the more simple overlooked things that are the problems. [/quote

You may be correct , I was thinking of changing to a one wire alternator but would hate to go with 12 volt if 16 volt is so much better.

In my case I worked at the Electrical garage at FCA. So testing this stuff was nothing new to me. My stuff was voltage drop checked it front to back under load. Charging was checked at the battery itself. Alternator was upgraded (75 amp). Though its still to small. Think about it. Cooling between rounds with big fans and your water pump. 3-5 starts per round going up to staging. Then a few minutes at most with the alternator running mostly at idle or low rpm. It doesn't have time to recharge what you are taking out. Tried adding a heat shield on the starter. Pulled the starter apart and tested all components. Tried a different starter. Tried 3 different pairs of batteries. I watched guys with low compression motors, small motors who have zero issue. But when the engine is big and the compression is up there, different story. Now in the late rounds the battery(s) are no longer at the fully charged 12.6 volts. They're down to maybe 12.2volts. 12.2 is roughly 50% state of charge. Resistance goes up with heat. Now your starter needs every bit of voltage it can get. The Voltage is what gets the job done.
Doug

Cooling between rounds is handled by my deep cycle battery I plug into when I get back to the trailer. Battery in car is pretty much used for just starting.
I prefer a single 12v battery. In a pinch their are two spares in the pickup if needed

Another advantage of running alcohol. 12 volt battery, used one wire 40.00 alternator bought off a table 8-10 years ago, (60 amp). Charge battery at home when I think about it.

I cranked the idle up on my car to a point to where the 1 wire “ is excited” 100% of the time the car is running….1100 - 1200 rpm or so. Running the fan and WP 3-5 minutes is all thats required to cool it off. First several rounds dont even have to use them as there is plenty of time before getting called again.
Cant stress enough…good wiring…. I have had off and on issues for years with keeping battery charged on different cars.
Two winters ago had my car professionally rewired front to back. Since then, i literally haven't had a battery charger within 100 yards of the car ever. Made 26 passes at Bowling Green two summers ago, never needed charging. Ever.
The retired electrical engineer who did the wiring told me how much of an effect doing what he did would have. He has been proven 100% correct. Car starts every time like its 16v. Spins over ultra fast, and its almost 12.5 compression. I think the 1 wire and extra amperage(95) helped as well.

I run a 105 amp alternator, with a voltage sense wire going to my main power point. Coil on plug full EFI, One fan(used to be two until recently) electric water pump, two electric fuel pumps. I run a single yellow top optima battery. I drive my car to and from the track, I have made as many as 12 passes in a day having to cool between rounds and never had a worry.

Check your ignition timing at cranking RPM and see what it is
If it is 18 BTDC or more that may be your issue on the motor kicking back on the starter when warm or hot
Been there, done that
Try having the initial, idle timing set at 17 degrees or less and the total at 34 to 36 degrees BTDC and see how that works for you

Everyone I know that's gone to a 16 volt system loves it and wishes they'd done it sooner.

Having said that, what you have SHOULD work fine.

to the OP,
Seems like you have all the right stuff, and you shouldn't be having any issues, so let me ask a few questions.

What is your timing when the engine is starting? Hopefully it's not 35 degrees locked out.

Also, did you do a voltage drop test on the starter circuit, and what are the results?

I can't tell you how many cars electrical "issues" i have fixed with a DVOM.


https://us.autologic.com/news/how-to-perform-a-voltage-drop-test

Joe
PS if the battery is in the back and you are doing the drop test, use a set of jumper cables.

You guys are always a wealth of knowledge. Cab the distributor is locked at 35 degrees . the distributor has always been locked out. I know its tough on the starter . That was another reason for thinking of a 16volt battery

Mine is locked out at 34 degrees, zero issues with Mopar starter

On that deal I would spin the motor on the starter first and then turn on ignition with the crank spinning to help stop the kicking back.
I had Hemi motor kick back against the starter years ago at the old Fremont Drag Strip northeast of San Jose,CA on the south end of the Oakland San Franscico Bay, it broke the nose off that stock starter
It was a real chore to change it on the ground with limited tools and space, 1970 Cuda with a set of early Hooker race Hemi chassis headers

16v not even a question. You will put it in and wonder why you never did it sooner.

I personally run one 16v D1600 XS Power battery with a 150amp (overkill) powermaster XS Volt one wire alternator and use an XS power intellicharger which is capable of charging 12v, 14v, and 16v battery. I run a K&R delay box, trans brake, line lock, air shifter, LED dial board, CVR water pump, maradyne fan, aeromotive fuel pump, and tail lights. When my car is running and everything is turned on, at a 1600 rpm idle, my battery has 18.5 volts from the alternator. I used to run no alternator and only charged in between rounds and still had ZERO issues with 16v, however, I converted to an alternator a few years ago and I will never go back. I am running 528 Cubic inch wedge, 14.2:1 compression, 850lbs of open valve spring pressure, 112 octane race gas, MSD 7AL2+, crank trigger, 37 degree timing. I still typically charge my battery in between rounds just because when there is a lot of down time, why not. However, once I get into a hot lap deal, I never have to worry about my car starting and once it fires, it gets juice from the alternator.

One thing to be careful of if you do switch to 16v, DO NOT CHARGE YOUR BATTERY WHILE RUNNING ACCESSORIES. So if you are running water pump and fan to cool car down, cool the car down then plug the charger in. You will fry your water pump if you charge and run the water pump at the same time. Mezeire warns people about this on their instructions. CVR says you can run the water pump and run the charger, but I have found that it will cause premature failure so just simply stay away from it.

I currently have a friend who runs two 12v batteries and has had issues with the car starting when its warm constantly. Tried different starters, different gauge wires, tons of grounds, kept a jump pack with the car like DVW said he does. He also runs low compression and alcohol, so he isn't running accessories in between rounds. He has tried multiple different batteries and the car still doesn't seem happy even with 1000 CCA batteries. We suspect maybe keeping heat in the car because the alcohol runs so cold could be causing him grief, however, I have been on him for years about 16v. This season I plan to lend him my spare battery and let him try it and I can guarantee once he puts it in, it will not be coming out.

Since you are locking the ignition, could you use one of the MSD starter savers or even the MSD adjustable timing control to start the car? I think the starter savers will let you choose between 10 or 20 degrees of retard, and the timing controller will let you select any value between 1-15 degrees. Could be an easy fix.

As for the 16 Volt battery, is it simply a drop in or do you have to change or protect any other electronics? I saw the tip about not charging and running the water pump at the same time. Sounds like if you run an alternator you need to go to one that will charge a 16 volt battery. Also sounds like you need a charger that will charge a 16V as well. What other watch outs are there?

I just rewired my car, replaced the starter, and set it up for two batteries in the trunk. I hate having to add the weight even though it is in the rear. I am not running an alternator but considering going to one, (more weight also). Sounds like a 16V battery, and alternator are the way to go. Probably less weight at the end of the day. Just want to make sure it will not require a lot of other changes.

I can’t believe how stupid we were back in the 1970’s ditching our alternators and going with one or two 12 volt batteries. I’m a one 12 volt user and alternator for life now. I did back to back tests years ago with a 16 volt and saw nothing in my Daytona.

cspracer. It shouldn't require many changes going from 12v to 16v as far as accessories go. Depending on your who makes your switch panel, relay board etc, the only thing I have found was that I needed to change the water pump and fan fuse to higher amperage fuse, again depending on who makes your switch panel, relay board, etc. If you run a K&R Engineering relay board/fuse panel, you won't have to change anything because all the fuses are already high enough. If you run an Auto Rod Control switch panel (which is what I run) then you would need to change the water pump and fan fuse to either 25 or 30amp, I cannot remember exactly what fuse is in mine. But other than changing the fuse, you don't need to change anything else accessory wise.

I would recommend checking the ignition timing in your car after switching to 16v. If you are using a distributor to time your car and are the distributor is not locked in, then you may need to adjust (just from my experience). If you run a locked out distributor and/or crank trigger, you shouldn't have to change timing of the ignition but I would still check it.

As far as an alternator goes, my Powermaster XS Volt alternator (Part #8148) has an adjustable regulator so it can be used on a 12v battery or a 16v battery. The alternator is adjustable from 13.5 volts-18.5 volts. I also did this in the event I ever had to use a 12v battery in an emergency situation, I wouldn't have to worry about needing an extra alternator, or disconnecting my alternator.

I would personally save the weight of the second battery and spend that money on the battery charger from the second battery. Like I said in my last post, XS Power sells a battery charger that can charge 12v, 14v, or 16v, battery, (part # 1005). It is pricey for the charger but again its like buying two battery chargers.

D1600 Battery part number
1005 Battery Charger part number
8148 Alternator part number

Stuff isn't cheap but it's worth it.

Thank-you for this very good and informative reply. It is expensive, I figure at least $1030 between alternator, battery and charger. Sounds like most folks who do this are glad they do. I really get tired of worrying about if the car will start or not, especially when the time between rounds gets lower.

May have to hold off on adding my Superbird wing this year and finish up the electrical!

One of the advantages of running a alternator is once the motor is running the correct size, or to big, alternator will provide all the current needed to run the car and charge the batteries at the same time
I have seen my voltmeter show 13.? volts on start up after sitting a long time between slow charging and having the carb needles stick open and flood the motor at the races, it showed less than 14 volts for around one minute and then showed 14+ volts for the rest of the day
My 15.to 1 comp ratio E85 motor starts fine on two group 24 R.V. Marine deep cycle 12 volt batteries

No problem happy to help. If money is tight you could always get the XS Power part number 1004 battery charger ($259.99 compared to $369.99 for part number 1005) which is dedicated 16v charger compared to the other charger I spoke about in the last post which can do 12, 14, or 16v. Also I know that 8148 alternator is expensive because its 150amp output ($418.99) and you could save some money there too by going with 100 Amp alternator part number 8138 ($353.99, Also 13.5-18.5 volt adjustable regulator), or even a 75amp alternator, part number 8174 ($273.99, also adjustable regulator as well). We have the 75 amp on my dad's roadrunner (16v system) and it does a great job. I think my engine builder runs a 55amp alternator (16v system) and his battery is always getting 18.5 volts with every accessory on.