Battery Relocation, Lithium Batteries, and Road Racing

[Atuca]

Hello all,

I would like to begin a conversation that I believe was self answering after it was brought up to me by Eric (Turbosax2) himself.

As I was building my race car, I came into reasons that required the relocation of my battery. The obvious solution for years has to been to place it in the rear of the car for better weight distribution.

That was until the invention of Lithium car batteries.

Lithium Pros C680 12V 800 Max Amps Powerpack Battery

If I am not mistaken, at less then 5 pounds, this battery possess the cranking amperage needed for our engines and would be perfect for my race car. Its a bit pricey at 500 bucks, but when we are talking about a race car where every pound counts and dry cell at 10-15 lbs and stock batteries being close to 40 lbs, it is a price I am willing to pay.

I have read you can build your own lithium battery and maybe I'll ask some questions about this in the existing threads here on tuners, but my dilima:

I have already purchased everything (except a battery) for the battery relocation as listed here in Eric's thread:

http://www.dsmtuners.com/forums/han...-relocation-project-log-16.html#post152022910

This is a very nice high quality collection of electronics and wire, but this is not something that is light. In fact it is extremely heavy, at what I would guess easily 20 pounds in wire if not more. While I plan to place the cut off switch at the Driver side A pillar of my roll cage which will save running both the alternator and starter wire front to back of the car in the instance Eric used with his rear mounted NHRA legal cut off switch, there is still a considerable amount of weight that would be added to the vehicle in wire that would completely negate the weight savings of the battery.

With a lithium battery you are losing the weight distribution over the rear passenger wheel battle, it becomes a matter of pure weightloss, not weight distribution, and at that point I can save weight leaving the battery mounting above the sub frame or maybe in the car near the firewall (in its battery box of course).

That is my dilima, and my question would be, what are you guys' thoughts. Are there rules specifically about where the location of the Battery can be in accordance with NASA and SCCA? Would you place it in the back of the car anyways to just keep it out of the way and out of the engine bay? If its mounted above the subframe, are there mounting kits available? Am I doing this all wrong and should I just use a relay switch like this:

T1 Battery Cutoff Kit

Here are the rules I could find:

http://www.nasaproracing.com/rules/ccr.pdf

18.8 Battery
The battery shall be securely fastened down to the car. No Bungee cords or rubber
cords may be used to function as the sole hold down mechanism. An electrically nonconductive
material must cover the positive battery terminal. Any battery located inside
the driver’s compartment shall be fully covered and firmly secured to the chassis in a
marine type battery case. True dry cell batteries may be mounted without a surrounding
case, however a case is still recommended. Note- there is a difference between “dry
cells” and “gel cells.” Gel cells still need to be mounted in a case.

18.9 Exposed Wires
There should be no exposed wires inside the driver’s compartment such as to interfere
with the safe operation of the vehicle. No live (hot) wires may be exposed anywhere in
the vehicle.

Please keep in mind this is 100% track only race car, and suggestions should be based on the mindset of quickest lap times.

Thanks!

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[Talyn]

I don't think you would have trouble reselling your battery kit, if it only weighs 5 lbs, I definitely would not incur the weight of a relocate kit, in fact even running a factory battery, I can not justify the added weight of the wiring, only reason I would relocate is if I needed the space for something else, and just a side note here, but is the lithium battery smaller? I ask because if cordless tools are any indication it might be smaller as well, my makita cordless drill and impact use lithium ion batterys, and they are half the size of an equivalent ni-cad.

 

[Atuca]

Here are the specs from the website:

Specs
Weight: 2.27Kgs / 4.99 lbs
Length: 182mm / 7.17 in
Height: 168mm / 6.61 in
Width: 77mm / 3.03 in
Reserve Capacity: 26min.
PHCA: 680
Watt-Hours: 141
Volts: 12
Charge Volts (max/alternator): 14.6
Charge Amps (normal/max): 55

 

[Miasma]

In regards to the electric cut out switch, I believe that the switch needs to be accessible from the outside of the car so in the case of a fire an emergency worker at the track can kill the power. I may be wrong, but that is how to the regulations work in my area.

Granted how light the battery is, and you are only adding more weight to put it in the back you might want to consider relocating it in the front. I'm assuming you are running into clearance issues with your factory battery location due to the magnus intake manifold??

I've seen before others mount there battery below the passenger headlight, which could simply be done extending your harness. You would need to fabricate your own mounts of course.

 

[Aproductions]

Length: 182mm / 7.17 in
Height: 168mm / 6.61 in
Width: 77mm / 3.03 in

Keep it in the front man. Look at those dimensions, it is soo tiny.

 

[Atuca]

A-piller is accessible from outside the car, I got the idea actually researching locations that were both accessable to the driver AND the crew. I was just going to do it in the back so that it would pass NHRA regulations as well per Eric, but I personally didn't feel safe not having access to it myself. (granted now I could wire relays in series with the switch I linked above....) The main concern was I wanted access while strapped in the car seat. Were you explicity told not to use the A piller for some reason in your area? Everywhere I can find says it is ok including the NASA forums.

As to the passenger headlight area, the portion of my car will not be accessible due to extra front bracing for an AMB aero kit. I think I am looking for a possible behind dash solution. I am already using the behind dash area for the fuse box (I have rewired the car already) I don't think it would be too troublesome to add it back there. I am just not sure.

*edit* you know Alex, I didn't really read the demensions... That is a very skinny battery indeed! I just looked at the photo but I just grabbed a measuring tape and wow.. I think you are right. I was going to use a battery box as it is recommended still even for dry batteries which is a standard sized box. Wonder if I should be considering a new battery box or just going with secure strappings and forget a box.

Here is the box I own (pic from Eric's thread)

From Summit:

Length (in):13.500 in.
Width (in):11.000 in.
Height (in):9.500 in.

Inside dimensions are approximately: L- 10.75 in.; W - 8.5 in.; H- 9 in.

 

[Miasma]

I've never been told "A-pillar isn't ok" specifically, only that to have it on accessible on the outside. I'm sure if you can prove it's quick access on the a-pillar it would be fine. I agree, having it in your own reach while driving is a good thing as well. It's more a precaution for if something happened to you and you were unable to reach it, that someone else could.

With how small it is, I would keep it up front.

 

[turbosax2]

Philip and I have been talking via PM's and he asked me to share some of the conversation publicly.

I definitely think the front is the right decision for you. The weight savings by keeping it up front will be better than better weight distribution front to rear by putting it in the rear. My main reason for putting the battery in the back was that I was totally opposed to going with a small battery, and still am if it's not Lithium - this is because my car sits outside (so I can't run a trickle charger to it) and it doesn't get driven for months at a time. I hadn't even heard of Lithium car batteries until this year, because they just are getting more popular now. And since I wouldn't go with a small battery, the battery had to be moved since I definitely didn't want a full size one in the engine bay. But if I could redo the setup now, I would put a Lithium battery up front using the T1 battery cutoff kit. I would have two kill switches - one within reach of the driver/crew to keep the safety officials happy at road racing events, and one on the rear bumper like I do now to keep drag racing safety officials happy. I would wire them inline so if either is flipped it will interrupt the circuit. The battery cutoff kit allows you to use small gauge wire for these kill switches rather than large gauge wire.

I would love to put the battery under the dash, but I'm pretty sure that is against NHRA rules, even if it is in a box. So it would most likely stay in the engine bay tucked down on the subframe.

That being said, I try my best to keep my car legal for all SCCA/NHRA/NASA etc. rules if possible, even if I probably will never race competitively in them. But if you never plan to drag race, just ignore the NHRA rules and make sure you follow the ones that will apply to your car.

I would recommend purchasing a battery rather than making your own. Nothing like having a "custom" part fail, then not being able to recreate it or fix it, and missing an event because of that. Another thing to consider is maybe purchase a Lithium battery that has the same footprint as a "normal" lightweight battery, that way a different could be used in a pinch.

 

[Atuca]

I am still really leaning towards the C680 by Lithium Pros, I think I am going to pull the trigger and then look at mounting solutions. I appreciate the consideration of other battery options Eric, and as the PC680 from Odyssey has a similar foot print at:

Length 7 1/16"
Width 3"
Height 6 9/16"

compared to the C680 from Lithium Pros at:

Length: 182mm / 7.17 in
Width: 77mm / 3.03 in
Height: 168mm / 6.61 in

I believe that means that the PC680 Hold Down - HD680 measuring:
9.5" x 6.25" x 3.1" will work for both batteries if for some reason I need a fall back solution.

Odyssey battery aluminum hold down

I didn't see any rules on Lithium batteries specifically, but I am assuming they are considered "dry cell" just the same as the Odyssey, which means neither will require an enclosed battery box.

 

[turbosax2]

I finally found the relay t1 uses for cheaper. The manufacturer is Data Panel - I couldn't find anyone who sold them so I gave them a call and was recommended to Waytek.

200A Solid State Battery Disconnect Switch, Deutsch Connector Included

They have a few other variations:
P: Solid-State: 1408: Search: battery disconnect


I was also eyeballing that Lithium Pros C680 - looks nice. It would be easy to mount with an STM or JMF small battery mounting kit if you wanted to keep it in the engine bay.

 

[wrencher]

I know the lithium technology has come a long way in the automotive sector due their recent use in the next generation hybrids.

The first question I'd have for them is what is the expected service life of this battery?
Take in account it's non use time, it's mounted environment (heat = bad) the particular voltage of the charging system to maintain it etc.
The lithium's are not up to par with wet/gel or dry cell lead batteries yet without an astronomical price.

A volt's lithium pack is 12K . All that & still has some inherent weaknesses of lithium batteries.
They're almost there but not quite yet IMHO.

 

[91-GS]

Keep in mind that Lithium batteries can get pretty hot. Also they can explode if damaged due to components shorting out inside. At least that is true for small batteries that are in cell phones or laptops.

Would suggest installing the battery in an aluminum box. Perhaps right behind the shifter where an arm rest is. That way it can be easily reached from the seat in case of emergency. Also it will be right in the middle of car and away from possibly getting damaged. Since there is no liquid in there, there is no need to worry about something leaking out in case of a roll-over.

 

[Atuca]

bumping this as I feel it is still relevant to the road racing and lithium ion battery topic of the thread.

I need assistance understand something I overlooked when first looking at this battery.

Charge Volts (max/alternator): 14.6
Charge Amps (normal/max): 55

After speaking with lithium pros on the phone, a sales representative transferred me to a tech, who said actually the C680 has a max charge volt of 14.2 and a max charge amp of 50A.

That point aside, he suggested that I get a 93mm Delco alternator that had a max charge amperage of 50A. This was decided by him after I informed him that my stock alternator (65A) was replaced by a stock Saturn SC2 alternator at a max charge amp of 80A. He said over the phone that even the stock alternator would not work with this battery.

This completely contradicts their website information:

Lithium Pros » FAQ's

Max charge rate. This rating is important. This is the max charge amperage that should ever be applied to the battery. Typical battery chargers will not exceed this but your alternator easily could. It is important to consider this rating when matching a battery to your vehicle. The alternator will supply the amperage requirements of the vehicle including recharging the battery. The amount of amperage available from the alternator beyond the vehicle's needs should never exceed this rating.

How can you determine this? You could get precise and measure it with an inductive DC clamp meter or by putting a large ammeter in line with the battery, discharge it 20% or so, and start the vehicle. The ammeter should show the current flowing from the alternator into the battery. (When you are connecting them, be sure to measure the current flowing into the battery only. You do not need to know the current flowing out of the alternator to other loads like the ignition system, fans, lights, etc.) That will give you the exact answer.

If your vehicle has the OEM sized alternator still installed, a simple guide is to take the alternator's rating and divide it by two. In general, this will represent the current typically available for battery recharge after the other needs of the vehicle are met. (i.e. Using this guide, a Chevy Tahoe with a 124A alternator would have about 62 amps available for recharging the battery.) Short bursts of amperage greater than this max charge rate of less than seven seconds that are simply replacing the energy used for a starting event are not a concern. On the other hand, recharging the battery from anything below 20% DOD with amperage beyond the max charge rate will overheat and damage the battery, will be viewed as abuse, and may void the warranty. If in doubt, buy the next size up.

I take this information and understand it that if I have 40A of electrical draw from my fuel pump, radiator fan, tail lights, ect, then 40A is available to charge my battery, still under the 50A max. But.. do I have to worry about what if my radiator fan is off and my tail lights are off and suddenly my draw is down to just 15A, does suddenly my battery get OVER CHARGED by the remaining and available 65A and damage the battery because it exceeds the max amperage allowed, OR is this battery only going to draw its max amperage that it requires.

Trying to just use a 50A alternator would really limit what I can do with my electrical system, meaning no electrical power steering, no electric water pump, no HID headlights.... ok j/k on the last one

I should also note, I have the 3 pin plug on my alternator tied into a power sensing distribution block, so that the regulator can sense draw on the electrical system. per http://www.dsmtuners.com/forums/cus...tant-improvements-saturn-alternator-swap.html

I've read a lot of different ways to look at this issue and I am going to send an email directly to the manufacture so I have this stuff in writing from them, but I wanted to ask our forums here as well.







My question can really be summed up much simpler as: does a 80A (or any high amperage alternator) overcharge the lithium ion battery with a Max charge rating of 50A.

 

[Archer Fabrications]

I'm not using a lithium, but I'm using the pc680 and it fits nicely.

Stock battery 40 lbs with mounting brackets

And pc680 at 14 lbs alone. I was looking at the lithium battery but couldnt justify 250 extra for 10 lbs lost.

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This battery is the same battery as the one posted but lead and not lithium. Same dimensions.

 

[Atuca]

Chatting with some folks on this subject:
Them:

I'm not the expert on Lithum batteries but they can be damaged if over charged at a higher voltage. This is for lower voltage ones like in your phone but see: "http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries" for explaination. I would think that ones used in cars would be designed for typical automotive alternator voltages however.

From your statement:

"I take this information and understand it that if I have 40A of electrical draw from my fuel pump, radiator fan, tail lights, ect, then 40A is available to charge my battery, still under the 50A max. But.. do I have to worry about what if my radiator fan is off and my tail lights are off and suddenly my draw is down to just 15A, does suddenly my battery get OVER CHARGED by the remaining and available 65A and damage the battery because it exceeds the max amperage allowed, OR is this battery only going to draw its max amperage that it requires."

I don't think you understand how alternators and current draw works. The system will only draw the amount of current it needs (up to the alt's max which let's say is 65A). If you don't have a battery and the systems draw 40A, then only 40A come out of the alt - not 65A. If you add a fully charged battery you still draw only 40A because the battery draws none. If the battery is not fully charged, you draw 40A plus whatever the battery needs to charge. The battery current is not constant however, nor predictable. Battery current decreases as the battery charges up because the battery's voltage increases while it's being charged (from something below it's voltage rating to slowly approaching it's voltage rating at which time it draws no more current).

Now this all assumes a constant charging voltage source from the alt which is normally there, since all alt's have a voltage regulator. This is nominally 14.4V but can vary some with engine rpm, high current draw, or different alts. So I can see where the tech says you may have a problem since he claims the max safe battery voltage spec is 14.2V. Still I find it hard to believe that an auto lithium battery wouldn't be designed to withstand all car voltages.

----------
Me:

Ok, First off, you are right, I don't have a complete understanding, so thank you for understanding.

I believe that an electrical device will only pull the amperage they need, so if only 40A are requested from the alternator, the alternator will only output the 40A, even if it is an 80A alternator.

My issue though is the battery company says to only charge it at a certain voltage (which is easy on an alternator with an adjustable regulator) and a certain amperage.

It's my understanding now that amperage has nothing to do with the battery or alternator, the alternator outputs UP to its max rating, but not always at its max rating. Buying a 500A alternator for a car the only uses 40A will not fry anything.

But if that is the case, why do you think the battery company has a max amperage recommended for charging? What do you take that to mean exactly max charge amp 55A.

The only thing I could think of that Max amperage is that a car running WITHOUT an alternator can output a max of 55A to the devices in the car, but since I want to run an electric power steering pump (that draws almost 80A) I most certainly will need an alternator, not to mention I road race, I cant charge the battery but once every 45 mins minimum. No alternator won't work in my case.

I guess I understand now why there is a max voltage, but the max amperage is still throwing me off.
----------
Them:

Too much current (amperage) can burn up (or kill) anything. So the battery company must specify the maximum charging current rating the battery can withstand to still work normally. Even lead acid batteries have a max current charge rating although it's not as critical (as lithium) and is not normally specified. But I assure you, putting 1000A through a lead acid battery will burn it up in seconds.

For passive (linear) devices like resistors or light bulbs, the current is directly related to voltage (I=V/R). More voltage produces more current. However batteries are not a passive device and so are a little different. They produce their own voltage (passive devices don't produce voltage) as well as their own resistance (passive devices generally have a fixed resistance). BOTH THE BATTERY'S OWN VOLTAGE AND INTERNAL RESISTANCE CHANGE WITH HOW MUCH THEY ARE CHARGED UP. While charging, their voltage increases up to their voltage rating and resistance decreases down to some tiny fixed value. The charging current starts out higher and decreases as they get more charged up to their operating voltage (or voltage rating). Once charged up to their voltage rating, they act more like a passive device in that if you apply more voltage you will force more current into the battery (and this will continue as long as you apply the more voltage). This will then damage a battery and is referred to as overcharging. The extra current being forced in doesn't add to the batteries charge - it just damages it (you can feel it getting hot and also boiling for a lead acid one). The lithium batteries cannot withstand this overcharging current as easily as a lead acid one. You can overcharge a lead acid one for minutes and get away with it without damage but not a lithium. So this is why the tech is serious about a max current rating.

However I still find it hard to believe they wouldn't design a lithium car battery to always withstand the normal 14.4V alternator output voltage as well as even 15V (and sometimes even 16V) that alts can produce in cars. If not, their lithium batteries would be failing shortly in most vehicles all over the world. But then I'm not a lithium battery expert!

Hope that helps.

 

[arrowhead]

I think you are making a simple decision, complicated.
Even if I may be the most weight nut in the world, I can not justify spending that kind of money, basic rule, keep weight between axles, weight distribution, put it on pass. side, place your kill switch in front and bottom of windshield, you may also use another one next to you, if that would make you feel better or safer.

The weight savings is not that much, I have seen cars stall on the track and then not have enough cranking power from the small batt.

There is a nice space behind the B pillar and all that would be needed is a base, from there you could put 2 terminals to the outside of car, that if you ever stalled on a pit stop, you could connect to them, also nice to charge the batt from.

 

[eviltsi]

We've had these batteries in several evos and gtrs and have never had a problem at all, they're pretty awesome. Im sure both exceed the 14.2v/50a output...it may be more of a "we're not gonna warranty that" kinda thing.

Weight savings would be 55 lbs over a stock relocated battery...worth every penny and relatively cheap in my opinion, I'll take <$10/pound any day.

 

[Atuca]

We've had these batteries in several evos and gtrs and have never had a problem at all, they're pretty awesome. Im sure both exceed the 14.2v/50a output...it may be more of a "we're not gonna warranty that" kinda thing.

Weight savings would be 55 lbs over a stock relocated battery...worth every penny and relatively cheap in my opinion, I'll take <$10/pound any day.

Exactly, there is no other weight savings like this that I can think of. I already own the C680 battery now, and this thread (at this point) was more of a I am double checking everything and noticed the charge amp limitation and wanted to be sure.

Eviltsi: you used this exact battery? The c680? What size alterantors where you guys running in those cars?

There is another battery by lithium pros that is a very similar to the 680 case size that is rated for 100A and I want to be sure I don't get them mixed up:

http://lithiumpros.com/shop/12v-lithium-powerpack-with-bms-3/)

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This battery however is twice the price at 1000 dollars, but I guess my point at the end of the day is the battery starts the car, and nothing more for my race car, the alternator powers the car. I don't desire power for my radio while the car is not running for example. (No radio anyways) So I don't believe I need the extra power from the battery to run things while the car is off.

If you can confirm in several cars with full alternators on a c680, then you are only confirming what I believe to be true: the importance is the charge voltage, not the max amperage the alternator can output to the rest of the car. And that is something I'll make sure is set correctly.

Arrowhead: the small battery here is no a small lead acid with low cranking power, this thing has a much higher CCA because if lithium ions ability to disperse it's energy, and can start engines up to 5.0l. It'll handle my 2.4l just fine

 

[arrowhead]

I am not questioning the power of the battery, but the cost I can not justify, I am also very aware it is not a lead battery.

The 51 series battery will fit just fine, and it would not be near 50 pounds.

I have seen cars either run off the track or come in for a pit stop where they required you to stop the engine while refueling or a drivers change and not have enough cranking power to start a very hot and sometimes flooded engine.

Just a heads up on my part.

 

[troppo loungo]

Any verdict or update on the 680 size lithium batteries? I see their C682 is rated for a 100A/14.4V alternator but site says sold out. It was on sale for $429. Any new experiences with these or other lithium batteries? Especially in this size.