Red Top batteries - Warning

Malcolm · 03-25-08, 05:50 AM

I run a Red Top 60 battery in my car. In fact I have just installed my third one as they kept dying which is not what was expected. I took the last one down to the factory as they are not too far from me and have learnt a few things that are perhaps worth sharing.

These batteries are more sensitive to charging and environment than you would first think.

Environment - they don't like too much vibration! Odd for a racing battery but that is what the factory told me. Therefore you need to have a thin layer of foam or other cushioning material to absorb vibration. Fortunately I have always had a 1/4 inch peice of dense foam in my car for this purpose.

Charging - this is where my set up fell over! First up, when I bought my first RT60 I was also sold a 0.5 amp charger made by the same people. Therefore it should be fine? Well no, not really! Once the battery was fully charged, using this 0.5 amp charger would only be ok for maintenance charging. The 2.5 amp charger that they also make would be better but the 8 amp charger (the one I now have) is the ideal one to get. Put these batteries on charge after you have used the car for maximum battery life is the message I got from the factory.

The next issue on charging is what your alternator pumps out. Not the ampage although that needs to be ok for the load made upon the battery/alternator by all the goodies on your car, but the charging voltage is absolutely critical. From what I have been told and have read here, you cannot over do the ampage side of the alternator as it has a regulator to give out what is necessary and no more.

But for Red Top batteries the voltage can kill your batteries if it is too low or too high. It needs to be in the range of 14.4 to 14.7 volts. Too much variation from these numbers and the battery will die much sooner than if properly charged. If you measure across the battery terminals when the engine is charging the battey and you get a reading below 14 or 15 volts or more, your battery will die sooner rather than later. I am not an electrical engineer but something like this happens. The reaction by the lead plates in the battery causes them to grow so they basically destroy the innards of the battery. I am now looking for a better alternator!

If you keep hammering your battery and not charging it up fully, this causes it to "sulphate" up internally also leading to damage and loss of performance. It may be possible to recover the battery in this circumstance but not always.

Bear in mind that these batteries can be good for 15 years if properly looked after and as they cost getting close to £300 it may be worth checking the other parts of your electrcial system to see how it is performing.

I would be interested to hear of other owners tales of woe or happiness!

DaveM · 03-25-08, 01:00 PM

My experience with Red Tops is OK, but the price is ridiculous. Have owned several race cars over 30 years including Formula Atlantics. Until about 15 years ago there weren't a lot of alternatives in the small weird sizes. Odyssey makes several sizes now priced at about $100. They last about 3 to 4 years which was about what the Red Tops did.

Malcolm · 06-16-08, 04:13 PM

Made some progress today with fitting my new alternator that charges at 14.5 volts measured across my battery terminals (not what it says on the volt meter in the car, it was under reading)!

Can anyone advise how to measure the amps an alternator pumps out? Meant to be 90 aH but I would like ot check if possible.

RichardH · 06-16-08, 06:22 PM

borrow a clamp type ammeter.

Ross Nicol · 06-17-08, 03:45 AM

Malcolm
The current output from the Alternator varies depending on the load. A flat battery will require charging and the alternator will supply a high initial charging current and then reduce this current as the battery charges up. An alternator should have a high enough current output to run the engine and all accessories as well as provide the battery charging current.The younger generation with boom boxes have quite often found they have to fit higher output alternators as the sound systems add a significant load on the system.The alternator's output voltage is regulated to around 14.5v and a higher voltage indicates a regulator problem and a lower voltage indicates problems with the alternator output.I use a voltmeter in the GT40 to satisfy myself the alternator is working but don't rely on it's voltage reading to be accurate.Of course the voltmeter reads 12v without the motor running and if it climbs to 14v plus when I start up I'm confident all is ok.To check an alternator for maximum output would require placing a suitable load across its output eg bank up some headlights.

Ross

Malcolm · 06-17-08, 04:43 AM

Thanks for the input. When I spec'ed the alternator, I did so wanting a distinct voltage output as mentioned to deal with my red top battery. Racemettle who made the alternaor for me set the regulator at 15v knowing that in practical terms this would drop to 14.5v when the car was running. It does precisely that.

I had asked for 120 amps but due to size restrictions and connection positions the 120 amp alternator they made initially did not fit and could not be made to fit so back it went. The one now on the car is beleived to be 90 amp and has all terminals on the side instead of on the rear face of the alternator. I think it is also lighter than my last alternator but that was not measured. I have run the car (until my fuel leak!) and had the wipers, headlights and fans all on at once and it all ran just fine. That is about the max amp load my car can produce as I don't have a Ross Nicol sound system! :-)

Cliff Beer · 06-17-08, 05:04 AM

Is the red top battery similar to an Optima battery?

I've had great experience with the Optima batteries (also a red top) - they'll sit unused for months(w/o any charging) and still have a great charge with lots of cca for a large V8. The one in my GT40 is six years old, never gets any maintenance or charging other than when the car is run (summers only) and operates like the day it was new. They're about double the cost of regular standard batteries at about $150 each but well worth it.

One thing I've found helpful in keeping batteries alive/healthy in an occasional-use environment is a battery cut-off switch. This seems to really make a difference in overall useful life.

Malcolm · 06-17-08, 01:01 PM

Looking at their web site I would say no as they refer to it as a lead acid battery. The DMS/varley red top batteries are gel batteries. Interestingly though the Optima web site refers to it being voltage sensitive in charging, same as the DMS red top.

Ross Nicol · 06-17-08, 08:34 PM

Yes voltage sensing is how the alternator knows how much current to feed the battery to charge it.Late model internally regulated alternators have a Bat sense wire which is a good idea as the battery voltage could be different to alt output voltage due to the old enemy (voltage drop).

Ross

Ross Nicol · 06-20-08, 09:50 PM

Woke up in a sweat this morning thinking, that info I gave on this thread was wrong and doesn't make sense,wish I could remove it.Anyway I hope I haven't put anybody out and I don't mind you thinking Ross is a nuff nuff.
Best to go back to basics-
A good test for a charging system (in a car with alternator) is to place a voltmeter across the battery and you should get -

12v or less (without the motor running) This is the Battery voltage only

14.4v or close (with the motor running) This is the Alternator output voltage applied to the battery.

Now with the alternator voltage held constant at 14.4v and this voltage being higher than the Battery voltage we get current flow from the alternator to the battery ( a charging current).
A flat battery has a low internal resistance so the alternator will supply quite a high initial current (amps) to the battery.
As the battery charges and it's internal resistance rises, less current will flow to the battery and it will eventually reach a fully charged state where it will only require maintanence current from the Alternator.This is why an ammeter gauge is good as it shows current drain when the alternator is not able to keep up. If the gauge reads in the green or to the right of centre with all electric circuits in the car switched on ( motor running),then you can say the alternator has the capacity to run the car and charge the battery too.Worst case is when the alternator does not have enough capacity left, after running the cars normal circuits to charge the Battery,result flat battery sooner than later.
Obviously the Battery voltage change can only be minimal (due to voltage drop when the charging current varies) and this is why a voltage test at the battery is a good indication of alternator operation.I'll find out more about the Battery sense wire on these new alternators and post what I find.Sorry again for the mis-information
Ross

Jim c · 06-21-08, 11:13 PM

Malcolm

To load test the alternator I disconnect the ignition.
Crank for a good 30-45 sec.
Connect ign and start.
With a clamp style amp meter you will get a reasonable idea.
On start up amps will be high and volts low.
Run at 1500 rpm as volts go up amps will drop.
If you have an amp meter in the car you wont need test meter.

Jim

Ray Tharp · 06-22-08, 02:55 AM

I too have not had good luck with Optima red top or yellow top batteries. I have been through three. I have gone to a larger alternator and not much improvement.

My first problem is that they were advertised as a great battery for a collectable cars or a car that is driven sparingly or seasonally. I too find them to be very sensitive to charging techniques. With my first battery I was told by the battery rep that the Obtimas don't like a slow charge so "hit it hard" meaning lots of amps. I found this to be WRONG. I then proceeded to ruin my second battery too using his advice-after all he sells them. Yeah right. So they may be a great battery but they are anything but maintaince free.

Then I was told that I needed a charger that has a "gel battery" or "spiral cell" charge setting. So I bought one and that's when I learned that you do not hit these batteries hard, but the damage was already done. I also was told once they go all the way down they never come back the same????

This week I bought a new glass mat gel battery made by Braille Inc. Not cheap but certainly light. 21 lbs and that is 1/2 the weight of the Optima. I bought the carbon fiber case model and we will see how it does. For sure I am going to buy the charger that they sell and recommend. Google their site.

I am going to call their tech line and see how a Battery Tender will work and if it is recommended.

At this point I am thinking maybe I should just get a sealed lead acid maintance free battery for $100 and chuck it in the trash every couple of years.

I will put some dense foam under it to minimize the vibration.

Now I will say my daughter has a Optima Red Top in Jeep Grand Cherokee. It is a daily driver year around and she has been served well even in harse cold weather.

I think the problems begin when they sit around,discharge and the wrong charger settings are used or too small of a alternator.

Tom Hudson · 06-22-08, 04:58 AM

I am no expert on Battery technology but as an Electrical/Electronic Engineer have, I hope, gained a fair amount of knowledge about Batteries and Alternators over the years. In anticipation of being corrected by someone with more experience than myself I will add some thoughts to the above posts.

Malcolm:

You mentioned that Racemettle set the regulator to 15v knowing that it would drop to 14.5v when the car was running. This doesn’t sound right. A modern Electronic Regulator should be able to control the Alternators output voltage to 14.5v under all loads from 0 to full load. Any Alternator Voltage above the absolute maximum of 14.5 will result in too much charging current flowing, which will seriously decrease the life of the Battery. This may have been the cause of your Battery problems, particularly as you mention you already cradle the Battery on a foam pad, I have found Batteries do not tolerate excessive shock loads for long.

In another post you mention that the Optima is not similar to the DMS/Varley type as the Optima is a Lead Acid Battery whilst the DMS/Varley type are Gel type.

A Varley Gel type is also a Lead Acid Battery, the Gel just means that the Electrolyte is not the normal Sulphuric Acid/Distilled water liquid solution but it is in a Gel form so the Battery can be mounted on its side if required.

Ross:

“12v or less (without the motor running) This is the Battery voltage only

14.4v or close (with the motor running) This is the Alternator output voltage applied to the battery.

Now with the alternator voltage held constant at 14.4v and this voltage being higher than the Battery voltage we get current flow from the alternator to the battery (a charging current).
A flat battery has a low internal resistance so the alternator will supply quite a high initial current (amps) to the battery.
As the battery charges and it's internal resistance rises, less current will flow to the battery and it will eventually reach a fully charged state where it will only require maintenance current from the Alternator.”

I agree with your first two lines but would disagree with some of the last paragraph. In my opinion the following more accurately describes the principles involved.

The internal resistance of a Lead acid battery in good condition is low, approx 0.01 ohms, whether it is in the fully charged or discharged state. It is not a rise in the internal resistance that causes the charging current to fall but an increase in the Batteries voltage from approx. 10.5v for a dead flat Battery to approx. 13v for a fully charged Battery. This voltage opposes the 14.4v Alternator output. It is this difference in voltages that dictates how much charging current will flow into the Battery.

Tom

Malcolm · 06-22-08, 07:05 AM

My previous alternators were undercharging not over charging. I have swapped info between battery manufacturer and alternator manufacturer and have had meetings with the battery manufacturer to nail the detail about what the battery requires and the alternator should give. The altenator I have now was agreed by both as the correct path to follow. It seems to be working very well for now. See where we stand two years down the line as only time will tell for me on this one. I am not an electrical person at all so cannot comment in too much detail other than what I have tried to relay above. All I really know is that gel batteries do charge differently to the regular car batteries and that my voltage reading across the terminals of the battery is in the range specified and all high ampage items on the car seem to work at once without any bonfires or flat batteries. I think I have to settle for that for now. If I make it to Le Mans Classic and back without incident I will be happy :-)

For others who read this thread, hopefully they will understand why you can't just chuck any old alternator on a car, you have to match it up properly to the other components being used.

Ross Nicol · 06-23-08, 11:37 PM

Malc - I think this is the reason for vibration shortening the life of the battery. Over time some of the lead in the plates falls off and drops to the bottom of the battery.It will eventually build up and short out the positive and negative plates of a cell.

Ross

Ross Nicol · 06-24-08, 07:51 PM

Tom - Thanks for your input, made me put in a lot of research into the matter, and uncovered answers to a lot of my grey areas with batteries and charging.I'm sure we have all grabbed a battery charger and used it to charge a flat battery without thinking about the technical aspects of what is happening.
The Batteries internal resistance is very low as you say and just like all power sources it causes a voltage drop at the output (bat terminals) when current flows. In a car the most dramatic example is when you crank the starter motor.The internal battery resistance small as it is (.01 ohms or similar) becomes significant when the starter draws a few hundred amps.
When the motor is running current flows into the battery (as long as you haven't turned all the accessories on).It is constant voltage charging as the Alternator output is regulated to approx 14.5volts.Now my problem with understanding this setup was 'what limits the current?' as the internal resistance is so low it cannot play a part.The answer is 'back emf' initially the flat battery with low back emf allows max current to flow into the battery but as it charges up the back emf rises to a point where a fully charged battery recieves very little current.This explanation is very hard to find in books.An ammeter displays the current reduction very well.
I hope you agree with me now Tom.

Malc
I came across an interesting article about different batteries requiring different regulated voltages for full charging.Optima was mentioned.What this means is, as you have done, ask the battery manufacturer what the alternater's regulated voltage needs to be.The ramifications of not matching battery and alternator can force you to externally recharge it and short battery life due to sulphating.

I hope others get something out of this,as far as I'm concerned I don't mind being wrong as long as I can learn from it.

Ross

Malcolm · 06-25-08, 04:02 AM

Agreed Ross, its just a shame my learning experience cost me two dead red top 60 batteries and an alternator! Thats nearly a set of tyres damn it! But the flip side is that I am now driving my car again (on the road only for now) in preparation for the LMC trip to see what else happens that needs sorting. I really feel odd driving the car on the road though! The other night a brand new BMW M3 convertible driven by an idiot did all he could to try and get me to race him, another idiot was driving along with his phone camera out taking pictures and then I got a round of applause from some young lads as I drove by (in an appreciative way to their credit). I guess I just need to get used to the reactions the car causes again, although I do think post Ford GT production the car is even more noticed than say ten years ago.