Which Yellow Optima Battery...

[drivesafe]

In a perfect world you want to "match" batteries in a parallel string (12V). The reason is that in a parallel string, the batteries will constantly fight to reach the same "state" in this case, the weaker of the two. Thus the reason you want the same age and same capacity.

Hi MilehighLR3, and sorry mate but this is just an old wife’s tale.

Many people get the requirements for wiring batteries in parallel mixed up with the limitations involved when wiring batteries in series.

With the exception of batteries being used in ultra high current applications, like when joining batteries together for winching, there is no reason why you can not mix different types of lead acid batteries in parallel set ups.

 

[schafari]

I am running the Traxide with the factory battery, an Optima Yellow top under the hood, and a Sears Platinum in the back. The Sears and Opima are both AGM. The Platinum is one awesome battery. (It is actually made by Odyssey, best in the biz.) I have had zero problems. The Traxide controls the charging and disconnect if needed.

 

[MilehighLR3]

Hi MilehighLR3, and sorry mate but this is just an old wife’s tale.

Many people get the requirements for wiring batteries in parallel mixed up with the limitations involved when wiring batteries in series.

With the exception of batteries being used in ultra high current applications, like when joining batteries together for winching, there is no reason why you can not mix different types of lead acid batteries in parallel set ups.

Wives tale? I wish that were true but my 27 years as an design and application engineer in the battery industry proves differently. Parallel strings are much more sensitive to varying voltages than series strings.

True you can mix the batteries but my experience (10 years @ shoe and event vehicles for SEMA and CES) a person that spends $200 (or $400) a battery (for a set) would prefer to get all the capacity they bought. You are correct, high draw apps make the situation worse.

 

[drivesafe]

Well MilehighLR3, I can only comment on what I have found from 20 years of designing and manufacturing Dual Battery Controllers and systems, and I have never come across a problem when paralleling different battery types that you would not find when paralleling identical battery types.

Furthermore and more specific to this thread, I have supplied well over a thousand DBS for D3s world-wide and most of these are using Optima D34 batteries, and to date not a single report has been made where the owner had a problem with their set up other than needing to replace their cranking battery and in most cases, this is usually cranking batteries of 5+ years old.

Add this to the fact that unlike all other Isolators where they simple connect the cranking battery and the auxiliary battery once the motor is up and running and then disconnect when the motor stops. MY isolators will connect the cranking battery and the auxiliary battery once the motor is up and running the first time after the isolator is installed and then, it may be months to years before the batteries are isolated again.

So if there was any REAL problem, it would have well and truly shown up by now.

As posted, this theory of not being able to parallel connect different types of 12v lead acid batteries is nothing but an old wives tale.

 

[MilehighLR3]

drivesafe,

I have always found it amazing that the developers of charging, isolating, and testing equipment for lead acid batteries rarely, if ever, consult a battery manufacturer to gain information on what happens to a lead acid battery in varying conditions, electrochemically.

My guess is that is the same in this case. While we can debate about each other's experience, credentials, or opinions I really have little interest in convincing you that the "wife's tale" can be proven with data.

That being said, I never replied that you cannot parallel different battery makes/models. My comment was in a perfect world you would parallel like product. I also commented that the higher capacity of the two will decrease to that of the lower capacity unit.

That doesn't mean that it's wrong, bad, or detrimental. It simply means that you will not be taking advantage of the full capacity of the higher potential. No one would pay for 10 gallons of fuel and be satisfied with 8, perhaps an extreme comparison but not out of line.

For those seeking the right battery, my advice is as follows: Identify the desired result. Understand the factors impacting the desired result. Select the battery that meets the need and budget.

Despite my years with Optima, I don't recommend them for everything. They are a great do it all solution. However if you to run a frig, lights, etc for a long time, probably not the best choice. Sears platinum or Odyssey or even Northstar would be a better choice form the ultra premium battery, although the Optima is far more tolerant to voltage.

As far as your isolator technology, happy for you that you've developed a successful product for the aftermarket and wish you much success.

 

[drivesafe]

MilehighLR3, for someone so self acclaimed in this field, how can you make such a fundamental error of mistaking the requirements and limitations of wiring batteries in series as being the same for wiring batteries in parallel.

There is no such requirement to wire identical SIZED batteries in parallel, whether they be the same type or different types of lead acid batteries.

If you have a 100Ah battery and require more power, you are NOT limited to adding another 100Ah of the same type, you can add an size battery from a 20Ah motorbike battery to a 200Ah Ag battery, and the paralleled batteries will now be in effect one bigger battery.

If you add a 20Ah battery to a 100Ah battery in a paralleled set up, you now have a total of 120Ah and the large battery won’t effect the smaller one and vice versa. Again, you have mistaken the requirements of series wired batteries.

Furthermore because we are talking about charging by an alternator, even when batteries are of different sizes and at different States of Charge, an alternator literally charges each battery at each battery’s individual charge requirements and independently of any other battery in the set up, and this has nothing to do with the way my isolators work, this is basic alternator fundamentals.

 

[MilehighLR3]

As I commented previously, inhale zero interest in debating one opinion versus another. Forums such as these should be used as resources and collective experience.

I suppose the fact that I am an a electrochemical/mechanical engineer with more than 25 experience specifically in the battery business with multiple battery battery pack doesn't earn me a little credibility. I suppose that the numerous tests and studies conducted by me on behalf of the likes of General Dynamics, British Aerospace Engineering, and the similar means in haven't a clue. I also suppose that the fact that I personally have conducted several thousand discharge and capacity tests for the big 3 and several European car makers means I obviously haven't a clue what i'm talking about.

That's ok, my feeling aren't hurt nor damaged in any manner. Re-read my comments, do as you see fit, and as I mentioned in previous replies, I wish you only the best in your endeavors.

 

[drivesafe]

Having loads of experience in a given field still doesn’t correct the fact that you have it wrong about paralleling batteries, and we are talking about batteries in vehicles not batteries in RAPS or UPS set ups, which will have totally different charging regimes.

We are talking about charging by an alternator and this makes all the difference, and this is the single ruling factor that makes all the difference. We are discussing a system that is based on constant voltage charging ( Taped Charging ). Whereas just about every other charging system is based on constant current charging.

Now if your theory was so true, with literally millions of vehicles world wide, with all sorts of dual battery set up, why are there not queues of vehicle lined up at battery service centres having their low capacity batteries being replace.

Mate, there is no smoking gun to back your theory.

 

[MilehighLR3]

My kind sir, the applications I sited have ZERO relation to Stand by power. They are all 100% automotive and passenger vehicle.

 

[drivesafe]

Then once again, where is the smoking gun.

What you are claiming is just not happening and in the case of those using my gear with an Optima for their auxiliary battery, are actually get the reverse happening.

Quite a large number of D3, D4 and RRS owners have reported that while they have been able to start their vehicles ( in most cases ) they had been getting low battery indications on numerous occasions prior to installing one of me dual battery systems.

With just one exception, everyone who has fitted my system and an Optima battery has found the error message is no longer appearing.

Furthermore, while I would not be surprised if many of these vehicles have battery capacities down to only 80% SoC while running around town, this has little to do with any form of permanent loss of battery capacity but is nothing more than a lack of charging time and is something I have regularly referred to as the Shopping Trolley Syndrome.

Shopping Trolley Syndrome is a common situation where a given vehicle is only driven for a short time, each time the motor is started.

This Shopping Trolley Syndrome is the prime cause for the low battery indication, but once my system is installed and because of the way it works, what happens is just before the vehicle is stared both batteries will be at about the same SoC.

The motor is then started and the vehicle is driven for a short time and the motor is then stopped but the drive time is not long enough for the cranking battery to be fully charged.

Now this is where you theory is not supported. The Optima, because of it’s ability to take high inrush currents, will charge quicker than the cranking battery and will be at a higher SoC when the motor is stopped.

The Optima will then slowly discharge into the cranking battery.

While this does not raise the cranking battery’s SoC by much at all, it is sufficient to keep the cranking battery at a higher state of charge even in Shopping Trolley Syndrome situations and and is a case where having two batteries wired in parallel is preventing a discharge and is the exact reverse of what you are claiming.

This still does not cover the available amount of power one needs and uses while camping or on trips, and the Shopping Trolley Syndrome does not apply here because in the vast majority of cases, someone going away for a weekend or on vacation, will be driving for many hours and this long drive time is where all the batteries in a vehicle will easily reach at least 90+% SoC, with most reaching above 95%, and all this capacity is then available.

Now if your theory was the case, then not only would the auxiliary battery be in a low state, as you theorised, at 20% less capacity, but because of the way my isolators work, the auxiliary battery would draw down the cranking battery and it would also be 20% worse off. This is just not the case.

Now with more than 5 years of set ups being installed and used in D3s, your theory would have shown up by now if it was fact, and people would notice something was wrong because they would be getting very short operating times before they needed to recharge their batteries.

The reality is that most people with my system installed, not only get better operating times between charges while off camping, they also tend to get longer life spans from their cranking batteries.

Again, none of this would be happening if your theory was fact, I reiterate, where is your smoking gun?