Fitting mobility 12volt AGM battery.

I have been having problems off and on for the past hour.

 

Seems like someone that works at a dealership. I'm not an EE but Ive been flipping cars for over 30 years.

 

The amount of active material, commonly called "paste", present in each cell is what sets its capacity (after it has been pasted on a lead-alloy casted grid and cured to eliminate free lead and reduce humidity).. . Each positive plate in a , let's say, 15 plates cell has a set capacity (in discharge) of 7 x pos plate capacity (generally, the positive plates are thicker than the negative plates, therefore 1 more negative is required per cell in order to do an optimal discharge).

Not all lead-acid batteries are "deep-cycle" batteries. This is the same for AGM batteries.Usually, the deep-cycle battery will have thicker plates than the other batteries. Also, starting batteries, or cranking batteries, have thinner plates, in order to provide a larger CCA or MCA. They also normally are made with separator materials that will allow much better flow of acid from positive to negative plates.

There should not be any free acid in an AGM battery cell, as it is guaranteed to not leak if the container is broken (this is especially critical in the aerospace and defense industries). However, low-end models will have more acid than required. Gel batteries will also not leak, as their electrolyte has been "gellified". The VRLA part of those batteries is simple a pressure release valve that makes sure the battery emits a minimal quantity of hydrogen gas. However, in the event of overcharge of the battery, the VRLA will release hydrogen gas.

Flooded Lead-Acid batteries have flame-arrestor bayonets or caps that eliminate the risk of explosion. They can also be supplied with catalytic caps in order to extend the period between required maintenance.

AGM and gell batteries have 1 positive aspect: they do not require maintenance, they are called "maintenance-free" batteries. This means no distilled water needs to be added every 3 to 6 months in order to keep the electrolyte level above the plates inside every cell. Flooded Lead-Acid batteries require maintenance, but if overcharge or severely undercharge happens, they can generally be regenerated by doing a corrective equalization procedure. AGM and Gel batteries, under the same conditions, are often rendered useless. This is why they are more common in backup systems and the automotive industry, where they generally get more "charge" than discharge. They are not heavily cycled at all. They are also regulated by sophisticated equipments, which ensures they last as long as possible.

No lead-acid AGM battery can claim to have a long cycle life at 100% DOD (Depth of Discharge). It is not physically and chemically possible. This is what the Lithium-Ion, NIMH, Nickel-Cadmium, etc. batteries are good or better at. However, nothing, yet, financially beats the capacity of lead-acid batteries in deep-cycling installations. The recommended DOD of all manufacturers of flooded, AGM and Gel Lead-Acid batteries is 50%.

We have batteries installed throughout the world, Flooded Lead-Acid, who are being used to power complete villages or manufacturing plants. They are really reliable and have long cycle life, but are very heavy and need maintenance.

It all depends on the application... and the will to maintain!!!

Finally, I would like to point out that the maximum recommended voltage for a full charged lead-acid battery is 2.1VPC, or 12.6V for a 12V nominal battery. The voltage could be higher if the battery was filled with higher density or specific gravity (SG) electrolyte and if the internal temperature was higher than 25 degrees Celsius. However, the voltage mentioned by BritPrius could indicate a few things:

- Overcharged battery (positive material deterioration)
- Undercharged battery (sulfated)
- High SG originally (we've noticed this in low-end models of batteries, in order to boost initial capacity and voltage)
- Surface voltage from a battery that was just taken off charge (generally, the 2.1VPC is measured after a 1/2hr rest, without any load or charge applied).

Regards,

Monius.

 

Thanks for the details Monius... It was hard to understand what you were saying without the details....

Do you think 'anti-sulfate mode' on a trickle charge charger once a month would be enough to address your concerns and thus allow for the reliability/successful use of an AGM mobility battery?

 

Monius- now that you have clearly established your credentials and seem to know a LOT of what you are talking about are you still maintaining, as you did in your post #54 that:
"I don't want to create any frustrations, but I would not recommend using those batteries in the Prius. Please stick to the OEM recommended batteries.
The charge-discharge characteristics of the Valve Regulated AGM batteries offered on this forum are very misleading.
A lot of R&D goes into the design of such batteries and trust me, a car with specifications such as the Prius will not work well with a battery designed for wheelchairs..."

I don't think we want to invalidate anyone's experience, especially Britprius and all that he has shared here.
But you have made a pretty definitive statement above.
Are you firm in your conviction?

 

I am heading to work. I just received the updated book of battery applications, which contains info on all vehicles, of any type, using a lead-acid battery on this planet. I will consult the book and then compare the 2 batteries.

Thank you,

Monius

 

The Battery Replacement Data Book specifies a group S46B24R battery, 270 O.E. CCA (@0F). It also mentions that the battery needs to be VRLA. This comes up to a 45AH battery @ 10HR.



BritPrius, do you know how much current is being fed to the battery while on charge, and what voltage? This would help me determine if this group S46B24R is really a necessity and also make sure that your choice of battery is getting the required charge to prevent sulfation.



From my experience though, 10AH should not make such a big difference, even if it represents 22% more capacity @ 10HR than the spec battery. 10AH / 10Hrs = 1A… No big deal!



Thank you,



Monius

 

Glad to see a second opinion from an independent source.

 

Hi John,

I have been designing and testing Flooded and AGM batteries for numerous years and also ensure our technical support and warranty departments are running well. At the moment, we are concentrating our efforts to design a new type of negative plate grid, with the help of different universities in North America and Japan.

I welcome all positive comments from this forum. At first, I did not want to get too complicated or "in-depth" in the subject. Now, I realize that I was vague in my first comments. I guess I can blame the long hours working in the lab

Regards,

Monius

 

John- what does ECU stand for?

 

Hi John, Eastern Battery Systems is a distributor of batteries. I don't work for them

Rolls Battery - Home is who I work for.

Thank you,

Monius

 

Civility at it's finest!

 

Monius- can you get me a deal on a Rolls...battery...or better yet the entire vehicle...???
Thanks for your contribution...