Optimus versus standard mixing

[n5ama]

I recently read a “ old versus new “ battery discussion. I recently bought a Optimus battery to replace a normal top cap battery and now wonder if that was a mistake. So far, no obvious problems. I have 5 batteries in my battery inventory and not sure if there is a charging rate issue between the two types or some other issue that might cause a problem.

What’s the experts opinion?

Thanks
Tom

[tkeithlu]

I'm not one of the experts.

You can get away with it, but will not get optimum performance or life from the battery bank. Plenty of batteries out there don't get perfect charging for those reasons or others. I may be risking my life, or at least my future on the forum, by saying that. Stand by for an explosion from an expert.

[Bycrick]

Whenever you connect multiple devices in parallel, since they will never be truly identical, they will not share the work identically. The more different they are (size, type, age,etc.), the more unequal will be the sharing. Hence, some will work harder than others. The overworked one(s) are likely to fail faster. So, ideally, you want to start with all of them as closely matched as possible. That’s the theory.

The practice is, like post #2 says, it will work, but won’t be "optimal." But it may be good enough. It’s not likely to smoke anything, though. Some of the batteries will work harder than others and they’re more likely to fail "sooner." If you have a choice, it’s better to match. If you don’t, then be prepared to replace them sooner than you otherwise might.

[n5ama]

OK, great info!
I don't have any high current equipment on board other than the engine starter. I do have the standard stuff like the chart plotter, mast lights, VHF radio and radar which I rarely use.

I was more concerned with over charging the regular batteries. I'm not sure of the charging specs on the Optimus versus the other batteries and didn't know how the other batteries in parallel would be affected as far as charge rate and the voltage level at 100% charge.

Thanks

[sailinglegend]

Originally Posted by Bycrick

Whenever you connect multiple devices in parallel, since they will never be truly identical, they will not share the work identically. The more different they are (size, type, age,etc.), the more unequal will be the sharing. Hence, some will work harder than others.

It is safe to mix the capacity of batteries to fit all the available spaces. Research by Lifeline Batteries has shown that a bank can be made up of different capacities and that the life of the batteries was not compromised, as long as they are all the same make and the same age they will have the same nominal voltage. This goes against most previous guidelines, but Sabre yachts, who use Lifeline batteries, regularly ship with different sizes to be able to get the maximum capacity from all the available space.

This should, in theory, apply to all battery types, not just AGMs.

[GordMay]

As others have noted, mixing batteries is never a good idea.

Do you have a Red Starting or Blue Deep Cycle [or Yellow] “OPTIMA” Absorbent Glass Matt [AGM] battery, in your [otherwise] Flooded Lead Acid [FLA] bank?

OPTIMA Charging ➥ https://www.optimabatteries.com/supp...pport/charging

Flooded Lead-Acid Charging ➥ Calculating Proper Charge Settings for Rolls Flooded Lead-Acid Batteries : Technical Support

[GordMay]

Originally Posted by sailinglegend

... Research by Lifeline Batteries has shown that a bank can be made up of different capacities and that the life of the batteries was not compromised, as long as they are all the same make and the same age they will have the same nominal voltage ...

Have you a primary source for this? I've read second/third hand reports of this research, but never seen it.
The OP has installed differing makes, chemistries, and ages of batteries; so, even if true, this wouldn't apply, in this case.

[sailinglegend]

Originally Posted by GordMay

Have you a primary source for this? I've read second/third hand reports of this research, but never seen it.
The OP has installed differing makes, chemistries, and ages of batteries; so, even if true, this wouldn't apply, in this case.

Latest Lifeline manual Rev F page 31 of 40 - under FAQs.

This whole manual is about principles of AGM batteries and charging and not about their battery catalogue. Everyone should read it.

[GordMay]

Originally Posted by sailinglegend

Latest Lifeline manual Rev F page 31 of 40 - under FAQs...

Thank you!

TECHNICAL MANUAL For Lifeline® Batteries
Document No. 6-0101, Revision F, May 6, 2019
➥ https://lifelinebatteries.com/wp-con...al-5-06-19.pdf

From APPENDIX B – FREQUENTLY ASKED QUESTIONS (FAQ’S), beginning page 30:

11. Do all the batteries in a series string have to be the same model/size?
Yes. Do not mix different models/sizes of batteries in the same string.

12. Are there any issues with having parallel strings of different battery models/sizes, as long as each string has the same model/size battery in series?
No, since the strings are in parallel they will operate at the same voltage level and will self-regulate. Refer to Section 5.2 for proper installation procedures for parallel strings. Make sure the batteries are all at 100% state of charge before connections are made.

13. Are there any issues with adding a new battery string in parallel with an old string?
No, since the strings are in parallel they will operate at the same voltage level and will self-regulate. Refer to Section 5.2 for proper installation procedures for parallel strings. Make sure the batteries are all at 100% state of charge before connections are made.

16. Can I replace one or several bad batteries in a series string without affecting the other batteries in that string?
Unless the string is fairly new (less than 12 months year old), replacing only the bad one(s) will cause the other batteries to be under-charged and/or over-discharged, which will negatively affect their performance
and remaining life. Therefore, it is best to replace the entire string. However, if it is decided to replace only one or some of the batteries, make sure all the batteries are at 100% state of charge before connections are made.