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Old 09-20-2016, 06:40 AM   #14
CMS
Senior Member


 
City: Casco Bay
Join Date: Feb 2016
Posts: 308
Quote:
Originally Posted by dhays View Post
Since the start battery and the house batteries are of different types (lead acid vs AGM)
They are both "lead acid" batteries though they may require differing charge voltages.

Quote:
Originally Posted by dhays View Post
is there a problem using the ACR to connect those two types together for charging purposes? I am not sure what the charging profile is for the Inverter/Charger, but if the Duo-chargers are any indication my guess is that it is set for lead acid. Not sure if this will hinder the charging of my AGM start battery as I believe it could accept a faster charge than what the LA house batteries can.
I know I have likely beat this horse to death but the battery type (in words on a charger eg; AGM, GEL, Flooded) is quite often pretty irrelevant. What is relevant is the batteries recommended absorption and float voltage.

As a group boaters really need to stop looking at the words on a chargers pre-set list and instead look at the VOLTAGES behind the words. AGM, GEL, Flooded, FDC etc. are words and they mean absolutely nothing without knowing the VOLTAGES behind those words.

One manufactures voltage for AGM will NOT always be the same as the next thus you should only focus on the VOLTAGES the words represent. Sometimes you can also see different absorption times behind the words and this too is very useful information. For some AGM batteries you will be much better served using the FDC setting than an AGM setting but a custom setting will always better be able to match the manufacturers recommended absorption & float voltages.

For example Trojan's are best charged at 14.8V absorption & 13.5V float for a PSOC type use. If an installed starting battery can also be charged at 14.8V & 13.5V then the charger can charge both even if one is flooded and the other AGM.

An ACR just applies the same charge voltages to each bank because they are charging in parallel.. This is really no different than most all so called "smart-chargers" which feature multiple outputs. If the float voltage requirements are also the same, or very similar, then one charger can feed two different battery types without issue. All batteries should be charged temp compensated..

VOLTAGE (and time or timer algorithm) is the key not the words.


While a smart charger may have outputs for "three-banks" it is still one charger with one single voltage setting used at a time. You can't for example put a GEL battery that needs 14.1V on output #2 and a Trojan that needs 14.8V on output #1 and then set the charger to FLOODED because you will cook the GEL battery. If you set it to GEL then you chronically under charge the Trojan and also ruin it.

Here is a prime example of ignore the words and focus on the recommended VOLTAGES


Here are some manufacturer suggested charging voltages:

AGM's - Which AGM Preset works?:

Lifeline AGM's = 14.4V & 13.4V = AGM Preset #1
Odyssey TPPL AGM's = 14.7V & 13.6V = Neither AGM Preset
Firefly AGM =14.4V & 13.2V = Neither AGM Preset
Mastervolt AGM = 14.4V & 13.2V = Neither AGM Preset
Full River AGM = 14.7V & 13.7V = Neither AGM Preset
Rolls AGM = 14.7V & 13.7V = Neither AGM Preset
East Penn/Deka = 14.6V & 13.6V = Neither AGM Preset
US Battery AGM = 14.4V & 13.4V = AGM Preset #1
Trojan AGM = 14.4V & 13.5V = Neither AGM Preset

This is why boaters should always focus on buying chargers that have a custom setting. Please do not focus not on the words but instead focus on the voltages that the words are representing..

How about Trojan Flooded batteries? Which Flooded preset works for Trojan flooded batteries??

Trojan Flooded = 14.8V & 13.5V = Neither are ideal. So you use custom and set it at 14.8V and 13.5V

How about Deka / East Penn Flooded

Deka Floded = 14.7V & 13.8V = Neither are ideal. So you use custom and set it at 14.7V and 13.8V

* This is but one example of one charger. Some so called smart chargers are so dumb as to only have three options AGM, GEL or FDC.

You will generally be best served to use the same brand and type of battery with a multi-output charger or ACR/VSR/Combiner etc. and set the charge voltages for those batteries correctly but they can certainly be mixed if the voltages align. If you have a mixed use scenario, always set the voltages for the most expensive bank....
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