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-   -   Mixing AGM group sizes (http://www.airforums.com/forums/f449/mixing-agm-group-sizes-114462.html)

mefly2 12-29-2013 08:04 PM

Mixing AGM group sizes
 
Looking to hear from someone who has mixed group 24 Lifeline batteries with either Group 27 or 31 AGM. Can they be charged together or must they be charged in separate individual banks?

We plan to add two AGM batts to the existing two Lifelines as supplied by AS with the solar option. The main concern is adding the weight to the tongue if we install the batts under the front bed ... your thoughts?

Thanks in advance.

Jim Clark 12-29-2013 08:30 PM

If you set them up as 2 Banks you can use a multi bank charger or a 1/2/B switch to direct charging. Beware the 1/2/B switch can cause some problems if you are not familiar with proper operation. Batteries in the same bank should be of the same type, age and lot if possible. Since you will have multiple charge sources you may want to charge just one bank and let an echo charger charge the other. On my boat i have a Group 31 AGM for start and reserve and a D4 as a house. I have all charge sources going to the the D4 with and echo charger connected between the banks and it automatically keeps the reserve batter charged. A 1/2/B switch selects use and can also be used to direct charging to the reserve battery if necessary. If you do not have one be sure to add a battery monitor to the system. I have a charger which will charge 3 banks, I have 2 of the charger outputs combined charging the D4 house letting the Echo charger handle the AGM 31 charging. This is a marine setup. My trailer just has the standard batteries with the standard charger and is not banked.

Here is a nice long thread which will explain everything I just attempted to explain.
http://forums.hunter.sailboatowners....t=echo+charger

Here is a thread about batteries here on Air Forums
http://www.airforums.com/forums/f37/...es-113150.html

http://www.pbase.com/mainecruising/image/141226335.jpg

mefly2 12-29-2013 11:04 PM

Many thanks, Jim.

lewster 12-30-2013 06:57 AM

Quote:

Originally Posted by mefly2 (Post 1397277)
Looking to hear from someone who has mixed group 24 Lifeline batteries with either Group 27 or 31 AGM. Can they be charged together or must they be charged in separate individual banks?

We plan to add two AGM batts to the existing two Lifelines as supplied by AS with the solar option. The main concern is adding the weight to the tongue if we install the batts under the front bed ... your thoughts?

Thanks in advance.

You will need a second charging source, as the absorption times vary for any given size of batteries. Also, as Jim said, any batteries in a given battery bank should be of the same size, and preferably the same age and manufacture date.

You should not inter-connect 2 battery banks of different size and age to a single charge source as they will never be properly charged; one bank will get more charge and the other less charge, and any draw will not come out of the 4 batteries evenly. It would be preferable to keep the 2 banks separate and use a marine manual combiner switch to connect bank #1 to the trailer, and then be able to switch to bank #2 when #1 gets depleted.

The Xantrex Echo charger will get the job done, but has no adjustments for the voltages to connect and disconnect the two battery banks. A better choice (IMHO) is the Magnum Energy Smart Battery Combiner: Smart Battery Combiner (ME-SBC) | Magnum Energy, Inc.

This is fully adjustable for voltages and will pass thru up to 30 amps from your fully charged #1 bank top the #2 bank, according to the settings on the panel. It is also water resistant and very easy to install. :D

mefly2 12-30-2013 08:38 AM

Thanks, Lew. The SBC looks even better!


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