LMTV Battery Replacement 24 Volt

[MatthewWBailey]

Following @Keith Knight 's lead and starting this Battery thread. Continuing his theme from the Alternator replacement thread...

1. a single place to get all the information for everything involved with changing the 12/24 volt Battery Pack with common automotive market Truck Batteries.

- For an A0/A1/A1R

2. keeping the change as simple as possible but maintaining all the functions and minimum AH, CCA requirements.

3. explaining the mod and benefits. If you must use abbreviations preface it with the full words and include pictures and diagrams or hand drawings. So anyone can understand what you are referring to.

 

[MatthewWBailey]

So to start with my A1, I just swapped out the group 24 batteries it came with and replaced with 2 group-65 Odyssey Extreme 950 CCA AGM batteries. 74 AH. 11" x 7.5h" x 7.2w"

Relief grinding was necessary to fit the 11" length. That center fiberglass spacer must be cut down. Then, they fit snugly without having to remove my 3rd battery. (The reason I didn't goto group 31's)

I'm hoping this will ease my cold start struggles. Without charging them out of the box, they kicked the starter over fast even after the 88Amp AIH draw for 40seconds.

 

[MatthewWBailey]

I kept my 3rd battery which was another group 24 from my original purchase. Only 3yrs old so still functional.

 

[Ronmar]

Probably should clarify what you are using as a power source and how that 3rd battery comes into play. Generally speaking it is not advisable to mix and match series string battery sizes and battery chemistry, as it makes it virtually impossible to balance the charges…

 

[MatthewWBailey]

Probably should clarify what you are using as a power source and how that 3rd battery comes into play. Generally speaking it is not advisable to mix and match series string battery sizes and battery chemistry, as it makes it virtually impossible to balance the charges…

Yes I forgot to mention that for the thread. The 3rd battery is only connected to X2 in the PDP, "12V Battery" line. It's powered by 2 x 20A victron inverters that draw power from the 24V ignition X3. So it is isolated from the 24v series string entirely except for the common "-" negative lead. It actually doesn't need to be there at all since 12v is manufactured by those 2 inverters. But I wanted 12V lights when the ignition is off. The nice side effect is that the 12V loads do NOT draw power from the ALT or 24V battery during startup. My Victrons are set to cutout ("Lockout") at 24V input power and "Restart" at 27.5V, so they are off during cranking and the subsequent inlet heater period. So during that period, the 3rd battery powers the 12V loads.

Again, I have no load or charge connections to the center point of the 24V series battery set. It's straight 24V.