Bad Batteries?

[sck_nogas]

FWIW, Optima Group 34/78 are just a little bigger than the Group 35s (I have not confirmed fit), but the battery posts are on the same side as the stock batteries, so less fiddling with the positioning of the clamps/cables. They also offer a bit more CCA at a slightly increased cost.

Group 35
Model: D35
Weight: 36.4 lbs
C20 Capacity:48 Ah
Post Type:SAE Post
CCA:620 Amp
Width:6.75 in
Length:9.38 in
Height:7.69 in

YELLOWTOP® D35

The YELLOWTOP® D35 is a high-performance AGM battery designed to deliver a strong burst of ignition power for a reliable start-up. Discover YELLOWTOP® today!

www.optimabatteries.com

---------------------------------

Group 34/78
Model: D34/78
Weight:43.5 lb
C20 Capacity:55 Ah
Post Type: Dual SAE/GM
CCA:750 Amp
Width:6.94 in
Length:10.06 in
Height:7.88 in

YELLOWTOP® D34/78

The YELLOWTOP® D34/78 is a high-performance AGM battery designed to deliver a strong burst of ignition power for a reliable start-up. Discover YELLOWTOP® today!

www.optimabatteries.com

Plus, they have the side mounts so you could make a copper bus-bar to connect them in series!

 

[delicadenny]

has anyone tried the (2) 34/78's? My single (group 65) battery wouldn't crank when the temps were ~25ºF the other day, so I'm gonna round up parts & pieces to convert to dual battery.

 

[Sputnik]

has anyone tried the (2) 34/78's? My single (group 65) battery wouldn't crank when the temps were ~25ºF the other day, so I'm gonna round up parts & pieces to convert to dual battery.

I replaced a double battery setup with a single Optima 34/78. I taped off/removed the unused terminals, but might add a second one eventually.

Below are comparison pictures of the batteries and the original setup. The Optima posts are spaced a little differently and the battery is slightly smaller (dimensionally) than the original, so a double Optima setup should have no trouble fitting.

 

[godzilla24]

They work well enough that I feel bad for my starter. They kick that engine over so fast and so hard, it doesnt even get a full rotation of cranking before it fires up. It's literally instant when you hit the key. Its the cold weather winter performance that I'm really looking forward to. Nothing makes my stomach sink like climbing into the van, exhausted, hungry, after a full day skiing when it's 20 degrees out and snowing hard. You hit the key and brrrruh...brrrruhhh...brruhh.... The engine is cranking over at like 10 RPM and you're thinking flagging down someone for a jumpstart in a blizzard is not what I want to be doing right now!

hahah - this is me in Vermont right now - I need to get those Optimas!

 

[Andy]

Loving this thread as I’m going down the battery rabbit hole here. It seems that any group 24 size battery should fit, but I saw an old post from @sk66 stating a group 27 would fit. Any thoughts on jamming two of these bad boys under the passenger seat?

Duracell Ultra BCI Group 27M 12V 92AH Deep Cycle, Dual Purpose (Starting/Cycling), Starting Marine & RV Battery - SLI27MAGMDC at Batteries Plus Bulbs

Group 27 12 volt AGM replacement deep cycle battery for marine, boat and RV use. Stay out on the water longer with this powerful 92 amp hour deep cycle battery!

www.batteriesplus.com

92AH capacity x2 would be fantastic for snow camping with my diesel heater and fan running all night.

Also, anyone know what the maximum DoD(depth of discharge) might be for a deep cycle agm battery?(I’m guessing I’ll need to contact the manufacturer) Everything I’ve read seems to say either 50% DoD or 80% DoD, not much consistency. Though I’m thinking @sck_nogas might be able to shine some light on batteries with his previous EV builds!(that pic in the white convertible was awesome!)

Thanks!

 

[sk66]

Loving this thread as I’m going down the battery rabbit hole here. It seems that any group 24 size battery should fit, but I saw an old post from @sk66 stating a group 27 would fit. Any thoughts on jamming two of these bad boys under the passenger seat?

Duracell Ultra BCI Group 27M 12V 92AH Deep Cycle, Dual Purpose (Starting/Cycling), Starting Marine & RV Battery - SLI27MAGMDC at Batteries Plus Bulbs

Group 27 12 volt AGM replacement deep cycle battery for marine, boat and RV use. Stay out on the water longer with this powerful 92 amp hour deep cycle battery!

www.batteriesplus.com

92AH capacity x2 would be fantastic for snow camping with my diesel heater and fan running all night.

Also, anyone know what the maximum DoD(depth of discharge) might be for a deep cycle agm battery?(I’m guessing I’ll need to contact the manufacturer) Everything I’ve read seems to say either 50% DoD or 80% DoD, not much consistency. Though I’m thinking @sck_nogas might be able to shine some light on batteries with his previous EV builds!(that pic in the white convertible was awesome!)

Thanks!

The OEM batteries are JIS spec which is a little different from the BCI group sizes. For the diesels group 27 matches the standard single battery the closest, and group 24 matches the optional dual battery (80D26R) setup the closest.

Single Battery
95D31R- 305 x 175 x 225 (mm)
Group 27- 306 x 173 x 225
Dual Battery
80D26R- 259 x 173 x 222
Group 24- 260 x 173 x 225

 

[scot]

Just curious how the Optimas held up this winter? Looking to make my next battery upgrade this year...thank you!

 

[Sputnik]

Just curious how the Optimas held up this winter? Looking to make my next battery upgrade this year...thank you!

I've had mine in since Nov 2020, and so far so good, no problems, but that short a time isn't really a gauge of their lifespan. Starting the van in the central Virginia winter cold is still a little rough at times, but that has more to do with the fuel system. A double battery or larger single battery would give me more cold cranking amps though. I can say their prices have definitely gone up, like everything else!

 

[Krumby]

I ended up with two yellow top optima batteries. Cranks right over and starts. These vans will not start at all with weak batteries now it fires right up instantly.
650.00 later for the batteries. There were two cheap Korean batteries in there. Only about a year and half old.

 

[Krumby]

Mahalo for the help sk66 I appreciate it very much.