Stack AGM Batteries

[Danjo]

I have two 200 Ah AGM batteries. To save space I’d like to stack them. Think this is OK?

[PNW_Steve]

I have seen it done but I would be concerned about heat buildup. All of the batteries that I have worked with in solar applications have had minimum spacing between batteries to allow airflow circulation.

Take a look at your batteries manufacturers specs.

[john61ct]

Not unless you make very secure "bunk bed" frames out of strong metal profile angle.

Each very well clamped down, wouldn't shift if you whacked it with a heavy sledgehammer.

[Danjo]

Originally Posted by john61ct

Not unless you make very secure "bunk bed" frames out of strong metal profile angle.

Each very well clamped down, wouldn't shift if you whacked it with a heavy sledgehammer.

10-4. That’s a concern, they are so ! Heavy!

[john61ct]

And even sitting on the floor need to be well strapped down into the vehicle chassis, not just sitting in a box.

[sepudo]

I'm also curious as to the best way to secure/stack batteries to the bus.

I have 6 100ah AGM gel batteries from renogy that I'm debating how to arrange in my bus. I don't know if I should do all 6 or start with 4,5 for starters. I could really use1 in my current rig (sprinter van)

[Danjo]

Originally Posted by sepudo

I'm also curious as to the best way to secure/stack batteries to the bus.

I have 6 100ah AGM gel batteries from renogy that I'm debating how to arrange in my bus. I don't know if I should do all 6 or start with 4,5 for starters. I could really use1 in my current rig (sprinter van)

What’s your bus?

[sepudo]

Originally Posted by Danjo

What’s your bus?

It's a 2003 Thomas Freightliner fs65 with a 3126 and Allison 2000

How about you?

[Danjo]

Nice! Have you considered a battery drawer?

[CHEESE_WAGON]

Weight can sag a rack and cause it to contact top-post terminals. I would not do this with top-post construction, only side-post.

[sepudo]

Originally Posted by Danjo

Nice! Have you considered a battery drawer?

I already have one for my 2 starter batteries. I have seen others with 4 batteries in the same spot but that would be a odd arrangement for my intended 6.
Unless you mean making a different drawer. That I haven't considered since I have plenty of room inside

[john61ct]

If you want to stack vertically, you will need a **very** well designed and robust welded rack, through-bolted to load-bearing framing or the floor.

Not a great idea IMO.

Originally Posted by sepudo

I have 6 100ah AGM gel batteries from renogy that I'm debating how to arrange in my bus. I don't know if I should do all 6 or start with 4,5 for starters

6x 12V batteries all in parallel?

Not a great idea.

If 6V so 2P3S layout to get 300Ah @12V, that's marginal but OK.

You really want to keep to 2 strings for optimal balancing of the current flow. 3 is the max IMO but going past 4 is likely going to reduce longevity a fair bit.

Plus 6V units are more robust last longer anyway.

The best GEL are Sonnenschein, made in Germany.

Deka makes decent ones under license in the US, hopefully Renogy is re-labeling either of those.

[kazetsukai]

Originally Posted by john61ct

6x 12V batteries all in parallel?

Not a great idea.

Would a "super capacitor" of the bank's voltage rating help with the longevity issues of parallelization at all? I'm thinking about for when I add more packs to my bank and have to parallelize again.

[john61ct]

I haven't come across anything like that, and can't imagine how.

Any explanatory links or past examples?

[AzironaZack]

Here's a good article about how to balance banks of parallel batteries. They seem to indicate that you can parallel as many as you want as long as you keep it balanced.

https://www.iotaengineering.com/ppli...edcharging.pdf

[john61ct]

Gibbo inventor of SmartGauge is the OG on that topic

http://www.smartgauge.co.uk/batt_con.html

But that is simply to stop the intra bank wiring from causing **greater** imbalances.

Even with the wiring perfectly balanced

which IMO is a lot more trouble than just buying the right cells/units for the size bank you plan

the imbalances past a grouping of 3-4 are still going to be an issue.

BTW note using 2V **cells** grouped at the lowest level, can have as many as you like before starting to serial them.

But not relevant for the small banks used for a van