Author Topic: Adding batteries, worried any Bay weight capacity  (Read 515 times)

Offline neoneddy

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Adding batteries, worried any Bay weight capacity
« on: March 16, 2019, 08:39:35 PM »
I found a thread about using back bay for water, which I do, 150 gal worth.

I use my middle bay for general storage and electrical, including batteries.  Right now I have  4 golf cart batteries , weighing 260 lbs total.

I purchased 6 12v UPS AGM batteries weighing 130lbs each, that would be 780 lbs. The weight overall doesn't worry me, the density does. These are tall skinny batteries.

Any reason I can't swap these in?  Total coach weight is around 33,000 lbs as-is.
Raising hell in Ham Lake, MN

1982 MCI MC9

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Offline richard5933

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Re: Adding batteries, worried any Bay weight capacity
« Reply #1 on: March 17, 2019, 03:58:57 AM »
Two questions..

Do you know the individual axle weights on your current setup?
Do you know the side-to-side weight (individual axle end weight)?

Assuming that he additional weight wouldn't put you over the weight limit for your axles and that it would still allow a large enough margin for safety, my only concern would be how it affects the side-to-side balance of the bus.

Can those AGM batteries be installed lying down flat or must they remain standing? If they're designed for either position you could build a false floor to lay them under and still have lots of usable space above them.
Richard
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Offline buswarrior

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Re: Adding batteries, worried any Bay weight capacity
« Reply #2 on: March 17, 2019, 08:01:39 AM »
Carry on, you'll be fine.

Have a look underneath to see the reinforcing, and note the thickness of the plate used to make up the bay floor.

The only thing I would add is a piece of plywood, to smooth out the floor, the ribs always seem to disrupt my spacing...

Happy coaching!
Buswarrior
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Offline neoneddy

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Re: Adding batteries, worried any Bay weight capacity
« Reply #3 on: March 17, 2019, 10:11:34 AM »
I want to say I was around 8k up front and 22k or so on the back, which means I'm missing 3k someplace, I'll need to find the CAT scale receipt.

My left to right weight is probably getting off, most of utilities are on the driver side, the new battery bank would be on that side as well, it would be a net gain of 500lbs or so.

I think I can mount these anyway but upside down. I saw many shipped laying down. I like the idea of keeping them upright to let me slide them in and out as I need if one goes bad or something.
Raising hell in Ham Lake, MN

1982 MCI MC9

6V92 / 4 Speed Auto (HT740) Video Build Log - Our Bus Conversion Website

Offline Ryker

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Re: Adding batteries, worried any Bay weight capacity
« Reply #4 on: March 19, 2019, 05:47:58 PM »
I had a 1999 Airstream diesel pusher with huge AGM batteries that ran my coach for days. 2 years ago I was going over the Tehachapi Pass for a 4 day campout. Going down the pass, I hit a big bump and heard a huge crashing sound. My mind was racing as to what happened because I was still driving fine. Looked in the mirror and saw cars swerving out of my way with pieces of god knows what flying behind me. Pulled over to find my beautiful batteries smashed to bits but still hanging on by one cable. I got battery acid all over myself tossing them into different bays. Went to Costco and bought a couple batteries to get us through the weekend.

And this is one reason that I now own a bus. Motorhomes are just not durable.
1974 GMC P8M4905A-615

Offline bandsaw

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Re: Adding batteries, worried any Bay weight capacity
« Reply #5 on: March 19, 2019, 08:28:09 PM »
Hello, I asked the Prevost factory conversion rep about their suggested weight limit per bay. He said they do not recommend putting more than 1,000 pounds in a bay.  I realize you are not converting a Prevost.  I changed my conversion layout based on his comment.

Thanks, Bandsaw.

Offline Jim Blackwood

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Re: Adding batteries, worried any Bay weight capacity
« Reply #6 on: March 20, 2019, 05:32:19 AM »
I'll have nearly double that in the rear bay of my DL3. Water weight primarily. Has anybody heard of a failure?

Jim
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Offline neoneddy

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Re: Adding batteries, worried any Bay weight capacity
« Reply #7 on: March 20, 2019, 05:52:57 AM »
Well, I've got the 200 gal of water in the back bay too. No issues thus far, but it's already out.
Raising hell in Ham Lake, MN

1982 MCI MC9

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Offline Fred Mc

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Re: Adding batteries, worried any Bay weight capacity
« Reply #8 on: March 20, 2019, 09:28:24 AM »
"I purchased 6 12v UPS AGM batteries weighing 130lbs each"
A little off topic but can you elaborate on these batteries.Are they new or used? Capacity.?
Etc

I see them on craigslist all the time but also see warning they are not a good deal.

Thanks

Fred

Offline neoneddy

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Re: Adding batteries, worried any Bay weight capacity
« Reply #9 on: March 20, 2019, 09:43:47 AM »
I have not used them yet, but if they are even at 80% life left,  I think they are a good deal.

I bought these from a local guy who gets pallets shipped in from data centers / hospitals , etc.  From what I understand these are for the transition time when the power is lost and when the generator(s) kicks on.

He tells me he tried to buy batteries that are 2-3 years old max, these are rated for 10 years, and have most likely been sitting on float for that time other than tests of the UPS and intermittent usage.   I bought 5 he had sitting on a in his warehouse all winter and he just got a shipment in that day and he gave me one of those as well for an even 6 for a cool $1000.  I bring up that one from the pallet because that one was most likely new.  It still had hardware in a bag and a bus bar taped to the side.   I tested the voltage on all of them and they all read 12.8 except the suspected new battery, that was 12.9 .   

I'm planning to try and install them today or tomorrow.  My plan was to charge them, then run a specific load on them  and then let them rest and take a voltage reading to get a sense of capacity.  I have a Victron shunt and everything, but that only calculates based on what you tell it.  For the time being I think I'm going to tell it 600AH  , it's a 24v bank, each battery is 205Ah @ 20 hr rate (185@ 8hr rate).  http://www.gsbattery.com/ind-products/pyl/PYL12V185FT.pdf  spec sheet here if you're interested.
Raising hell in Ham Lake, MN

1982 MCI MC9

6V92 / 4 Speed Auto (HT740) Video Build Log - Our Bus Conversion Website

Offline Fred Mc

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Re: Adding batteries, worried any Bay weight capacity
« Reply #10 on: March 20, 2019, 11:49:43 AM »
Thanks. Looking foreward to your tests.

Regards

Fred

Offline neoneddy

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Re: Adding batteries, worried any Bay weight capacity
« Reply #11 on: March 20, 2019, 11:14:26 PM »
Out with the old, in with the new.

So far so good.   I have them all hooked up now, tomorrow morning they get their first solar charge. 

I set float around 27.2 and absorb around 28.8, alternator is around 28.2 still, I dropped it down, but it's a fine line between the no-gen light being on from too much solar, or not enough alternator juice.  This appears to be working so far.

Right now the batteries have been holding at  25.2 for most of the night.  I'm only pulling 2 amps unless the fridge is on, but it's just sipping from the 600Ah Available.   I'll know more tomorrow.
Raising hell in Ham Lake, MN

1982 MCI MC9

6V92 / 4 Speed Auto (HT740) Video Build Log - Our Bus Conversion Website

Offline daveola

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Re: Adding batteries, worried any Bay weight capacity
« Reply #12 on: March 24, 2019, 06:24:07 PM »
Don't know what bus you have but my guess would be that you'll be fine.

Evidently during the Greyhound days they company would toss engines into the bays to move them between depots and those weigh a literal ton.

In my MCI 102A3 I have almost twice that battery weight.  10 Group 8D AGMs in my front bay on one side, that's 1300 pounds, and I've had it that way for over a decade with no weight issues (apart from a failure on the front leveler which I suppose could have been connected, but I doubt it).

Foolishly I also put my water on the same side of the bus in the back bay, and at 100-200 gallons, that was probably a mistake.  Would do that differently if I did it again.

Offline neoneddy

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Re: Adding batteries, worried any Bay weight capacity
« Reply #13 on: March 25, 2019, 11:13:13 AM »
Took a quick trip out of town in the bus, so far so good.

Only snag I ran into was my 250 amp DC breaker is actually only good to 100 or so, I have an electric 2500 watt water heater that needs to run for 10-15 minutes every 2-3 hours.  So imagine my surprise when i wake up to a low voltage alarm.   Anyway, once I sorted that out and only heated water with the bus engine running, solar coming in with 1000+ watts or the genny running I was taking a hot shower just fine.

I need to devise a proper metered test on these to get a sense of health.   I'm also considering doing a recondition charge, when I intentionally bring it down to 20-30 SOC and then back up.  Thoughts on that?   On my Victron monitor I showed 80% SOC at it's lowest.  I intentionally flipped the DC breaker and the bank measured 24.5 (I let it settle for a few minutes, it was 12.4 under a 10 amp load before, so no false surface charge reading here) .   This leads me to believe they are performing well and almost new still.   I'd like to do a 50% discharge and see how that measures up.   

Attached is a chart I found for AGM batteries and SOC based on open circuit voltage.

Raising hell in Ham Lake, MN

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Offline daveola

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Re: Adding batteries, worried any Bay weight capacity
« Reply #14 on: March 25, 2019, 11:48:00 AM »
If I read that correctly, you're likely to be damaging those batteries pretty quickly if you regularly go to that SOC.

My experience with multiple rounds of AGMs is that they just don't come anywhere near the published lifecycle based on repetitive SOC.  They're pretty disappointing.

Someday I would love to put in a LiPo pack.