Shoot the bull with me

UncleJerm76

I’m heading towards the finish line on my CC 36v build up; with 22” Lumber Jacks, a Honda front end, long travel shocks, blah blah blah. Anyways, I noticed on the BBB site they have a few models which they claim can go 40+ miles on a single charge and a couple of them are even full time 4WD — That sir, is darn right impressive. I would love to entertain the thought with you guys of riding my cart in the woods all day long. I haven’t been bitten by the speed bug (yet) so I’m only interested in extending my current performance as long as humanly possible. ….wait that didn't come out right

Anyway, I don’t use my bagwell for anything since it’s under my utility bed, so my thoughts were this, if I doubled the number of my batteries (to a total of 12 - 6v) by putting them everywhere possible and wire them so that I have two 36v banks and then parallel those two banks to the cart so it’s still only “seeing” 36v - then I would get much longer run time correct? Anyone attempted something like this before? Any drawbacks other than weight? I don't claim to be a expert, does my drawing look correct?

Reference: http://www.catastrophenetwork.org/?p=436

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JohnnieB

I don't know if anyone has done it before, but I wouldn't doubt it.

Your drawing is electrically correct.

Of course, all the batteries should be near equals, since a bank of 180AH batteries probably wouldn't play well with a bank of 220AH batteries.

Pros:
Greater run time. Possibly more than double, since you'll only be drawing half the amps from each bank.
Greater battery lifespan since you won't be working them as hard.

Cons:
More weight
Longer charge time.

scottyb

Correct me if I'm wrong but it looks like this will add 400 pounds to an 800 pound cart. That equals 50% more weight = increased load = more amperage used for the same propulsion?

pggroves

Don't forget the ability to stop all that extra mass.....

UncleJerm76

For me, I can live with the added charge time. I once also read somewhere that the length of cables going from battery to battery in the same bank should be identical? Is that true?

UncleJerm76

I wonder if the rear of the club car could handle it? Obviously there are spring options out there to compensate - but if its too much for the frame or the axles or the hubs then its a no go. Even worse if I ever decided to put a rear seat back there and load up with 4 adults ...I never expected twice the run time but I was expecting close to it. ...This isn't looking like too good of an idea now.

UncleJerm76

No worries about the stopping performance I would loose, its just for puttin around in the woods. BUT If I was WOT and had to stop in an emergency - that would probably rate about a 9 on the pucker-scale!!! Then I would have to factor in the cost of new underwear and fixing the giant crease that would be in my seat. If the brakes on my cart ever become an issue, I still have the disk brakes from the Honda front end I could hook back up.

UncleJerm76

<OR> Mount one of these in the rear? Less weight than doubling the batteries and with a minimum run time of 7.5 hours under full load and maximum run time of 20hrs - it should extend the run time of my current batteries to last most of the day??? It wouldn't be enough to power the cart on its own, but would be used to charge the batteries as they drain to make them last longer? Similar to the EZ-GO Exceed?

JohnnieB

All the interconnecting battery cables should be the same gauge and long enough to allow the cables to flex rather than putting stress on the battery terminals. Basically the interconnecting cables should be a curved line rather than being a straight line from post to post.

Where possible and practical, the length should be approximately the same, but more for cosmetic reasons than electrical.
The difference between a 1' 4Ga cable and a 2' 4Ga cable is only 0.0002485 Ohms, so a few inches one way or the other isn't going to matter much.

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Scottyb and pggroves brought up issues I overlooked.

Because of the added weight, the cart will draw more amps during acceleration and climbing hills. Cruising at a steady speed on level ground will also be more, but probably not much more since rolling resistance doesn't change much with a 50% change in weight

Stopping the cart will definitely be more difficult due to the increased mass.

Also, it'll be very easy to exceed the cart's max carrying capacity.

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The least complicated way to get more run-time is going to higher Amp-Hour batteries.
For example, a 6X T-105 battery pack stores 9.0 kWh of energy while a 6X T-145 battery pack stores 10.32 kWh.
That is a 14.7% increase in storage capacity with only a 60 lb gain in weight.

More along your original line of thought, two banks of three 12V (T-1275) in parallel will yield 11.94 kWh.
That's a 32.7% gain in storage capacity and 120 lb gain in weight.

Andy4639