12v vs 6v batt experts fire away

[3WheelDumbo]

I know, not again.... In all the dumb questions I ask this one is a little different. I'm not talking about 12v auto batts or marine batts. I found a pretty good deal on Trojan T1260 they are a year old and roughly 90% SOC. If I got these to replace the 6 6v interstate batts that are about 68% SOC would I notice a huge differance?? Also wondering what kind of run time I would get our of it under average conditions (I know, hills etc effect time) These would be used in an 88 marathon resistor cart. I can get four of these, use 3 for the 36v drive and one for the 12v acc. or..... load all 4 on the drive and get a 48v charger... hmmm

Or should I just wait and suck it up and buy 6 6v. The deal is I can get 4 of these for 300.00 instead of 600 to 800 on the 6v. Battery experts fire away..

[rib33024]

A cart was not meant to run on 3 12v batteries, it will but it will not have a long run time,, here's some info, the search will answer most of your questions



http://www.buggiesgonewild.com/searc...RID%3A11&hl=en

[sportcoupe]

The T1260 are only 140AH on their best day which is just over half a normal set of 6-6v T105's are so you could only expect 1/2 the run time of a normal 6-6v cart.

[tyhuck]

I have seen several 48v carts that have 12v batteries instead of 6v, and per their website Badboy Buggies run on 6 12v batteries, but again these aren't the marine type.

[3WheelDumbo]

OK, just for the question to be asked....what about 6 12v with 3 being in parrallel with 3 more? This would give you the 36v but provide more lead, the current draw should be split between the two sets of 3 batts effectively reducing the draw or providing additional resource when leaded (under load). True or Theory????????

[scottyb]

1 year old batteries that reach only 90% SOC have been damaged and there is no guaranty you will get any kind of useful life from them even if you could live with the reduced run time. (3/12v hold considerably less amperage than 6/6v) Ask the seller to charge em up to 63v and let them sit for 24 hours, then check the voltage. It should read very close to 50.9
If not keep looking.

[JohnnieB]

Originally Posted by 3WheelDumbo

OK, just for the question to be asked....what about 6 12v with 3 being in parrallel with 3 more? This would give you the 36v but provide more lead, the current draw should be split between the two sets of 3 batts effectively reducing the draw or providing additional resource when leaded (under load). True or Theory????????

I meant to respond earlier, but SWMBO (She Who Must Be Obeyed) intervened with a "Honey-Do" list.

It is true in both theory and fact.
Here is a comparison of 36V battery packs made up of various Trojan deep-cycle batteries commonly used in golf carts.

And here is a cut&paste from the Trojan Battery user guide on the subject.

Basically you can get more AH's but you are still at 36V and higher voltages are more efficient.

[3WheelDumbo]

Thanks Johnnie....

I think that's what I'm looking for.... was trying to figure out how to increase run time (AH) on this old marathon. It's a resistor cart so it eats AH, I actually enjoy the slow mellow speed of the cart and don't need it to be faster, and it has plenty of power with my wife and grandson on the cart with me so I'm good with the 36v. Sounds like I'll be running 12's when I get to new batteries.

Brings up another question, would the charts for SOC remain the same since the voltage would remain the same?? I would think it would change because the SOC is also based on capacity correct?

****, I need a tin hat my brain is starting to hurt..

[JohnnieB]

The cost of 6 12V deep cycle batteries is going to be higher than the cost of 6 6V batteries, so your overall operating expense will probably go up since the increase in run-time, battery lifespan, etc. is only about 20% to 30%.

However, to answer the question about voltage vs Soc, it will stay the same.

The SoC is the percentage of the AH capacity remaining stored in the battery.

When the at-rest voltage is 37.5V (80% SoC) a 100AH battery has 80AH left in it, a 200AH battery has 160AH left in it and a 300AH battery has 240AH left in it, etc. etc. etc.

-----
Food for thought.

Apparently, you and yours like the low speed of a resistor cart. (Which is a good thing since it is a three-wheeler.)

In a series wound motor, max speed is determined by pack voltage and with a resistor cart with the pedal pushed to speed 4, full pack voltage is applied to the motor, so assuming the high current cables and connections are in good condition, the top speed you have now is all the top speed you will get, unless you change the final drive ratio (Tires height and/or differential gear ratio).

I'm not sure if your cart can be converted to a controller type drive, but if it can, it will be far more efficient and you can get much longer run-times form a standard 6 x6V battery pack.

If interested, give Scotty a call and let him know what your wants and desires are.
http://www.cartsunlimited.net/Scotty...rsion_Kit.html

[3WheelDumbo]

Thanks guys, ya'll have helped alot since I got this thing a few weeks ago. Not real sure what direction it will take. Right now I'm two weeks out from our local rally where it will get abused for sure, then I'll have a whole year to work out what to do. I'll look at the cost to benefit ratio after ROT Rally and determine. If I upgrade the controller I will definately give Scotty a shout, just on a budget till then.

Thanks again to everyone for all the input on my dumb questions.