What Are Advantages of 72v AC???

[Gregorio]

Originally Posted by Revolution

The higher voltage does not mean higher power. The little motor in your vacuum cleaner runs on 120 volts, but it won't even make a golf cart roll.

That is not exactly a fair comparison.

[konakid]

Thanks again for everyone's time to share such info - it is interesting.

One question that I didn't ask, but was hoping to get insight into, has (I think) been answered. That is - why was the controller in my new 72v system of lower amperage than what I was reading here that many were upgrading to. If I have been reading correctly, AC does not need these very large amp controllers to supply adequate power - correct?

When I was mentioning maintenance as a possible downside of the larger AC systems, I was thinking also of batteries. First - with having to replace more batteries periodically - but I was also wondering if there were any differences in actual battery life and/or differences or concerns in the actual maintenance of the batteries.

[Gregorio]

Originally Posted by konakid

One question that I didn't ask, but was hoping to get insight into, has (I think) been answered. That is - why was the controller in my new 72v system of lower amperage than what I was reading here that many were upgrading to. If I have been reading correctly, AC does not need these very large amp controllers to supply adequate power - correct?

When I was mentioning maintenance as a possible downside of the larger AC systems, I was thinking also of batteries. First - with having to replace more batteries periodically - but I was also wondering if there were any differences in actual battery life and/or differences or concerns in the actual maintenance of the batteries.

Back to my original statement of VOLTS x AMPS = WATTS. Higher voltage does not need as many amps to achieve the desired wattage or power level.

I don't think AC or DC has any bearing on battery maintenance except that AC might be slightly more efficient but higher voltage typically means more batteries. That could be a slightly bigger cost factor. However, similarly sized (physical, not AH) 6x12v are roughly the same or sometimes LESS than 6x8v.

[HiTechRedNeck]

72v = more holes to put water in

[Gregorio]

Originally Posted by HiTechRedNeck

72v = more holes to put water in

[konakid]

Originally Posted by Gregorio

I don't think AC or DC has any bearing on battery maintenance except that AC might be slightly more efficient but higher voltage typically means more batteries. That could be a slightly bigger cost factor. However, similarly sized (physical, not AH) 6x12v are roughly the same or sometimes LESS than 6x8v.

Yeah - regarding the vehicle I just ordered, I was curious as to why they used 9x8v batteries instead of 6x12v. Was there a reason for that? When I do eventually need to replace them - should/could I go that route? If I can easily fit them, of course.

[HiTechRedNeck]

Simplifying again--

More lead = more run time.
8v batts seem to last longer as far as run time and years of service.
In RXV's 6 year old 12v's are rare. 6 year old 6 & 8's are common in TXT's.

Probably a good batt configuration to stick with.

JohnieB is resident battery guru-- he can provide AH charts and stuff for 8v vs 12v.
He is best source around for batt configuration info.

[JohnnieB]

Originally Posted by konakid

Yeah - regarding the vehicle I just ordered, I was curious as to why they used 9x8v batteries instead of 6x12v. Was there a reason for that? When I do eventually need to replace them - should/could I go that route? If I can easily fit them, of course.

From a business point of view, the fundamental reason is profit margin.
Fewer battery failure during warranty period and a greater driving range to advertise.

From an engineering point of view, it is Storage Capacity.

A lead-acid battery pack is made up of 2V cells. A 36V pack has 18 cells connected series, 24 cells make a 48V pack and it takes 36 2-volt cells to make a 72V battery pack.

The cells typically come packed 3, 4 or 6 to a box and are called 6V, 8V and 12V batteries. Since the boxes (battery cases) used all have roughly the same height, width and length, to pack a greater number of cells in the same sized box, you have to use smaller cells, which have less storage capacity.

Attached is a chart comparing the kWh of storage (and weight) for 72V packs made up from various Trojan 8V and 12V batteries.

In a nutshell, the higher the kWh of storage, the further the cart can be driven on a single charge and the longer the batteries will last before they need to be replaced.

[konakid]

Thanks for all the great info guys.

My curiosity always gets satisfied when I post here.