would you stay 36 or go 42? my dilemna

[JohnnieB]

Originally Posted by porthole

36 or 48
48 - 6 x 8 or 8 x 6

I can see the obvious improvement of jumping to 48 with a TXT.
But when going to 48, and assuming you know you will be buying a charger, already have a capable controller, solenoids, cabling etc, How do you decide between the 6 or 8 battery combos?

Our cart is mostly used for camping trips for my wife to get around. Figuring we usually have no issue charging it each day, and I doubt it gets more then a mile or 2 miles of use, doe sit really pay to try and squeeze in the 2 extra batteries using the 6's?

Will torque be the same? We do at least one trip a year that has an approximate 6 degree 1/4 mile long hill that we hit at least twice a day for 5 days or so.

Overall cost is something to factor in too for me.
Aside from the charger which is a given, if I go with 8 -6's I can run my pricey HD solenoids (also have the reversing solenoid) off of 6 batteries.

So, 8 x 6 = $$$, use my solenoids
6 x 8 = $$$, buy new solenoids.

Speed is not that big of an issue for us. But some extra torque sure would help just getting it into my toy hauler.
Given occasional use which is better in the long run?

If I understand the situation correctly, you've got a TXT with a series motor, aftermarket controller and solenoid, the F/R switch has been replaced with a F/R relay set-up and it is currently running on a 36V battery pack.

Correct me if I am wrong, but it doesn't sound like you are having range (run-time) or speed issues, but you want a bit more torque occasionally.

A 48V pack made up from six 170AH batteries (IE: Trojan T-875 or similar) will give you roughly the same run-time and battery lifespan as the standard 36V pack made up from six 225AH 6V batteries.
Using Higher AH 8V batteries will give you a longer run-time and lifespan.
Attached is a list of 8V batteries sorted by AH and then alphabetically by brand name.

A 48V pack made up of eight 6V batteries will give you the longest run-time and lifespan, but stashing all of them under the seat is difficult and putting two in the bagwell may not be feasible. Also, the two additional batteries will add about 120 to 150 pounds of weight to the cart, so it will be like carrying an extra passenger all the time.

Either the 6x8V or the 8x6V will give you the same torque (and speed). The 6x8V just won't do it for as long.

Check the actual specs on your main solenoid and reversing relays, they just might operate at 48V.
If not, you can add a resistor or 12V lightbulb in series with the coils to reduce the 48V down to the 36V range. (You'll have to measure the amps they draw at 36V to figure out what size resistor or which bulb to use)

Tapping the battery pack for a lesser voltage is a bad idea. It imbalances the pack, which in turn reduces lifespan.

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I was looking for range rather than speed or torque, and I'm lazy, so I'm going with with seven 6V batteries (42V), which fits under the seat with minimal effort.

Might work well for your application also. (Food for thought)

[yurtle]

Originally Posted by JohnnieB

A 48V pack made up of eight 6V batteries will give you the longest run-time and lifespan, but stashing all of them under the seat is difficult and putting two in the bagwell may not be feasible.

I was looking for range rather than speed or torque, and I'm lazy, so I'm going with with seven 6V batteries (42V), which fits under the seat with minimal effort.

You can always install one under the seat and one in the bagwell, which leaves some usable space there.

[flharleycop]

Originally Posted by JohnnieB

If I understand the situation correctly, you've got a TXT with a series motor, aftermarket controller and solenoid, the F/R switch has been replaced with a F/R relay set-up and it is currently running on a 36V battery pack.

Correct me if I am wrong, but it doesn't sound like you are having range (run-time) or speed issues, but you want a bit more torque occasionally.

A 48V pack made up of eight 6V batteries will give you the longest run-time and lifespan, but stashing all of them under the seat is difficult and putting two in the bagwell may not be feasible. Also, the two additional batteries will add about 120 to 150 pounds of weight to the cart, so it will be like carrying an extra passenger all the time.

Either the 6x8V or the 8x6V will give you the same torque (and speed). The 6x8V just won't do it for as long.

Check the actual specs on your main solenoid and reversing relays, they just might operate at 48V.
If not, you can add a resistor or 12V lightbulb in series with the coils to reduce the 48V down to the 36V range. (You'll have to measure th

--------

Might work well for your application also. (Food for thought)

JohnieB how do you charge the 42v system you have? Will the 36v charger work or is there a fix for it?

[JohnnieB]

Originally Posted by flharleycop

JohnieB how do you charge the 42v system you have? Will the 36v charger work or is there a fix for it?

A 36V charger won't fully charge a 42V battery pack and there is no fix that I know of.

I use a 42V DPI Accusense Charger. Scottyb sell them for the same price in 36V, 42V and 48V.
http://www.cartsunlimited.net/48v_Battery_Charger.html

[flharleycop]

Originally Posted by JohnnieB

A 36V charger won't fully charge a 42V battery pack and there is no fix that I know of.

I use a 42V DPI Accusense Charger. Scottyb sell them for the same price in 36V, 42V and 48V.
http://www.cartsunlimited.net/48v_Battery_Charger.html

Is that variable or once you do 42v if you want a 48 you have to buy another one? Also if I read that correct this one has a trickle charge once the charger stops so it would be a good choice for leaving cart on charge when not being used?

[JohnnieB]

Originally Posted by flharleycop

Is that variable or once you do 42v if you want a 48 you have to buy another one? Also if I read that correct this one has a trickle charge once the charger stops so it would be a good choice for leaving cart on charge when not being used?

I posed similar questions to DPI a while back.

The difference between their 42V and 48V Accusense chargers is the the control board (and the labeling).

My original question was about upping the 36V DPI I already had to 42V by changing the control board.
(All that is inside the case is a transformer, control board and an ammeter)
I was told that wouldn't work because the transformer used in their 36V charger won't put out a high enough voltage to charge a 42V battery pack, but their 42V and 48V chargers both used the same transformer.

So, it appears the my 42V DPI charger can be converted to a 48V charger by replacing the 42V control board with a 48V control board, which costs about $130, or a little less than half the price of a new charger.

------------
Actually, the DPI goes into "Float" charge at the end of the regular charge cycle, which is very different than "Trickle" charge.

Trickle charge is either constant current, current limited, or completely unregulated low current.
There are some variables, but a trickle charge can allow the cell voltage to climb into the gassing range and expose the plates if the fluid level isn't closely watched.

On the other hand, a Float charge is voltage regulated at a constant voltage that is above the At-Rest voltage (2.122VPC), but below the gassing voltage (2.35VPC) and the current varies to offset the self discharge rate and parasitic loading.

In the Trojan battery mode, the DPI floats at 2.19VPC, for Exide it is 2.20VPC and for US Battery it is 2.21VPC.

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Basically, the DPI charger is plugged into my cart when I'm not using it and whenever I go someplace on it, I start my trip with a "fully" charged battery pack.

Or at least as fully charged as "L9" (Dec-2009) T-105 batteries that would only charge to 85% SoC when I got them, can be.
It took a couple months of judicious "Overcharging" (no snake oils, just distilled water and battery chargers) to get them to take a 95% charge and the last time I checked, they were holding 97% SoC after a 28 hour rest.

My cart (stock PDS with 2Ga cables and 18.3" tires) uses about 4.5AH per mile in Mild-Hill mode on the 8-10 mile trips I routinely take, which gives me a theoretical range of a bit over 20 miles staying above 50% SoC, but I wanted around 30 miles with a fudge factor for battery aging, so I went with seven 245AH batteries. I'm not sure what the range will be when I get it put together, but if it isn't enough, I'll probably add an eighth 245AH battery and change the control board in my 42V charger.

[flharleycop]

Originally Posted by JohnnieB

I posed similar questions to DPI a while back.

The difference between their 42V and 48V Accusense chargers is the the control board (and the labeling).

My original question was about upping the 36V DPI I already had to 42V by changing the control board.
(All that is inside the case is a transformer, control board and an ammeter)
I was told that wouldn't work because the transformer used in their 36V charger won't put out a high enough voltage to charge a 42V battery pack, but their 42V and 48V chargers both used the same transformer.

So, it appears the my 42V DPI charger can be converted to a 48V charger by replacing the 42V control board with a 48V control board, which costs about $130, or a little less than half the price of a new charger.

------------
Actually, the DPI goes into "Float" charge at the end of the regular charge cycle, which is very different than "Trickle" charge.

Trickle charge is either constant current, current limited, or completely unregulated low current.
There are some variables, but a trickle charge can allow the cell voltage to climb into the gassing range and expose the plates if the fluid level isn't closely watched.

On the other hand, a Float charge is voltage regulated at a constant voltage that is above the At-Rest voltage (2.122VPC), but below the gassing voltage (2.35VPC) and the current varies to offset the self discharge rate and parasitic loading.

In the Trojan battery mode, the DPI floats at 2.19VPC, for Exide it is 2.20VPC and for US Battery it is 2.21VPC.

----------
Basically, the DPI charger is plugged into my cart when I'm not using it and whenever I go someplace on it, I start my trip with a "fully" charged battery pack.

Or at least as fully charged as "L9" (Dec-2009) T-105 batteries that would only charge to 85% SoC when I got them, can be.
It took a couple months of judicious "Overcharging" (no snake oils, just distilled water and battery chargers) to get them to take a 95% charge and the last time I checked, they were holding 97% SoC after a 28 hour rest.

My cart (stock PDS with 2Ga cables and 18.3" tires) uses about 4.5AH per mile in Mild-Hill mode on the 8-10 mile trips I routinely take, which gives me a theoretical range of a bit over 20 miles staying above 50% SoC, but I wanted around 30 miles with a fudge factor for battery aging, so I went with seven 245AH batteries. I'm not sure what the range will be when I get it put together, but if it isn't enough, I'll probably add an eighth 245AH battery and change the control board in my 42V charger.

Thanks for the information, I am going to first get my registration process finished and then look at the controller upgrade from ScottyB package. I am still on the sidelines because it seems there are a few doing it now and not seeing the returns they expected. My current stock ST Sport 2+2 36v is getting between 17-19 depending on wind, sun, bugs whatever but its pretty consistent at 18 and the range seems really good. I have the 22 tires but in one of your post you talked about tire pressure eating up speed. My tires pressure at a max of 10 and I am running 14 to get what I get now. If I had known I would of searched for higher pressure tires but I am a new to this and did what until I knew more. I would like to see 25 mph but anything less than that doesn’t seem to be worth the bucks for the upgrade. Thanks for your help.

[yurtle]

I assume one could buy a 48 volt DPI charger and use resistance to make it 42 volts, until the upgrade?

[JohnnieB]

Originally Posted by yurtle

I assume one could buy a 48 volt DPI charger and use resistance to make it 42 volts, until the upgrade?

The charge sequence for the DPI is a low current (~5A) until the on-charge voltage reaches a predetermined VPC (Volts per Cell), then goes into a constant current mode at about 18A until voltage reaches from 2.35VPC to 2.50VPC (Depending on which battery brand is selected) and switches to a constant voltage at that VPC until the dV/dT criteria for the battery brand is reached. After the regular charge cycle completes, it goes into a float charge mode that varies from 2.19VPC to 2.21VPC depending on brand.

I'm not sure a fixed resistor could fool 48V DPI into charging a 42V battery pack without adverse side effects.
Might be able to do it with a 6V incandescent light bulb, but it would have to pass 18A, which would be about 108W.

[yurtle]

Your probably right. The charger has to see a minimum voltage to even cut on, so it would initially see less than 42 volts with a fixed resistance. It would also need to slowly reduce the resistance, to simulate a battery coming up to charge. Maybe just buying a new board is the best.