EV tuktuk batteries

[Superflan]

Hi,

I'm helping on a project but more the time passes by, more I have doubt about the way I'm going.

Vehicles are tuktuk-factory "eTuk", 7 seats version. Batteries are worn, not all the same in packs, therefore to be replaced.

The factory batteries are presumably Trojan T-105, but I can see some are fitted with T-145, which are same size but higher.

viewed from up above, the batteries are in this arrangement :

Code


+-------+-------+-------+

| - + | - + | - + |

+-------+-------+-------+

| - + | - + | - + |

+-------+-------+-------+

| - + | - + | - + |

+-------+-------+-------+

| - + | - + | - + |

+-------+-------+-------+


Electrically, they are in series, making a 72v battery pack.

I'm planning fitting some Yuasa DCB105-6 (or 125, or 145) in place of those batteries, but I'm wondering why those are marked as "semi-traction" by some vendors, where Trojan T-105 batteries are labeled as "traction". As I understand, both are same construction/technology inside, and both deep cycle ? Yuasa costs half the price of Trojan.

Could I research and fit some 8V (9 of them) or 12V (6 of them) if they physically fits ?

I understand I'll surely have to give up the factory mounted watering kit (nice one though) if I go away from Trojan's batteries.

 

[ragtoplvr]

All your lead acid batteries in a series arrangement (what you have) need to be the same size, age and brand. If not here is what happens, as you discharge some run down first, and current is still forced thru them They charge up backwards. This damages them and they short out, very short life.

They all should be recharged completely before put into the battery pack. The vendor should do this, but in a third world country this seldom happens. All the connection should be clean and tight.

Second thing is deep discharge (like running until it will not move) shortens the life of the batteries. They might only last 100 cycles where if you only ran them down halfway before charging, they might last 1000 cycles. Trojan batteries (here ) are good quality, and so is Yuasa I would get the largest capacity rated (145) rated for traction use, (check with Yuasa do not trust vendor) Then try not to run them down. Do not overwater. Just over the plates before charge or just touching the ring after charge. If they are spitting out acid, your charge current is too high, charge voltage too high or charge time too long. All those things shorten the life. So try to avoid running them down until it does not move. A cheap voltmeter can be useful to check the charger, they do fail on occasion. The battery maker will tell you recommended voltages to charge.

As long as all the same brand, age, size 6V, 8V or 12V will not matter. 8V individual chargers are less common.

Good luck

 

[Superflan]

Thanks for you insight.

What bothers me about 105 vs 125 vs 145 is that the 105 and 125 are the same physical dimension, even weight is very close, so I don't know if going for 125 models instead of 105 means that I'll be getting less robust products. However, going for 145 models which are only a little higher, doesn't inspire me much.
The other thing is the cost for a consumable that will not last eternally:

160€ per unit for the DCB105-6, 220 for the 125, and 280 for the 145. This brings me to 2000€, 2700, or 3400€ for the bigger ones.

What 6v charger would you recommend? Do you trust single point watering kits ?

 

[ragtoplvr]

adjustable voltage/ current limited lab supply is what I use, they are quite inexpensive these days and you can charge everything from a motorcycle battery to a truck battery (slowly) . You need a bulk charger for the entire string, I assume you have that

Rod

 

[Superflan]

The bulk charger is bolted onto the vehicle, it's a Delta-Q Technologies QuiQ 1500 ; 72V 20A output :

https://delta-q.com/product/quiq-1500-industrial-battery-charger/

For the individual 6V battery charger, my understanding is I need something like a current lab supply, or a deep cycle automatic charger capable of handling big 200+ A batteries (and I have trouble figuring such chargers).

 

[ragtoplvr]

What is the standard voltage and current there. I said Lab supply becasue it can charge 6,8 12V something that is hard to find otherwise. They are also not as sensitive to voltage in variations. Many of them work on anything from 90 to 277 Volts.

Can you get chargers from anywhere. If you are never going to use the 8V batteries then any common 10 amp 6/12 volt charger will work well. as long as designed your your islands voltage.

Rod

 

[Superflan]

Rod, thanks again for your help.

Our mains is 230VAC, 50Hz.

My concern about chargers is that when I was using CTEK chargers with 12V batteries exceeding the max battery capacity specified for the charger, it seemed to never end. I thought it would just take more time, but no, it ran forever in charge mode and didn't switch to trickle. Those did this with many different starter batteries that were bigger than the charger rated.

For sure I'd prefer a switched than a linear power supply in the future 6v charger I'm looking for, but I understand it could cost a lot if I'm looking for a 25A 6V charger or something (I looked at the recommended charge profiles from Yuasa).

Here's for the DCB105-6:

Phase 1 (Constant-current)
constant current charge at 22.5~29.3 amperes until the
battery voltage measures between 7.14~7.29V/Battery
(25°C) on charge voltage.
Phase 2 (Constant-voltage)
constant voltage charge at 7.14~7.29V/Battery (25°C)
until the current measures between 2.25~6.75 amperes.
Phase 3 (Constant-current)
constant current charge at 2.25~6.75 amperes until the
battery voltage measures between 7.5~8.1V/Battery
(25°C) or until dV/dt reaches to less than 0.035.
*END OF CHARGE at 110~120% of AH returned.
*Note: Charging condition (Voltage, Current, Time) will vary depending on battery size, charger
(Charging Type, Output) depth of discharge and temperature.

 

[ragtoplvr]

Are you planning on doing all your charging using the 72 volt charger? Then the 6V charger would only be used to charge the batteries before first use. The 72 volt charger should keep the batteries equalized and charged with minimum water use. Use distilled water.

If so than any charger will work, you just need to do an initial 24 hour charge, then you should never need to do it again.

That charger can any brand.

 

[Superflan]

Yep, 6V for initial setup before putting batteries in the vehicle and then using the onboard 72v charger.

I'd like to find a 3-step 6v charger than can handle those 200A batteries.

 

[Rmay635703]

T105's give best lifespan/bang for buck
T145's give the most capacity but at a much higher cost per cycle
T125's are close to t105's but higher capacity and sometimes a better deal depending on the market

T875's (8 volt) are decent batteries if you don't need much runtime but aren't usually a good value in $/capacity

 

[Cujet]

Just looking at the Trojan website, I'm amazed that the T105 weighs just over 60 pounds and has 1.1KWH capacity at the 5 hour rate.

Their lithium battery is just under half the weight by KWH capacity. I had thought it would be much lighter.