new Lithium Batteries but cart lasts 5min

[dksochan]

I have a 2006 ezgo txt pds drive cart lifted 6” and 12.5 “ tires i just put 3 new lithium ion batteries in rated at 12v and 40 Ah in series... allied has 3 12v 50Ah as a package....I thought 40 Ah wiuld not be a big change from their package....My accessories are on a seperate 12v supply charged seperate..what happens is I have a full charge of 40.8 pack volts ....I take the cart less than a half mile and it is dead no movement...I went through the wiring and made sure everything is exact as the carts schematic... why is it dead to many amps and the BMS shuts them down...because I put it on the chargers(3seperate) and immediately back up to pack voltage and it goes another half mile and dies...not sure at all why???

[JohnnieB]

The standard Lead-acid battery pack for a 36V PDS cart stores roughly 8.6kWh of energy (225AH X 38.2V when fully charged = 8595Wh) and you are trying to run it with a battery pack that holds 1.63kWh of energy. (40.8V X 40AH = 1632Wh), or 18.98% of the stored energy.

Plus, you mentioned the cart has a 6" lift. That typically means a tire height of 23" or so, which reduces the torque by 22% which in turn cause the cart to use more energy to move, further reducing the range.

Bottom line: Too much load for too little storage capacity.

[Pat911]

It’s not the storage capacity that’s the problem, It’s the maximum current. I couldn’t find full specs on your battery but I doubt that your 40aH pack can supply the continuous current required to run your cart. Most Lifepo4 packs can only supply 1C continuously, that’s 40A. Even if it’s rated at 2C then it’s still only 80A continuous.

So, one of your BMS’s is shutting down on high current and plugging it back into the charger wakes it up again instantly, hence the ability to go a few more minutes before shutting down again. The only fix is to get a pack with a higher discharge current rating. You could get another 3 batteries and put them in parallel but then you have 6 BMS’s all doing their own thing, very messy.

Putting series connected 12v lithium batteries in a golf cart is not good practice, you should get a single pack with the voltage you require so that there is only one BMS controlling it.

Cheers
Pat.

[Hottdoggin]

Originally Posted by Pat911

It’s not the storage capacity that’s the problem, It’s the maximum current. I couldn’t find full specs on your battery but I doubt that your 40aH pack can supply the continuous current required to run your cart. Most Lifepo4 packs can only supply 1C continuously, that’s 40A. Even if it’s rated at 2C then it’s still only 80A continuous.

So, one of your BMS’s is shutting down on high current and plugging it back into the charger wakes it up again instantly, hence the ability to go a few more minutes before shutting down again. The only fix is to get a pack with a higher discharge current rating. You could get another 3 batteries and put them in parallel but then you have 6 BMS’s all doing their own thing, very messy.

Putting series connected 12v lithium batteries in a golf cart is not good practice, you should get a single pack with the voltage you require so that there is only one BMS controlling it.

Cheers
Pat.

100%

[dksochan]

Thank you very much for telling me what exactly I was thinking..Just recently dove way into my research on batteries and it all makes sense now ... i just went back to 6 6volt 225 Ah batteries...the correct Lithium Ion package is a 36v 100Ah minimum.. and at 3400$ will just keep the cart going along correctly Thanks again all of you👍👍👍

[Briboy]

What Brand Batteries are the ones that have failed?

[ojo]

He wrote Allied...?

[Briboy]

Originally Posted by dksochan

i just put 3 new lithium ion batteries in rated at 12v and 40 Ah in series... allied has 3 12v 50Ah as a package....I thought 40 Ah wiuld not be a big change from their package....

The OP compared what he used to Allied.

I have 4 Allied 12v 50ah and my cart is fine. I get 15 to 20 miles per charge with this set up, Lots of torque and plenty of speed. 0 Issues.

[Pat911]

Hi Briboy,

The battery didn’t fail, it just didn’t have the required continuous current supply required for his cart and as a result, one of the BMS’s shut down on high current.

His cart is a 36v cart, which will draw more current than your 48v cart, everything else being equal. His batteries are only 40aH, less than your 50aH ones and he’s running larger wheels. A tripple whammy. I bet his peak current is well over 100 Amps with continuous current on flat ground being around 50-70 amps. Never stood a chance.

Cheers
Pat.

[Briboy]

I understand what is happening, My question was more about what brand/style of battery used so others don't waste time and money trying to get away with an upgrade that will never work.
Being Cart parts can get expensive quickly (and me being Cheep and very capable) I am one of those people who always shops around and looks for alternative solutions, many times I shopped Lithium alternatives until I got a deal that fit my budget.
So the question still stands,
Were these a Name Brand?
Were they a cheep set of E-bike batteries off eBay/Amazon?
What were they?
So we don't make the same mistake.