# Gbs lfmp 100ah on golf car



## Ziggythewiz (May 16, 2010)

Lithium doesn't really have much of a peukert, that's usually left out of the equation. You can usually just times the total Wh by .6 (or .7 for max range) and divide by the Wh/mile to get a safe range that will give long life to the cells.

For lead the multiplier is more like .3 so your your 225AH comes out in between the max life and max range ratings for lithium.

What is the payload for this thing? You'd probably be losing 300 lbs in batteries.


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## gaston (Aug 18, 2009)

Ziggythewiz said:


> Lithium doesn't really have much of a peukert, that's usually left out of the equation. You can usually just times the total Wh by .6 (or .7 for max range) and divide by the Wh/mile to get a safe range that will give long life to the cells.
> 
> For lead the multiplier is more like .3 so your your 225AH comes out in between the max life and max range ratings for lithium.
> 
> What is the payload for this thing? You'd probably be losing 300 lbs in batteries.


Vehicle weights are on the link I posted but they are confusing and tricky. Total weight with battery and with accessories, no passengers is around 1700lbs. (vehicle weight around 1200 plus 8 T-105 are around 500lbs).
Load capacity is 1200lbs but sometimes it gets more weight. So total weight to be moved is around 2500 to 2900lbs.
The advertised (not in web site) range is 24miles on a single charge, but of course that is a lot less when climbing hills with lot of passengers and depending battery performance, perhaps less than half range without loosing torque.

There will be a lose on battery weight of total 360lbs (lead acid 496lbs, versus Lithium around 135lbs for the 4 batteries (16cells)), that's a lot, of course, but given the steep and long incline the vehicle must climb, it is always energy demanding.

How about BMS?

Thanks for your input!


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## Ziggythewiz (May 16, 2010)

If you balance your batteries properly, and have some decent monitoring you don't need a BMS. Do you know how many amps you currently pull? Max for 10 seconds? 30 seconds? Average? 

If you're upgrading the controller you'll probably need more than the 100 ah lithiums.


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## Yabert (Feb 7, 2010)

gaston said:


> How about BMS?


If you don't want to care about battery monitoring, I would suggest you this BMS http://minibms.mybigcommerce.com/products/MiniBMS-16-cell-Master-Board.html
Simple and work very well!


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## dougingraham (Jul 26, 2011)

gaston said:


> I have a set of 4 batteries GBS-LFMP100AH (totaling 16 cells) to make a 48v pack and the seller of batteries, which I will not mention, promised this will increase the range of the following vehicle I will give details below.
> According to simple logic based on all the information about Li-Ion batteries, and having in mind Peukert effect, I presume the range of the vehicle will actually decrease.
> 
> Also it has been advised that no BMS is needed, and I disagree with this since we are talking of 16 cells system that will eventually need charge balancing.
> ...


Ignoring the fact that to get any life at all out of lead you should discharge to no more than half, the Peukert effect will reduce your Trojan batteries to about 135AH equivalent. Lead Acid batteries generally sag more than lithium and that is most likely true here as well. When pulling high currents the battery current will have to be a higher with lead to obtain the same power because of the voltage sag. The other contributing factor is the weight. In a hilly area the extra weight of the Lead batteries are going to kill your range. 496 lbs of lead vs 112 lbs of lithium is a difference in weight of two to three people.

I would estimate an overall increase in usable range of perhaps 20%.

You really dont need a BMS. Just a charger that will cut off at the proper voltage. For your 16 cells this would be somewhere between 56 and 57 volts. LiFePo4 cells do not drift out of balance unless some outside influence causes it to do so, like a BMS. Once in balance they will stay there. I suggest a bottom balance and then charge to about 56 volts. Check with a DVM weekly until you grow bored with seeing no change in balance. Then switch to monthly until you forget to do it and then don't worry about it. There is nothing wrong with the idea of a BMS, but the implementation is tricky. To do it correctly the BMS cannot power itself off of the cell. It cannot load the cells at all.

Best Wishes!


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