lithium compared to 6 V golf cart

[nova]

how do I figure the number of 100AH to multiple 6V paired GC batteries = 12volts

say 4 6v
6 6v

I was thinking two would give the same power capacity as 6 in double series 6volt is that correct?

[SunEagle]

I am not sure what your question is.

I will say that 2 x 6V 100Ah batteries wired in series will get you a 12v 100Ah system

If you took 2 of those 12V systems and wired them in parallel you would get a 12V 200Ah system.

Voltage adds when wired in series and Amphours add when wired in parallel. So 6 x 6V 100Ah batteries can be wired to get you a 12V 300Ah system.

[nova]

But since they are more efficient isn't 12 volt 100Ah lith like having more than 100 Ah wet cell?
If so I would think I could have fewer
In other words 6 6volt GC wet cell be replaced with 2 rather than 3 12v 100ah lit

[SunEagle]

But since they are more efficient isn't 12 volt 100Ah lith like having more than 100 Ah wet cell?
If so I would think I could have fewer
In other words 6 6volt GC wet cell be replaced with 2 rather than 3 12v 100ah lit

You will be able to drain a lithium battery much lower then an FLA type. The problem is the cost of most Li chemistry batteries is much higher then FLA. You have to compare the cost to the number of cycles and depth of each cycle to see which is a better solution.

[Ampster]

In addition Lithium batteries are more efficient than Lead Acid chemistries. They also don't lose their charge as fast as Lead Acid. Depending how you charge them that cost can be figured into the life cycle cost.

[robeyw]

LiFePO4 VS PB golf cart is a good question and there is a lot of price variation in each class. I purchased 8 240AH LFP cells for a delivered price of $1400 and 186 AH Exide golf cart batteries for $70 each. I don't expect the $70 batteries to perform like those that cost twice as much but my idea is to combine the high cycle life advantage of LFP with the lower KWH cost of Pb. Whether or not this is a good choice depends on their calendar life. I have had 10 years from the Exide batteries in backup service and expect the LFP cells to be serviceable at reduced capacity in 20 years. Another thing to consider is the maintenance of the Pb cells and coordination of the 2 types. I have to use the LFP battery to fully charge the Pb cells monthly to try to avoid long term sulfation. If I was using Pb only, I would have to be able to break it into 2 parts and use one to charge the other overnight which would mean doing the operation twice as often. If the predictions of a price drop for LFP prove correct, the Pb cells will be replaced with LFP at the end of their life.

[Mike90250]

cycling batteries to charge other batteries is a unusual strategy. Why not simply purchase enough watt hours of the lead acid and forgo the problems of managing 2 incompatible chemistries from 2 different solar arrays & charge controllers. Then you have the issue of managing the charge from a 15V Li battery to charge a 12V FLA battery. (a 12v battery cannot charge another 12v battery) The complications are enough to drive me mad, and I like convoluted stuff.

[robeyw]

cycling batteries to charge other batteries is a unusual strategy. Why not simply purchase enough watt hours of the lead acid and forgo the problems of managing 2 incompatible chemistries from 2 different solar arrays & charge controllers. Then you have the issue of managing the charge from a 15V Li battery to charge a 12V FLA battery.

The problem with Pb cells is that they are slow to charge and when not fully charged, the sulfate crystals consolidate and become hard to convert back to a charged state so charging from time to time for much longer than the sun will shine is required. A good question is "Why not simply purchase enough watt hours of the lithium and forgo the problems..." and I explained that. There is one solar array and one charge controller and the lithium battery carries the load until it is too discharged then the lead battery takes the load. A sub-optimum but simple interconnect for the 2 batteries is shown in https://www.solarpaneltalk.com/forum...and-care/page5 post dated 11-28-2019. A simple fly-back power supply will boost the voltage from one battery to charge another efficiently.