# In defense of Lead!



## ken wont (Jul 6, 2016)

If your trips are less than 10 miles .. Lead is fine.

If you don't want to spend $$$$ on a fancy-antsy super-duper BMS .. Lead is fine.

If you don't want to spend $$$$ on a fancy-antsy super-duper battery charger .. Lead is fine.

If you are new to EVs and overwhelmed by all the high-tech stuff you need to learn .. Lead is fine.

If you are planing on eventually up grading to Lithium and moving the Lead to your solar and\or wind battery bank .. Lead is fine.


----------



## tawma1100 (Jun 23, 2016)

This is ga2500ev. I lost my login in the purge.

There is no defense for lead. Let's take them one at a time:



ken wont said:


> If your trips are less than 10 miles .. Lead is fine.


That's just an unreasonably low range for anything other than a toy vehicle.


> If you don't want to spend $$$$ on a fancy-antsy super-duper BMS .. Lead is fine.


A BMS is only required if there is a need to extract every every available watt of capacity from the pack because a BMS either burns of redistributes energy from fully charged cells to less than fully charged ones.

But if one simply doesn't overcharge any cell, then a BMS is completely unnecessary.

Now cell monitoring is another matter. However there are cell monitors/alarms for batteries up to 8S via the balance plug that are less than $5 USD each. They are all over EBay.


> If you don't want to spend $$$$ on a fancy-antsy super-duper battery charger .. Lead is fine.


A complex charger isn't required. Lithium can be bulk charged. Also balance charging can be done one cell at a time. The money comes into play to replace manual simplicity with automation.


> If you are new to EVs and overwhelmed by all the high-tech stuff you need to learn .. Lead is fine.


Somehow you seem to be intimating that there is some inherent simplicity with lead acid that doesn't exist with lithium. With both chemistries the rules are exactly the same:

1. Don't overcharge
2. Don't overdischarge
3. Use monitors, cutoffs and alarms to make sure 1 and 2 are enforced.


> If you are planing on eventually up grading to Lithium and moving the Lead to your solar and\or wind battery bank .. Lead is fine.


You fail to mention the downsides of lead:

1. Lead is heavy
2. Lead has much lower power density
3. Lead has much lower power cycle life.
4. Peukert effect severely affects availabloe capacity
5. Lead no longer has the big cost advantage it once carried. 

ga2500ev


----------



## dh1 (Dec 21, 2015)

In a garden tractor such as the GE Elec-Trak's the added weight of the lead acid batteries is a benefit to the tractor as it increases traction, pulling power and the use of the tractor.
This is probably the only case where this happens.


----------



## Matej (Dec 4, 2015)

dh1 said:


> In a garden tractor such as the GE Elec-Trak's the added weight of the lead acid batteries is a benefit to the tractor as it increases traction, pulling power and the use of the tractor.


But you can use an equal weight worth of lithium batteries and have a much more powerful tractor.


----------



## Yabert (Feb 7, 2010)

dh1 said:


> In a garden tractor such as the GE Elec-Trak's the added weight of the lead acid batteries is a benefit to the tractor as it increases traction, pulling power and the use of the tractor.
> This is probably the only case where this happens.


Even in this case, you are better to use high quality recycle lithium battery (Leaf, Volt, Tesla) and build an heavy steel battery box


----------



## dcb (Dec 5, 2009)

I wound up using leaf modules on my elec-trac, works just fine for my purposes (mowing, pulling a trailer a bit, it had no problem dragging very large chunks of brush to the curb either). Lead would have been close to $1000 and only last a few seasons, whereas the 15 leaf modules were ~$1500 without trying too hard (and 15 modules is overkill, [email protected]).

It helped that I had them sitting around though, was sorely tempted to use lead till I remembered I had them and the project they were for was a long way from completion. Even 10 modules will get you [email protected] I'm gonna give 5 modules a go when I re-purpose 10 for a bike (which would be far cheaper than the recommended lead batteries).

Also I use the built in-charger, and just keep an eye on it, making an educated guess with the built in timer.

Edit, here's my bms  http://www.diyelectriccar.com/forum...-pack-balance-monitor-batt-bridge-165953.html


----------



## dh1 (Dec 21, 2015)

Matej said:


> But you can use an equal weight worth of lithium batteries and have a much more powerful tractor.


Lead acid battery pack is 360lbs using the lower rating 6volt batteries, 420lbs with the higher capacity batteries. For sure you would gain run time and a bit of power only due to less voltage sag from the battery pack in high current draw conditions. 



Yabert said:


> Even in this case, you are better to use high quality recycle lithium battery (Leaf, Volt, Tesla) and build an heavy steel battery box


I priced out a lithium pack once, 36volt 200 amp/hr they wanted $5000. plus tax, charger, bms. I don't know enough to know if used/recycled lithium batteries are good and don't have the $$$ for a new set. I would love to have though.



dcb said:


> I wound up using leaf modules on my elec-trac, works just fine for my purposes (mowing, pulling a trailer a bit, it had no problem dragging very large chunks of brush to the curb either). Lead would have been close to $1000 and only last a few seasons, whereas the 15 leaf modules were ~$1500 without trying too hard (and 15 modules is overkill, [email protected]).
> 
> It helped that I had them sitting around though, was sorely tempted to use lead till I remembered I had them and the project they were for was a long way from completion. Even 10 modules will get you [email protected] I'm gonna give 5 modules a go when I re-purpose 10 for a bike (which would be far cheaper than the recommended lead batteries).
> 
> ...


The point I was trying to make is that the heavy weight of the lead acid batteries gives the tractor more traction and is the only case where this happens. I know weights can be added, wheel weights, suitcase weights, loaded tires, but the lead has already done some of this for you. 
EV want to be light so they can go faster farther on a charge.
A light weight tractor can't push/pull much.


----------



## dcb (Dec 5, 2009)

I understand the weight portion, but there doesn't seem to be a cost advantage to lead, especially with cycle life and the boneyards populated with electric vehicles. Mostly I'm debunking the "fancy shmancy charger and BMS" perception though, they are as cheap as anything else to charge and monitor if you understand them (especially at the lawn tractor level)


----------



## ishiwgao (May 5, 2011)

dh1 said:


> The point I was trying to make is that the heavy weight of the lead acid batteries gives the tractor more traction and is the only case where this happens.


another application for lead batteries being useful (which i guess would be not really applicable in this forum) are for forklifts too. 

the lead batteries act as a counterweight for the forklifts when they are lifting heavy cargo on the other end, so changing it to lithium wouldnt work. You'll just be rendering the whole forklift useless.


----------



## dh1 (Dec 21, 2015)

ishiwgao said:


> another application for lead batteries being useful (which i guess would be not really applicable in this forum) are for forklifts too.
> 
> the lead batteries act as a counterweight for the forklifts when they are lifting heavy cargo on the other end, so changing it to lithium wouldnt work. You'll just be rendering the whole forklift useless.


I never thought of that, but true the batteries also form the counterweight.


----------



## Duncan (Dec 8, 2008)

ishiwgao said:


> another application for lead batteries being useful (which i guess would be not really applicable in this forum) are for forklifts too.
> 
> the lead batteries act as a counterweight for the forklifts when they are lifting heavy cargo on the other end, so changing it to lithium wouldnt work. You'll just be rendering the whole forklift useless.


NO wrong!
The lead batteries make the whole vehicle heavier - if you want a counterweight you put the weight where it does the most good - which is where you will find the weights on a forklift

With a lighter battery you will end up with a few more weights and an overall lighter vehicle able to do the same job with less energy and fewer constraints


----------



## dcb (Dec 5, 2009)

yah, on the other side of the coin I gained about 500 lbs in payload capacity, plus the front 3 battery box is empty storage now (ooh, I should make a custom cooler for it!)


----------



## dh1 (Dec 21, 2015)

This my 1974 EGT200 garden tractor made by General Electric, all original, new batteries. The 6 x 6volt golf cart batteries weigh about 360lbs total. 
Tractor weighs with batteries 900lbs, plus 150lbs for the mower deck, 1050lbs total, plus the driver.

I have sat on this thing for 3hrs non stop cutting grass, that drained the pack down to the point where the contactors started cutting out.
Only did it once, wanted to see how long it would run for. GE claims 3hrs and they were right.
A heavy tractor is not needed to cut grass but when you start climbing steep hills, wet slippery conditions, want to tow trailer or push stuff with a dozer blade or pull a one bottom plow, cultivator or set of discs though the garden then you want the extra weight.
https://www.youtube.com/watch?v=3RnqYJAVhk4


----------



## dcb (Dec 5, 2009)

well, I did flip it once (got too close to a guy-wire), very glad it wasn't full of lead for that  plus I can put it on it's side by hand for whatev.


----------



## ken wont (Jul 6, 2016)

Weight is also a plus for Snow-Blowers.
How well do Lithium batteries perform at -20 degrees?


----------



## TerryH (Jun 9, 2012)

We charge our 3P60S 222v pack with a string of 4 golf cart chargers in series and monitor/balance with LiPo Pals. Nothing complicated about it.


----------



## piotrsko (Dec 9, 2007)

ken wont said:


> Weight is also a plus for Snow-Blowers.
> How well do Lithium batteries perform at -20 degrees?


About the same as FLA. They are happier at shirtsleeve temps.

I think both types have their pro's and cons, but the deciding factor should be cost per watt hr. My lead pack cost .20 @ wh, the volt pack was .15, and sometime can be had for less still. Having said that, some people have access to battery recycling so their prices could be lower that way.

Otoh battery maint for the lead pack cost $100, the volt pack required an eltek charger that cost $500 all done, and I have to disassemble the pack every quarter to verify balance.

My $0.02 YMMV.


----------



## Moltenmetal (Mar 20, 2014)

The only benefit remaining to lead in vehicular applications is that they're easy to balance- you just overcharge the shit out of them and make hydrogen with whatever energy isn't used in charging.

If you're comparing lead to Li-ion with BMS, the first cost of a lead pack is still lower than that of a used Li-ion pack with BMS. BMS is necessary safety equipment on the high energy chemistries used in OEM EV batteries in my opinion, which is why all the OEMs have BMS in their designs. I don't consider it optional, though some people will substitute the BMS with their own vigilance and feel OK about that, I would never be among them. But in terms of $ per mile driven for a pack which has to go beyond about 500-1000 cycles in its lifetime, Li ion still wins even with the investment in a BMS.

For the DIY crowd, the option to buy a used OEM Li-ion battery pack is simply irresistible unless you live somewhere that those packs are just not available- and even then, Duncan imported a used Volt pack from the US to New Zealand for about $500 so that too is a surmountable obstacle.. I don't understand why anyone would bother with lead for a car conversion project unless it was intended more as a toy for an experiment rather than as real transportation.

Stationary UPS applications where the battery spends most of its time at 100% SOC and is only rarely deeply discharged? OK, there lead is still king, until somebody comes up with something better intended for grid storage. It's coming, though we're not there yet..


----------



## PStechPaul (May 1, 2012)

I still think there is some justification for using lead-acid batteries, although the arguments are not as strong as a few years ago when lithium was much more expensive and not as widely available. As indicated above, lithium can be had for about $0.15/W-h, so a minimal 10 kWh pack would be about $1500. I got a new 100 A-h (1200 W-h) lead-acid battery for about $70, so 10 of them would be 14.4 kW-h for $700, but at 1C Peukert effect drops actual energy to about half that. When the 3-5 year life of lead is compared to 10-15 for lithium, the long term value becomes more obvious.

But for a simple lawn tractor or golf cart, used only occasionally, and on a tight budget or for experimentation, lead is certainly more affordable and perhaps safer. You might be able to get starter batteries at a junkyard for about half the cost of new, so a 14 kW-h pack of ten might be only about $400, and may do the job for a year, at which time you might get $50 back for recycling. Any "bad" batteries can be readily replaced from a junkyard or auto supply store.

If you want to try using a VFD and industrial three phase motors, you need at least 250 volts, which would be 20 x 12V batteries, which would be about $1500 and weigh 1200 pounds or more, so not very practical for a small tractor or golf cart. You could use smaller SLA batteries, such as 12 A-h for about $20 each, but 20 of them would be $400 and have a nominal energy of only 2.9 kW-h.

But I have shown how to obtain 250 VDC from a single 12V 17 A-h SLA, and even better, from several in series. I found that two small lawn-tractor size batteries in series (24V) were enough to power a 2 HP 3 phase motor on a stripped-down riding mower. The actual power was less than 1/2 HP, or about 350 watts. I am working on an isolated DC-DC converter that will accept 12, 24, or 48 VDC nominal, and produce 250-300 VDC at about 1 kW. The parts will be less than $50. You can also modify an automotive 12 or 24 volt to 220 VAC inverter to supply the DC for a VFD, at about $50/kW, but non-isolated.


----------



## veedub ev (Feb 10, 2017)

tawma1100 said:


> A BMS is only required if there is a need to extract every every available watt of capacity from the pack because a BMS either burns of redistributes energy from fully charged cells to less than fully charged ones.
> 
> But if one simply doesn't overcharge any cell, then a BMS is completely unnecessary.
> 
> ...



I beg to differ. The stuff you list here pretty much describes a BMS system, one that checks the cell voltages, cuts off the charger when one cell is full, and shuts off load when the first cell reaches minimum voltage. Even if cells are balanced at first, they will go out of balance. Lead acid will just dissipate voltage disparancies as heat, where as the lithium will just keep increasing voltage until cell damage occurs. I know, because I have damaged cells. That was before I installed a bms system. In the 5 years I ran lithium before bms, I had to replace 8 cells due to damage. 

That being said, with a bms system and lithium batteries, you will be better off in the long run. Have more power available, and will last years longer than lead. And your car will be much lighter, allowing for better performance.

Lead can be run without any bms, with a standard charger. Something to be said for simplicity.

Summary: if you're technical and a tinkerer, go with lithium and a bms system. If you're not technical, go for lead.


----------

