DIY Electric Car Forums banner

1 - 14 of 14 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter #1
My VW Bug has 10 lead acid batteries that need replacing. Is there a lithium ion battery that would be a drop-in replacement, i.e., it would have the same shape and be 12 volts? Or could I somehow buy or scavenge lithium ion cells and assemble them to make a 120 volt battery to take the place of the 10 lead acids?
 

·
Registered
Joined
·
4,783 Posts
My VW Bug has 10 lead acid batteries that need replacing. Is there a lithium ion battery that would be a drop-in replacement, i.e., it would have the same shape and be 12 volts?
Yes, but that's a really expensive way to go. These replacements are usually not intended for EVs, but rather for recreational vehicles. An example: Battle Born.
 

·
Registered
Joined
·
740 Posts
You must work with bare cells and a capable BMS drop-ins have crippled and inaccessible internal BMS.

In the US figure 5-8x the price of quality lead per Ah.

And very risky to try secondhand units, hard to match, likely very limited remaining life, rarely good value.
 

·
Administrator
Joined
·
6,115 Posts
You must work with bare cells and a capable BMS drop-ins have crippled and inaccessible internal BMS.

In the US figure 5-8x the price of quality lead per Ah.

And very risky to try secondhand units, hard to match, likely very limited remaining life, rarely good value.
Ignore John

The best bet by FAR is to use the battery pack out of an EV

I'm using the battery out of a Chevy Volt - I paid $1800US for it 16 kWh
It's made of a number of individual modules that can be configured as you want

CHEAPER than Lead and better than aftermarket Lithium
 

·
Registered
Joined
·
740 Posts
Yes of course if you have the skills & knowledge to safely work with scavenged EV packs.

Take my response as within the LFP context reacting to the drop-in suggestion.
 

·
Registered
Joined
·
4,783 Posts
The "drop-in" requirement is key. It does make sense to want a ready-made configuration of cells, packaging, and BMS, but the problem is that for there to be a commercial product, there needs to be a common configuration to fit.

The problem with a 12-volt configuration in an EV is that you end up with many (ten in this case) of these units, probably without a coordinated BMS. Technically it can certainly work (they're just 4S LFP modules), but since these are usually made for applications which only need 12 volts, they're usually not designed to be connected in series in a coordinated way.

I've seen at least one supplier offering a single unit to replace the entire 48-volt set of lead-acid batteries in a golf cart, which is practical because there is a common configuration to replace: they're essentially all 48-volt nominal, consisting of six 8V or eight 6V GC2-sized batteries in a row. The advantages of a single unit over combining smaller units include avoiding the need for parallel connections (such as 4S2P of 12-volt units), reducing cost and complexity of packaging a wiring, and including on lithium-specific charger in the package.

Completely drop-in doesn't seem likely to work out reasonably for a 120-volt conversion from lead-acid. The most practical might be a combination of some reasonable number of pre-assembled modules (with BMS components) plus a central BMS master and charger. Chevrolet Volt modules and BMS are potential components for that approach.
 

·
Registered
Joined
·
740 Posts
Victron has several different lines of packaged system banks, with their proprietary BMS open to communications with a central controller.

I believe they use the "drop in" label with one, and perhaps that can be set to allow high C rates (more than the usual .5-1C anyway).

Not cheap but perhaps worth checking out.
 

·
Registered
Joined
·
740 Posts
Trojan recently released its Trillium line, but not sure if actually shipping yet.

Also their BMS has some comms facility rather than being completely isolated like BB.
 

·
Registered
Joined
·
4,783 Posts
Victron has several different lines of packaged system banks, with their proprietary BMS open to communications with a central controller.
Victron Energy has some good stuff. In this case, the Lithium battery 12,8V & 25,6V Smart line might be suitable. As John mentioned, it needs a master controller for BMS, so only the case and power wiring is "drop in".

Trojan recently released its Trillium line, but not sure if actually shipping yet.

Also their BMS has some comms facility rather than being completely isolated like BB.
I had not heard of Trojan's Trillium line, but apparently only the TR 12.8-92 has any connectivity beyond the battery case, the literature barely mentions that CAN connection, and according to the user's guide:
The Maximum Nominal Bank Voltage for Trillium Batteries is 51.2V.

For comparison, AM Solar's range of lithium battery banks are all shown in parallel configurations only, even though residential solar installations commonly operate at higher voltages.
 

·
Registered
Joined
·
78 Posts
My VW Bug has 10 lead acid batteries that need replacing. Is there a lithium ion battery that would be a drop-in replacement, i.e., it would have the same shape and be 12 volts? Or could I somehow buy or scavenge lithium ion cells and assemble them to make a 120 volt battery to take the place of the 10 lead acids?
What size are those LA batteries ? My first bet would be 16 Nissan Leaf modules, for 121.6 nominal voltage. You'd need something like Zeva or Batrium to monitor the state of the pack though, 32s is quite large for most other BMSes.
 

·
Registered
Joined
·
15 Posts
I bought my last pack from evtv motor verks. Doing a bug you could go with the calb ca100FI and get way better range than you did with lead acid.
 

·
Registered
Joined
·
9 Posts
Are your batteries wired in series for 120 volts? I have some 24 volt Lithium Ion battery packs already assembled which you could wire in series to achieve 120V or more if fully charged. It would take 5 of these batteries to get you 120V. These are built with Boston Power Swing 4400 batteries and they are all spot welded with copper bus bars and balance connector leads attached to them. These batteries are 24V 35AH each with an 8P7S configuration. You could also wire more of these packs in parallel to increase the amp hours. I am also including a spec sheet of the Boston Power Swing 4400. These batteries could be shrink wrapped or better yet have an enclosure made for them proper proper safe installation. All these batteries are new/NOS.

I also have individual cells, different holders etc. for any kind of battery that you might want to assemble.

Take a look at the attached photos and if what I have is of interest, send me a PM and we will work to put a package together for you.

I have been selling on Ebay for years if you need a reference, just check my feedback under my user name there ...same as here Headrc.

Richard
 

Attachments

1 - 14 of 14 Posts
Top