Profiling Lester Summit II charger for LiFePO4 battery

[Rockten]

I have a Summit Lester II charger that I bought a year ago when I had lead batteries. Can I use it for my newly bought LiFePO4 battery (1 x 48v/ 80ah)?

I am asking the above since I was advised in a another thread not to use the cheap charger that came with the lithium battery since it could shorten the life of my new lithium battery. This was after I noticed volt readings and volt drops after charging with the cheap charger that were strange.

I found attached pdf-file on how to choose the correct profile for the Lester charger for LiFePO4 on the Lester app. I found this pdf on the link below:

https://assets.website-files.com/62b...stallation.pdf


Is this good-to-go or do you disrecommend this? Should I buy a special charger for lithium batteries instead?

[simicrintz]

I had to have a custom Schauer charger made for my pack. Bought the Lester being told (by Lester) that it would work only to be told after the purchase that it would not (and they would not take it back ). Be very specific if you consider the Lester with them before you purchase to make sure it will work for your application.

[Fairtax4me]

It depends on exactly which lithium battery you have.
Lester has worked with a handful of manufacturers to develop profiles for their specific Lithium packs. Not all lithium batteries are created equal so using a charge profile that is not catered to the specific battery brand and type could lead to problems.
Use the Charger connect app to check if Lester has a profile designed for your batteries, brand, model, capacity, etc. If they don't have it on the App then they will very likely tell you they don't recommend using the charger for those batteries.

Charging lithium is not as cut and dry as it may seem. Any charge parameters that are outside of a very specific tolerance can cause failure of the battery, in dramatic and/or disastrous fashion.

[Rockten]

Originally Posted by simicrintz

I had to have a custom Schauer charger made for my pack. Bought the Lester being told (by Lester) that it would work only to be told after the purchase that it would not (and they would not take it back ). Be very specific if you consider the Lester with them before you purchase to make sure it will work for your application.

Thanks to everyone for all your feedback. @simicrintz: who custom made your Schauer charger for you?

Can others recommend other brands of chargers suitable for 48v lithium batteries?

[Pat911]

I cannot recommend one to you as I'm in a place where we use 230V, not 110v

Honestly, lithium chargers are not that complex. What you need is a current limited constant voltage power supply. That is pretty much it. Much simpler than a Lead Acid charger.

The charger will put out its maximum current until the battery voltage gets to the charger voltage. At this point, the current will taper off to zero. When the current gets to 1/10th of the initial charge current, the charger should switch off.

There are two parameters you will need to look at, the maximum charge current, and lithium can be charged very fast if you like, and the voltage. Preferably get one with an adjustable maximum voltage.

Cheers
Pat.

[simicrintz]

Originally Posted by Rockten

Thanks to everyone for all your feedback. @simicrintz: who custom made your Schauer charger for you?

There was a guy from Santa Cruz (IIRC) who was on here for a short time that built the same battery pack as I did and he and I bounced stuff around as we each built our carts. Somehow he became a dealer for a lot of cart stuff, including the Schauer chargers. Since he custom profiled his cart and understood our battery packs, he was able to have Schauer custom build both of our chargers.

I think he went by Left Coast Kiteboarding and his name was Monte; you may be able to PM him or PM me and I can see if I have his info somewhere. It wasn't cheap but I have never had to worry about it and it is definitely a quality charger.

[Pat911]

There is no special customisation required for lithium battery chargers except for the Constant Voltage point. Getting one with an adjustable CV point gives you all the customisation you require. They are readily available from AliExpress, eBay, Amazon etc.

I got a 60v 33A (2kW) CC CV power supply with adjustable CV and CC (constant current) points and it makes the perfect lithium battery charger. I’m using a 21 module Nissan Leaf battery.

[Rockten]

Originally Posted by Pat911

There is no special customisation required for lithium battery chargers except for the Constant Voltage point. Getting one with an adjustable CV point gives you all the customisation you require. They are readily available from AliExpress, eBay, Amazon etc.

I got a 60v 33A (2kW) CC CV power supply with adjustable CV and CC (constant current) points and it makes the perfect lithium battery charger. I’m using a 21 module Nissan Leaf battery.

Thanks. Is the one with description attached ok?

My seller also told me that my 48v/80 ah lithium battery has 16 cells. Can I use this information to find a correct charger?

[Pat911]

No, I wouldn’t go with that as that needs extra electronics to make it work.

16 cells is a standard LiFePO4 configuration. LiFePO4 cells have a maximum charge voltage of 3.65V but will get to approximately 98% at 3.45V and 99% at 3.55V. The key here is that the cells are allowed to saturate for an hour or so once the voltage is reached.

So, 3.65 x 16 = 58.4v maximum
3.55 x 16 = 56.8v
3.45 x 16 = 55.2v

I would personally set the voltage at anywhere between 55.2v and 56.8v.

This is the charger I use

https://www.ebay.com.au/itm/18464504...3ABFBMisbI4Odg

It’s not waterproof but I don’t need it to be. It has adjustable voltage and current and can fully charge a 100Ah battery in around 3 hours. It will operate from 110v but be aware that it will draw 2000W at full power, that’s over 18A from your mains supply. I don’t believe your standard receptacle can be used with that charger in the US.

Cheers
Pat.

[Rockten]

Originally Posted by Pat911

No, I wouldn’t go with that as that needs extra electronics to make it work.

16 cells is a standard LiFePO4 configuration. LiFePO4 cells have a maximum charge voltage of 3.65V but will get to approximately 98% at 3.45V and 99% at 3.55V. The key here is that the cells are allowed to saturate for an hour or so once the voltage is reached.

So, 3.65 x 16 = 58.4v maximum
3.55 x 16 = 56.8v
3.45 x 16 = 55.2v

I would personally set the voltage at anywhere between 55.2v and 56.8v.

This is the charger I use

https://www.ebay.com.au/itm/18464504...3ABFBMisbI4Odg

It’s not waterproof but I don’t need it to be. It has adjustable voltage and current and can fully charge a 100Ah battery in around 3 hours. It will operate from 110v but be aware that it will draw 2000W at full power, that’s over 18A from your mains supply. I don’t believe your standard receptacle can be used with that charger in the US.

Cheers
Pat.

MANY THANKS! I do not live in the US. I have both 110v and 220v available at my house.

When I charge my 48v/80ah lithium battery with the cheap charger it came with, my volt meter reads 58.8v when the charger is still on it (even after it stops charging, with a green light) but it drops to 55.8v as soon as I take off the clips of the charger off. You told me the following on this: "The charger isn’t controlling the end of charge point as it should. The battery has a Battery Management System (BMS) and it’s job is to protect the cells from being overcharged, and in your case, it is the BMS that has intervened and cut charging. At this point, the charger puts out its maximum voltage but the BMS prevents it from getting to the battery. This is not an ideal scenario as the cells are not permitted to saturate and the BMS should not be the charge controller, it is the last line of defence in protection. Lastly, lithium behaves very differently to lead acid and LiFePO4 voltage will settle after being charged. You’ll find once you start using it, it will drop very quickly to 52-53v and then sit there for most of its discharge cycle. It will then drop very quickly again once it’s almost depleted."