What should I use to charge LTO batteries on bench?

[fisherus]

I have a question regarding charging my LTO SCiB batteries to equal voltage before I parallel them in my battery bank. Because my Sol-Ark 12k is almost 500miles away from my batteries I recently purchased, I want to have them charged to 60V each. After I get them charged to equal levels, so they can be paralleled, I will be taking them up to my off-grid farm for installation. I am trying to find a fast way to charge them, as I am limited on time. Other than using a bench power supply I have, that has a 60V 5A maximum or splitting the batteries into two 30V batteries by removing the buss bar between the two 12 cell packs and charging each with a Buck converter, does anyone have any ideas for charging them?

 

[snoobler]

Equalizing cells is vastly more important than equalizing groups of cells in series. If unable to equalize cells, I'd break them down to groups of as few cells as possible.

How important is it that they get fully charged? I would expect getting them to any sensible SoC is fine particularly if you have means of charging at their destination.

 

[fisherus]

The cells are all equalized but several batteries are at different voltage rates. Before I can parallel the batteries to each other and the others in my bank I am adding them to, they need to have their charges raised to 60.0V. It is hard on a bench power supply to charge batteries of this voltage for a very long period. Most need a 3.0V-12V increase to get to the 60.0V Nominal voltage level of my others. So I am looking for an AC-DC unit that will charge them to the Nominal voltage level. I have installed a BMS in each battery I have been charging them using my power supply but, because of the exceptionally high C rate, it would be a lot faster if I could connect directly to the Pos. and Neg. terminals and disconnect the BMS.

 

[snoobler]

Unfortunately, high voltage and high current supplies aren't cheap or readily available, but this would work nicely:

PM3 24V Series - PowerMax Converters

PowerMax PM3 Series 110Vac to 24Vdc Battery Charger/Converters for 24V battery banks, Off-Grid, Trucking, Telecoms and powering 24V equipment

powermaxconverters.com

Works as both a 3-stage 24V charger, OR an adjustable DC supply. Available with up to 50A of charging. Should be able to charge the two halves in parallel at 30V.

I have a few of the 12V units - 1 in an RV and 2 for "other" applications.

Or...

Amazon.com

20A unit that could probably get you to 28+V

A couple of those, and you've have 40A effective charging.

 

[SolarKopf]

I am using 24v 30A chargers from BigBattery.com - https://bigbattery.com/product/24v-30a-dc-charger/. I split the packs and use these to charge to 29.2v. Its not 30v but its the fastest thing I have found for less than $150. Remember Will's DIYSOLAR coupon code for an additional 10% off.

 

[fisherus]

Yes, I've done that but finally bought a couple of really good bench chargers that will charge up to 5 AMPs each. Automatically go into Nominal voltage on topping and they are steady and fast.

 

[MadMax03]

Been a while since you asked, but it's a good title and my response could help for future reference. You can buy old server PSU's and build your own high current DC chargers for crazy cheap. Takes a little mechanical aptitude, but none of us would be here if we didn't have that. For LTO (and LFP), a lot of guys will have large enough banks where a few of these PSU's paralleled up would charge in a hurry without hurting anything.

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Below is just a practical representation of one with some pictures:

BimmerBoost