SOK battery charging question

[carguy4471]

I'm looking to put a lifepo4 in my small camper. My converter is fla/agm and does not have a lifepo4 setting.

I have read that battleborn (in their faq) will bulk charge at 14.4 and float at 13.6, this is exactly what my converter outputs. So one of these would work.

Would an SOK battery charge in the same manner? On the mobile-solarpower website it says that an SOK is considered a "lead acid replacement because you can use them with standard chargers". Is this because it has a bms and I'm not doing a DIY?

What's the skinny here? Can I charge an SOK at the 14.4/13.6 that my converter puts out?

Thank you all so much for the help!!


Duane

 

[rmaddy]

I'm charging my SOK batteries with those same voltages and it seems to be working just fine.

 

[RVLiFe]

I have a WFCO WF-9855 converter in my RV. It has never charged any of my batteries with 14.4v. It seems to only ever charge at 13.6v. Maybe I just need to let my LiFePO4 battery discharge to under 12v or something but that isn’t going to happen anytime soon. So my suggestion is to get a different converter that has a dedicated lithium mode (WF-9855LiS) or allow your current charger to charge up to 13.6v and then top them off with a AC/DC charger (Victron IP22,IP65 or IP67) at least once a month to ensure that they are top balanced by the BMS using 14.6v that SOK recommends. Actually, SOK says any charge between 14.2v and 14.6v is fine.

 

[carguy4471]

My wfco is an 8712. There aren’t many made that small with lithium charging that I can find.

Would piggybacking a 120v lithium charger behind my converter be ok? I could just toss a noco 10amp or something back there onto the battery line. It shouldn’t hurt the converter, I don’t think.

 

[elewis33]

I'm charging my new SOK battery (12V100) with this DROK AC to DC power supply. Will Prowse used this in one of his budget milk crate build videos.

Amazon.com

I'm setting this to 14.6 volts before connecting it to the battery and according to the specs it's always running at 10 amps. When I connect it to the battery the voltage indicator on the device changes to apparently match the voltage of the batttery, and then it slowly increases as the battery charges.

I've left this connected to the battery for over 6 hours and it only goes up to 13.7 volts and using a voltmeter on the battery says it's sitting at 13.4 volts.

This is more of a question about the power supply than the battery. So here goes. Does anyone else use this power supply and have you had a similar experience? And is there really any difference between this device and a "purpose built" LiFePo battery charger? They all put out power at a certain volts and amps so

And if I should start a new thread that's fine. Just let me know if this should be elsewhere.

 

[RVLiFe]

I’d say that you still have a ways to go before that battery is fully charged. The charging voltage doesn’t change much until the end of its charge (See attachment). As long as it’s putting in the 10 amps then I’d say you’re good. Just let it keep going. Bigger charger will just give you shorter charge time but they all pretty much do the same thing if they are designed for LiFePO4.
Personally, I would prefer a charger that will switch over to constant voltage once it hits 14.6V or shut off. But keep an eye on it and once it hits 14.6V let it sit for no more than 30 minutes if you want it to fully charge the battery. Any longer and you will risk hurting the battery.
is this your primary source of charging that battery?

How to Find Happiness With LiFePO4 (Lithium-Ion) Batteries –...

By: Rob Beckers You have just sold your first-born into slavery, remortgaged the house, and bought yourself a lithium-ion battery! Now you want to know how to take care of your precious new purchase: How to best charge lithium-iron batteries, how to discharge them, and how to get the maximum...

www.solacity.com

 

[elewis33]

Thanks for the response @RVLiFe. No, this is not my primary charging method. I actually bought the DROK for a smaller (20Ah) battery and never got around to setting it up so I decided to give it a go on this SOK 12V100 after I fully discharged it over the weekend.

I'm planning to charge the SOK with two 375 watt panels and a Victron 100/30 SCC. I'm also going to setup an AC-DC charger but will probably go with something in the 30-50 amp range, since the SOK can take up to 50 amps.

 

[RVLiFe]

If @Will Prowse used it then I’d say it should work for you. Sounds like you have a handle on it but I don’t personally like anything that doesn’t have an auto shut off or that constantly feeds voltage to your battery. I can’t understand why Battle Born recommends Progressive industries charge/controllers for RV’s that never shut off. BAD IDEA if you aren’t there to monitor it constantly.
I’m going to be charging only up to around 90-95% using solar and then once a month or so, I’ll hit the battery with a full charge using this:

Amazon.com

It actually works quite well.

 

[elewis33]

I've been considering these guys for higher power/faster charging.

Amazon.com

https://www.amazon.com/dp/B0074JVN3...olid=1UMYBD2JLZOJ9&psc=1&ref_=lv_ov_lig_dp_it

Seems like the 45 amp unit has some brains and does all the charge stages that LiFePo likes. These are obviously more expensive but I actually got pointed to these by the technical team at Lion Energy, where I got my 20 Ah battery.

 

[RVLiFe]

I've been considering these guys for higher power/faster charging.

Amazon.com

https://www.amazon.com/dp/B0074JVN3...olid=1UMYBD2JLZOJ9&psc=1&ref_=lv_ov_lig_dp_it

Seems like the 45 amp unit has some brains and does all the charge stages that LiFePo likes. These are obviously more expensive but I actually got pointed to these by the technical team at Lion Energy, where I got my 20 Ah battery.

Those aren’t designed for LiFePO4. They might work and charge to 80-90% but I prefer one like this:
WFCO WF-9855-LIS Deck Mount Converter/Charger with Lithium-Ion Switch - 55A

https://www.amazon.com/dp/B08KJJF7L8/ref=cm_sw_r_cp_api_glt_fabc_4T0Y9JP3RR7RE6MQX45N

It charges a LiFePO4 at a Constant Current of 50Amps for between 1 and 4 hours until it detects 14.6V then drops to 13.6V. It’s a better charging profile than most other RV Charger/Converters in my opinion and it’s designed specifically for LiFePO4.

 

[elewis33]

That's good to know. I thought the 45 amp unit with the IQ module could do LiFePo.

Isn't a power supply, like the ones mentioned, by definition a constant current/constant voltage charger, by virtue of thee fact that it puts out it's stated amperage and the voltage is set (in the case of my DROK unit) by a voltage control on the power supply itself?

I'm sure you can tell that I'm no electrical engineer and just trying to navigate this whole landscape, so I'm definitely open to learning as much as I can.

 

[RVLiFe]

That's good to know. I thought the 45 amp unit with the IQ module could do LiFePo.

Isn't a power supply, like the ones mentioned, by definition a constant current/constant voltage charger, by virtue of thee fact that it puts out it's stated amperage and the voltage is set (in the case of my DROK unit) by a voltage control on the power supply itself?

I'm sure you can tell that I'm no electrical engineer and just trying to navigate this whole landscape, so I'm definitely open to learning as much as I can.

Can Lead Acid charger be used for LiFePO4 batteries ? - Glider Battery Shop

Hi guys, The question we recently get from our customers is if “LiFePO4 batteries can be charged with Lead Acid charger”. Please find below the answer why it shouldn’t be done. Simple answer: it is POSSIBLE, but you have to be VERY CAREFUL and you RISK your battery life. A 12v lithium LiFePO4...

glider-battery.eu

It’s what happens after the battery reaches the determined voltage that differentiates what the next step is in the charge cycle. You don’t need a long absorb or an equalize or trickle charge with LiFePO4. A two stage CC/CV works the best. A lot of the chargers that I’ve played around with don’t even want to go into a bulk mode unless the battery is very low so I can not seem to get the stated amperage out of the chargers. They go into absorption mode right away which is not ideal for charging. This is my experience anyway and I’m sure that different chargers have different algorithms. Hope this link helps a little.

 

[Dinky]

If @Will Prowse used it then I’d say it should work for you. Sounds like you have a handle on it but I don’t personally like anything that doesn’t have an auto shut off or that constantly feeds voltage to your battery. I can’t understand why Battle Born recommends Progressive industries charge/controllers for RV’s that never shut off. BAD IDEA if you aren’t there to monitor it constantly.
I’m going to be charging only up to around 90-95% using solar and then once a month or so, I’ll hit the battery with a full charge using this:

Amazon.com

It actually works quite well.

Will that charger get me by until I get the rest of my solar setup done? I have 2 SOK 100a batteries, new in the box. I presume I can use this charger for the initial charge of both batteries together?
Thanks for your informative posts on charging!
Kind Regards,
Steve

 

[RVLiFe]

Will that charger get me by until I get the rest of my solar setup done? I have 2 SOK 100a batteries, new in the box. I presume I can use this charger for the initial charge of both batteries together?
Thanks for your informative posts on charging!
Kind Regards,
Steve

I don’t see why it wouldn’t work. It will just take longer with both of them. I think it’s recommended that you charge each battery individually first before hooking them together. This ensures that they are at the same voltage and more importantly, the same state of charge. Since voltage doesn’t change much in a LiFePO4 battery, it’s difficult to really know it’s state of charge until it’s fully charged, from there you can use a battery monitor/shunt to help to keep track of its SoC.

The biggest concern that I have with your charger is that you have to make sure you shut it off once it hits 14.6 volts and not let it sit at that voltage for more than 15-30 minutes or else you risk overcharging your batteries. A proper LiFePO4 charger should quit charging.

 

[Dinky]

I don’t see why it wouldn’t work. It will just take longer with both of them. I think it’s recommended that you charge each battery individually first before hooking them together. This ensures that they are at the same voltage and more importantly, the same state of charge. Since voltage doesn’t change much in a LiFePO4 battery, it’s difficult to really know it’s state of charge until it’s fully charged, from there you can use a battery monitor/shunt to help to keep track of its SoC.

The biggest concern that I have with your charger is that you have to make sure you shut it off once it hits 14.6 volts and not let it sit at that voltage for more than 15-30 minutes or else you risk overcharging your batteries. A proper LiFePO4 charger should quit charging.

Thanks again! I read the article you attached above "Finding Happiness With LifePO4 Batteries", that was really an eye opener and a super helpful read! Again, thankfulness is motivated by your thoughtful info!
Kind Regards,
Steve

 

[futureproof]

With that DROK power supply, just use it in conjunction with a voltage sensing relay and cut off the charging input at a preset voltage.