SOK 206AH BATTERY CONCERNS

[Rocksnsalt]

Hello, I’m no electrical expert and hope to get some feedback re the SOK 206ah batteries I’ve been considering for my sprinter van.
These comments were sent to me by someone much more knowledgeable than me, any comments?

It's a 200 AH battery with a 40 amp recommended charge limit. That's ridiculously small. Maybe OK for a small B2B, but not for an aux alternator. A standard 0.5C charge rate would be 100 amps, and that's what Victron specs for their 200 AH battery. Even worse, max discharge rate is 100 amps. I haven't even found what the nominal discharge rate is, it likely is as small as 50 amps. Most 120V appliances running off an inverter will need more than 100 amps, so whatever is nominal is basically unusable for van life unless you use multiple of them. These limitation are caused by a wimpy BMS and small internal wires.

 

[sunshine_eggo]

Hello, I’m no electrical expert and hope to get some feedback re the SOK 206ah batteries I’ve been considering for my sprinter van.
These comments were sent to me by "someone" much more knowledgeable than me, any comments?

It's a 200 AH battery with a 40 amp recommended charge limit. That's ridiculously small. Maybe OK for a small B2B, but not for an aux alternator.

Charging of LFP should typically be done with a DC-DC charger not directly with an alternator. "Someone" should know this.

A standard 0.5C charge rate would be 100 amps, and that's what Victron specs for their 200 AH battery. Even worse, max discharge rate is 100 amps. I haven't even found what the nominal discharge rate is, it likely is as small as 50 amps.

These are BMS limitations. The BMS is self-contained within the battery. Victron batteries require interface with an external BMS, or they are effectively unmanaged.

Most 120V appliances running off an inverter will need more than 100 amps, so whatever is nominal is basically unusable for van life unless you use multiple of them. These limitation are caused by a wimpy BMS and small internal wires.

That's true, but 100A @ 12V is 1200W, which will power many things. If the current limit is a problem, get a different battery or put another battery in parallel.

 

[Dzl]

As Sunshine (and someone) mentioned these are most likely BMS limitations not cell limits. While that doesn't change anything in a practical sense for the end user, it does mean that you shouldn't take the specs you listed as an indication that the cells themselves are inferior or anything.

Cutting back on the BMS current ratings is one place that drop-in replacement companies can save a buck, and since they are all currently engaged in a race to the bottom, they will cut costs where they can. For the companies with longer warranties and cycle life guarantees, its also possibly a convenient way to ensure their batteries are used somewhat gently. As far as spec's go, 0.5C max discharge isn't so bad, its what some of the cell manufacturers are now basing their cycle life numbers on, and at 0.5C you are going to be draining your battery pretty damn quick, and generating some heat. 0.5C means you would go from 100% to 0% SOC in 2 hours.

As to the 0.25C charge rate (it looks to be 50A, not 40A btw according to the SOK website), I agree that that is not great. I think 0.5C max charge rate is more reasonable. BUT the ballpark of ~0.2C to 0.3C is right around the sweet spot for charging when it comes to battery health/longevity from what I recall. So being limited to this does limit your flexibility/ability to quickly recharge, but will also promote greater longevity. 50A / 0.25C means you can charge from 0-100% in about 4hrs assuming no loads. Not trying to say its not a low limit, it is at the very low end of what I would consider, and doesn't give you much wiggle room.

I think you can dismiss, the concern someone had about finding the nominal (reccomended) discharge rate. Since the BMS is the limiting factor almost certainly, not the cells themselves, the cells reccomended discharge rate is likely equal to or greater than the 100A limit.

But there point about the BMS being weak, might carry some weight. The low specs do mean that there is a much greater likelihood of operating much closer to the BMS's limits, much more of the time. That is not ideal. But also, I imagine something that SOK has probably taken into account, or something that people would be complaining about if there were issues (maybe peopel are complaining, idk).

In any case, if the 0.5C discharge rate is a concern/limitation for you, I think you should be adding more battery capacity, there are good reasons beyond the limitations of the batteries to want to stay mostly below <0.5C anyways. The charge rate is definitely something to consider though.

I believe the cells used in SOK batteries are Ganfeng cells. You can find Ganfeng datasheets in the resources section of the forum.

 

[Dzl]

Also note, the SOK 206Ah batteries have lower current specs than the 100Ah batteries.

(well technically the same specs 50A/100A, but equivalent to double the C rates)
2 x 100Ah = 200Ah would give you 100A/200A limits
1 x 206Ah = 206Ah would give you 50/100A limits

If you need the higher C rates, the smaller batteries look to be the better choice.

SOK Battery

SK12V100,SK12V206,SK12V206H,SK24V100,SK48V100

www.sokbattery.com

SOK 24V 100 Ah batteries

Anyone using the SOK 24v 100 Ah batteries? Looking at two of them (200Ah) for a 24v MPP LV2424 all in one charger/inverter. Or maybe the LV3024. I am thinking that the 24V batteries would be easier to charge to SOC with the MPP LV2424. Any thoughts? Or would two 12v 206 Ah in series be better...

diysolarforum.com

 

[Rocksnsalt]

Also note, the SOK 206Ah batteries have lower current specs than the 100Ah batteries.

(well technically the same specs 50A/100A, but equivalent to double the C rates)
2 x 100Ah = 200Ah would give you 100A/200A limits
1 x 206Ah = 206Ah would give you 50/100A limits

If you need the higher C rates, the smaller batteries look to be the better choice.

SOK Battery

SK12V100,SK12V206,SK12V206H,SK24V100,SK48V100

www.sokbattery.com

SOK 24V 100 Ah batteries

Anyone using the SOK 24v 100 Ah batteries? Looking at two of them (200Ah) for a 24v MPP LV2424 all in one charger/inverter. Or maybe the LV3024. I am thinking that the 24V batteries would be easier to charge to SOC with the MPP LV2424. Any thoughts? Or would two 12v 206 Ah in series be better...

diysolarforum.com

The 206ah models are a pretty small case, very space efficient, I was thinking 2 of them and I’m set… until you pointed out the 100ah look to be a better choice.
Space is of paramount importance in a van build.
So perhaps I should be taking a closer look at the EG4 12v/5.12kw/400ah rack battery ?

 

[Dzl]

Space is of paramount importance in a van build.

You cant say that strongly enough! Every square inch matters.
Although, in many cases the specific dimensions matter as much as the actual size, size it can be a bit like tetris when you get to actually fitting everything in. Something that is a little bigger but fits the space perfect can be much better than something technically smaller but the wrong dimensions (unless you are building from scratch/have a blank canvas).

So maybe I’ll be looking closer at the EG4 12v/5.12kw/400ah rack battery now. ?

Worth looking into for sure.

 

[bryn]

I have noticed that most of these prebuilt battery packs have low charging/discharge rate, i guess its cheaper to spec them like that and if something goes wrong the supplier can blame it on the user.

I picked up a 240ah lithium battery pack in the plastic case around 4 years ago, for my campervan, the selling point was the 200ah BMS, as i see 100ah discharges using the inverter to cook.

I opened it up a few weeks ago as i was having issues with a disconnect, and i noticed it was a Daly BMS, i did a balance charge and capacity test, it pulled 240ah, i wasn't expecting that

i know its best not to have it at 100%, but it has spent most of its life sitting there, as the solar keeps it topped up.

I need more ah, so im building a 608 ah EVE battery bank to replace it, i'm lucky it'll fit in my battery housing area that i built.

Those Rack Batteries would be ideal, from the tear downs they are well built, i just couldn't find a way to fit them in my current campervan.

These are the future as they are quite cheap, use can bus and are well made

 

[rmaddy]

Even worse, max discharge rate is 100 amps. I haven't even found what the nominal discharge rate is, it likely is as small as 50 amps.

This is wrong. The SOK specs state that the battery has a "max continuous discharge current" of 100A. It also states it can handle 200A for 3 seconds.

Of course 100A of discharge current means you can support 1000W of inverter per battery in parallel on a 12V system or 2000W of inverter per battery in parallel on a 24V system.

 

[corn18]

I have pulled 286 amps for 10 minutes from my 2 12v 206Ah SOK batteries. I have pushed 60A into one and 120A into 2 for long periods. Go on the SOK Facebook page and there are multiple tests on the SOK BMS that indicate it is capable of way more than SOK states. SOK even says they are considering changing the listed specs, but they haven't yet.

The two batteries have more amps available than my Multiplus II 12/3000 needs for max output. More batteries are always better, but 2 work for me.

I do wish they had bluetooth capability, though.

They are quite compact:

 

[sunshine_eggo]

Battery makers routinely de-rate the specs (capacity and currents) for service life/warranty consideration.

 

[vangoski]

Charging of LFP should typically be done with a DC-DC charger not directly with an alternator. "Someone" should know this.

Hello, I'm the someone who wrote that text. This is what I said which you quoted:

"Maybe OK for a small B2B, but not for an aux alternator. "

You do not use a B2B (DC-DC) for an aux alternator, you wire it direct. My aux alternator puts out 280 amps all of which is usable for charging. So a 206AH battery that charges at only a 0.25C rate is inadequate for me because I can charge a decent battery twice as fast. The SOK charge rate is more suitable for a B2B which is what I said. Obviously it would be OK for solar as well.

These are BMS limitations. The BMS is self-contained within the battery. Victron batteries require interface with an external BMS, or they are effectively unmanaged.

Fair point about the Victron, that was a bad example. Better examples are Battleborn or a LION as Will Prowse points out in his review of the SOK. They charge faster and source more current.

That's true, but 100A @ 12V is 1200W, which will power many things. If the current limit is a problem, get a different battery or put another battery in parallel.

Well it won't power a microwave oven, a coffee maker, nor an induction cooktop (via inverter), so it's useless for me. And no, one does not run their microwave oven or induction cooktop for 2 hours at a time. I currently run all of that on 200 AH of lithium, plus a diesel heater, fridge and DC circuits for lights, device charging, etc for up to two days on that. And then it gets 100% charged in 1-2 hours via my aux alternator.

The SOK may be a good value for the money, but one needs to understand its limitations to know if it's going to meet their needs. Don't just buy it and then discover it's not. This is why there are people selling, "brand new still in the box" SOK batteries. This is what I was trying to relate to @Rocksnsalt

 

[Rocksnsalt]

Well now, this should be interesting…
?

 

[sunshine_eggo]

Hello, I'm the someone who wrote that text. This is what I said which you quoted:

Hello Someone! Nice to meet you.

"Maybe OK for a small B2B, but not for an aux alternator. "

You do not use a B2B (DC-DC) for an aux alternator, you wire it direct. My aux alternator puts out 280 amps all of which is usable for charging. So a 206AH battery that charges at only a 0.25C rate is inadequate for me because I can charge a decent battery twice as fast. The SOK charge rate is more suitable for a B2B which is what I said. Obviously it would be OK for solar as well.

Ah. Gotcha. Can you charge your 200Ah of lithium at 280A?

Fair point about the Victron, that was a bad example. Better examples are Battleborn or a LION as Will Prowse points out in his review of the SOK. They charge faster and source more current.

Don't want to bother with LION, but Battleborn...

https://1t1pye1e13di20waq11old70-wpengine.netdna-ssl.com/wp-content/uploads/2019/01/BB10012-Spec-Sheet.pdf

12V/100Ah, 100A max

No 200Ah option - only single 50A/24V or 100A/12V except for...

https://1t1pye1e13di20waq11old70-wpengine.netdna-ssl.com/wp-content/uploads/2021/02/BB8D-Spec-Sheet.pdf

270Ah, 300A only $2300

I still don't think even BB is a good example. Your aux alternator would fry everything except the monster battery that probably wouldn't physically fit.

Well it won't power a microwave oven, a coffee maker, nor an induction cooktop (via inverter), so it's useless for me.

700W microwave burns about 1100W. Coffee makers burn 900-1100W (unless you're a keurig snob, those burn >1300W). If you can find one of the rare non-pulsed induction cooktops, you can use them at lower power settings.

And no, one does not run their microwave oven or induction cooktop for 2 hours at a time.

I can believe some dolts leave their induction cooktop on for longer than intended. I've been a dolt at times in my life for other, yet similar reasons.

I currently run all of that on 200 AH of lithium, plus a diesel heater, fridge and DC circuits for lights, device charging, etc for up to two days on that. And then it gets 100% charged in 1-2 hours via my aux alternator.

[Tony the Tiger] That's GREEEEEEAAAAT![/Tony the Tiger]

The SOK may be a good value for the money, but one needs to understand its limitations to know if it's going to meet their needs. Don't just buy it and then discover it's not. This is why there are people selling, "brand new still in the box" SOK batteries. This is what I was trying to relate to

Can't disagree with you. This applies to every single component in the van build. Did you actually convey this to the OP, or did you just bash the battery?

 

[vangoski]

Hello Someone! Nice to meet you.



Ah. Gotcha. Can you charge your 200Ah of lithium at 280A?



Don't want to bother with LION, but Battleborn...

https://1t1pye1e13di20waq11old70-wpengine.netdna-ssl.com/wp-content/uploads/2019/01/BB10012-Spec-Sheet.pdf

12V/100Ah, 100A max

No 200Ah option - only single 50A/24V or 100A/12V except for...

https://1t1pye1e13di20waq11old70-wpengine.netdna-ssl.com/wp-content/uploads/2021/02/BB8D-Spec-Sheet.pdf

270Ah, 300A only $2300

I still don't think even BB is a good example. Your aux alternator would fry everything except the monster battery that probably wouldn't physically fit.



700W microwave burns about 1100W. Coffee makers burn 900-1100W (unless you're a keurig snob, those burn >1300W). If you can find one of the rare non-pulsed induction cooktops, you can use them at lower power settings.



I can believe some dolts leave their induction cooktop on for longer than intended. I've been a dolt at times in my life for other, yet similar reasons.



[Tony the Tiger] That's GREEEEEEAAAAT![/Tony the Tiger]



Can't disagree with you. This applies to every single component in the van build. Did you actually convey this to the OP, or did you just bash the battery?

One uses a regulator with an auxiliary alternator to charge at the appropriate rate for your battery.

Some actual current measurements at my battery for the following appliances via a Victron 12/3000 inverter.

700W Microwave: 107 amps
Keurig (guilty as charged): 113 amps
Induction cooktop on high: 140 amps

And obviously there are other loads going on at the same time, fridge, maybe heat, lights, charging etc.

So as you can see, a single SOK 206 will not work for me, and I would not recommend it for a vanlife person, especially if they need more than a paltry 0.25C charge rate. I don't really know what else to tell you.

 

[Rocksnsalt]

I just want something like the 12kw Volta system in the Storyteller Overland Sprinters, that’s all. ?
And that 800amp alternator they’re running.
Ohh SnaaaP.
??‍
That’s right people… a 48v 12kwh power system… IN A VAN.




12kwh of storage and up to 3.6kW of AC power.

 

[sunshine_eggo]

One uses a regulator with an auxiliary alternator to charge at the appropriate rate for your battery.

Some actual current measurements at my battery for the following appliances via a Victron 12/3000 inverter.

700W Microwave: 107 amps
Keurig (guilty as charged): 113 amps

I'm married, so I have one too. As much as I dislike it, it's actually pretty good. Fast brew time, and nothing to remember to turn off. Good compromise. 1300W+ for a few minutes vs. forgetting to turn off the drip maker.

Induction cooktop on high: 140 amps

Yeah, if they pulse, they're brutal.

And obviously there are other loads going on at the same time, fridge, maybe heat, lights, charging etc.

So as you can see, a single SOK 206 will not work for me, and I would not recommend it for a vanlife person, especially if they need more than a paltry 0.25C charge rate. I don't really know what else to tell you.

We're not disagreeing, and it may not be right for the OP. It sounded more like "battery bashing" than "one needs to understand its limitations to know if it's going to meet their needs"

 

[vangoski]

I'm married, so I have one too. As much as I dislike it, it's actually pretty good. Fast brew time, and nothing to remember to turn off. Good compromise. 1300W+ for a few minutes vs. forgetting to turn off the drip maker.



Yeah, if they pulse, they're brutal.



We're not disagreeing, and it may not be right for the OP. It sounded more like "battery bashing" than "one needs to understand its limitations to know if it's going to meet their needs"

Well, remember this started as a private conversation between two people that got elevated. Not complaining, but I would probably have used a more diplomatic tone had I worded it for public consumption.

 

[Dzl]

One uses a regulator with an auxiliary alternator to charge at the appropriate rate for your battery.

To be clear, you are talking about using an external regulator with your aux alternator, yeah?
This was not clear from the first couple comments in this thread.

How has that been working for you? Its a solution that seems more popular in the marine world, haven't heard many first hand experiences installing/using an external regulator for vehicle applications, and I'm quite curious about it. How was the difficulty of install/setup? What sort of charge current do you see? Biggest downsides?

 

[sunshine_eggo]

Well, remember this started as a private conversation between two people that got elevated. Not complaining, but I would probably have used a more diplomatic tone had I worded it for public consumption.

We're not disagreeing. I can be a dick sometimes.

 

[vangoski]

We're not disagreeing. I can be a dick sometimes.

Yes, we're in "violent agreement". I'm new here so on my best behavior. Wait until you get to know me.

 

[Rocksnsalt]

It’s true!

 

[vangoski]

To be clear, you are talking about using an external regulator with your aux alternator, yeah?
This was not clear from the first couple comments in this thread.

How has that been working for you? Its a solution that seems more popular in the marine world, haven't heard many first hand experiences installing/using an external regulator for vehicle applications, and I'm quite curious about it. How was the difficulty of install/setup? What sort of charge current do you see? Biggest downsides?

Yes, external regulator. I'm pretty sure all of the aux alternator products use external regulators for control purposes, charge profiles and the like. Balmar has the lion's share of the market, but Wakespeed is now coming up to speed (so to speak) as well. Wakespeed indeed designed their suite of products for the marine world, but they work great in RVs, particularly for lithium systems.

My system has a DIY battery based on Fortune cells (thanks, Will), Wakespeed regulator and REC BMS. The BMS is connected to the regulator via a CANbus. The BMS actually controls charging based on its fine-grain visibility into what the cells are doing, and sends current requests to the Wakespeed which in turns sends exactly that much current to the battery. They call this a remote-battery-master configuration. There's no charge profile because the regulator is simply doing what the BMS tells it to do. The BMS has settings for battery size and your desired C rate which it uses in conjunction with cell voltages to calculate how much current to request. Usually it's requesting your full desired C rate until it's full. So with my 200 AH battery, I'm generally charging at around 100 amps. I will be adding another 8 cells to for 400 amps total. I'll only need to change the battery size parameter and I'll be charging at 200 amps with no other changes.

I was an early adopter of this technology for use in a van and pretty bullish on it. The install is actually pretty easy and logical and nothing that anyone who works on charging systems can't handle. Setup is easy too. As an early adopter, I had some bugs bringing up the system that were worked around in firmware by Wakespeed. But the system is rock solid now and should work for anyone else right out of the gate.

Sorry, I get carried away talking about this stuff. I have a build thread about it on the Sprinter forum here. https://sprinter-source.com/forums/index.php?threads/89088/

 

[Rocksnsalt]

Yes, external regulator. I'm pretty sure all of the aux alternator products use external regulators for control purposes, charge profiles and the like. Balmar has the lion's share of the market, but Wakespeed is now coming up to speed (so to speak) as well. Wakespeed indeed designed their suite of products for the marine world, but they work great in RVs, particularly for lithium systems.

My system has a DIY battery based on Fortune cells (thanks, Will), Wakespeed regulator and REC BMS. The BMS is connected to the regulator via a CANbus. The BMS actually controls charging based on its fine-grain visibility into what the cells are doing, and sends current requests to the Wakespeed which in turns sends exactly that much current to the battery. They call this a remote-battery-master configuration. There's no charge profile because the regulator is simply doing what the BMS tells it to do. The BMS has settings for battery size and your desired C rate which it uses in conjunction with cell voltages to calculate how much current to request. Usually it's requesting your full desired C rate until it's full. So with my 200 AH battery, I'm generally charging at around 100 amps. I will be adding another 8 cells to for 400 amps total. I'll only need to change the battery size parameter and I'll be charging at 200 amps with no other changes.

I was an early adopter of this technology for use in a van and pretty bullish on it. The install is actually pretty easy and logical and nothing that anyone who works on charging systems can't handle. Setup is easy too. As an early adopter, I had some bugs bringing up the system that were worked around in firmware by Wakespeed. But the system is rock solid now and should work for anyone else right out of the gate.

Sorry, I get carried away talking about this stuff. I have a build thread about it on the Sprinter forum here. https://sprinter-source.com/forums/index.php?threads/89088/

It’s ok, these are your people to talk that stuff to.

 

[fratermus]

Welcome to the forum. I think you'll fit right in.

You do not use a B2B (DC-DC) for an aux alternator, you wire it direct. My aux alternator puts out 280 amps all of which is usable for charging. So a 206AH battery that charges at only a 0.25C rate is inadequate for me because I can charge a decent battery twice as fast.

Are you idling to recharge? If so, faster charging does makes sense as one can reduce time idling the engine.
If one doesn't have time pressure (driving from place to place, or maybe solar is helping out) I'd think the lower 0.25C rate would be gentler on the batteries than 0.5C, especially in colder temperatures.

a single SOK 206 will not work for me, and I would not recommend it for a vanlife person,

If vanlife means Instagram hashtag-vanlife with apartment-style amenities then I agree. If it means people who live in vans in my experience meeting a few hundred vandwellers over the past few years I'd say the majority (or at least plurality) are using solar to recharge ≤200Ah lead banks. Those folks would likely be delighted with the smaller SOK 100Ah.

My fulltime boondocking use case: maximum load is ~300w, typical loads ~150w, all loads run off solar in the daytime, and I use 30-40Ah overnight. For me a SOK 206Ah would be overkill and unnecessary expense. Horses for courses, as they say.

especially if they need more than a paltry 0.25C charge rate.

0.25C is paltry compared to your charging capacity, but not paltry for LFP in general. I'd be surprised if the typical member of this (admittedly solar-centric) forum was charging lithium at ≥0.25C. I have 750w of solar charging a 100Ah LFP and under normal conditions it charges at less than 0.25C.

 

[vangoski]

Welcome to the forum. I think you'll fit right in.

Thanks!

Are you idling to recharge? If so, faster charging does makes sense as one can reduce time idling the engine.
If one doesn't have time pressure (driving from place to place, or maybe solar is helping out) I'd think the lower 0.25C rate would be gentler on the batteries than 0.5C, especially in colder temperatures.

I don't understand your question about idling. I charge whenever the battery is below 100% and the engine is running, and it's generally charging at my preferred 0.5C. Once I populate the rest of my cells and increase my battery to 400 AH then there will be some roll-off of current at idle. Although I've already seen it put out around 150 amps at idle, so not much degradation. The van is diesel, btw, and idling for extended periods is bad for them.

I'm not aware of any downside to charging at 0.5C. The batteries can handle 1C, so 0.5C is already conservative. If you have references to such information, I'm all ears. My batteries are always warm because they live inside the van. The BMS is temperature savvy, so if there were temperature ranges that needed less current then it would call for less power. It does kill the power at low temps close to freezing, as those charging at those temps can damage the battery.

If vanlife means Instagram hashtag-vanlife with apartment-style amenities then I agree. If it means people who live in vans in my experience meeting a few hundred vandwellers over the past few years I'd say the majority (or at least plurality) are using solar to recharge ≤200Ah lead banks. Those folks would likely be delighted with the smaller SOK 100Ah.

My fulltime boondocking use case: maximum load is ~300w, typical loads ~150w, all loads run off solar in the daytime, and I use 30-40Ah overnight. For me a SOK 206Ah would be overkill and unnecessary expense. Horses for courses, as they say.



0.25C is paltry compared to your charging capacity, but not paltry for LFP in general. I'd be surprised if the typical member of this (admittedly solar-centric) forum was charging lithium at ≥0.25C. I have 750w of solar charging a 100Ah LFP and under normal conditions it charges at less than 0.25C.

Ha, you should check out the Sprinter forum. We have guys there with 1100 AH lithium batteries running AC all day. I'm more towards your camp, but I like hot food and hot coffee and my heated mattress pad in the winter.