Provolt Lithium Batteries

[wayno]

HI all,

Any thoughts or experiences with the Provolt brand?
If no good, what should I go for?

I ask as I have no idea of what I am looking at. What's good and what's not.

Wayno

[T1 Terry]

Best sit back with the beverage of choice, this might be a long read

If you are really well equipped in the wallet dept, you can't go past a full Victron install, hard to beat, reliable and has all the bells and whistles ... but they are not cheap .....

If you don't have the $$ for the Victron system, go for the Enerdrive gear, but you'll still need to have a big wallet, get the factory installed system and not the drop in B TEC G2 I'll explain further down why any drop in is poor choice.
Beware though, you don't get the true advertised capacity, it's all in the fine print, you just need to follow what is actually being communicated through the "not so plain" specifications.

As an example https://enerdrive.com.au/product/300ah- ... ttery-12v/ claimed as 300Ah but looking through the specs


Model EPL-300AH-12V-COMPACT
Nominal Capacity 300Ah 3840Wh
Nominal Voltage 12.8V
Life Cycles* 80% DOD ≥1500 Cycles

See if you can find what the * denotes, good luck with that, what it is actually saying is you can have 80% of the advertised capacity, 300 x 80% = 240Ah, but the important bit

Charge Discharge
Mode: CC & CV
Max & Min Voltage: 15V 11.5V
Standard Current 0.3C,90A 0.3C,90A
Max Constant Current 1C,300A 1C,300A
Operating Temperature 0°C-+45°C -20°C-+60°C
Max Charge Voltage 14.20V
Float Voltage 13.50V

You can actually get 300 amps out and put 300 amps in .... but the recharging temp is the tricky bit, no charging below 0*C or above 45*C if you have travelled much in Australia, you'll know these temps are often exceeded at either end of that scale, yet the discharge temp range is fine for Australian conditions ....

Now check against the BTEC drop in 300Ah G2 specs
https://enerdrive.com.au/product/epower ... m-battery/
You can't have that 300 amp max current and this is probably because the BMS is inside the battery, so not only the physical size of the BMS is restricted, but so is the ability to dissipate the heat generated. The heat generated by 300 amps passing the IGBT (the type of transistor used for DC current @ low voltages) would produce enough heat to require multiple fans if not water cooling of a large heat sink. An IGBT is used in place of a contactor because the contactor just takes up too much space .... and still needs air around it to cool the latching coil ....
The system used in factory installed Enerdrive set up uses an external contactor (2 contact points with a large surface area compared to a relay with single contact point and the contact face is generally not as large) they use a high current pull down coil to slam the contactor closed fast (to avoid arcing across the contacts) and a heavy spring to snap to it open quickly for the same reason. Once the contact has settled into the closed position, a secondary coil is left to hold it closed, this reduces heat generation and battery capacity waste.


There are a lot more differences between an external BMS in comparison to an internal BMS, the other major difference is the type and capacity of the cell balancing system, actual physical size and heat generation are also factors in why an internal BMS can't have the same capabilities an external well engineered one can handle.

If our workshop hadn't burnt down, many may say my opinion is biased, but as we no longer have a dog in this fight, I'm simply sharing what 12 yrs of hand on experience has taught me .... drop in batteries are just waiting to bite you in the wallet.

T1 Terry

[wayno]

Many thanks T1,

Very pleased to get this advice from you. The wallet is fat enough for either, but do not want to waste it on crap. Thank you for helping me to avoid that,

Best sit back with the beverage of choice, this might be a long read

If you are really well equipped in the wallet dept, you can't go past a full Victron install, hard to beat, reliable and has all the bells and whistles ... but they are not cheap .....

If you don't have the $$ for the Victron system, go for the Enerdrive gear, but you'll still need to have a big wallet, get the factory installed system and not the drop in B TEC G2 I'll explain further down why any drop in is poor choice.
Beware though, you don't get the true advertised capacity, it's all in the fine print, you just need to follow what is actually being communicated through the "not so plain" specifications.

As an example https://enerdrive.com.au/product/300ah- ... ttery-12v/ claimed as 300Ah but looking through the specs


Model EPL-300AH-12V-COMPACT
Nominal Capacity 300Ah 3840Wh
Nominal Voltage 12.8V
Life Cycles* 80% DOD ≥1500 Cycles

See if you can find what the * denotes, good luck with that, what it is actually saying is you can have 80% of the advertised capacity, 300 x 80% = 240Ah, but the important bit

Charge Discharge
Mode: CC & CV
Max & Min Voltage: 15V 11.5V
Standard Current 0.3C,90A 0.3C,90A
Max Constant Current 1C,300A 1C,300A
Operating Temperature 0°C-+45°C -20°C-+60°C
Max Charge Voltage 14.20V
Float Voltage 13.50V

You can actually get 300 amps out and put 300 amps in .... but the recharging temp is the tricky bit, no charging below 0*C or above 45*C if you have travelled much in Australia, you'll know these temps are often exceeded at either end of that scale, yet the discharge temp range is fine for Australian conditions ....

Now check against the BTEC drop in 300Ah G2 specs
https://enerdrive.com.au/product/epower ... m-battery/
You can't have that 300 amp max current and this is probably because the BMS is inside the battery, so not only the physical size of the BMS is restricted, but so is the ability to dissipate the heat generated. The heat generated by 300 amps passing the IGBT (the type of transistor used for DC current @ low voltages) would produce enough heat to require multiple fans if not water cooling of a large heat sink. An IGBT is used in place of a contactor because the contactor just takes up too much space .... and still needs air around it to cool the latching coil ....
The system used in factory installed Enerdrive set up uses an external contactor (2 contact points with a large surface area compared to a relay with single contact point and the contact face is generally not as large) they use a high current pull down coil to slam the contactor closed fast (to avoid arcing across the contacts) and a heavy spring to snap to it open quickly for the same reason. Once the contact has settled into the closed position, a secondary coil is left to hold it closed, this reduces heat generation and battery capacity waste.


There are a lot more differences between an external BMS in comparison to an internal BMS, the other major difference is the type and capacity of the cell balancing system, actual physical size and heat generation are also factors in why an internal BMS can't have the same capabilities an external well engineered one can handle.

If our workshop hadn't burnt down, many may say my opinion is biased, but as we no longer have a dog in this fight, I'm simply sharing what 12 yrs of hand on experience has taught me .... drop in batteries are just waiting to bite you in the wallet.

T1 Terry

At this stage I am almost sure I will opt for this van. So will go minimal and option up later. I think that's what you mean.
Hope we will be able to catch up.

Cheers,
Wayno

[T1 Terry]

If you can go for a minimum capacity lead acid battery option and see how much that improves the price over any lithium option they offer.

Extremely early days yet, like I haven't even ordered the samples yet, but my plan is to test the newest "ion" battery that contains no lithium or cobalt .... sodium ion cells. They sort of have a similar voltage range as the LYP cells we were using, but the hope is the freight costs will be better if I can convince the carrier they are not dangerous goods.
From there, if they work as well as they claim, I'm planning on building a BMS for this chemistry so they will become a house battery option that doesn't suffer the restrictions placed on all batteries with lithium in their name .......

If you are interested, if it all pans out, I'll need field testing rigs, mine will be one but an independent tester would be great, one who knows very little about batteries would be ideal ... do you think you might fit that category ?

T1 Terry

[wayno]

Hi T1,

Sounds like a plan, as long as my van doesn't burn down at some stage.

Not sure how soon I will get hold of this rig, not ordered yet, still investigating the specifications.
It is a bit sad actually, I see they have a great product, but their marketing is hopeless.
Not enough cash to take the big leap I think.

However, I am persevering with them as I think it is a great fit for what I am looking for.

I will let you know when I will be picking it up as soon as I know when.

Cheers and thank you for your effort.

Wayno

[Mrcoolabah1au]

Ok just put it on insurance

[T1 Terry]

The other reasons I'm looking at designing house battery systems using these sodium ion cells:

A) the electrolyte is basically water, so non flammable

B) they claim they can better handle being deeply discharged yet recover without damage ..... yet to verify that

C) hopefully the freight costs will be better because they would not be considered dangerous goods .... yet to verify

D) get away from the hysteria the media has generated over any battery with lithium in the title

E) possibly put a product to market that hasn't been "bastardised" by those hoping to jump on the "lithium" bandwagon and sell rubbish to the unsuspecting public because they just don't know the catch words to look for or the specs that aren't actually there that would show the product was rubbish


I know that "not enough cash to take the plunge" all to well, still no insurance money as yet, and none of my stuff was covered by the insurance anyway

T1 Terry

[wayno]

Hi T1,
I hear your pain mate. After your advice, I think I will stick with the sealed AGM set up or maybe Gel for now.
Thinking or putting a slimline AGM in behind the back seat of the D-max, a KickAss 170 ah setup.
Then put double or more in the van.

Still thinking though!

Cheers,

Wayne

[T1 Terry]

Hi T1,
I hear your pain mate. After your advice, I think I will stick with the sealed AGM set up or maybe Gel for now.
Thinking or putting a slimline AGM in behind the back seat of the D-max, a KickAss 170 ah setup.
Then put double or more in the van.

Still thinking though!

Cheers,

Wayne

AGM maybe, but forget about GEL or Lead Crystal, they do not suit cyclic use.

Gel requires a very limited charge and discharge rate to avoid hydrogen and oxygen bubbles in the gel electrolyte. The bubbles form between the gel and the plate and these spots sulphate, gradually (or very quickly if there are a lot of bubbles) reducing both the capacity and charge/discharge rate due to the loss on contact on each plate.

Lead Crystal requires a very complex recharging regime to recover the capacity each cycle, resulting in a continual loss of capacity until completely discharged, the recharging regime before the battery can be used again is quite complex and not suitable for the average user who just wants to live off grid without the hassles

T1 Terry

[native pepper]

The other reasons I'm looking at designing house battery systems using these sodium ion cells:

T1 Terry

The problem with sodium ion batteries is they currently have a very low cycle life, they've worked out why, now they have to work out a good fix for the problem and once they do that we may have a low cost long term solution to batteries. Can't describe the problem technologically, my head spins when it gets into physics, but think it revolves around the ions lining up in a certain way which breaks down the crystallisation of the cells and lowers life span. Once they solve that problem they should be right to go.

Thinking about it had an idea that if they reversed the polarity during the charging process for milliseconds in pulses it may shock the ions into the right order extending the cycle life dramatically. The idea came to me when using a small conditioning charger on my backhoe as that pulses but doesn't reverse polarity, so thought maybe the sudden shock of polarity reversal may do the trick. After all A/C switches polarity, why not DC to stabilise charging ions in sodium ion cells.

There's probably many technical reasons why that wouldn't work, but as the electrolyte is mostly water it may be interesting to see if it worked. Sometimes going outside the box of understanding and thinking laterally brings forward solutions not on the radar of the technological mindset

If slow hand was still around, he'd probably give it a go, as he was as mad as me when it comes to experimentation with the unknown and we had some great times doing that with lithium, especially lifepo4 which we found to be pretty well safe under any conditions and the charge parameters we developed seem to be holding up with the life of my lifepo4 systems. Know of a couple of people who followed manufactures recommendations and their lifepo4 packs have not lasted much over 10 years before starting to losing capacity.

Had gel batteries in my bus before lifepo4, and agree with Ti, found them to not handle daily cycling very well at all.

Don't know much about lead crystal batteries, they say they have lifespans of 18 years and can be fully discharged. But they don't tolerate temperature changes and lose capacity from high temperature variations, they also have a low discharge rate are heavy and expensive. What problems do you see Ti, be interested to know.