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baltik Samba Member
Joined: April 08, 2015 Posts: 440
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Posted: Tue Aug 13, 2019 9:04 am Post subject: New Record? 120 usable Amp Hours under Driver's seat |
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Wanted to share my latest and greatest setup.
4x 120AH LifePo4 Prismatic cells that fit very nicely in the AUX battery space. These are made by CATL which is a huge Chinese Lithium manufacturer (OEM supplier for BMW and a number of other large EV makers). I have measured over 120 usable hours using conservative voltage cutoff settings on these.
These are industrial cells (they tend to look a little rough) that can be sourced on Alibaba and the like for around $500 (don't forget those tariffs). One of the issues is that they are drilled for M4 studs at the factory which is pretty small, and a lot of resellers are redrilling them to M6 (so check if you are going to order). They also tend to have the serial number scratched off. I have been told that the production lines are used for major contracts during the day but they keep them running at night for non-OEM resale, presumably the profits on these are pocketed by management and serial numbers are removed to avoid being traced. Don't know how true this is but it's a story I heard from multiple suppliers and the serial numbers are consistently removed.
I am using an Electrodacus SBMBS40 to control the pack - which is an incredibly powerful and flexible piece of hardware. It balances the cells, provides a real time State of Charge Meter (similar to Victron BMV). Will shut off charge if temperature drops below a certain level. Will shut off the alternator charge once cells are full, and will disconnect the load if the cells are drawn down too much. It also has WiFi, logging and is almost infinitely customizable.
Because these are Lithium, there are a number of major advantages:
1 - Huge increase in energy density. My batteries weigh 25.2lbs , are smaller than the starting battery, and store more (usable) energy than 2 GC2 deep cycles at 140lbs
2 - Faster charging. These batteries can be charged at 40A+ all the way until full. No float or anything else to deal with - so you can go from empty to full in ~3 hours.
3- Huge increase in cycle life. These are are rated for 3000 cycles so they should outlive most of our vans...
There are also some drawbacks:
1 - Need for a Battery Management System. A BMS is a somewhat lose term with no defined functionality. Ideally it should do the following:
a) Balance the cells - unlike lead acid the cells are not self balancing, a BMS will reallocate energy from the the cell with the highest voltage to the cell with the lowest.
b) Provide overvoltage/undervoltage cutoffs to ensure you get the cycle life that you paid for
c) Disconnect the charge source if temperatures drop below freezing (Lithium batteries will be permanently damaged if you charge at sub zero temps)
2. Another item to think about is alternator charging. This gets a little controversial since there are a number of drop-in LifePO4 manufacturers that say this is ok to do (battleborn being one of them), The problem with this is that these LiFEPo4s will essentially max out your alternator (they could easily pull 70+amps) and this will take a pretty heavy toll on our aging electrical and alternator systems. The other issue here is making sure that the requisite 14.2-14.6 volts are delivered to the battery and the last issue to solve for is how to disconnect the battery from the charging source once full... I use a Renogy 40Amp Dc to Dc charger to ensure that all of the above needs are met, but others have bypassed this step...
Lastly, a Lifepo4 setup can be achieved on the cheap if one already has an adequate solar setup... A victron or similar MPPT controller has LifePo4 setting, has a temperature input and can be programmed not to charge below freezing. At that point a basic BMS can be sourced for $25 https://www.aliexpress.com/item/32875971231.html add a Victron Battery protect for $40 to disconnect loads if batteries get too low and you have a relatively cheap and fully functional Lithium system (with no alternator charging)
For those interested in the subject I recommend Will Prowse's youtube channel and website
https://www.youtube.com/channel/UCoj6RxIAQq8kmJme-5dnN0Q
https://www.mobile-solarpower.com/
(renogy DC to DC 40Amp charger under the swivel seat)
PS - I did buy 2 battery sets so I have a pack to sell. If interested and located in the bay area, PM me |
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yabert Samba Member
Joined: August 12, 2019 Posts: 148 Location: Québec
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Posted: Tue Aug 13, 2019 9:42 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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Nice integration!
I've also played with 12V lifepo4 cells in the past. A BMS is not a necessity if you understand the cells voltage and have a charger to equalized the cell one by one fully charge before connecting them in serie.
To protect the cells from over charge I use a DC-DC* with 14V output (3.5V per cell), but an adjustable MPPT controller can do the same.
*in my case 360V dc to 14V dc.
Depending of the cell quality, it could be need to redo a top charge once a year or less.
Protect the cells from low voltage and low temperature is important, but LFP cell are pretty safe and robust. Accidently, few years ago, some of my cells on a project were drop to 0.1V during few months, bus despite that I was able to recover many with still 80% of the original capacity. |
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shagginwagon83 Samba Member
Joined: February 07, 2016 Posts: 3786 Location: VA/TN
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Posted: Tue Aug 13, 2019 9:42 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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This is really incredible. You even covered cold weather charging.
I have just one question. Most LifePo4 batterys have internal battery monitoring system.. These are just cells right? With a fully external BMS. _________________ Brandon
"Jo Ann" - '83.5 Westfalia EJ22e w/Peloquin
Instagram @joannthevan |
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baltik Samba Member
Joined: April 08, 2015 Posts: 440
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Posted: Tue Aug 13, 2019 9:52 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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shagginwagon83 wrote: |
This is really incredible. You even covered cold weather charging.
I have just one question. Most LifePo4 batterys have internal battery monitoring system.. These are just cells right? With a fully external BMS. |
Correct - I chose to go this route because there wasn't anything even at 100AH that would fit that space in an integrated solution (hence gowesty sells a 50AH lifepo4 kit)
Also I found the internal bms solutions somewhat lacking. many don't have low temperature cutoffs, I didn't like some of the parameters being used as well - for example many won't disconnect your load until 12.5V which is already doing damage to the battery. There is also a lack of disclosure as to exactly how these internal BMSs work (ie will they disconnect when individual cells are over discharged or the entire pack is below a certain threshold and thus individual cells may be significantly lower/higher). |
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vwhammer Samba Member
Joined: May 20, 2006 Posts: 998 Location: Boulder CO.
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Posted: Tue Aug 13, 2019 11:05 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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I have also been eyeballing the 200 amp version of the cells you are running.
seems like people are having good luck with the brand and the price is hard to beat.
EDIT: Actually the brand I am looking at and I keep seeing is CALB not CATL
Maybe they are the same maybe not.
Hard to tell with these chinese brands.
I am also awaiting my SBMS40 from Dacian.
I am a little bummed that it does not do MPPT but at the time it was and currently still is the only controller that you could set the right charge profile to charge lithium chemistries other than LiFePO4.
I will likely use it with the much larger system that is going in my 4x4 van and the smaller system going in the 2wd will get a Victron 100/30 charge controller that I bought for another project that I ended up bailing on.
It's nice to see the same battery and charge controller in use in someone else's set up.
I have only see one other set up so far that is running the SBMS and they also have the same brand of cells.
They are using a fancier model of those cells but its still the same brand I think.
Seems like a good combo. |
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baltik Samba Member
Joined: April 08, 2015 Posts: 440
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Posted: Wed Aug 14, 2019 7:44 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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@ vwhammer
Agreed that it's a bit of a bummer that there is no MPPT on board, though I understand the reasoning - in a typical home installation one can control for shading and simply add more panels.
The CALB batteries I have seen tend to have a plastic casing (except the 72AH version) and are a much larger profile per amp hour than the aluminum ones. If you are less space constrained than me, they are a good choice. |
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DanHoug Samba Member
Joined: December 05, 2016 Posts: 4715 Location: Bemidji, MN
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Posted: Wed Aug 14, 2019 8:08 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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i just want to add that using a DC to DC charger such as the Renogy DCC-1212 is THE correct way to tie a house battery together with a starting battery. it provides isolation, charge current limiting, and the correct charge profile for the house battery you've selected. at a $130, it is a no-brainer. _________________ -dan
60% of what you find on the internet is wrong, including this post.
'87 Westy & '89 Westy both 2.1 4spd
Past projects can be found at--
www.thefixitworkshop.com |
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vwhammer Samba Member
Joined: May 20, 2006 Posts: 998 Location: Boulder CO.
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Posted: Wed Aug 14, 2019 9:30 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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Perhaps my confusion comes from seeing two different batteries with the same chinese words or letters in the upper left hand corner.
The white one clearly says CALB on the case and the blue ones look a lot like the cells you have.
Of course don't read chinese so who knows what that actually says.
Could just be the seller or something. |
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ALIKA T3 Samba Member
Joined: July 30, 2009 Posts: 6316 Location: Honolulu,Hawaii and France
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Posted: Wed Aug 14, 2019 10:29 pm Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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baltik wrote: |
shagginwagon83 wrote: |
This is really incredible. You even covered cold weather charging.
I have just one question. Most LifePo4 batterys have internal battery monitoring system.. These are just cells right? With a fully external BMS. |
Correct - I chose to go this route because there wasn't anything even at 100AH that would fit that space in an integrated solution (hence gowesty sells a 50AH lifepo4 kit)
Also I found the internal bms solutions somewhat lacking. many don't have low temperature cutoffs, I didn't like some of the parameters being used as well - for example many won't disconnect your load until 12.5V which is already doing damage to the battery. There is also a lack of disclosure as to exactly how these internal BMSs work (ie will they disconnect when individual cells are over discharged or the entire pack is below a certain threshold and thus individual cells may be significantly lower/higher). |
Very nice finding indeed! I looked for hours online to try to fit something like your set up,but you get sidetracked all over the internet
I am waiting on one 100 Ah battery that should fit under the seat as a big unit, with integrated BMS. I really didn`t want a BMS though as I don`t trust them. Hopefully it will get here one of these days, it came by boat from China as it is a royal PITA to get any battery shipped to Hawai`i.
My friend is one of the most renowned battery researcher, so we`re gonna put this baby up to some fancy tests in his lab and make or at least modify the BMS so I don`t drive with my ass over a powerful bomb _________________ Silicone Steering Boots and 930 Cv boots for sale in the classifieds.
Syncro transmission upgrade parts in the Classifieds.
Subaru EJ22+UN1 5 speed transmission
http://www.thesamba.com/vw/forum/viewtopic.php?t=416343
Syncro http://www.thesamba.com/vw/forum/viewtopic.php?t=4...num+gadget |
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beach_creature Samba Member
Joined: April 11, 2014 Posts: 532
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Posted: Mon Aug 26, 2019 11:34 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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I really like this system. I’m currently using a Victron 75/15 mppt charge controller. I think all I need is the BMS. I think even using a common port BMS will work. Victron says if the BMS disconnects do to low voltage and the PV is still connected to the charge controller, that this will not damage the controller. This is contradictory to what Will Prowse says in this video. https://m.youtube.com/watch?v=_PgthByAYz4&t=1396s
I have a question about if the BMS disconnects because of either low or high voltage and using a common port BMS. If disconnect because of low voltage, will charge from the PV re-open this BMS to allow charging of the cells?
And same, if it disconnects because of high voltage, will it open to allow consumption through the load of the solar charge controller? The use of a BMS is new to me and I am trying to figure this all out.
I also only use 12V appliances and do not use an inverter to use household appliances. So the battery protect is not needed and I can continue to use the Load output of the Solar charge controller to operate appliances. The software of the Victron charge controller has parameters for low voltage disconnect and can be manually programmed.
So with this set-up, I only need the cells and the BMS.
But this does not allow alternator charging.
The Renogy battery to battery charger looks great and is an option for sure. I want to see what the Victron battery to battery charger will do. It is supposed to come out by November 2019. I think using all Victron would have easier management of the systems.
Something I do not have, but really should, and especially if using lithium batteries, is a temp sensor at the battery under the drivers seat. This area can be way colder than where my controller is mounted.
I need to pick up a Victron Smart Battery Sense. This I’m sure would also be utilized by the Victron battery to battery charger when it comes out.
Thoughts? _________________ 84 Westy
1.9TD AAZ
5spd manual with Locking Peloquin TBD |
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baltik Samba Member
Joined: April 08, 2015 Posts: 440
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Posted: Tue Aug 27, 2019 7:53 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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I have never played around with the deligreen style common port BMS, but my understanding is that they will allow a charge if disconnected due to low voltage and vice versa. Otherwise the BMS would be unusable once tripped. I think the BMS and Victron combo (along with the victron temp sensor) is all you need for a solar only setup. It gets messier with the alternator as you already know, a lot of variables involved - battery pack size, alternator capacity/health, alternator wiring gauge. People run 100AH banks directly off the alternator all the time, for me a $120 Renogy DC to DC seems like affordable and reasonable insurance to make sure it runs well |
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beach_creature Samba Member
Joined: April 11, 2014 Posts: 532
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Posted: Tue Aug 27, 2019 4:51 pm Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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Cool. Thanks for the reply! _________________ 84 Westy
1.9TD AAZ
5spd manual with Locking Peloquin TBD |
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beach_creature Samba Member
Joined: April 11, 2014 Posts: 532
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Posted: Fri Aug 30, 2019 12:31 pm Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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Anyone in the Lower Mainland interested in doing a purchase of the battery cells? They are cheaper buying two or three sets compared to a single set. _________________ 84 Westy
1.9TD AAZ
5spd manual with Locking Peloquin TBD |
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oakvander Samba Member
Joined: August 16, 2018 Posts: 17 Location: Oakland, California
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Posted: Thu Sep 12, 2019 2:48 pm Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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ALIKA T3 wrote: |
I am waiting on one 100 Ah battery that should fit under the seat as a big unit, with integrated BMS.
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Hi Alika - Can you let us know where you found this battery? I'm in the market for something similar but every 100Ah with a BMS seems too large for under the seat. Thanks. _________________ '88 Westfalia, 1.8T |
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Love77 Samba Member
Joined: September 25, 2019 Posts: 18 Location: Philadelphia
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Posted: Thu Oct 10, 2019 6:47 pm Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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baltik wrote: |
I have never played around with the deligreen style common port BMS, but my understanding is that they will allow a charge if disconnected due to low voltage and vice versa. Otherwise the BMS would be unusable once tripped. I think the BMS and Victron combo (along with the victron temp sensor) is all you need for a solar only setup. It gets messier with the alternator as you already know, a lot of variables involved - battery pack size, alternator capacity/health, alternator wiring gauge. People run 100AH banks directly off the alternator all the time, for me a $120 Renogy DC to DC seems like affordable and reasonable insurance to make sure it runs well |
I’m loving everything you’re saying but I’m not smart enough to put it all together. Do you have a schematic of your entire system?
Thanks! |
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ALIKA T3 Samba Member
Joined: July 30, 2009 Posts: 6316 Location: Honolulu,Hawaii and France
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Posted: Thu Oct 10, 2019 11:58 pm Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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oakvander wrote: |
ALIKA T3 wrote: |
I am waiting on one 100 Ah battery that should fit under the seat as a big unit, with integrated BMS.
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Hi Alika - Can you let us know where you found this battery? I'm in the market for something similar but every 100Ah with a BMS seems too large for under the seat. Thanks. |
Still waiting on mine, I think I got screwed :/ _________________ Silicone Steering Boots and 930 Cv boots for sale in the classifieds.
Syncro transmission upgrade parts in the Classifieds.
Subaru EJ22+UN1 5 speed transmission
http://www.thesamba.com/vw/forum/viewtopic.php?t=416343
Syncro http://www.thesamba.com/vw/forum/viewtopic.php?t=4...num+gadget |
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baltik Samba Member
Joined: April 08, 2015 Posts: 440
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Posted: Fri Oct 11, 2019 8:47 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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Here ya go
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jocoman Samba Member
Joined: August 11, 2016 Posts: 425 Location: Ottawa, Canada
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baltik Samba Member
Joined: April 08, 2015 Posts: 440
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Posted: Tue Jan 21, 2020 9:07 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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i think this video should answer most of your questions:
https://www.youtube.com/watch?v=6hgs2jQoEcI
bottom line, it will work but build quality will (likely) be poor and it wont fit in the aux battery location |
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jocoman Samba Member
Joined: August 11, 2016 Posts: 425 Location: Ottawa, Canada
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Posted: Tue Jan 21, 2020 10:56 am Post subject: Re: New Record? 120 usable Amp Hours under Driver's seat |
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Wow. Thanks for the link.
Stay away from that!. However, he suggests putting cells and a bms together as a diy project to save cash.
Anyone know what cells and what BMS to order. _________________ '86 Westfalia 2.0L Zetec
'97 Volvo 850 AWD Turbo
" The fun never stops" |
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