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dobryan Samba Member
Joined: March 24, 2006 Posts: 16474 Location: Brookeville, MD
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Posted: Thu Mar 25, 2021 6:53 am Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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buspor63 wrote: |
Howesight wrote: |
I think that using up that 310Ah will be more of a chore than re-charging. So far, I am not seeing any appreciable net discharge in my 280Ah battery, but it is early days and I have just been running my TF-65 fridge at 25F plus some use of my CDH. But so far, I am seeing that I would really have to work at creating loads that would use up the 280Ah of capacity. I suspect that the 30 amps from the Victron might well be enough
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So, what I gather here is, spend more on batteries and the DC/DC and skip the solar and solar charge controller. |
It really depends on your usage and needs.
Add up how many days you want to camp at a time times the daily power use you will have each day and see what that number of Amp Hours is. _________________ Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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shagginwagon83 Samba Member
Joined: February 07, 2016 Posts: 3786 Location: VA/TN
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Posted: Thu Mar 25, 2021 8:09 am Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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xoo00oox wrote: |
Do you think it would overheat the alternator by continuously pulling 60 amps? |
I plan on running a subaru 135amp alternator.
Also, for what it's worth - I DO 100% agree that 60amp is overkill. But the Renogy unit has this feature:
The DC-DC battery chargers feature 50% current limiting from the rated specification when
connecting the LC Terminal to a 12V source. Current Limiting is instant and recommended to
be connected to the same location as the D+ ignition cable.
So my thought is I'm going to 90% of the time run it at 30amp mode. However IF I need to - I can run it 60 amp mode.
My thought also is the unit will last longer given it's running at 50% most of the time. _________________ Brandon
"Jo Ann" - '83.5 Westfalia EJ22e w/Peloquin
Instagram @joannthevan |
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1988M5 Samba Member
Joined: January 23, 2016 Posts: 674 Location: Santa Cruz, CA
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owokie Samba Member
Joined: May 21, 2003 Posts: 532
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Posted: Thu Mar 25, 2021 11:01 am Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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shagginwagon83 wrote: |
xoo00oox wrote: |
Do you think it would overheat the alternator by continuously pulling 60 amps? |
I plan on running a subaru 135amp alternator.
Also, for what it's worth - I DO 100% agree that 60amp is overkill. But the Renogy unit has this feature:
The DC-DC battery chargers feature 50% current limiting from the rated specification when
connecting the LC Terminal to a 12V source. Current Limiting is instant and recommended to
be connected to the same location as the D+ ignition cable.
So my thought is I'm going to 90% of the time run it at 30amp mode. However IF I need to - I can run it 60 amp mode.
My thought also is the unit will last longer given it's running at 50% most of the time. |
Hell, get real fancy and put a temp switch on the alternator that stops the dc/dc when things get too heated. |
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shagginwagon83 Samba Member
Joined: February 07, 2016 Posts: 3786 Location: VA/TN
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Posted: Thu Mar 25, 2021 4:27 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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Ah yeah looks like I signed myself up for a project. I guess a microcontroller to interface with obd2. Basically if I need the 60 amps, RPM has to be above 2k for last 30 seconds, else set current to 30 amps.
Might as well throw in a temperature sensor and smoke sensor. Ironically the wires are already ran from the dash to the engine bay. _________________ Brandon
"Jo Ann" - '83.5 Westfalia EJ22e w/Peloquin
Instagram @joannthevan |
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Howesight Samba Member
Joined: July 02, 2008 Posts: 3262 Location: Vancouver, B.C.
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Posted: Thu Mar 25, 2021 5:31 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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buspor63 wrote: |
Howesight wrote: |
I think that using up that 310Ah will be more of a chore than re-charging. So far, I am not seeing any appreciable net discharge in my 280Ah battery, but it is early days and I have just been running my TF-65 fridge at 25F plus some use of my CDH. But so far, I am seeing that I would really have to work at creating loads that would use up the 280Ah of capacity. I suspect that the 30 amps from the Victron might well be enough
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So, what I gather here is, spend more on batteries and the DC/DC and skip the solar and solar charge controller. |
No, that's not the message I meant to convey. First, I am impressed (so far) with how long my 280Ah battery will run my power-hungry TF-65 fridge (set at 20 degrees F), charge some rechargeable lights, and run a few sessions of testing my CDH (an 11 amp draw on start-up). But if you buy the Redarc or Renogy DC-DC chargers, both units have a built-in MPPT solar charge controller, so you do not have to get a second device for your solar panels and you can bring and use those panels on longer stays in one location.
I was also very impressed with how quickly my 40-amp rated Redarc BCDC1240D charger replenished my 280Ah battery from alternator power. When the LiFePo4 is discharged to, say, 85% capacity or below, (just estimating for now pending my State of Charge meter install), then the Redarc commences charging at 43 amps. That's a lot of power! Four drives to and from my office over two days (40 minutes times 4) brought my batteries up to an indicated 95%. The solar equivalent of the 43 amps just mentioned is right around 600 watts. I only have 300 watts of solar panels and plan to only bring 200 of that due to space constraints (the 2 100-watt units fit in the luggage rack).
We do mostly weekend camping with a few longer trips. At this time, even for a 4-day weekend, I can't see how we could burn through 240 amp hours (assuming I leave 7% room at the top and 8% at the bottom of the SOC curve) with the electrical draws that we use. We don't use an inverter or any induction heaters or the like - - just lighting, mobile phone charging, the refrigerator, and laptop charging from time to time. YMMV. _________________ '86 Syncro Westy SVX |
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bobbyblack Samba Member
Joined: May 21, 2015 Posts: 4333 Location: United States, Iowa
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Posted: Sat Mar 27, 2021 5:25 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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Okay, well, just found a box on my porch.. Even though it was raining, I had to get some initial findings done, kids seemed to be willing to jump in too! Definitely a hungry device...
5 devices (4 phones and 1 TV) pulling 'net from the roof.
_________________ '87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch |
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Howesight Samba Member
Joined: July 02, 2008 Posts: 3262 Location: Vancouver, B.C.
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Posted: Sat Mar 27, 2021 7:09 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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Famous Quote:
"And it would have worked if it weren't for those meddling teenagers". _________________ '86 Syncro Westy SVX |
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pnwkayaker Samba Member
Joined: April 01, 2008 Posts: 918 Location: Sammamish, WA
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Posted: Sat Mar 27, 2021 8:03 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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Is that a Starlink? I assume you just let it rest on the roof - how difficult do you think would it be to pack/unpack daily (for example, if stored on a Pelican box for transportation)?
Also, could you please explain what's your reading and what are your findings? It is a power-hog?
I'm registered for the service but it's not due to be available in our area till 3Q I believe.
_________________ 87 Syncro Westy EJ25 ("Tardis")
Seattle Meetup at Marymoor (link)
A collection of Simple Useful Mods (SUM) (link) |
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bobbyblack Samba Member
Joined: May 21, 2015 Posts: 4333 Location: United States, Iowa
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Posted: Sat Mar 27, 2021 8:40 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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Starlink, ya. Mobile'ish I guess. I think deployment would take you about 3 minutes. If you made a decent travel box, it would be okay. I am not sure of how to 'ask it' to change its pole position, which would make forming a case a trick. Maybe near the end of a campout you'd orient the base so that would then get the antenna to then fit it in a foamed in box.. Hard to imagine right now.. Needs much more contemplation.
Amway, I don't know how to interpret much from the 3 1/2 hours it was out, I decided that the rain and wind were justification to put it back in the garage. So, a couple shots of battery state.
The engine run time was under 4 minutes so I am not sure what to make of the two following screen caps. From the last few times I watched, the dc-dc charger might have given it close to 38 amps.
_________________ '87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch |
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shagginwagon83 Samba Member
Joined: February 07, 2016 Posts: 3786 Location: VA/TN
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Posted: Sat Mar 27, 2021 8:40 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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Dammmnnn that Starlink tho!!
I'm signed up. Curious what amps it pulls and how hard it was to install on top of your van _________________ Brandon
"Jo Ann" - '83.5 Westfalia EJ22e w/Peloquin
Instagram @joannthevan |
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bobbyblack Samba Member
Joined: May 21, 2015 Posts: 4333 Location: United States, Iowa
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Posted: Sun Mar 28, 2021 7:52 am Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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I just set it up there over my skylight so I could watch it move to locate sat trajectories.. I saw 15 amps for a good 7 minutes while the motors did their job. I'm not sure how much the motors do after it acquires an optimal angle. The least draw I saw was 9 amps with all android devices disconnected and TV off.
When it got windy I set it in the luggage rack and found it easy to secure to the footman's loops, maybe 30 seconds there using Velcro strapping. The cable was easy enough to bring in the lower front edge of the slider, no problem or pinching with the door closed. I think a network jack could be jerry rigged in a Westy hookup box easy enough. _________________ '87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch |
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pnwkayaker Samba Member
Joined: April 01, 2008 Posts: 918 Location: Sammamish, WA
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Posted: Sun Mar 28, 2021 7:59 am Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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Curious, how do you power the antenna? Does it require an inverter or can it use 12v?
bobbyblack wrote: |
I just set it up there over my skylight so I could watch it move to locate sat trajectories.. I saw 15 amps for a good 7 minutes while the motors did their job. I'm not sure how much the motors do after it acquires an optimal angle. The least draw I saw was 9 amps with all android devices disconnected and TV off.
When it got windy I set it in the luggage rack and found it easy to secure to the footman's loops, maybe 30 seconds there using Velcro strapping. The cable was easy enough to bring in the lower front edge of the slider, no problem or pinching with the door closed. I think a network jack could be jerry rigged in a Westy hookup box easy enough. |
_________________ 87 Syncro Westy EJ25 ("Tardis")
Seattle Meetup at Marymoor (link)
A collection of Simple Useful Mods (SUM) (link) |
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bobbyblack Samba Member
Joined: May 21, 2015 Posts: 4333 Location: United States, Iowa
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Posted: Sun Mar 28, 2021 8:28 am Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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pnwkayaker wrote: |
Curious, how do you power the antenna? Does it require an inverter or can it use 12v?
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Looks like industry standard POE (I think 48V) but the supplied transformer is 110V, so it would take an adapter of some other sort. Perhaps the website has options. I was more focused on a roof mount or pole mount option when I was looking, and didn't notice a section for 12V adapter. I have a bit of over-the-top inverter in my rig, as I was having a hard time sourcing a DC television... Also my laptop, and several other of my 'tools' are easier to use 110V ac than to find and purchase DC alternatives.
Edit: Looked at my account, no, I don't see anything listed for power supply options. Although I do see some articles on upcoming versions of this for boats, or RV's so, I would guess there will be more options later. _________________ '87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch |
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dobryan Samba Member
Joined: March 24, 2006 Posts: 16474 Location: Brookeville, MD
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Posted: Thu Apr 01, 2021 12:21 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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I need to order a BMS for my new batteries. I can confirm that they have M6 studs.
I was holding off on ordering the Overkill BMS since it comes in 2 sizes, M6 and M8. But now the Overkill unit is sold out and no projected restock.
So, anyone got a good reference on a BMS that does the proper job and has bluetooth to an app?
TIA. _________________ Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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bobbyblack Samba Member
Joined: May 21, 2015 Posts: 4333 Location: United States, Iowa
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Posted: Thu Apr 01, 2021 12:28 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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dobryan wrote: |
So, anyone got a good reference on a BMS that does the proper job and has bluetooth to an app?
TIA. |
Page 11 on this thread.
gtinseth wrote: |
I found the same BMS hardware that Overkill uses on aliexpress for $58 shipped at https://www.aliexpress.com/item/32858179124.html? Click on the 4SLFP120A UARTRS485 button to get the fully loaded version. This works with the same app that Overkill uses (probably because it is the same BMS).
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_________________ '87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch |
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dobryan Samba Member
Joined: March 24, 2006 Posts: 16474 Location: Brookeville, MD
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Posted: Thu Apr 01, 2021 12:32 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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bobbyblack wrote: |
dobryan wrote: |
So, anyone got a good reference on a BMS that does the proper job and has bluetooth to an app?
TIA. |
Didn't Brandon mention the OverKill was just a name slapped on the same units from another provider? Like 10 pages ago? For like less than 1/2 the cost?
I'll look back, and edit if I find it. |
I remember something like that but I did not see it when I looked again.... but this is a long topic. _________________ Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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bobbyblack Samba Member
Joined: May 21, 2015 Posts: 4333 Location: United States, Iowa
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Posted: Thu Apr 01, 2021 12:33 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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dobryan wrote: |
I remember something like that but I did not see it when I looked again.... but this is a long topic. |
Page 11
Ya, I misremembered the original poster of the AliExpress unit.. edited my above post. _________________ '87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch |
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ProspectiveOwnergon Samba Member
Joined: May 22, 2020 Posts: 211 Location: SoCal
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Posted: Thu Apr 01, 2021 1:23 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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So then...why buy OverkillBMS? Does it provide any benefit aside from stateside shipping? |
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bobbyblack Samba Member
Joined: May 21, 2015 Posts: 4333 Location: United States, Iowa
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Posted: Thu Apr 01, 2021 1:30 pm Post subject: Re: LiFePO4 Batteries: Discussion Thread |
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ProspectiveOwnergon wrote: |
So then...why buy OverkillBMS? Does it provide any benefit aside from stateside shipping? |
I got the Overkill, I like the "if you can break it, I will replace it, forever" part. Not sure AliExpress feels the same on that.. _________________ '87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch |
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