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T3TRIS
Samba Member
Joined: October 30, 2017
Posts: 299
Location: Portland, OR
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 Posted: Thu Dec 01, 2022 7:36 pm Post subject: Re: Externally mounting the Redarc DC-DC |
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| MarkWard wrote: |
| I spent a lot of time thinking about what size dc to dc charger to get. I ended up with a 20amp charger. My alternator is a 120 amp charger. Camped with the heater running I use maybe 10 amps a night. Once on the road, my SOC is 100% in less than an hour of running the engine. Curious, how much power are you folks using in a 12 hour period? |
There’s also the element of camping several nights and days in one spot. The amp usage over that period of time can quickly climb especially with more features built into the rigs. Overbuilding the battery system usually has the end goal of making it invisible. It’s a luxury, sure, but it’s nice never to have to worry about a depleted battery despite camping several days in the shade with nice comfort and features. It’s not for everyone of course, but the footprint of a well built ~300Ah lithium battery can be considered modest compared to the conveniences it offers. I’m building a 300Ah system right now with all the guts that should fit nicely in about half of the Westfalia bench storage, including all the fuses, low voltage disconnect, shunt, killswitch, and 30A shore, solar and DC charging.
Though I guess that’s not really the point of this thread  again, a capacity question distraction!
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Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 17105
Location: Retired South Florida
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| Posted: Fri Dec 02, 2022 5:16 am Post subject: Re: Externally mounting the Redarc DC-DC |
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True there is no one size that fits all.
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shagginwagon83
Samba Member
Joined: February 07, 2016
Posts: 3794
Location: VA/TN
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| Posted: Fri Dec 02, 2022 6:54 am Post subject: Re: Externally mounting the Redarc DC-DC |
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Question: Does switching profiles while charging damage the charger?
Answer: Good question Brandon, the charger won’t allow a profile change whilst charging, this can only happen whilst the charger is idle and not engaged…
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Brandon
"Jo Ann" - '83.5 Westfalia EJ22e w/Peloquin
Instagram @joannthevan |
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T3TRIS
Samba Member
Joined: October 30, 2017
Posts: 299
Location: Portland, OR
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| Posted: Sat Dec 03, 2022 12:16 am Post subject: Re: Externally mounting the Redarc DC-DC |
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| shagginwagon83 wrote: |
Question: Does switching profiles while charging damage the charger?
Answer: Good question Brandon, the charger won’t allow a profile change whilst charging, this can only happen whilst the charger is idle and not engaged… |
Not ideal but not the end of the world either I guess. First stop and go would change the profile. I wonder if the profile would change if the charging side of the BMS is deactivated and reactivated (as can be done with Bluetooth BMS). Or if the profile didn’t get a chance to change, the battery could still be charged up to 90%. And 90% with 280Ah or 300Ah is still way more than enough for a long weekend of electrical debauchery 
_________________
Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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shagginwagon83
Samba Member
Joined: February 07, 2016
Posts: 3794
Location: VA/TN
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| Posted: Mon Feb 26, 2024 9:16 am Post subject: Re: Externally mounting the Redarc DC-DC |
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So internally mounting the Redarc 50amp dc-dc without any passive cooling results in the unit overheating and throttling your charging speed, pretty significantly.
I plan to relocate the unit to the rear pillar, behind the tail light, for airflow cooling. I will have to add a switch to control charging profiles for my unit.
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Brandon
"Jo Ann" - '83.5 Westfalia EJ22e w/Peloquin
Instagram @joannthevan |
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shagginwagon83
Samba Member
Joined: February 07, 2016
Posts: 3794
Location: VA/TN
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| Posted: Mon Feb 26, 2024 9:32 am Post subject: Re: Externally mounting the Redarc DC-DC |
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| MarkWard wrote: |
| Curious, how much power are you folks using in a 12 hour period? |
In Baja, two people working on their laptops 8 hours a day, with 200w of roof-top solar, we were consuming about 100-150ah a day. We had a 300ah and a 150ah battery on board, and we had to move every 3 days to recharge our battery.
It's mainly my i9 laptop with it's 230w charger. While charging, it pulls 12amps DC / hour.
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Brandon
"Jo Ann" - '83.5 Westfalia EJ22e w/Peloquin
Instagram @joannthevan |
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