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electrical:12v:b2b [2018/12/28 10:38]
frater_secessus [Sterling]
electrical:12v:b2b [2020/03/23 10:13]
frater_secessus [Renogy]
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 ====== Battery to battery chargers ====== ====== Battery to battery chargers ======
  
-A b2b (or //dc-dc//) charger is a type of [[electrical:​12v:​alternator|isolator]] that boosts charging voltage to the house battery. ​ These typically cost more and deliver ​less current than normal isolator types+A b2b (or //dc-dc//) charger is a type of [[electrical:​12v:​alternator|isolator]] that boosts charging voltage to the house battery. ​ These typically cost more and are rated for less current than normal isolator types.((but they will provide more current overall during longish drives. ​ See below.))
  
 [[https://​amzn.to/​2RY2GNQ|{{ https://​images-na.ssl-images-amazon.com/​images/​I/​3131jBgz9LL._AC_US218_.jpg}}]] [[https://​amzn.to/​2RY2GNQ|{{ https://​images-na.ssl-images-amazon.com/​images/​I/​3131jBgz9LL._AC_US218_.jpg}}]]
-This kind of controller boosts the chassis voltage to voltage appropriate for proper Absorption.  ​+This kind of controller boosts the chassis voltage to voltage appropriate for proper ​lead-acid ​Absorption.  ​ 
 + 
 + 
 +===== limitations ===== 
 + 
 +Lead-acid batteries require two things to get fully charged: 
 +  - a high enough [[electrical:​12v:​charging#​absorption_stage|Absorption voltage]] (Vabs) 
 +  - enough //time// at that voltage for the battery to stop accepting much current.(([[electrical:​12v:​battery_capacity|C/​100]] to C/200)) 
 + 
 +DC-DC chargers address the first requirement,​ but unless you are driving for //hours// the isolator still won't have enough time to fully charge the batteries. ​ DC-DC chargers were first marketed for cruisers (powered boats) since they run the engines ("​cruise"​) for hours each day. 
 + 
 +**Charger throughput is generally limited** to 20-30A since higher rates would dictate $$$ internal components. This isn't as big a limitation as it might seem, since lead-acid [[electrical:​solar:​status#​in_absorption|current acceptance drops substantially throughout Absorption]]. Untested theory: ​ [[https://​boondockplan.wordpress.com/​2019/​04/​11/​on-the-ctek-d250s-charger-and-smartpass/​|b2b chargers might work well beside normal isolators]]; ​ this is essentially the $$$ CTEK SmartPass setup described below.  
  
 ===== CTEK D250 series ===== ===== CTEK D250 series =====
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 The most common b2b charger with '​dwellers is the [[https://​amzn.to/​2RY2GNQ|CTEK D250SA]], a 20A solar/alt controller. ​ It has connections for both alternator and solar panel input + MPPT function, although the MPPT algo may not be partcularly robust.  ​ The most common b2b charger with '​dwellers is the [[https://​amzn.to/​2RY2GNQ|CTEK D250SA]], a 20A solar/alt controller. ​ It has connections for both alternator and solar panel input + MPPT function, although the MPPT algo may not be partcularly robust.  ​
  
-The [[https://​amzn.to/​2TozjWu|SmartPass accessory]] ​bypasses the D250SA ​when the house battery wants > 20A of current.  This will generally ​happen in the first half of Bulk mode. When the house battery ​demand drops below 20A control is handed back to the D250SA ​for boosting ​to Absorption voltage.((https://​www.4x4community.co.za/​forum/​showthread.php/​292297-Ctek-250-upgrade-to-smartpass?​p=3823781#​post3823781))\\ +The [[https://​amzn.to/​2TozjWu|SmartPass accessory]] ​adds 80A of alternator-voltage charging ​when Vbatt is low enough that the alternator can still charge it directly.  This combined charging((up to 100A)) ​will happen in the first half of Bulk mode. As house battery ​voltage rises to normal alternator voltage ​the smartpass can no longer contribute. ​ At that point the 20A D250SA ​continues voltage-boosted charging ​to Absorption voltage.((https://​www.4x4community.co.za/​forum/​showthread.php/​292297-Ctek-250-upgrade-to-smartpass?​p=3823781#​post3823781))\\
- +
-Note:  the CTEK D250SA((and the pre-2018 D250**S** model)) panel voltage (Vpanel) maximum is 23v.((https://​www.ctek.com/​storage/​ma/​b21ecd5d5e5943a995474cf36d586451/​956c3913c8cc4319bb4e47baea0c6d82/​pdf/​A78BBB08A9DF8976DB79E21271E091489ACEF47A/​D250SA-manual-UK-EN.pdf,​ pdf))+
  
 +Note:  the CTEK D250SA((and the pre-2018 D250**S** model)) panel voltage (Vpanel) maximum is 23v.((https://​www.ctek.com/​storage/​ma/​b21ecd5d5e5943a995474cf36d586451/​956c3913c8cc4319bb4e47baea0c6d82/​pdf/​A78BBB08A9DF8976DB79E21271E091489ACEF47A/​D250SA-manual-UK-EN.pdf,​ pdf))  There are user reports that the unit is [[https://​www.4x4community.co.za/​forum/​showthread.php/​322874-CTEK-D250S-Problem?​s=a2bc518379e50466c9ec523e8b114053&​p=4270868#​post4270868|repairable after overvoltage or polarity damage]]. ​ It requires >= 80w of solar for reliable solar charging.(())(()) ​ [[https://​duckduckgo.com/?​q=ctek+mppt+problems&​ia=web|There are anecdotes that the MPPT algorithm is not particularly robust]] and is better thought of as an add-on for the alternator charging circuit.((https://​expeditionportal.com/​forum/​threads/​ctek-250s-poor-solar-performance.198052/​))
 + 
 ===== Sterling ===== ===== Sterling =====
  
 [[https://​amzn.to/​2SkqVXq|{{https://​images-na.ssl-images-amazon.com/​images/​I/​41iC+8sIvJL._AC_US218_.jpg }}]] [[https://​amzn.to/​2SkqVXq|{{https://​images-na.ssl-images-amazon.com/​images/​I/​41iC+8sIvJL._AC_US218_.jpg }}]]
 The Sterling Pro Batt Ultra series is alternator-charging only, but can be configured to exact [[electrical:​solar:​charge_controller_setpoints|setpoints]]. The BB1260-12 is a 30A example and costs about $50 more than the D250S above. ​ The Sterling Pro Batt Ultra series is alternator-charging only, but can be configured to exact [[electrical:​solar:​charge_controller_setpoints|setpoints]]. The BB1260-12 is a 30A example and costs about $50 more than the D250S above. ​
 +
 +===== Renogy =====
 +relays
 +[[https://​amzn.to/​33HJ8ns|{{ https://​images-na.ssl-images-amazon.com/​images/​I/​51Hu4-7NxOL._AC_UL160_SR160,​160_.jpg}}]]
 +
 +  * DC1212 series DC-DC isolators in 20-40((and possibly 60A according to manual nomenclature)) output. ​ Switched on by ignition circuit on the D+ port.((https://​www.renogy.com/​content/​RNG-DCC1212-20-BC/​DCC1212-204060-Manual.pdf)) DIP switches for battery type. [[https://​www.renogy.com/​content/​RNG-DCC1212-20-BC/​DCC1212-204060-Manual.pdf|manual]] (pdf)
 +  * DCC-series of voltage sensing b2b chargers in [[https://​amzn.to/​2NGIP6U|20A]] and [[https://​amzn.to/​33HJ8ns|40A versions]].  ​
 +  * DCC50S [[https://​amzn.to/​2QYuswm|50A model with MPPT charging]]. MPPT input limited to 25v.((per the manual)) - [[https://​www.renogy.com/​content/​RBC50D1S-G1/​RBC50D1S-G1-Manual.pdf|manual]] (pdf)
 +
 +
 +
  
 ===== Redarc ===== ===== Redarc =====
 [[https://​amzn.to/​2VgTre7|{{ https://​images-na.ssl-images-amazon.com/​images/​I/​417F858GCdL._AC_US218_.jpg}}]] [[https://​amzn.to/​2VgTre7|{{ https://​images-na.ssl-images-amazon.com/​images/​I/​417F858GCdL._AC_US218_.jpg}}]]
 Redarc makes [[https://​amzn.to/​2VgTre7|a 25A b2b charge with MPPT]] similar to the CTEK. Redarc makes [[https://​amzn.to/​2VgTre7|a 25A b2b charge with MPPT]] similar to the CTEK.
 +
 +===== Ring Automotive =====
 +
 +Ring makes [[https://​www.ringautomotive.com/​en/​product/​RSCDC30|a 30A DC-DC charger]].
electrical/12v/b2b.txt · Last modified: 2020/07/03 16:15 by frater_secessus