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electrical:12v:b2b [2018/12/28 10:38]
frater_secessus [Sterling]
electrical:12v:b2b [2019/11/12 09:48] (current)
frater_secessus [limitations]
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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 won't have enough time to fully charge the batteries. ​ DC-DC chargers were first marketed for cruisers (boats) since they run the engines 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]]. ​
 ===== CTEK D250 series ===== ===== CTEK D250 series =====
  
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 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]] 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))\\
  
-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))  It requires >= 80w of solar for reliable solar charging.(())(()) ​ There are reports 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/​)) ​ FIXME 
 + 
 ===== 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 =====
 +[[https://​amzn.to/​33HJ8ns|{{ https://​images-na.ssl-images-amazon.com/​images/​I/​51Hu4-7NxOL._AC_UL160_SR160,​160_.jpg}}]]Renogy makes b2b chargers in [[https://​amzn.to/​2NGIP6U|20A]] and [[https://​amzn.to/​33HJ8ns|40A versions]].
 +
 +This charger has preset profiles for battery types.
 +
  
 ===== 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.1546022335.txt.gz · Last modified: 2018/12/28 10:38 by frater_secessus