electrical:12v:diysmartpass
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electrical:12v:diysmartpass [2023/06/23 15:20] frater_secessus [20A DC-DC 20A DC-DC + 20A solar controller + MOSFET isolator: $243-$304] |
electrical:12v:diysmartpass [2023/07/28 17:09] frater_secessus [challenges] |
- stop the isolator from passing voltages >Vfloat from alternator to house bank during Float stage. This should be a minimal problem with lead batteries((which can usually [[electrical:12v:eternal_absorption|tolerate high floats]])) and with driving times limited to a few hours. It //could// be a problem with Li batteries and many hours of driving. Note: it is not clear that the Ctek combo addresses this issue. The only approaches known to prevent excessive voltage during float are the combo DC-DC and the solenoid + HVD in conservative mode (see below). | - stop the isolator from passing voltages >Vfloat from alternator to house bank during Float stage. This should be a minimal problem with lead batteries((which can usually [[electrical:12v:eternal_absorption|tolerate high floats]])) and with driving times limited to a few hours. It //could// be a problem with Li batteries and many hours of driving. Note: it is not clear that the Ctek combo addresses this issue. The only approaches known to prevent excessive voltage during float are the combo DC-DC and the solenoid + HVD in conservative mode (see below). |
- **isolators have no control over current**. In reality the combo might make **20A+120A** (dead house bank, big alternator, cool temps, Bulk stage) or it might make **20A+1A** (when battery bank is approaching alternator voltage). There is no guarantee that the DC-DC will be making 20A, either. If your bank is only accepting 15A then having 140A theoretical on tap will not matter. | - **isolators have no control over current**. In reality the combo might make **20A+120A** (dead house bank, big alternator, cool temps, Bulk stage) or it might make **20A+1A** (when battery bank is approaching alternator voltage). There is no guarantee that the DC-DC will be making 20A, either. If your bank is only accepting 15A then having 140A theoretical on tap will not matter. |
| - provide for [[electrical:12v:self-jumpstarting|self-jumpstarting]]. The method Ctek uses for this appears to be FET-based like main isolation: "Is a smart combination of relays (actually MOSFETS) that |
| connects starter and service batteries. This enables current from your alternator to charge both batteries".((https://www.ctek.com/storage/5CDB4E293A03CBF6442A620EC8E49CFB548CB48E9BF93425638077279A13BBA1/ac5639c5feaa46d38411ebd69f915b5b/pdf/media/65589cee7d4342e0891e2130149be66f/SmartPass%20120S.pdf)) [Dual MOSFET packs in series? - secesssus] |
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electrical/12v/diysmartpass.txt ยท Last modified: 2024/03/20 16:06 by frater_secessus