# Blowning fuses with a 15Amp battery charger

**URL:** <https://community.victronenergy.com/t/blowning-fuses-with-a-15amp-battery-charger/10935>\
**Category:** Q&A and troubleshooting\
**Tags:** agm\_battery, marine, beginner\
**Created:** [8 November 2024 15:12 UTC](https://community.victronenergy.com/t/blowning-fuses-with-a-15amp-battery-charger/10935 "2024-11-08T15:12:11Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Bristol](https://avatars.discourse-cdn.com/v4/letter/b/9fc29f/32.png) [@Bristol](https://community.victronenergy.com/u/Bristol)\
**Post date:** [8 November 2024 15:12 UTC](https://community.victronenergy.com/t/blowning-fuses-with-a-15amp-battery-charger/10935/1 "2024-11-08T15:12:11Z")

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Hi  
I continue to blow fuses and need some help troubleshooting. I have a sail boat with a typical battery and charging system.  
A house bank of lead acid and an AGM starter battery, an alternator for each. I have a 15A Victron charger between the house bank and the starter battery to keep it topped off when on shore power or at anchor. I have 2’ of 10 AWG wire with a 30amp fuse in line between the house bank and the Victron. When I start the engine this fuse blows, otherwise it is good, ie when connected to shore power and engine is off.

The odd thing is that the Victron charger replaced a Magnum charger. The only thing that has changed in the set up is the AGM and the Victron.

i have the settings to, AGM profile and regular alternator and have rechecked my wiring connections.

Any and all advise is very much welcome.

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**Author:** ![pwfarnell](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/pwfarnell/32/2341_2.png) [@pwfarnell](https://community.victronenergy.com/u/pwfarnell)\
**Post date:** [8 November 2024 15:29 UTC](https://community.victronenergy.com/t/blowning-fuses-with-a-15amp-battery-charger/10935/2 "2024-11-08T15:29:37Z")

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Which model of charger, assuming a DC to DC is what you mean.

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**Author:** ![Bristol](https://avatars.discourse-cdn.com/v4/letter/b/9fc29f/32.png) [@Bristol](https://community.victronenergy.com/u/Bristol)\
**Post date:** [8 November 2024 16:25 UTC](https://community.victronenergy.com/t/blowning-fuses-with-a-15amp-battery-charger/10935/3 "2024-11-08T16:25:29Z")

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i posted the wrong specs on the original post. its a 30A not a 15A.

VICTRON ORION-TR SMART 12/12-30 30A (360W) ISOLATED DC-DC CHARGER OR POWER SUPPLY

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<div class="post-metadata">

**Author:** ![pwfarnell](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/pwfarnell/32/2341_2.png) [@pwfarnell](https://community.victronenergy.com/u/pwfarnell)\
**Post date:** [8 November 2024 17:01 UTC](https://community.victronenergy.com/t/blowning-fuses-with-a-15amp-battery-charger/10935/4 "2024-11-08T17:01:14Z")

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> [@Bristol](#):
>
> VICTRON ORION-TR SMART 12/12-30

No wonder it is blowing, the manual recommends a 60A fuse. The unit will output 30A and input more than that. For 2ft it also recommends 10mm2 cable (8awg) but it is right on the change between 10 and 8 awg.

See Section 4.2 of the manual.

| Voltage rating (Input or output) | External battery protection Fuse | 0.5m | 1m |
| --- | --- | --- | --- |
| 12V | 60A | 6mm2 | 10mm2 |

[www.victronenergy.com/media/pg/Orion-Tr\_Smart\_DC-DC\_Charger\_-\_Isolated/en/installation.html](https://www.victronenergy.com/media/pg/Orion-Tr_Smart_DC-DC_Charger_-_Isolated/en/installation.html)

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<div class="post-metadata">

**Author:** ![Bristol](https://avatars.discourse-cdn.com/v4/letter/b/9fc29f/32.png) [@Bristol](https://community.victronenergy.com/u/Bristol)\
**Post date:** [8 November 2024 18:03 UTC](https://community.victronenergy.com/t/blowning-fuses-with-a-15amp-battery-charger/10935/5 "2024-11-08T18:03:58Z")

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ah, great thanks