# Smoking mppt controller **URL:** \ **Category:** Q&A and troubleshooting\ **Tags:** parallel, beginner, mppt\_controllers, offgrid\ **Created:** [21 April 2025 09:49 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561 "2025-04-21T09:49:38Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Gpd](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@Gpd](https://community.victronenergy.com/u/Gpd)\ **Post date:** [21 April 2025 09:49 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561/1 "2025-04-21T09:49:38Z")
Good morning, First had it connected to one litime lifepo4 24v 100ah battery, everything worksd fine. Then I connected two litime lifepo4 24v 100ah batteries in parallel. When I connected them to the mppt it made a strange noise and started smoking! My system is, Inverter smart 24/2000. Mppt smart 100/50. 2x litime lifepo4 24v 100ah batteries. 2x 480w panels. Fully charged both batteries and connected them in parallel for 24 hour’s before connecting to my charger. Is the mppt controller abel to handel this? Or was I unlucky and recieved a defective unit? Any idea’s please? Thanks. ![20250418_111221](https://europe1.discourse-cdn.com/victron/original/3X/e/0/e0c86d404f0b790df9f61a87ab5c1507a680e00c.jpeg) ![20250418_135545](https://europe1.discourse-cdn.com/victron/original/3X/5/3/534c17c8b9c3020c2d0188142b8c0ff57e477bfb.jpeg) ![20250417_173322](https://europe1.discourse-cdn.com/victron/original/3X/d/f/df7582bf761a33e3091349b083600e5d9a4726c5.jpeg) ---
**Author:** ![water\_rat](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/water_rat/32/45_2.png) [@water\_rat](https://community.victronenergy.com/u/water_rat)\ **Post date:** [21 April 2025 10:03 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561/2 "2025-04-21T10:03:33Z")
There is not a fuse or breaker to be seen anywhere. Reverse battery connection to the mppt will blow the internal (non replaceable) fuse. Higher than 100v PV voltages will damage the mppt. The mppt can be powered via the battery, or pv. Any bluetooth connection? ---
**Author:** ![Gpd](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@Gpd](https://community.victronenergy.com/u/Gpd)\ **Post date:** [21 April 2025 11:07 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561/3 "2025-04-21T11:07:23Z")
Hi, There is no longer Bluetooth connection. ![17452334825506209933237764209546](https://europe1.discourse-cdn.com/victron/original/3X/5/7/5762ccde468a35734df4b776115af825cbcad9e8.jpeg) These are th fuses. 1x 125a and 1x 40a. ---
**Author:** ![ChiefSolar](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/chiefsolar/32/22791_2.png) [@ChiefSolar](https://community.victronenergy.com/u/ChiefSolar)\ **Post date:** [21 April 2025 11:16 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561/4 "2025-04-21T11:16:07Z")
> [@Gpd](#): > > 2x 480w panels. Hello there. Welcome in the blue community. Say. Could you please add the brand, type and/or the full specs of your solar panels? Also. At what time did this happen? A nice sunny day? ---
**Author:** ![Gpd](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@Gpd](https://community.victronenergy.com/u/Gpd)\ **Post date:** [21 April 2025 12:04 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561/5 "2025-04-21T12:04:22Z")
Ok guy’s, I think I see the problem! Might have accidently by past a fuse. Talk about beginner’s luck. Don’t laugh too hard, feel a bit silly now. Will let you know if I have solved it. Thanks for the input. ---
**Author:** ![ChiefSolar](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/chiefsolar/32/22791_2.png) [@ChiefSolar](https://community.victronenergy.com/u/ChiefSolar)\ **Post date:** [21 April 2025 16:32 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561/6 "2025-04-21T16:32:05Z")
Ehm. You bypassed a fuse, and that caused the smoke? ---
**Author:** ![Gpd](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@Gpd](https://community.victronenergy.com/u/Gpd)\ **Post date:** [21 April 2025 19:42 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561/7 "2025-04-21T19:42:17Z")
When I reconnected I ran the red charger lead direct to the battery instead of via the 40a fuse. Which I think if the mppt is rated for 24v 200ah it should not go up in smoke. I have 2x ja solar 445wp panels. And yes it was very sunny when I reconnected. Verzonden vanaf [Outlook voor Android](https://aka.ms/AAb9ysg) ---
**Author:** ![Gpd](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@Gpd](https://community.victronenergy.com/u/Gpd)\ **Post date:** [21 April 2025 19:44 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561/8 "2025-04-21T19:44:28Z")
Verzonden vanaf [Outlook voor Android](https://aka.ms/AAb9ysg) > **(attachments)** > > ![Screenshot_20250403_194558_Samsung Notes.jpg](https://europe1.discourse-cdn.com/victron/original/3X/4/e/4e00f535d2515bc80e3b75becd55b778d159814e.jpeg) ---
**Author:** ![ChiefSolar](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/chiefsolar/32/22791_2.png) [@ChiefSolar](https://community.victronenergy.com/u/ChiefSolar)\ **Post date:** [21 April 2025 21:15 UTC](https://community.victronenergy.com/t/smoking-mppt-controller/29561/9 "2025-04-21T21:15:40Z")
Still puzzled about where the smoke was coming from. Was it smoke or a spark?