PSU and control panel dead after Lithium battery installed

[Fontie]

Friend of mine recently had 2X 100amp Lithium batteries, 70amp B2B, Solar controller and charger installed when he picked the van up it was all working correctly but by the time he got home the control panel above the hab door wouldn't come on and the PSU EC700 was dead no beep when you pushed the black on button mains or 12v, company that fitted it came to his house that night to try and fix they couldn't. To cut it short PSU and control panel were sent to Apuljack to investigate and repair, it turns out the control panel CPU is fried. Has anyone got any idea what would cause this. The company that did the job are adamant the Lithium etc was installed correctly and its coincidence the control panel died. I must add he is completely happy with the company that did the work and are going to cover the cost of repair as a good will gesture, Has this happened to anyone else where the control panel and possibly PSU have self destructed ?

 

[Jimbohorlicks]

Too much of a coincidence ,it must be down to a misfitting.They will probably find out more when apuljack get hold of the CPU and PSU.Its a good job that the fitting company are going to put it right at no extra cost

 

[Pausim]

I had some mystery high voltage surges when I first installed lithium and B2B. It only happened when I turned the engine off and the DC voltage shot up to about 18V and then faded back to a normal voltage. I was never sure what caused it but I guessed it might be some unexpected interaction between the electronic devices connected to the battery. The motorhome did not have a Sargent PSU but an unexpected voltage might be what fried it.

I did find a solution. I had connected the B2B directly to the battery without disabling the original split charge system and putting this right stopped the voltage surge. Failure to disable the split charge system with a directly connected B2B creates a loop and this should be avoided, it may not have caused the voltage problem but putting it right cured it.

A few years later I had the equipment transferred to a new motorhome by an auto electrician and he also got it wrong, I don’t think he really understood the loop problem. I put it right with an extra relay in the system.

 

[Fontie]

Thanks for the explanation Pausim I will pass on this to my friend.

Thanks again.

 

[The Wino]

I had some mystery high voltage surges when I first installed lithium and B2B. It only happened when I turned the engine off and the DC voltage shot up to about 18V and then faded back to a normal voltage. I was never sure what caused it but I guessed it might be some unexpected interaction between the electronic devices connected to the battery. The motorhome did not have a Sargent PSU but an unexpected voltage might be what fried it.

I did find a solution. I had connected the B2B directly to the battery without disabling the original split charge system and putting this right stopped the voltage surge. Failure to disable the split charge system with a directly connected B2B creates a loop and this should be avoided, it may not have caused the voltage problem but putting it right cured it.

A few years later I had the equipment transferred to a new motorhome by an auto electrician and he also got it wrong, I don’t think he really understood the loop problem. I put it right with an extra relay in the system.

Sounds like it's the b2b installation thats the problem rather than going to lithium batteries.

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[Pausim]

Thanks for the explanation Pausim I will pass on this to my friend.

Thanks again.

He may have a different problem but happy to share my experience.

 

[Pausim]

Sounds like it's the b2b installation thats the problem rather than going to lithium batteries.

That was my experience but the Li battery and B2B have been behaving themselves since then and playing together nicely.

 

[autorouter]

To cut it short PSU and control panel were sent to Apuljack to investigate and repair, it turns out the control panel CPU is fried.

If the problem is what Pausim suggests, then (I know it's a bit late now) the easiest way to disable the split charge relay is to have someone like Apuljack remove the relay by desoldering. If they already have it on the bench taken apart for repair it's only 5 minutes to do that.

Some of these distribution/fuseboxes fitted to newish MHs with smart alternator/B2B have a box with the relay missing, so it's a perfectly acceptable solution.