Swapping out power center

[Burrito]

I’m installing a new PD4135 in my 89 Burro and most of it is pretty straightforward but I was wondering if someone can tell me what this ‘block’ is. I’m thinking it’s a shunt? The black wire on the right is the + lead to the battery and the one on the left goes to the old converter.
Thanks in advance.

[Jon Vermilye]

My guess is a thermal circuit breaker.

[Burrito]

Should I leave it when I install the new converter and just connect the battery positive from the converter to it? Or should I take it out and see if I can get a better idea of what it is? The old converter was original so maybe it needed something different? If it’s helpful, here’s a pic of the converter I’m removing.

[sokhapkin]

Keep the circuit breaker, you want it in the positive wire near the battery.

[Burrito]

Originally Posted by sokhapkin

Keep the circuit breaker, you want it in the positive wire near the battery.

Thank you, I’ll leave it in place.

[gordon2]

Originally Posted by sokhapkin

Keep the circuit breaker, you want it in the positive wire near the battery.

Well it rather looks like a fuse or self-resetting circuit breaker. Such as this. And maybe quite old. If its a self resetting type then I would get rid of it because in case of a fault in the wiring it will reconnect and the fault will still exist. That could even start a fire if the fault is a short circuit. Better to use a fuse that kills the power until you fix the problem that caused the fuse to blow. Self-resetting breakers are for use with a break-away switch because even if there is a wiring fault, the risk of not having trailer brakes in a disconnect is higher.

Furthermore, unless there is another fuse or protection device between it and the battery, then all the wire from the battery to that point is not protected. Best practice is to have a fuse as close to the battery post as is reasonably possible. For the primary (main) fuse, I'm a fan of the Blue Seas battery post fuses... you can't get any closer to the battery and this protects the wiring right from the battery:
https://www.bluesea.com/products/519...k_-_30_to_300A
You need to buy the holder and seperate fuse, and its a little pricey but worth it IMHO. If your battery is not a sealed type then you do need to clean the corrosion once in a while, but you have to do that with the ring terminals on the post anyway.

So I would get the battery post fuse, or use an inline fuse on the wire outside the battery box, 1-2 inches from where it comes out of the battery box. Then run the main wire of sufficient gauge to support max current (and fuse matched) to the converter. And yes, maybe a new converter if that is not a "smart charger" type.

And if you decide to replace the converter then it makes sense to get a LifePo4 compatible converter / charger. Then when you need to replace the battery, just get a LifePo4 of the same size and you nearly double your useable capacity and have that capacity for maybe ten years.

[Burrito]

Originally Posted by gordon2

Well it rather looks like a fuse or self-resetting circuit breaker. Such as this. And maybe quite old. If its a self resetting type then I would get rid of it because in case of a fault in the wiring it will reconnect and the fault will still exist. That could even start a fire if the fault is a short circuit. Better to use a fuse that kills the power until you fix the problem that caused the fuse to blow. Self-resetting breakers are for use with a break-away switch because even if there is a wiring fault, the risk of not having trailer brakes in a disconnect is higher.

Furthermore, unless there is another fuse or protection device between it and the battery, then all the wire from the battery to that point is not protected. Best practice is to have a fuse as close to the battery post as is reasonably possible. For the primary (main) fuse, I'm a fan of the Blue Seas battery post fuses... you can't get any closer to the battery and this protects the wiring right from the battery:
https://www.bluesea.com/products/519...k_-_30_to_300A
You need to buy the holder and seperate fuse, and its a little pricey but worth it IMHO. If your battery is not a sealed type then you do need to clean the corrosion once in a while, but you have to do that with the ring terminals on the post anyway.

So I would get the battery post fuse, or use an inline fuse on the wire outside the battery box, 1-2 inches from where it comes out of the battery box. Then run the main wire of sufficient gauge to support max current (and fuse matched) to the converter. And yes, maybe a new converter if that is not a "smart charger" type.

And if you decide to replace the converter then it makes sense to get a LifePo4 compatible converter / charger. Then when you need to replace the battery, just get a LifePo4 of the same size and you nearly double your useable capacity and have that capacity for maybe ten years.

Thanks for this detailed info, this looks like a great option. So I would get the 30A fuse since that’s what the main breaker in the converter is, right? And, can I keep that old circuit breaker in place in addition to this or do I need to get a bus bar instead?

The converter I’m installing has a smart charger and can work for lithium, which I plan on getting when this lead acid battery dies.

Thanks for your help!
Anne

[gordon2]

The fuse is to protect the wiring and connectors, so the fuse size depends on what size (gauge) wire is used and how much current it will carry (and to a much lessor extent some other details such as how it is run, and expected temperature). Length matters but not so much in a small camper.

So I can't tell you for sure the right size fuse without more info. But that being said, if its a 30 amp (or less) converter and the camper has no unusual electrical appliances, and you use 10 gauge wire then chances are that 30 amp fuse is right. It is what is used in my Scamp with a 30 amp converter.

Some Lithium converters might dump more current than that into a LifePo4 battery however. What model are you planning on?

[Burrito]

Originally Posted by gordon2

The fuse is to protect the wiring and connectors, so the fuse size depends on what size (gauge) wire is used and how much current it will carry (and to a much lessor extent some other details such as how it is run, and expected temperature). Length matters but not so much in a small camper.

So I can't tell you for sure the right size fuse without more info. But that being said, if its a 30 amp (or less) converter and the camper has no unusual electrical appliances, and you use 10 gauge wire then chances are that 30 amp fuse is right. It is what is used in my Scamp with a 30 amp converter.

Some Lithium converters might dump more current than that into a LifePo4 battery however. What model are you planning on?

The converter is a PD4135 it’s a 35amp converter.
I’m only running 2 outlets on the AC side and interior led lights, water pump and a maxxair fan on DC. I will be adding a couple of usb outlets but that’s it for electrical. There’s no A/C, refrigerator or heater.

I don’t have a battery picked out yet, I’m about a year out on that-any feedback on battery would be appreciated.

I’m still not clear if I can keep that old fuse block in place and just add the new fuse block at the battery or if I need to remove the old block?

[Motoboss]

I don’t believe you need both. One is sufficient. I agree with a battery mounted fuse but if the current wire is sufficient from the battery to the current breaker I see no need to change it, other than just an upgrade.

[gordon2]

So far we are only guessing what the device is.. and no idea if its as old as the camper. I would get rid of it and use a fuse near the battery.
For ongoing LifePo4 battery reviews subscribe to Will Prowse on Youtube:
https://www.youtube.com/channel/UCoj...q8kmJme-5dnN0Q

[redbarron55]

The auto reset breaker will protect the wire as long as it is properly sized as after it resets it will already be hot and ready to trip again with the addition of just a little heat.
The issue is that after a few trips it may bot reset at all.
A standard trip free breaker is a good choice, however.
Auto reset breakers were used in single engine Cessna aircraft for a long long time with no real issues.