Need the solar/power pros to weigh in

luthj

Engineer In Residence
WRONG,

The Plates are it's memory and the condition of the plates are what dictates how much memory it can retain. which is why when they are stripped down and reconditioned they can perform they should, and the only time that does not work is when the Lead is degraded.
I am not even sure what you are referring too, as those words don't have specific meaning in the world of batteries and battery chemistry.

Regardless, not going to argue with you. But the white papers and industry research are available with a few googles for those interested.
 

TantoTrailers

Active member
Since I don't have a wall to mount the monitor through I had to get creative and found a little box that fits both the monitor and shunt! As soon as the Victron IP67 arrives I can get everything wired up cleanly.

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shade

Well-known member
But those sucks because it forces a super tidy wiring job.
I'd have to find the right box. I'm making my own cables, so I can keep things pretty tidy, but surface mounting everything isn't such a bad thing.

If I don't mount the BMV in a box, I may mount it through a hole in the guard I use to cover everything. I just picked up several large pieces of multi-wall polycarbonate sheet that will work well for that, and might be useful for an insulated battery box/cover.
 

TantoTrailers

Active member
So I know I'm jumping ahead but I am trying to think about options for charging while driving. The solar panels in the bed of the truck did not work well and you guys pointed out some good reasons why.

I guess I have 2 options?

1) Maintain battery voltage (no charge) using the 7 pin - maintaining the battery may not be a bad deal especially since my drives from home are 7+ hours sometimes on a Friday...any gotchas with this setup?

2) DC to DC charger


In the above link there is a diagram, what are the little attachments on the positive side of the battery connections? My trailer battery is at the back of my rig...about as far from the alternator as I can get....is DC-DC charging practical in my situation without upgrading the alternator? I think the distance would be something like 25' of wire if not more depending on how I run it. IF practical, should the charge controller go in the galley near the battery or somewhere in the truck near the alternator? This is all future planning, I don't really want to do the DC-DC system since it's more $$ more complication and more opportunity for something to go wrong (complexity).
 

luthj

Engineer In Residence
If you want to go cheap, you can pick up a single voltage DC-DC boost converter from amazon cheap. Something in the 5-10A range would work fine for long drives. Set it for around 14-14.4V, and use a relay to activate it with the ignition.
 
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shade

Well-known member
So I know I'm jumping ahead but I am trying to think about options for charging while driving. The solar panels in the bed of the truck did not work well and you guys pointed out some good reasons why.

I guess I have 2 options?

1) Maintain battery voltage (no charge) using the 7 pin - maintaining the battery may not be a bad deal especially since my drives from home are 7+ hours sometimes on a Friday...any gotchas with this setup?

2) DC to DC charger


In the above link there is a diagram, what are the little attachments on the positive side of the battery connections? My trailer battery is at the back of my rig...about as far from the alternator as I can get....is DC-DC charging practical in my situation without upgrading the alternator? I think the distance would be something like 25' of wire if not more depending on how I run it. IF practical, should the charge controller go in the galley near the battery or somewhere in the truck near the alternator? This is all future planning, I don't really want to do the DC-DC system since it's more $$ more complication and more opportunity for something to go wrong (complexity).
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The S1 circuit is for a remote On/Off switch, which may be needed if Engine Sensing doesn't work with your application.

The DC-DC charger would go in the galley, near the house battery. You'd want to minimize voltage drop from the alternator to the DC-DC charger, but it's not as critical as with other installations since it's designed to increase voltage. I don't see a specific recommended voltage drop range in the manual. You can use this calculator to figure that out, and order cable from them.

Like John said, you can save money with a less expensive DC-DC charger, especially since you're using a lead battery.
 

TantoTrailers

Active member
If you want to go cheap, you can pick up a single voltage DC-DC boost converter from amazon cheap. Something in the 5-10A range would work fine for long drives. Set it for around 14-14.4V, and use a relay to activate it with the ignition.
That sounds like a good plan! I will need to do some digging on how all that would connect. I assume the same goes for location - in the galley near the house battery?
 

luthj

Engineer In Residence
DC-DC converters are pretty simple. Connect input to vehicle electrical system. Connect output to battery. Fuse appropriately. They need good airflow for cooling, and generally should be mounted reasonably close to the house battery.

A quick google turned up this DC-DC converter, 50W output, overcurrent protection, etc. You need to verify it will boost output, but it looks like it. The spec sheet shows output is adjustable, likely with a pot on the board.

 

shade

Well-known member
DC-DC converters are pretty simple. Connect input to vehicle electrical system. Connect output to battery. Fuse appropriately. They need good airflow for cooling, and generally should be mounted reasonably close to the house battery.

A quick google turned up this DC-DC converter, 50W output, overcurrent protection, etc. You need to verify it will boost output, but it looks like it. The spec sheet shows output is adjustable, likely with a pot on the board.

Pretty straightforward, but 50W is pretty puny, though. I like how Mouser indexes their catalog.

 

TantoTrailers

Active member
What type of wiring would I need for a 10Amp DC/DC Converter sitting in the galley of my trailer 25-30' from the vehicle battery? When you say "vehicle electrical system" do you mean straight to +/- of the battery? 10A fuses on both ends of the positive? Sorry this is way over my head...for now.

18# shows about 3.3v drop over 25' according to the Calculator you linked earlier...I'm not sure if that is acceptable? Seems like a lot for 12V but I am a n00b in this field
 

luthj

Engineer In Residence
Look at the DC-DC chargers input voltage range. Take your alternator voltage and determine how much voltage drop you can tolerate, and then calculate the wiring needed based on the rated charge current.

You will want to run that style of dumb converter through a relay, ignition triggered will work fine. If you are only dealing with 50w or so, you can just use a factory accessory circuit. Once you break 100-200W, a dedicated circuit from your distribution block, battery, etc may be called for.

For example. 13.9 alt votlage and 12.5V minimum input voltage. So a drop of 13.9-12.5=1.4V 1.4/13.9=0.10, or 10%.
 

luthj

Engineer In Residence
Also, take into account efficiency, your vehicle side load is going to be 25% higher watts than the output. Use that to calculate your load amps based on the alternator voltage (plus a little margin). I would assume 11A on the load side for the 100w unit.
 

TantoTrailers

Active member
Hmm, that 100W looks like it might be the sweet spot for a cheap trickle charge solution. This is literally for the days that I spend road tripping from boondock site to boondock site. I spent 4 days exploring southern Illinois 2 weekends ago and I was in the truck moving pretty much all day during daylight, plenty of time to charge from the alternator.

I will need to check the voltage coming off my alternator so I can get the voltage drop I can tolerate so I can get a good idea of the wiring size needed. Hoping I can just use the accessory wiring off of my 7 PIN. The BMV should show me some charge data for this setup right? Amps/Volts/Watts into the battery?

Also, is this the type of relay I am looking for?

Sounds like this may happen sooner than I thought hahaha.......damn!
 
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