Making the change from lead acid to lithium - a thread with pictures

Lenny HB

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Oct 18, 2007
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Repace the 90 with an 80, you could go higher.

Not sure how the Votronic handles too much input I know the Victrons are OK with it might be worth asking them.

Relisticly when are you going to get full output from the panels mid June southern Spain?

You could just fit a switch inline with the panel for the odd occasion when you are likely to get full output.
 
OP
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Sep 29, 2019
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Repace the 90 with an 80, you could go higher.

Not sure how the Votronic handles too much input I know the Victrons are OK with it might be worth asking them.

Relisticly when are you going to get full output from the panels mid June southern Spain?

You could just fit a switch inline with the panel for the odd occasion when you are likely to get full output.

Good point ref the switch, my mate did this on his off grid home. Worked a treat.

Will have a think while I am at work over the next few days and see what I can source and what will be easiest.


Count the cells on the panel. The 90w I guess is a 12v 36cells and the 275 is a 30v 60 cells panel.
Agree is cheaper to get another 275w panel, if controller allows.

Thanks, will do that as soon as I can see it in the light.
 
OP
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Sep 29, 2019
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While gathering bits, I have double checked the cable size.

Invertor is currently wired with 25mm cable. From what I have read, that’s enough for the expected draw of around 100 amps.

The battery will be fused at 125 mega fuse and inventor at 100 amp mega fuse.

The cable I have is only 16mm so I need some more to go from the busbar to the battery. I only need a metre, just checked out the price and it’s £20 for a metre of red and black.

So I got these for the same price.

Amazon product
I can now use what I need and make a jump start pack with a spare battery for keeping in the garage. :)

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OP
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That’s not a bad price at all.

Bizarre but the jump leads still work out cheaper and delivered via Amazon for free tomorrow after just ordering.

I find it bizarre how they can do stuff so cheap.
 
Dec 2, 2019
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Not a bad prise if is copper. It can be aluminium copper plated as I found out with a 5m kit from B&Q. I kid you not, took it back with the clamp cut and got a full refund. They pulled the hole stock from the shelves to re price as copper plated.

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OP
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Not a bad prise if is copper. It can be aluminium copper plated as I found out with a 5m kit from B&Q. I kid you not, took it back with the clamp cut and got a full refund. They pulled the hole stock from the shelves to re price as copper plated.

I did check the reviews and they said it was copper and 25mm, I have heard the same horror stories about jump leads. They arrive tomorrow so will let everyone know. :)
 
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I presume you have used jump leads for their actual purpose? They get quite warm - and they are only used for a few seconds. How long will your inverter be on?

They say they are rated to 600 amps, which is tosh. The crocodile clips won’t take near that.

The total load with the inverter at full whack of 1200 watts will be 100 amps. This is about a metre from the battery. Everything I have read indicates this is within the accepted range for that size cable.

I don’t think apart from testing, it will ever be at full whack.

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Dec 2, 2019
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Depends, for 3-5seconds the claps could do 800-1000 amps. The length is a big factor of resistance to. If a cable has a nominal rating, over a distance that will be de rated as much as the length dictates. Also full duty cycle is a factor to. Free air or conduit as well influences the duty length of time. On victron inverters manual always states the recommended cable size for a given inverter. I found it to be always one size up, for full duty cycle and permanent installations.
In your case the 25mm will work up to a meter with minimal voltage drop at full chat. Don’t forget that every connection is a potential resistance, and you try to minimise it with a good cable and crimps. I would of got ready crimped if you don’t have a hydraulic crimper. The 35mm would of been perfect. But that’s just me.
 
OP
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Depends, for 3-5seconds the claps could do 800-1000 amps. The length is a big factor of resistance to. If a cable has a nominal rating, over a distance that will be de rated as much as the length dictates. Also full duty cycle is a factor to. Free air or conduit as well influences the duty length of time. On victron inverters manual always states the recommended cable size for a given inverter. I found it to be always one size up, for full duty cycle and permanent installations.
In your case the 25mm will work up to a meter with minimal voltage drop at full chat. Don’t forget that every connection is a potential resistance, and you try to minimise it with a good cable and crimps. I would of got ready crimped if you don’t have a hydraulic crimper. The 35mm would of been perfect. But that’s just me.

I don’t disagree at all, you are right, the 35mm would have been ideal.

The 1200w inverter is there because it was cheap and can run a hairdryer on low if we ever need to. It’s mainly used for electronic items and slow cooker occasionally. I have thought about getting a smaller one as a 500 watt one would be fine, but then the one we have works so.

Thanks for the tips, all help gratefully received.

I even got a proper crimp tool instead of just hitting them with a hammer. :)
 
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Sep 29, 2019
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Little bit getting sorted today before I go on nights.

Inverter is removed and I am redoing the crimps as the live was getting warm when testing at full blast.

Testament to the quality of my previous crimps the cable is heat damaged. Lesson learnt, hammer and cold chisel doesn’t give a good crimp. :-(

F0454F6C-4E83-4675-AC47-6AC6563E4EB0.jpeg

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OP
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Another tip, warm the Motorhome when it’s freezing outside. I can’t feel a bloody thing or use my fingers properly. Fan heater on full blast!

image.jpg

New crimp tool seems to work well. I would prefer a more solid base to hit with hammer but it seems to be solid and the right shape. I would have got a plier type one but had cheap ones in the past and they have been rubbish! This seemed the better option.

The cable is a tight fit between the battery compartment and the inverter location so I will have a mare getting it run if I take it out again.
 
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That’s the sensor cable sorted and ready.

Sitting waiting for when I am ready to install the B2B which is going at the back of the EBL under the passenger seat.

A345A69F-30C0-465B-9816-FB831CD2F239.jpeg

F3EA10E6-DAA3-4525-BCE9-D9BCD7F99981.jpeg

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OP
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Inverter is back in and now with much better crimps. That’s it for today, best go to sleep now! After I have ordered more crimps, why do you never have enough of the right ones?

A8D8F562-1C96-477C-A2A2-30E9C205C4FF.jpeg

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OP
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Jump leads are here.

I can confirm they are copper core and are 25mm. Weird as they have no markings on the cable at all.

2E17CB7A-2165-491E-AF60-D50E34B4C3FF.jpeg

Old confirmed 25mm on the left and new jump leads on the right.
 
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I have also decided to put a switch on the leads from the solar panels to the regulators.

I need to cover up holes from the old regulator that was mounted on the left as you come in the Motorhome at head height. I was going to use a standard 1 gang light switch as they will take 10 amps and won’t look odd.

For the bigger panel I will be going for a 20 amp switch in the battery compartment.
 
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Checked the voltage at the different panels. Alas one is 21 volts and the other is 36.

Having priced up a new panel and brackets and sikaflex, a new controller is about the same price so I am putting another controller in. This will give me some redundancy in case of issues as well.

This is the old controller which is being replaced with a switch.

579C8C1F-11FF-4E9C-83ED-6F7B1B745133.jpeg
 
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Hidden the holes nicely and I can now switch the panel off if needed.

Bit of tape to remind me not to switch it until I am ready.

image.jpg

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OP
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That’s all the connections done for the solar.

You can also see the smart shunt power and engine battery wires now connected. All three temperature sensors are waiting to be tidied up as well.

Now to add the battery cables.

5FE491A3-7143-4049-AE5A-1B07727B3E36.jpeg
 
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Covers are on the busbars and battery cables are in.

The moment of truth!

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