Schaudt LRM 1218 over panelling

[ben0069]

Hello everyone,
I am looking for advice as to whether I can safely add a third 100 watt panel to my existing two 100 watt panels. Each panel is 24.3 volts and 5.21 amps, they are all the same brand. Wired in parallel with 4mm sq solar wire into the schaudt lrm 1218. I have the LT 320 panel and the TF 50 battery sensor and all is working well.
I have calculated the amps to be 15.63 and volts to remain the same, the part I am unsure of is; the max wp of the 1218 says 275 watts but with the third panel it would raise to 380 watts (15.63amps x 24.3volts), and also leaving room for the affect of cold temperatures.
I have contacted Schaudt (now lippert) and they said they no longer deal with individual customers and sent me the manual that I already have.
The information is probably on the manual but I am unable to see it (work it out)...
Thanks
ben
saundersfoot

 

[RogerIvy]

Have you considered upgrading your controller to a Victron 100/30?

It will cope with your three panels and a provide really useful info.

 

[ben0069]

Hi Roger
I have wired the schaudt to the starter battery too, that's why I was hoping to leave it alone.

 

[Lenny HB]

I'm confused how does adding a third 100 watt panel to the exsisting two 100 watt panels make 380 watts?

If you total is only 300 watts it will probable be OK as you will never see full output from the panels if mounted flat on the roof unless you are near the equator.

If you do get too much input into the LR1218 it will probably shut down like most controllers apart from Victron which just waste the excess in heat.

 

[peterc10]

Hi Roger
I have wired the schaudt to the starter battery too, that's why I was hoping to leave it alone.

I used to have the schaudt LRM 1218 in my Hymer being fed by 250W of solar. When I changed to Lithium I needed to change it because it did not have a Lithium profile. I chose a Votronic MPP350 because it had a lithium profile and (unlike Victron) a trickle charge to the leisure battery. After the change the Votronic it seemed to me to be producing more amps than the Schaudt used to do.

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[ben0069]

Lenny,
maybe I have confused myself with all the reading, I thought wattage was amps x volts so with the 3rd panel, 3 x the amps (parralel) x the volts is 380. Unless that calculation is irrelevant to me just adding a 100 watt panel which does only make 300 watts ?

peterc10,
I have looked at the votronic mpp350 and have read that lenny uses it also, it's just the schaudt is quite new to me and with the panel fixed and wired in with everything working well it was the easiest and cheapest option.

 

[tonka]

My van came with the LR1218 fitted and 2 panels.. Did OK but never performed great.
Bought van in 2019 and it was originally registered in 2014, my suspision is that the solar was fitted in that first year, so making the panels 10 years old.
On recommendations from Funsters i changed the LR1218 to the Votronic 250 which is MPPT and that did the leisure battery with a 1 amp feed to the engine battery.

Earlier this year i went over to lithium, the Votronic and original panels never seemed to be doing much compared to others i spoke to at Fun meets. I bit the bullet and removed old panels, found they were 100watt when i looked at the labels underneath.
Replaced the solar regulator with the Victron mppt 100/30 £90 and a ebay deal got me 2 x 170w Ecoworthy panels for £120..
BIG difference, solar is working far far better.. SO it may be worth considering a complete upgrade rather than just adding a new panel to an old system.. Remember the LR1218 is a PWM regulator so not as good as the MPPT.

PS.. IF you do want a Votronic 250 mppt I have one for sale.

 

[RogerIvy]

Hi Roger
I have wired the schaudt to the starter battery too, that's why I was hoping to leave it alone.

We’ve removed a few of those and replaced them with a combination of a Victron MPPT and a Battery Master. Works really well, and most people really enjoy the data provided by the Victron MPPT.

 

[Lenny HB]

used to have the schaudt LRM 1218 in my Hymer being fed by 250W of solar. When I changed to Lithium I needed to change it because it did not have a Lithium profile.

You had the old LR1218 not the LR1218.

Lenny,
maybe I have confused myself with all the reading, I thought wattage was amps x volts so with the 3rd panel, 3 x the amps (parralel) x the volts is 380. Unless that calculation is irrelevant to me just adding a 100 watt panel which does only make 300 watts ?

Very confused.

I now use all Victron gear.

 

[autorouter]

I am looking for advice as to whether I can safely add a third 100 watt panel to my existing two 100 watt panels. Each panel is 24.3 volts and 5.21 amps,

What exactly are those two voltage and amps values? Maybe they are the Open Circuit voltage (Voc) and Short Circuit current (Isc) values. You should be using the maximum power (Vmp and Imp) values for calculating the power output. You should find that Vmp and Imp multiply together to give just about exactly 100W.

If they are 3 x 100W, flat on the roof (ie not tilted) you are unlikely to see more than 80% of 300W, ie 240W max.

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[Guigsy]

With Victron solar controllers, supplying too much current on the solar side is fine (provided the cabling is up to it), it just maxes out at the highest level the controller can convert to battery charge. The issue is you can't go over the rated voltage of the controller. I'd assume that the Schaudt is the same. As you're wiring the panels in parallel, you should be fine because you're still only pushing 25v. And as the controller is rated at 275w, it'll be rare that any photons will be going to waste. It's likely to only happen in the height of summer when you're very likely to be wasting captured energy anyway later in the day because the battery will be full, so getting a bigger controller will probably not make a material difference to your battery charge.