Asking for help modifying existing solar array for better performance

[barnakiel]

Originally Posted by Frugal

If you suspect one of the panels is not producing correctly try shading each panel with a light blocking item (rug or towel) and check your output reduction.
With your series linkup a dodgy panel should be obvious but if they were all in parallel you may not pick up the loss or partial loss of one panel.
Cheers

I think this is also done when they are in parallel. Shading the faulty one does not change the total output. Hence you know it is faulty.

Cheers,
b.

[tinkrman69]

I can't imagine running that many Amp/hrs a day. I don't conserve at all and I use 120 average and 160 when using a lot of 120 AC tools. hell I had 6 people onboard for a month in the Bahamas, all of them parting well into the night and we averaged about 150 amp/hrs. and they were leaving lights on in every cabin, the fridge ran almost constant the inverter was charging computers all day ;-)

You talk about you charge capacity but not how many Amp/hrs of storage capacity. It doesn't matter how much solar you have if you don't have a big enough bank to store it. If you take a 100 amps out of 500 amps of storage, bringing the state of charge to 80% you'll need about 120 amps to recharge that bank. If you take 250 amps out of the same bank...50%...you'll need over 300 amps to replace it and that will have to come in a couple stages....bulk charge and float charge....with solar you won't have enough hours in the solar day to achieve that, hence ending up with an under charged battery. You also state that some panels are in series...increacing the voltage. when it goes to the charge controller that voltage has to be stepped down to an acceptable voltage for the batteries. you'll notice the heat generated at the controller? that heat is measured in watts, same as amps are. all energy is heat. So that heat is amps that is going to the air and not the battery. also the more components and connections you have the more amps you loose.

[barnakiel]

Originally Posted by tinkrman69

we averaged about 150 amp/hrs

A genset, huh?

The OP is into a solar array.

b.

[StuM]

Originally Posted by tinkrman69

I can't imagine running that many Amp/hrs Amp hrs a day. I don't conserve at all and I use 120 average and 160 when using a lot of 120 AC tools. hell I had 6 people onboard for a month in the Bahamas, all of them parting well into the night and we averaged about 150 amp/hrs Amp hrs. and they were leaving lights on in every cabin, the fridge ran almost constant the inverter was charging computers all day ;-)

You talk about you charge capacity but not how many Amp/hrs Amp hrs of storage capacity. It doesn't matter how much solar you have if you don't have a big enough bank to store it. If you take a 100 amps Amp hrs out of 500 amps Amp hrs of storage, bringing the state of charge to 80% you'll need about 120 amps Amp hrs to recharge that bank. If you take 250 amps Amp hrs out of the same bank...50%...you'll need over 300 amps Amp hrs to replace it and that will have to come in a couple stages....bulk charge and float charge....with solar you won't have enough hours in the solar day to achieve that, hence ending up with an under charged battery.

Here we go again:

http://www.cruisersforum.com/forums/...ml#post1933764

And the OP said he has LiFePO, so he doesn't have the problem of Bulk/Absorption/Float charging. His batteries will take all the Amps his solar can throw at them and Peukert is not a major issue for him either.

You also state that some panels are in series...increacing the voltage. when it goes to the charge controller that voltage has to be stepped down to an acceptable voltage for the batteries. you'll notice the heat generated at the controller? that heat is measured in watts, same as amps are. all energy is heat. So that heat is amps that is going to the air and not the battery. also the more components and connections you have the more amps you loose.

???

[MarkJ]

Firstly, you are charging at only 13.8volts. Thats very low. Mine is 14.3 when heavily used, currently 14.0 and tomorrow i will drop it to 13.8 because i am not using much.

For you fancy~pancy batteries what does the book say the charging voltage should be?

Secondly, if you have 30 amp controller you cant get more than 30 amps.

3) the wire that goes into your battery, is it fuesed? Is it a thick wire? Many fuse boxes only have a thinish wire.

4) If you need to make water etc, you stick the charging voltage up.

5) if you are really using 250 or near amps per day you need to pay a professional to have a look.

6) if you are generating 250 amps per day on 800 watts i think you are doing fine.

Mark

[autumnbreeze27]

Ok, I'm back from the border run with my new charger controller.

I've got 12 awg wire running from the panels to the controller, so I like series wiring to keep the voltage higher so I can get away with the smaller wire.

As for life support systems:
Fridge - 5A
Freezer - 5A on 50% duty cycle
Electronics when underway - Autopilot, Chartplotter, VHF, etc
Lights (LED except for anchor light unfortunately)
Fans
Aft head
Water pump

The things that drain the battery beyond solar recharge capacity:
Compressor (for hookah)
Watermaker
Water heater (don't run that too often anymore!)
Washdown pump
LCD TV/computers

I put the MPPT at 13.8 after doing a lot of searching, particularly this thread:
LiFeP04 custom charge settings for Morningstar MPPT-60 [Sitemap] - Cruisers & Sailing Forums

I don't really have any specs on my LifePO4, it's a balqon and they never were much help. It's 5KWh, 400ah. Typically if I'm at 100% in the late afternoon, by the morning not doing any major non-lifesupport stuff I'm usually at around 80%, which means I'm burning about 80ah during the night.

I'm smart enough to know if I'm pulling 5amps and the victron shows +25 that it's really getting 30a.

Here's a pic of my panels with a diagram showing how the wire runs.

[autumnbreeze27]

Here's a pic of how I'm proposing to change it.

This is kinda like an Apollo mission here, I only have what's on the boat, and what I can get from maybe an autoparts store. I was hoping to get some more stuff while in SD but between my back, which I jacked up working on the boom, and my bowels, I'm pretty sure Karl Strauss tried to kill me with some bad lettuce on a burger on the night I arrived, I didn't get nearly as much accomplished as I'd hoped.

I just reprogrammed my solar controller for 14v and turned off the battery charger. i will try the towel trick once the panels are in clear sun and see what results I get.

I'm off to check the bilges for spare parts.

[autumnbreeze27]

The other thing I plan on doing is elevating them a little off the top, because I think they're cooking like that.

[autumnbreeze27]

Just performed the towel test. What I found:

I have 4 panels on the bimini, and 4 on the dodger. The 4 on the dodger are Lensun 100W panels, the 4 on the bimini are renogy 100W.

If you look at the panels from high up on the stern, I numbered them
1-2-3-4 (dodger/lensun)
5-6-7-8 (bimini/renogy)

Power readings when covered:
1=143W 2=143W 3=134W 4=141W
5=260W 6=275W 7=272W 8=270W

The sun was somewhat variable during the readings unfortunately, but clearly I see a huge power difference on the dodger vs bimini. I'm thinking I should isolate them that way instead of port and starboard? (ie: run all the dodger panels to one solar controller, and run all the bimini panels to the other)

[tinkrman69]

260 a/h daily usage and 400 a/h of storage? It's not more charging you need it's storage. if you take a battery down 50% you'll need to put back around 75% but if you only take 20% you'll only have to put around 25% back in to bring it back up.

lithium or lead acid you shouldn't rate your storage to 50% usage. you may be able to keep a high voltage at a lower charge, with lithium,but it doesn't mean it won't take the time out of its over all life.

sounds like your solar is around 300 + a/h a little shy or your usage,considering the amount add for charging. but even if you add another 100 a.h you still don't have enough storage. another 200 a/h storage also, might pull it off.

[StuM]

Originally Posted by tinkrman69

260 a/h daily usage and 400 a/h of storage? It's not more charging you need it's storage. if you take a battery down 50% you'll need to put back around 75% but if you only take 20% you'll only have to put around 25% back in to bring it back up.

lithium or lead acid you shouldn't rate your storage to 50% usage. you may be able to keep a high voltage at a lower charge, with lithium,but it doesn't mean it won't take the time out of its over all life.

sounds like your solar is around 300 + a/h a little shy or your usage,considering the amount add for charging. but even if you add another 100 a.h you still don't have enough storage. another 200 a/h storage also, might pull it off.

260Ah out of 400 with LiFePo4 is not a problem. Neither is Peukert effect.
Those two factors along with the faster charge acceptance are the big advantages of lithium technology.

He needs to put back very little more than he takes out - certainly not 50% more.

[tinkrman69]

Originally Posted by StuM

260Ah out of 400 with LiFePo4 is not a problem. Neither is Peukert effect.
Those two factors along with the faster charge acceptance are the big advantages of lithium technology.

He needs to put back very little more than he takes out - certainly not 50% more.

Ahh, some people can't seem to read a whole statement. I never said 50% more. but what ever the battery construction you'll have to put more back than you take. the deeper the discharge the greater the difference. a capacitor would be the only storage device that wouldn't require more in put than discharge. But then they haven't perfected slow discharge and/or leakage of capacitors.

[StuM]

Originally Posted by tinkrman69

Ahh, some people can't seem to read a whole statement. I never said 50% more.

> "if you take a battery down 50% you'll need to put back around 75%"

Don't know what they are teaching today, but when I went to school, 75% was 50% more than 50%.

i.e.
50% of 400Ah = 200 Ah
75% of 400Ah = 300 Ah.

So your statement was the equivalent of "If you take a battery down to 200Ah, you'[ll need to put back around 300Ah."

That's an extra 100 - which is 50% of the 200 taken out.

but what ever the battery construction you'll have to put more back than you take. the deeper the discharge the greater the difference. a capacitor would be the only storage device that wouldn't require more in put than discharge. But then they haven't perfected slow discharge and/or leakage of capacitors.

I didn't say you wouldn't have to put back any more,

I said "He needs to put back very little more than he takes out - certainly not 50% more. " and that Peukert effect is "not a problem". ( I admit to over simplifying, I used "Peukert effect" as a shortcut for charge/discharge ratio resulting from Peukert effect and other battery characteristics).
With LiFePo4, the charge/discharge efficiency is over 95%, compared to typically around 60-70% for LA - so he may have to put in a few more Ah when recharging from 50% SOC. But those few Ah are negligible compared to LA.

[tinkrman69]

if what you are saying was real world accurate, the OP wouldn't be on here asking for help, saying he doesn't have enough power. What I stated was the SIMPLE solution. Why complicate it?

50% more or 25% more in your argument is only semantics. So end of discussion there!

[StuM]

Originally Posted by tinkrman69

if what you are saying was real world accurate, the OP wouldn't be on here asking for help, saying he doesn't have enough power. What I stated was the SIMPLE solution. Why complicate it?

50% more or 25% more in your argument is only semantics. So end of discussion there!