choosing the rite panel

[lilly]

im wanting to charge 36 volts with 3- 100 watt 12 volt panels . my electric 36 v charger goes to 45 volts to fully charge the set of batteries.

i need to know what panels would do this? would 3-12 v panles at 36 v do the job?

[lilly]

no answers, maybe ya know this: can i connect 2 12 volt and 1 18 volt panel together to get 42 volts?

[littleharbor2]

3 in series should give you about 54 volts which is about right for charging a 36 volt battery. Note, the voltage will be pulled down to just above the actual battery voltage and rise as it charges.

[lilly]

littleharbor2, what voltage panels are you saying will get 54 volts in series?

[lilly]

i got it, 3-18 volt panels but the thing is 54 volts would probably over charge.

another thing ive been looking at is a boost charger. my question is do solar chargers and boost chargers do the same thing or does a boost charger charge better?

[SunEagle]

i got it, 3-18 volt panels but the thing is 54 volts would probably over charge.

another thing ive been looking at is a boost charger. my question is do solar chargers and boost chargers do the same thing or does a boost charger charge better?

A quality charger should not over charge a battery system regardless of the input voltage

[lilly]

Im seeing that in my quest to figure solar out.

tell me this please, if im using three 12 volt 100 watt panels with a boost charger should i connect the panels for 12 volt or 36 volt input , im charging a 36 volt battery bank. controller im looking at is 12-70 volt input

which way would do the fastest charge? if any difference at all.

also how many amps does the controller need to be?

thanks

[Bala]

Im seeing that in my quest to figure solar out.

tell me this please, if im using three 12 volt 100 watt panels with a boost charger should i connect the panels for 12 volt or 36 volt input , im charging a 36 volt battery bank. controller im looking at is 12-70 volt input

which way would do the fastest charge? if any difference at all.

also how many amps does the controller need to be?

thanks

I suspect this is a 36v battery set up?

Assuming it is then you would not charge it at 36v, it will be higher. The battery specs will tell you what voltage and amps to charge at.

What is known as 12v panels are generally around 22v. You need to look at the specs on the back of the panel.

The controller you listed can take 70v in, so could take three 22v panels in series. But! The panels are generally rated at 20 or 25c temp and can increase voltage when it is colder so that is a consideration.

Higher input v is better as you can use smaller cable.

[SunEagle]

I suspect this is a 36v battery set up?

Assuming it is then you would not charge it at 36v, it will be higher. The battery specs will tell you what voltage and amps to charge at.

What is known as 12v panels are generally around 22v. You need to look at the specs on the back of the panel.

The controller you listed can take 70v in, so could take three 22v panels in series. But! The panels are generally rated at 20 or 25c temp and can increase voltage when it is colder so that is a consideration.

Higher input v is better as you can use smaller cable.

I did not see the Amp Hour rating of the battery system. From past knowledge you should use about 1/10th the Amphour rating as charging amps so it also depends on the panel Isc rating and if the charge controller is a PWM or MPPT type.

[lilly]

Bata im really not worried abought the cold,i live in florida, a little cold would be nice.

ok then, i will connect the panels in series, everything is being shipped now,can't wait.

thanks for the help guys