[RE-wrenches] 24 vs. 48

Carl Hansen solarwks at cybermesa.com
Tue Jan 17 12:23:05 PST 2012


Another advantage of 24v over 48v is when you have loads that are more 
appropriate at 24v , like DC circulation pumps on solar heating systems, 
The Elsid, Laing and Hartel circ pumps don't come in 48v and the 
Flowlight booster pump 48volt version is too noisy if the pump will live 
in a utility room attached to the house.  I live with a 48v system and I 
ended up adding a Solar converters transformer to knock all my DC loads 
down to 24volt, I had to add a capacitor to the transformer to handle 
the starting surge of the Flowlight, kinda funky and I wouldn't do that 
on a clients system. I usually stick with 24volt battery banks for these 
reasons.

Carl Hansen
Hansen&Sun Elect.

On 1/17/2012 11:38 AM, R Ray Walters wrote:
> The only advantages of 24 v are that you can create smaller KWH battery banks, and that Bergey's XL.1 was only available in 24 v.
> Anytime the design allows, I jump to 48 v.
>
> R. Walters
> ray at solarray.com
> Solar Engineer
>
>
>
>
> On Jan 17, 2012, at 11:11 AM, Nathan Jones wrote:
>
>>
>> Mark,
>> It would seem to be a wash. As the voltage is halved the amperage is doubled in the battery bank. This would seem to require doubling the charging amperage so nothing is gained. On a system of any size the 48 volt gets the default nod here. Charge controllers handle twice the solar. Parallel battery strings are eliminated, or at least held to two. Wire sizing might be reduced on the low voltage side of things. And much easier future expansion possibilities, too.
>> Cheers,
>> Nathan Jones
>> Power Source Solar Inc
>>
>>
>> ------------------------------
>> On Tue, Jan 17, 2012 10:56 AM CST Mark Frye wrote:
>>
>>> Not really on topic to Jay's question, but...
>>>
>>> Is 48v always better than 24v?
>>>
>>> How important is bulk charging current to overall battery life?
>>>
>>> In some cases, isn't it better to use a 24v inverter/charger which can
>>> develop a higher charge current for a battery bank that has a higher AH
>>> rating?
>>>
>>> Mark Frye
>>> Berkeley Solar Electric Systems
>>> 303 Redbud Way
>>> Nevada City,  CA 95959
>>> (530) 401-8024
>>> www.berkeleysolar.com
>>>
>>> -----Original Message-----
>>> From: re-wrenches-bounces at lists.re-wrenches.org
>>> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of jay peltz
>>> Sent: Tuesday, January 17, 2012 8:43 AM
>>> To: RE-wrenches
>>> Subject: [RE-wrenches] battery buss bars
>>>
>>> Hi All,
>>>
>>> Where do I find buss bars for a battery parallel problem?
>>>
>>> I've got to fix a brand new ( not me) system, that has 4 sets of L-16's at
>>> 24v.
>>> Yea yea why didn't they go to 48?
>>>
>>> So I want to use buss bars to parallel them, and looking for premade ones.
>>>
>>> Thanks in advance,
>>>
>>> Jay
>>>
>>> Peltz power
>>>
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