16 pcs T105RE vs 8 pcs T16RE

[uffehe]

I'm looking at replacing my existing bank of 8 Trojan T105REs in my 48v system, and would like to upgrade the capacity at the same time. I'm considering getting more T105REs (new set not mixing with my old ones), or 'upgrading' to T16REs. As far as I can tell, T16REs cost about twice as much as T105REs per piece, but are rated at 370Ah vs 220 Ah for the T105REs - meaning I get only 84% (370/2*220) of the capacity for the same amount of money.

I understand that it's better to avoid paralleling battery banks, and that there is some extra cost and hassle with additional wires etc. But are there any other compelling reasons to go with the bigger batteries?

Thanks.

Uffe.

[Sunking]

I understand that it's better to avoid paralleling battery banks, and that there is some extra cost and hassle with additional wires etc. But are there any other compelling reasons to go with the bigger batteries?.

Yeah they last a lot longer. What more do you need to know? DO NOT MIX OLD AND NEW BATTERIES

There is no such thing as a T16RE. I think you mean a Trojan L16RE-B a 6 volt 370 AH battery which should be less expensive than T-105RE if you compare at the Watt Hour unit cost.

[Logan5]

there is no "VS" 8 of the L16's for 400 AH @ 48 volts is perfect. Why even consider Parallel strings? with 2 parallel strings you have 2X the cells to inspect and fill.

[uffehe]

Sorry for the typo - I meant L16RE-B which as you point out are 6v 370 AH batteries.

So my options are to either buy (all new - I won't be using any of the old batteries):

a) 8 pcs of L16RE-B for a single string giving 48v. If they cost USD 332,- each, then this is a total of USD 2656,- for 8, giving ~ 2656/370 = 7.2 USD/AH @ 48v.
b) 16 pcs of T105RE and make 2 strings of 8 batteries in each, and parallel the 2 strings. If these cost USD 175,- each, then this gives 16*175 = USD 2800,- giving 2800/(225*2) = 6.2 USD/AH @ 48v.

What am I missing?

[Sunking]

What am I missing?

Perhaps I am missing something like what country are you in? Those prices you quote are quite higher than I know of in the USA and a bit lop sided.

FWIW do not use AH to find cost. Use Watt Hours as it eliminates voltage and conversion errors. A 6 Volt 225 AH battery is not equal to a 8 volt 225 AH battery. AH do not mean anything unless a Voltage is specified. Watt Hours is the energy you want to know, voltage and current are irrelevant.

Watt Hours Capacity = Battery Voltage x AH

[uffehe]

I'm actually in the Philippines, but the prices I quoted were from US online shops (http://www.ecodirect.com/Trojan-Batteries-s/74.htm). They're a bit pricier here, but the difference is even more pronounced with the L16s costing about twice that of the T105s.

Since both battery types are 6v I believe my calculations should be valid.

Given that those are the prices I can get, would you still recommend I go for the L16s?

Thanks.

[uffehe]

I'm actually in the Philippines, but the prices I quoted were from a US online store (http://www.ecodirect.com/Trojan-Batteries-s/74.htm). The prices are a bit higher here, but the difference even more pronounced, with the L16s costing about double that of the T105s.

As all the batteries are 6v, I believe my calculations should be valid.

Given that these are the prices I can get, do you think it is worthwhile getting the L16s?

Thanks.

[Wy_White_Wolf]

Do you really want twice as many cells to check the level of or take hydrometer readings? 2 strings will double the maintenance that you are currently doing.

WWW

[uffehe]

Obviously I would prefer to have fewer batteries to maintain. But at 10%-15% higher cost, I'd be prepared to do. So the question is whether there are other advantages i.e. longer battery life, lower internal losses etc.