Pre amp Rechagable battery replacement advice please

My BL Audio Battery preamp is no longer holding charge for more than an hour.
I need to replace the two 16AAA battery packs.

having taken the lid off I’m very impressed with the build quality

They appear to be model car battery packs but do you think I am likely to be able to source these made up somewhere?

Is making a DIY spot welder to make my own a very bad Idea?

Final question - Is a 24v power supply normal for recharging because I am not 100% certain if it is the original charger?

cheers in advance

Looks like 16 x 1.5v batteries which i guess are in series to make 24v

Does it charge one battery pack while playing with the other?

Yes it does. They are in a 16x AAA 4.8V pack each battery is 1.2V - I have been unable to find any but I did find a 4x AA pack that gives 4.8v ams 2500 mah that could work it would fit OK in the plastic container.

I now have small concerns regarding recharging but it appears in the original specific case a trickle charge is acceptable - So I’m hoping the same applies with the new packs.

Are the individuals AA or AAA size


Any of these look ok?

Type F maybe? (whatever that is :grinning:)

Bit spendy.

They won’t fit - I can fit 2 packs of 4 in square config.
these fit. Also Ni-Mh are meant to be better.

These are cheaper and made of AAA batteries.

But still not cheap as you need 8 sets.

Just noticed that the ones you listed have a far higher capacity.

No i only need 2 sets the 4 sq AA ones to give the same capacity as before.

Unfortunately I just ordered the wrong version from eBay.
Hopefully I can cancel my order?

How do you get to that conclusion? Are the packs connected in series or parallel?

I may have made a knobber but if the total bank voltage is 4.8v I havent
I will check again tomorrow

now you mention itI suspect that I am wrong though and the total voltage is 19v

Box opened - It does to me look like series connection 4 x 4.8V.
Fortunately the nice man on eBay allowed me to cancel my order.

So now I’m struggling to find something to fit in the box thats not prohibitively expensive.
Pete can you please verify that this looks like 4 x 4.8v in series for each 16 pack?


Yes, looks like they’re joined in series.

Verify by measuring the voltage going to the pre.



I get 15. 3v from one pack 12.5v from the other so series connection verified.

Now to search for the best value packs so far it’s £4 for a pack of 4 - Not sure I’m going to get better but I will try

If you just need the batteries, the Amazon ones are meant to be rebadged Eneloops, so should last a long time

You need to be careful. Is there any sort of charging control circuitry in these things? NiMH cells are supposed to be charged at constant current (and generally NiMH require temperature sensing or -ve ΔV to detect the end of charge). Constant voltage charging is for Lead acid and Lithium ion batteries. Getting it wrong will at best result in shortening the life of the batteries, at worst a fire or explosion. They can be properly nasty if you get it wrong.

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What about getting some battery holders yourself, nailing them to a plank, wiring them up and powering with that? It would mean you could control the charging yourself, by removing them and putting them into a decent charger.

Like these for a quid each