Batteries ?

[Model Builder 4]

Hello everyone, as the headline say's ( Batteries ), i know this post may be a little tedious to the more experienced members of you on the site and you've most probably been asked this question a thousand times already but i would really appreciate any help on this subject before i go spending my hard earned on something that is no better than i've already got or on a substandard product , i've recently bought my first tank (HL Sherman ) and i'm looking to upgrade the battery of it to a NI-MH one, it came with a NI-CD 1700 as standard, I don't want to turn this question into the - which type of batteries are the best to go with question as i understand that a lot of you will have their own preference of battery types and reasons for it, so i'm looking more for a decent brand name and supplier for these as i've already decided to go with the NI-MH'S, what i would like to know is if anyone can recommend an above average quality battery and charger and a retailer for these products in the UK, i would also like to know what capacity rating of battery to get as the standard one is only 1700mh. I'm looking for one with a reasonable run time and also charging time, i expect to pay a little bit more for this but do not wish it to run into the ( got to hide it from the misses type price ) i've trawled the usual online sites for them but to a newcomer like me it can be quite daunting as there's a lot of options out there and as i've already stated i do not want to waste a load of money on rubbish, so that's why i would prefer a recommendation from the knowledgeable members on here as a lot of you have most probably been there and done that, i'm looking to purchase one fairly soon so any advice will be gratefully received

Cheers,
Lee.

[Tankbear]

Hi Lee,

Try contacting Forgebear here on the forum, I think he has some Mato 3300mah batteries which should your run time (and charge time).

Forgebear is a vender here and is highly recommended by everyone here.

Also consider a better charger the stock Hl one is rubbish.
Ian.

[ALPHA]

One word MB4....LIPO....Once you go lipo...you will never look back ...you will need a different charger though

With that said...keep your stock battery for testing your tank anytime you do mods

ALPHA

[wibblywobbly]

A decent quality Nimh battery will keep your tank going for well over an hour.

Two things to know:

Volts - You need a 7.2v battery.
Mah - This is how long the battery will last. The bigger the number the longer it will last.

Quality:
Cheap batteries will not keep giving out enough volts to keep your tank running, no matter what the Mah rating is.

There are batteries on Ebay with all sorts of high Mah ratings on them, they are either not the rating that they claim, or they use the reject bin cells in them, they will not last 5 minutes in a tank.

Known good brands:
Turnigy and Vapextech. A 3700mah battery is good for a long run time. You can go higher, but remember that a bigger Mah battery requires a longer charge time. There are other good brands these are just examples. Two 3700mah batteries mean that you can swap batteries and charge the flat one. One 5000mah battery will last longer but the tank can't be used when the battery is on charge.

Battery Charger:
You should also invest in a battery charger that has what is called 'peak detect'. This means that when it has detected that your battery is fully charged it will drop the charge rate to a trickle charge just to keep it topped up. Decent chargers will go up to 4amps on the charging cycle, the HL one is something like 4 milliamps, which is just a trickle. 4 amps will charge a 3700mah battery in about 20 minutes. Charging a battery without peak detect runs the risk of overcharging and this will damage the cells.

Nimh batteries like a high charge rate, and they are best used hot straight off the charger. They drop their capacity to around 80% within 24 hours.

Why are quality batteries so expensive, what is the difference? : A fully charged battery is giving out 8.4v. Start using it and the voltage drops to 7.2v quite quickly. A quality battery is designed to maintain a consistent voltage for a long while and then drop the volts to where it needs recharging. Cheap ones are lucky to get 8.4v, and the graph is downward as soon as it is used, it then drops below the point at which it can run a tank after only a few minutes. Tank electronics detect a 6v charge and cut the electrics to avoid damage to the board, so you are looking at 7.2v-6v=1.2v to play with, that is the voltage level that has to be maintained by the battery.

Lipo's will give a longer run time, but they are not cheap, and neither are the chargers. You would also be wise to change the battery connectors as the Tamiya style ones are not designed for Lipo's, one member on here watched his melt. The Tamiya connectors are 15amp rated which is enough for normal use, but a tank can pull 20amps under stall conditions. Lipo's require a lot more care as if they short out there is a higher risk of fire damage. When they go...they go big time.

In all honesty there is no such thing as a cheap quality battery, no matter which way you decide to go. I learnt this the expensive way!

RobG